Possible to test if ignition switch is culprit?

GravityGuy · 06:03 PM

I put about 100 miles on my '85 N/A since taking delivery on August 8th. Last Wednesday (August 16th), my wife and I went out for a nice drive to enjoy the 90 degree weather. The car performed flawlessly. We parked it in the garage, and went to bed very happy! The next day, I come home after work and decide to go for a fun spin through the hills. Only problem is, the car won't start. It turns over, but won't start. A brand new battery and starter were installed immediately upon delivery, and the car has no problem cranking away. (side note: prior to my taking delivery, the car was not driven at all since June /03. It was delivered from the 1st owners house to my shop--Squire's Autowerke--door to door by flatbed.)

Since then, this is the troubleshooting I've done:

__Added 2 gallons of premium gas as the needle was initially resting right next to "E,"

__Experienced a gut wrenching "oh *****" moment as I thought the timing belt may have failed, and my motor was broken.

__Checked compression on each cylinder. Perfect 180 PSI on each one. Breathed a sigh of relief, believing this invalidated my suspicions of a broken timing chain/motor.

__Searched the Pelican Parts forum and found the thread titled "The neverending." Of particular interest was the "5 minute Quick Test" suggested by SoCal Driver (one of my favorite personalities on these boards).

__Checked for power at the coil by turning the key to the "run" position, and checking the positive lead to the coil as per the instructions, and discovered NO POWER at the coil(!). (Yeah! Making headway).

__Ordered Haynes Manual in order to have reference material when checking the ignition switch and wiring per SoCal's 5MQT.

Now that the manual is here, I realized it would be good to be pretty darn sure its the ignition switch before I start tearing the steering column apart. Imagine a med school grad who's dissected frogs, but never cut a person. That's me with cars. I might just make things worse.

What I'm wondering is if there is any secondary test I could perform that might validate or invalidate the theory of that ignition switch as the source of the starting problem. Is there any way I can try to bypass the ignition switch and start the motor, thereby isolating it as the issue? Alternatively, should i just have a flatbed pick up the car and take it to the shop? Even though the shop isn't cheap, it might take me 10x as long to make the fix.

Razorback1980 · Razorback1980's Garage

Run a wire from the positive side of the battery to the black wire on the coil. That bypasses the ignition switch for power to the coil.

Eldorado · 08-23-2006, 06:20 PM

taking out the ignition switch to test it was one of the first operations i did on my car... it's really simple..

GravityGuy · 08-23-2006, 06:48 PM

Razorback1980--Thanks for the tip about Britwrench. Already shot off the PM. About the wire--does it matter what I use? Can I just hit the local Ace/Home Depot and grab a sufficient length? Is it more complicated than that?

Eldorado--Did you have to remove the steering wheel and disasemble the steering column? Based on the Haynes manual, it looks like that is the case.

SoCal Driver · SoCal Driver's Garage

You have replaced the timing belt???

If not do it now or your will be eating the valves.

The jumper from the battery to the coil will eliminate part of the ignition switch. You need to jumper between aux fuse 2 and 3 (on the early 944's) to get the fuel pump to run. Might also have to jumper the power to the DME. Check out www.clarks-garage.com for the jumper to substitute for the DME relay.

Eldorado · 08-23-2006, 08:34 PM

hey Jay...

you remove the steering wheel... 1 nut.

then (provided it's an early 85) you have to remove the wiper switch/turn signal.... 4 screws, flat head.. just pulls off..

then, if memory serves, there's an allen bolt that you can see through a hole in the under side of the dash...

it's very straight forward.. haynes was what i used and it was quite simple... just take it one step at a time..

GravityGuy · 08-24-2006, 09:00 AM

Guys, I owe you an apology. Turns out, the filament in my test light was broken, and I highly suspect there IS power to my coil. Also, here is what I forgot to mention in my first post:

__I tested for spark on each plug while doing the compression test. With the plug securely inserted into the wire and resting on the intake manifold (and the compression tester installed in the cylinder), I had my wife crank the car. No sparks.

This is what lead me to test the coil with the faulty test light. Faulty equipment, faulty results. However, I did make a cable using 12 ga. wire and two aligator clips which I connected to the positive terminals of the coil and the battery. There were some interesting noises, and my door locks engaged/disengaged. I immediately removed the jumper cable, and checked the test light, discovering the missing filament.

