ignition indicator lamp

[Monkey Wrench]

a while back when replacing a fuel pump in my volvo I had a "brainfart" and thought hey why not wire up a small bulb so I can see when my fuel pump has power , and then if I have a starting say bad relay etc, then the light can prove to me at a glance wheather or not I have power at the pump, it simplifies the first steps f troubleshooting.

Ive also seen a whole lot of threads here where people are going into quite time consuming steps to figure out if they have an ingition spark when they have a no start. even to the extent of involving an ossiloscope to look at the engine sensors and the pulse.


well it happened that my ford van started missing, I dont mean just the odd misfire but the thing became like driving a bucking bronco . ok I could ignore the poor starting and stalling in traffic, but this made it undriveable.

so after plugs rotor and wires and no real result I thought well it's probably the sensor in the distributor , that's how the ford and some of my volvo's find TDC, without a crank sensor, the porshe uses a TDC and a speed reference sensor..

ok so to cut to the chase , do I have ignition yes it runs, is it flakey? dont know maybe a loose fuel rail wire or a number of other things..

so I pull the coil out , clan all the connections and splice in 3 feet of wire and at the end a small LED I connect them to the primary coil.

now I can tell at a glance , when cranking it blinks at a fast rate, , if running its on constantly, if I have an interruption in ignition I should see the lamp blinking off in conjunction with the bucking bronco effect.

I tried to remove the gear to change the reluctor or hall sensor or whatever it is in there I had a spare distributor, should have heated it, a cog of the gear broke easily so that ended that affair for now , I dint feel like taking the one in the van apart. I can get a cheapo or a rebuilt one or I can muck with the existing distributor I just like to have a whole spare distributor ready so I can just plunk it in if it fails, they have a module strapped to the side that fails commonly and leaves them in a non start mode.
many pack a spare module anyway..

I wondered if adding this LED could affect anything else, I dont think it will drain much juice form the primary coil it has a very low current demand. I wonder if it may affect my radio, haven't seen any problems but haven't really test driven yet.
it has idle issues, stalls but that's a separate issue Ill clean the throttle plate , check some sensors etc.. thats just taking me off topic ..

so fuel pump power LED, ignition LED maybe there are some other places I could connect remote LED sensors to?

now with that if , lets say, a DME relay fails or some gremlin crawls into the DME or something similar and that inhibits spark.
- I should be able to see that right away..If I have no spark even if its an intermittent I think this helps a lot. if or when I dont have ignition, sure I can check spark at the plugs or delve into why, it really doesn't change anything functionally.

I think this helps, just knowing if the primary has a pulse in real time, is great to know straight away especially when roadside under a frustrating no start condition. why mess with the DME relay if you know the promary has a pulse all Id be doing is leading myself astray of the issue. , unless the DME relaymade the ful pump die, then same symptom cranks, wont start right?

similar with power to the fuel pump. I also dont think an LED in parallel with the pump adds any significant power loss that would affect anything. so when I change a fuel pump now I add an LED and a couple of wires to a point where i can see it.

the newer relays do have LEDs for this purpose so that might just duplicate it,, if you have a solid state one.

the "mod" just adds two LEDs , I thought I'd just put them below my dash where I can see them if I need to. the speedo or tachometer blip does indicate that it's seeing the engine sensors but I think this is a bit more conclusive, as soon as you do not have a primary that is not pulsing then the troubleshooting can start with that knowledge.

in this way, Im not pulling plugs to decide if I have a pulse. for example, due to a lack of fuel issue.. so it just helps make it more quickly understandable.

i'll see if it interferes with the radio but haven't seen that it does, at least not yet. could be a shielded cable.

are there other places where it would be handy to have a sensing LED?

I thought Id share this as I think it s a really easy thign to add and cheap and i think it can help just make things a bit less confusing, when trouble occurs.

now I can drive my van and when it starts bucking I should be able to see if my ignition is being turned off intermittently.. If I see the two coincide its probably an intermittent component in the distributor. I just wanted to be able to see that in real time. This is just a way to narrow things down, it's just a way to "dumb down" the initial steps of troubleshooting.

if I do have an ignition pulse, I know it should have a spark.. if I see my light on or blinking when starting I know that's normal and I probably do have a spark so I can then focus on fuel etc. it would not show a weak coil or a broken wire, I just know if it has a constant pulse at the primary coil or not.