Working on the assumption that there should have been sparks at the plugs when I did the crank test, I decided to check the simplest possible problem--the wires.

The wire that runs between the coil and the distributor looks pretty darn corroded on the distributor end. So here is my next dumb question. Could corrosion be enough of a problem to prevent a car from running? I suspect so, and am feeling pretty dumb for taking so long to even check these things. Frankly, it should probably have a tune up anyways since the wires, plugs, distributor cap all appear vintage, and for all I know may even be the originals.

I'll post a couple of pics of the coil/distributor wire to show the distributor end.

GravityGuy · 08-24-2006, 09:01 AM

GravityGuy · 08-24-2006, 09:04 AM

Have you guys ever heard of a car running perfectly one day, and then the very next day not starting, simply because of corrosion in the ignition system between the coil and the plugs?

Razorback1980 · Razorback1980's Garage

Could happen. Something broke somewhere..just not sure where without the testing. Buy a digital multimeter and a noid light and that will help you find what you need. SoCal Driver also has a "five minute" test plan (do a search and it will surface many times) here that will help you find it...if not maybe he'll step you through how to test this. Follow his instructions carefully, he will not steer you wrong.

924RACR · 08-24-2006, 04:17 PM

From condensation, yes, but it WAS a British car.

As for taking the ignition switch out of the equation - haven't you guys ever heard of hotwiring a car??? Really... and I'm not a Detroit native, only lived here for 6 years!

Reach up under the dash, unplug the ignition switch, use a couple jumpers, one to go from, what's it, I think the battery is 15, to terminal 30 (yes, they're all marked) and touch one from 15 to 50 (the starter), remove when cranked. Real easy. Takes me about 2 minutes...

SoCal Driver · SoCal Driver's Garage

The part of the stock plug wires that would result in no spark to the plugs is where the wire screws into the connector under the weather boot. There are crimped ends on the wires that have threads and these ends are then screwed into the connectors. It's becoming common for the coil to plug HV (High Voltage) wire to corrode inside the weather boot and pull out of the crimped on end.

Check out www.kingsborne.com for the 944 stock wires. Somewhere in their web site they have a picture of the ends.

Note that with 11 feet of wire and ten tips you can rebuild/replace the wires on the 944. Only takes a $200 tool to crimp the ends onto the cables.

924RACR · 08-25-2006, 07:12 AM

Actually you can get the tool for around $50...

SoCal Driver · SoCal Driver's Garage

Quote:

Originally posted by 924RACR
Actually you can get the tool for around $50...

Please provide the source.

Razorback1980 · Razorback1980's Garage

Hey Jay,

Did you do the SoCal five minute test yet? If so, what did you find?

GravityGuy · 11:51 AM

Not yet. I did not have the proper tools or any reference materials beyond SoCal Driver's list. I wanted to have *something* to look at which confirms what each part is before I start going hog-wild in there.

I did pick up a multi-meter yesterday, and tested my battery and the positive lead to the coil. Both measured 11.98 volts, so I know there should be enough power to the coil for it to be generating spark.

The next step on SoCal's list is to check for power at the injectors. I didn't touch those just yet because I just don't know where I should be checking. Probably sounds dumb, since there are electrical connectors on top of each cylinder near the fuel rail, but I am going to wait until Sunday. I asked my father if he'd be willing to come hang out and supervise my efforts from a comfortable chair, scotch and rocks in hand.

Also, I feel less enthusiastic about testing the injectors simply because there is a problem that's already been identified which is completely unrelated--the plugs are not sparking when the engine cranks over.

Given the fact that there is power *to* the coil, it seems like the plugs should still fire, but they're not. So, wouldn't it be reasonable to assume that the problem would be found somewhere between the coil itself and the plugs? My father did swing by the other night, and he said the wires are in good enough condition that it is unlikely they're the problem.

Could it be something as simple as a failed coil? That is my current suspicion. Perhaps this is little more than the unfounded guess of the F-N-G.

Razorback1980 · Razorback1980's Garage

Probably not the coil...they rarely fail.