I think with an older car, its nice to know that from the drivers seat. if it helps me once it's paid for, its only a dollar or two . a 12V LED and two wires, you probably have that in your junk box.
the little bulb holder I had might have a resistor, not sure, it only seemed to illuminate one way. Ive done this with a small incandescent but thought eh LED might have a faster reaction rate. I figured a filament bulb has a slower warm up and cool down time. I found no real difference it still blinks when cranking and glows constant when running.

since this is in parallel with the primary coil of the distributor it does take some amps to run which it does steal some minute amount of current from the primary coil, but I think since its only an LED, this is going to be a non issue.

would it make sense to install a "niod light" on the fuel rail or could I just use an LED in parallel in the same way? would that be useful? it would show the injectors getting a pulse. some of them may fire together,in banks, I know in the van or i my volvo there are two sets , but it fires some injectors together in unison. in my van the injector location would be hard to see , need to remove the engine cover. so maybe an LED in a similar manor could monitor that pulse.. from the drivers seat.

I dont want a bunch of added gauges and non OEM mumbo jumbo but figured this was simple enough, they might bother me by being distracting, and If so I can tuck them out of view, unless needed.

[walfreyydo]

Maybe you can just make a temporary jumper so you arent adding a bunch of aftermarket wiring/hacking into the factory wiring allowing you to test it when needed, and stow it away when not.

[Jfrahm]

I think a person who is capable of setting up something like this is likely to not need it in the field. It might also introduce problems, failure points, that are unnecessary.
However a few items on-board might be wise:

1 - Old-timey xenon timing light and a way to clamp the trigger down (e.g. electrical tape)
-- Point it so you can see it when cranking
--- Check the #1 and the coil lead
-- A spark checker would be better but hard to see in the daytime from back near the ignition key
-- Whatever, keep a spark checker onboard also and make sure it can be connected to the coil lead or spark plug lead. It can be home made.

2 - Multimeter and prepared terminals and jumpers
-- Make a jumper that can power the fuel pump through the DMM on DC Amps AND the DME
-- Check fuel pump current when cranking. Is it high? (maybe a stuck fuel pump) low? (maybe not building pressure). If the pump is not drawing current that's also a clue.
-- Obviously be able to see DME and FP voltage when cranking.

That said, what's next after you check this stuff? Maybe you could unstick a stuck fuel pump by reversing the polarity or hitting it with a rock. You'd already have a spare DME relay or jumper. You'd have to be capable of spotting a problem you could then fix on the side of the road or there's no point and you should just get towed home in disgrace.

What are some issues you could fix and get home? Loose distributor rotor, bad DME relay...?

[Monkey Wrench]

on later 944s they fixed it but in my early 85 they put all the wiring in such a place that you need to remove the drivers seat and stand on your head ;-)

took my van for a spin last night , it still runs horribly for other reasons but it made the trip to obtain a free washer and dryer from some super rich ocean shore house, its beside a light house and I think the most expensive neighborhood , 10 million dollar homes..

anyway the home buyer wanted to renovate so posted all the appliances for free and my washer needs to be duck taped closed to run and some bearing is hooped in my dryer, so now I got standard white things.

I watched my added LED as I drove, it told me I have a constant spark so I think its a fuel related issue. I have to clean the throttle plate and maybe remove the intake manifold which is awkward in a van..

I am ok extending the wires, they are good connections and soldered up nice so I'll leave the thing. it had no affect upon my radio. one day when it wont start I can look and see.. when the ignition module failed I wondered if it had spark and went the normal route to find out.

I dont normally carry a lot unless its an out of town trip then I pack all sorts of stuff just in case, seldom they are actually needed..

I think my most interesting roadside repair was my old volvo, it blew a camshaft lobe, valve sunk, adjusted valves, and they would not stay adjusted for more than a mile so I pulled over.. pulled the rocker, pulled out the pushrods and the sparkplug.. reassembled without the 2 pushrods and with out one spark plug.

I drove it home, 200 K on 3 cylinders, sounded really funny breathing in and out through the spark plug, but I made it. it saved a long tow. it actually ran quite nice ;-)

i had a neat one in a VW bug, ran out of gas had no cash, darnit I'm stuck..

had a little 1/4" hose. siphoned the last bit out of gas I could out of the tank, put it in a oil bottle, I scavenged a liter or so that the fuel pump couldn't reach.

opened the engine lid and tied a little bucket there, I had a 22 shell, so I heated it up with my lighter, and stuck it through the bucket. somehow I poked out the primer.. stuck my 22 shell through the bottom of the bucket. stuck my hose on that.
wired it to the open engine cover, presto ! makeshift gas tank! now I had gravity feed and it got me home. ;-) ran out part way , got about another pint or so more or so.. enough to get myself out of trouble.

i broke a throttle cable and put a stick or something under the throttle drove it home on fast idle.

I learned how to drive with no clutch, start it in gear and get the timing right, that worked too. I had a delivery job , little "ford fiesta" , it had a good tranny.. so I learned how to drive pretty well in that car with no clutch ;-)

lent my van to a friend , he comes

back freaking out because it stalled in traffic "almost killed him" he says,, I shook my head thinking of all the cars I've driven that stall so often that I got used to it,, never thought of it as a safety risk ;-)

I used to drive old volvos a lot , Id never pay attention to the pads, Id keep spares though, as soon as I heard metal , Id just use the E-brake for the rest of the day.. and the gears..
ebrake worked good either but I knew I did have brakes if I needed them. it never gouged the rotors because as soon as I heard metal on metal I'd basically stop using the brakes unless to avoid a crash.

I was smiling when I read the racers explanation about setting up his brakes for a turn, so he'd pat the brake before he needed them to "set them" it made me smile because I had lots of cars I'd call "double pumpers", that's where you need to hit the brakes twice before they actually do anything ;-)

one of the scariest ones was driving a VW bug with steering box got so worn out that the bearings in t he steering box fell out .. i was going over a bridge which is curved, it would not turn.. headed for head on,, I had to turn slightly into traffic and it unlocked, that worked, got off the bridge and could literally spin the steering wheel .. bearings all fell out of their cage.

I did the drum brakes on that car, they had been turned down so far that the actual drums broke and came loose from the rest,, so the wheels could turn without the drums turning , it wasn't very visible, it still held the brakes shoes in place properly, they just didn't actually do anything. ;-)

I learned to doubleclutch pretty well so I can go into any gear at almost any speed , I found I could make it scream jut the right speed and dump it into a low gear, who needs luxuries like brakes ;-)

I was fixing a car, stripped out a bleeder on a front caliper. rats! how do I go get parts then,, well soldered up the brake line.. i've still got more wheels with brakes right?

wow it was surprising, I could turn the car with the brakes, wow did that ever make it dodge to the right.. scary, but I was able to go get my parts..

I dont always carry a meter because the battery would surely be dead and I dont want loose my nice fluke, but with a light bulb, and a hunk of wire you can do most electrical tests, wire is easy to find in a car, you just look for the longest pieces that arent; necessary, like speaker wires etc, fix them later. if you need hose to siphon there is usually wiper fluid hoses. a jug of milk, or even beer can fill a rad too. not the best but if it gets you home its a way..