Ok, your logic makes sense and I thought the same way at first..thankfully SoCal and some others have taught me a few things. Just because you have fire to the coil does NOT guarantee you a spark. Here is what has to happen. The coil has two sides to it. One is the power from the switch and the other is controlled by the DME. The side controlled by the DME has to be grounded by the DME at just the right times (controlled by the reference sensor to set the timing) to deliver power to the center of the coil and on to the distributor. So since the DME controls so much you have to make sure your DME is working properly which is why you need to test the injectors because the DME controls them too. If the injectors do not have power, then the DME relay is probably not working and needs to be replaced so the DME can control the grounding of the coil. Hopefully that was explained correctly and makes some sense. Strongly suggest that you cruise over to Britwrench's or pick up a DME relay from Pelican here. You need one anyway. I understand your hesitation to go hog-wild (like your choice of terms by the way...you'll have to think to get that) so maybe just grab a new DME relay and stick in there and that will help with some of the steps.

GravityGuy · 01:59 PM

Sunday update as promised!

Results of SoCal Driver's "5 Minute Quick Test."

"Check the power at the coil and injectors with the key on":
Power at battery: 12.52V. Power at Coil 12.49V. Power at Injectors 12.48V.

"Power at coil and injectors points to a bad reference sensor. The connector may be corroded and/or not plugged in all the way, or cracked and may have broken the wires inside. Check if the sensor is working by pulling a plug wire, inserting a spare plug, grounding the plug to the intake and craking the engine. If there is spark, then the reference sensor is working":

Pulled the first plug wire, pulled the plug, inserted the compression tester (not because it is needed for this test, but to fill the plug hole since I don't have a spare plug yet) inserted the plug back into the wire, grounded the plug, cranked the engine & there were no sparks.

My Hayne's manual does not include any information on the 'reference sensor' so I searched google and found this article >http://www.clarks-garage.com/shop-manual/ign-02.htm< referring to the "Speed and Reference Sensors." Based on the pictures in that article, I believe I found the sensors themselves at the back of the engine, and the connectors as well. There are two connetors that are located slightly behind and to the center of the oil fill cap, approximately the same heigth, stacked vertically. They look brand new, with zero corrosion whatsoever, and not even any dirt on them at all. (Consistent with a summer-driven only, 28k car).

The clark's garage article provides instructions on testing the reference sensors which I believe is probably quite good. But based on what I've read there, it is simply not something I am willing to do myself.

As a side note, I did go ahead and order 3 DME/Ignition relays from PP and Britwrench was friendly enough to sell me a DME/Fuel pump relay on Friday. Replacing the fuel pump relay did not solve my problem (obviously, hence the need for the Sunday tests). After finally getting the new relay installed, I had my wife crank the car several times while I listened at the passenger's side rear wheel for the fuel pump. Interestingly to me, I was never able to hear anything at all.

Given the fact that the car needs the timing chain service done, and very likely has succumbed to the familiar clutch failure that plagues these cars, I think a flatbed may be called in on Monday to pick up the car and drive it to be serviced by Britwrench at his friendly facility. Since the car already needs significant work, and will be at the shop, it seems like this should be a fairly easy side project to take care of at the same time.

SoCal Driver · SoCal Driver's Garage

Britwrench will get it straightened out.

When there is power at the coil the ignition switch is working. When there is power at any of the injectors then the DME/fuel pump relay has closed it's first set of contacts. Note that power to the injectors also means that the DME is seeing power.

Checking with the spare spark plug tells you wither the reference sensor and possibly the DME is actually working. No spark at this point can be either one -- or both. Can also be as simple as a bad HV cable between the coil and the dist.

keep the board informed as to what is found out.

GravityGuy · 11:35 AM

Tom, Hugh, Vaughn,

Your feedback on these threads has been great. Thanks for sharing. Here's what Britwrench has done so far:

*Car had no fuel pressure: I'd already installed the Fuel Relay, so Mark (aka Britwrench) installed a new fuel pump & filter. Bingo. Pressure is right where it should be.

*Car ALSO had no spark: Testing the wires showed the wire between the coil and distributor has excessive resistance (just as you suspectedl Hugh!). The ignition DME is also suspect (it seems like the DME failure is simply a rite of passage for 944 owners). Both parts on order, should be in the car by this afternoon.

Once the car is starting and running again, I'm going to debrief Mark on the process of troubleshooting he followed. At this point, it seems as though he may be cruising down the list of the usual suspects and simply replacing the parts as he goes. In a shop environment, I'd actually prefer they do this, as the hourly rate of doing tedious diagnostics could easily end up costing 50-60% of what simply replacing the parts would cost. At least this way those pieces can be expected to perform for a while with few issues if any.