I knew a guy that ran his clutch on mazola oil ;-) in a 944 that would be putting mazola inthe brakes which is a very bad idea, the clutch cylinder is probably gone anyway and almost any liquid can get the clutch working.

a pickle I got myself into recently in my van bloody beating down rain, flooded roads, I hit a pothole bent the rim like a pretzle..
wheel is done, so I'm at the side of the road no where close to walk to, busy highway too,,and darnit I forgot my cell phone too..

so I had a jack but from a crown victoria, it would lift but not far, so I'm looking for blocks and stuff , used the parts of the trailer hitch as blocks.. I had a couple o small bits that werent; very square,, stlll not great Ineeded a larger block..

three times I get the wheel off the ground, which is a challenge with stupid little car jack.. it rolls forward or back. falls down. by this point its 2 am I m soaked right through and very distressed.. If I had not i forgot my cell phone or I could have called a wrecker.. sat and thought .. gee how can I get this spare tire on?

finally I realized , I need a pot hole ! so I find the deepest pot hole I can, which almost put me on the road... semis whipping by my face.. anyway i put the opposite back wheel in it, then i had some chain and stuff so I wrap it around the tire , now set the half working parking brake and jack it , it helped just enough that i got the wheel off the ground without the whole pile of crooked little blocks and stuff toppling over.. worked!

funny that it was a pot hole that took out the rim and it took the cooperation of another a pot hole to fix it.. should have seen it, ,it broke the bead so badly.. must have been an inch hole between the rim and the bead.. the brand new tire did survive . it fell into a deep hole and the rim hit, not the tire.

next day I reported it and met the highways engineer there, he said good luck getting the city to pay for my rim. insurance wont pay, they would have if I just said a piece of junk fell off a truck in front of me..

he blamed the waterworks because they did a cut and patch on a manhole.. had a hard time finding a spare rim, found a super rusty one, painted it bought a couple tires.. now I have one nicely painted rim.

[djnolan]

Isn't there an aftermarket relay that has led's for this?

[Monkey Wrench]

there is a solid state relay available that has LED's that indicate, I believe fuel pump power and power to the ECU ( or DME) I dont think it does anything to verify if you have ignition pulse, yes there are other ways to verify ignition pulse.
here is what the solid state relay LED's can show:
-----
Ignition SW – (Yellow) Input signal to power up fuel injection system and enable fuel pump control.
Fuel Inj. Power – (Red) Output indicating the fuel injection system is powered up.
Ctl. Fuel Pump – (Blue) Input signal indicating the DME has commanded the fuel pump on.
Fuel Pump – (Green) Output indicating the fuel pump is powered up.
-----

verifying ignition pulse at the primary "proves or disproves " that the engine sensors are working, at least somewhat, the DME is performing its job of supplying a pulse to the power stage and the power stage is functioning and sending the pulse so far as the ignition coil primary.

troubleshooting a no start issue requires breaking the problem down, isolating probable causes, so going straight to weather or not the pulse exists is just basically helping isolate the problem.

hooking up an LED straight to the primary coil shows weather these parts are functioning , at at a glance , in real time. this is basically just "jumping to the chase" it is not a replacement for other checks and observations , they are still all valid.


If you found that there is no pulse then you can divide the problem further and check that the DME has power, whether it is properly grounded , if there is a voltage drop on the hot wire, if engine sensors are functioning , if the sensors are providing a pulse to the DME, if the DME is providing a pulse to the powerstage and if the power stage is working. You can involve an oscilloscope.

verifying a pulse to the primary does not provide info on weather you have fuel being injected or if there is a problem with the secondary or cap or plug leads or plugs.

Its merely a way of breaking the problem down more quickly than for example, looking for an engine sensor malfunction by employing an oscilloscope to to verify weather or not an engine sensor has a valid response to find out if this is the cause of a no start situation.

you would still want to do the above if the ignition has no pulse, and sure a signal could be flaky or intermittent. a scope may help see that or isolate it. Its possible but not normal to monitor a scope when driving, you might need an inverter to power it is it runs on 110

the LED is a lot easier to keep your eye on real time , when driving or upon encountering a no start situation. It is a lot more simple. it does not replace what a scope can show you.

an LED may show a intermittent problem of a missing pulse while driving, for example. if you observed an intermittent pulse at the primary perhaps coupled by an engine intermittent. you'd of course still need to delve into the actual cause. Then yes, you may need to break out the O-scope to properly prove the cause.

so lets just say for example you have a bad wire from a sensor, its creating an intermittent issue, so for this example, that's the actual cause. the result is that the car stalls or starts missing, its running very rough.

checking with a scope in this state may verify the sensor works fine, because it is when you checked it, but when the engine torques, when driving, it is pulling on a wire so then it is causing a intermittent pulse att eh primary coil. the problem is nothing to do with the coil, but you can see theresult of the issue there and so you have narrowed down the possibility of it being , for example , an interittent fuel pump.

by the way, the LED on the solid state relay wont tell you the pump is intermittent either, it merely verifies the contacts of the relay are trying to send power to the pump, it won't produce any info about dead or intermittent pump , or an issue of a bad lead from the relay to the pump.

basic troubleshooting normally involves breaking the problem down into sizable chunks. eliminating possibilities , zoning in to narrow down possibilities in order to isolate and prove the issue.

Yes there are other approaches and some different techniques which are also valid.

in essence checking if the primary has a pulse and seeing that it does would lead me to checking if it has fuel , maybe trying quick start to prove if its a lack of fuel issue and not a no spark issue.

the LED will not show if I have my plug wires mixed up or if I have forgotten to install the rotor in the distributor, or if I have a loose plug or coil lead. those are symptoms that come "after" the coil. its only a basic check that verifies the system prior to the coil is functioning, at least well enough to produce an ignition pulse.

[djnolan]

MR,

When I have a no start problem, the first thing i check is to listen to the fuel rail for fuel sloshing showing the fuel pump is running. On the 944 you have to jumper the dme relay to check this.

If there is fuel, then I check for spark by pulling off the #1 plug wire, connecting a spare spark plug, grounding that spark plug with an alligator clip, and then cranking and looking at the plug for spark. The spark should be hot, white or blue and not yellow/orange.

This method gets me in the ballpark.

ps. I didn't know that you could diagnose pulse with a simple LED

[Monkey Wrench]

I didn't know one could hear fuel sloshing in the fuel rail. i might just stick the fuel line in a jar see if there is some gas spurt, if so its maintaining some fuel pressure , give it a quick crank see if fuel comes out.

jumping the relay is ok but I'd be likely to forget what wires ,easier to figure out at home. for my volvo I made myself a get home too, Just an old relay with the wires jumped , I added a fuse. If I stick it in the pump runs. in that car there is a prepump in the tanks so there are two checks. You can pull the fuse of the main pump and do the jar trick. in tank pre pump still runs then.


I find the plug spark check not hard, but easier with a helper. Sure you can jump battery to starter with a hunk of wire while holding the plug to ground, a bit awkward.. if at home I'd tape the button down on my timing light.

I don't think adding the LED to the coil is problem , you could just put it right on the coil too. i just wanted to be able to see it when driving. Ill just tuck it up under the dash unless I need to see it.

I'm not afraid to mod a harness. anything like that Ill do properly unless its just a check. solder, heat shrink I used the right color of wire even ;-) found a hole in the firewall, Ill put a grommet for it to pass through, good to plug the hole anyway.

if you grounded those wires out it would cause trouble, I put them in some black vinyl tubing, same as other wires. I used auto wire, but all you need is a tiny wire to run a tiny LED.

another trick than can be handy is just to take a black marker and label each relay , what it does. saves some head scratching later when you forget, easier to find them when they click, but sometimes if they fail they don't click and that can cause a little mystery as to where the heck it is.

good to know which fuses and which relays are essential to get home, and what is non essential wiring.


If i unhook anything complicated, Ill take pics but also sometimes use this, it's handy to have one, to number wires. the spools of tape can be replaced when they run out, If you buy it, you can get extra 1's, it's the most common used.. You can get those from any electrical parts distributor.
You can get little booklets of numbers instead, a bit cheaper. saves confusion especially if I'm pulled away from a wiring job. I sometimes put them on my spark plug leads too , saves any confusion.

https://www.gescan.com/products/27-wire-termination-supplies/05-marking-labeling/08-wire-markers/08-tapes/p-TU1NU0RSNg==-3m-canada-sdr-6-scotchcode-wire-marker-tape-refill-roll-number---6


I have a different brand but as an example these little fiberglass scratch brushes are handy for cleaning connectors and such, put some contact cleaner or alcohol on them, they dont leave conductive fibers like steel wool does and they reach small spaces. used for cleaning jewelry you might find them in electronics parts places.

https://pepetools.com/en-ca/products/fiberglass-scratch-brush-retractable-red-3-pack

careful with steel wool , it burns better than you may think and a spark can ignite it. If you have a little ball of it, try lighting it with a match to see. , yes it burns quite well. yes steel is flammable. we forget its actually flammable because it's rare to see it burn like that.

what kind of electrical cleaner do you guys like? the deoxit is often reported as best or the only one that works, but its pricey.. I found some antique bolt loosener. Ill sometimes use that then something else to wash that off. like alcohol, it really stinks. I think the EPA omitted the stinky stuff that actually works. I find electrical contact cleaner easily, problem is , it doesn't work.

[djnolan]

the fuel flows in a circular path back to the tank via the FPR and FPD and you are right there to listen to it when the pump starts. And just prop the spark plug up where you can see it through the windshield. The late 944 dme jumper is real easy, just jumper the three large terminals and you have the fuel pump and dme jumpered to the power lead. The dme relay is pretty clearly labled on the later 944s. Not sure about the early cars.

I think doubly and triply about opening up the fuel system. Even if the engine is cold, a spark could ignite spilled fuel. or there is the chance of fuel leaking when the engine is running after reassembly. this could be disastrous in an enclosed garage. Fro safety reasons this is why I favor the test described above first.

[originalowner]

Originally Posted by Monkey Wrench

jumping the relay is ok but I'd be likely to forget what wires

Not a problem if you make your jumper correctly.

[originalowner]

Same with alarm jumpers.

[944 Ecology]

Originally Posted by originalowner

Not a problem if you make your jumper correctly.

You don't even need the labels... just look for the wide sockets in the dme relay hole.

[Monkey Wrench]

thank you George, Ill save those images, making jumpers isn't hard then.
my car died some years ago and I'll need to resurrect it but there should be a reason for a no start problem included, somethign that subsequently caused it to be parked and left to wait.

I don't doubt it was a DME issue but I want to change the belts and clean the whole fuel system before I even try cranking it.

my attempts to get started into my early 85 944 keep getting pushed aside by my other cars that I use for work breaking down, and taking priority.. the Porsche never was a driver since I owned it, but its not in such bad shape, Mostly just needs everything looked at from sitting unused for so long. brakes stuck, fuel turned to goo, belts too old to be trusted.

will these jumpers work for my early 85 ?

Phil

[944 Ecology]

Originally Posted by Monkey Wrench

will these jumpers work for my early 85 ?

Yes, just not as easily accessed as the oval dash cars with the fusebox on top of the cowl.

[originalowner]

Originally Posted by 944 Ecology

You don't even need the labels... just look for the wide sockets in the dme relay hole.

Cool. I've never had mine out, so I didn't know. Thanks George.

[wwdwgs]

knowing MW, he'll run extra wires from DEM fuel relay to the dash or center console with a big, fat LIGHT, which would read "IGN".

[Jfrahm]

Originally Posted by originalowner

Cool. I've never had mine out, so I didn't know. Thanks George.

You should carry the jumper but also check and possibly replace your relay if it's the early part number and update it to a quality part with the 993 part number.
When they fail you can be in the fast lane or in a bridge or something and that's easily avoided with the updated part.

The solid state relays are popular but a good Stribel mechanical one has worked fine for me for many years, many cars.
I do not recommend the "pump prime" solid state relay for safety reasons.

[944 Ecology]

I made up a bunch of two wire jumpers back in the day, and put one in every 944 I ever drove. Cheap to make (about 10 cents per) and dead nuts simple and idiot proof. When I bought a 944 turbo on the other side of the continent, the only part I brought with me was a jumper. Never needed it, drove from California to New York by way of Florida (it was February) and the car never skipped a beat. Still have it today, as a test mule for DME and KLR testing.

[originalowner]

Originally Posted by Jfrahm

update it to a quality part with the 993 part number.

Thanks for the hint.

[Monkey Wrench]

some 30 years back i used to fix printing machines,
I' d get called in because it wouldn't start and often it would be a worn relay , pitted and blackened relay contacts. if i didn't have one I'd clean the contacts to keep them running and order a new one so they wouldn't have downtime.

when the SSR's became available they seemed like a great advantage, that is until they do fail and then you can't clean them to fix, a replacement is necessary.

maybe jumper is a good fix, for my volvo I just gutted an old one so I have a relay that is jumped and fused, if a pump is direct shorted it would blow the fuse for example, but in that, that relay isn't powering the DME as well, so its a less complex relay.

the only advantage there is having the circuit fused but it is probably already fused at the source. a chain is only as strong as its weakest link anyway so two fuses dont really add much of a safety measure. maybe it's just a little easier not to go wrong with the connections as the relay base only fits one way.

I think the reason why I mentioned actively monitoring the coil primary is because Ive seen a lot of confusion around the DME, where different electrical checks were suggested.

some posters. for example in a no start situation were led into checks of the engine sensors themselves. sure an engine sensor can cause that, it could even cause an intermittent.

basically a quick check of the pulse at the primary is just an easier way to monitor whether the engine has lost its pulse.

in a no start situation. I know we can all check spark with a spark plug too. I thought it may help troubleshoot a possible no spark, or intermittent spark condition. by adding 2 wires and a simple LED it allows a way to know if you have a consistent primary pulse without even leaving the drivers seat.

sure the cap can crack or a plug wire can come off or a coil could go bad, and you then have a primary pulse and no spark, but I feel these issues are not usually ones causing confusion.

if you had an intermittent primary pulse it doesn't solve it, but it lets you know its not some other issue like with fuel etc. If you can verify you have a pulsing primary maybe you can skip over some no start reasons such as a faulty or intermittent engine sensor or it's cable ,Its got a primary pulse, the no start condition is not due to a bad or intermittently bad engine sensor, nor a bad ground to the MCU. simple as that. you have ignition , check ! so check fuel next.

If you like sure do the spark plug check, provided you have a spare plug or a wrench then you can find a way to prop it up so you can see it and keep it grounded or find a helper to hold it so you can see it all possible , sure maybe you have the sort of girlfriend handy that isn't afraid of doing such lol.. ;-) can I meet her? ;-)


so for example a suspect engine sensor is obviously working so long as there is a consistent ignition pulse. It just dumbs down the troubleshooting steps. If I saw an erratic missing pulse then I'd look at the engine sensors, so long as it's flashing consistently, it's got its pulse.

it can happen for example , when in the garage the engine sensors all test and work fine, but when you torque the engine out on the open road. it causes wire strain and a fault that only lasts a short period of time. If the LED went out even momentarily and you could see this from the drivers seat then you'd know to look for the actual cause of an intermittent problem.

nothing complicated here. Its not really much of a modification.. two wires and an LED, use it if it helps, ingnore if you like , all ok.
if you wanted , one could wire a LED or tiny bulb two wires and 2 alligator clips, that will solve lots , if you throw in a 9 V battery its an easy way to do a continuity check..

I sometimes like using a 9V battery to check things, like trace a wire from here to there. put 9V on one end, go to the other end wihtthe other side of the battery . and look for 9V between that and some other wires..

no other wire in the car has 9V so when you do get your probe on the other and and see 9V you know you haven't mistaken it..


i have phone internet and cablevision cables all over in my house all lead to a panel. If I want to trace them I just feed the outlet 9 V, then go to the panel, the one with 9 V is the one I'm looking for... there I found it.. simple and easy that way. i know no other wire in that panel is carrying 9 volts. just small 12 V light bulb some wire and a 9V battery and you cna perform most of the things you could do with a meter.

need extra connectors? pop the things off a dead 9V, they clip together easy , make a nice easy connector.. ok for temorary wiring , things like that.

the pins aren't protected but its simple and very cheap, Just like me ! ;-)