won't run

enzo1 · 10-02-2009, 10:13 PM

sunday ran fine.....following sunday started having problems, like
ignition was cutting off, then coming back on & backfired a few times{loud} barely made it home, died at stop light...waited 15 minutes, started up long enough to make it 5 miles , read forum & determined it might be points, checked them & replaced as they were worn(don't know how it was even running) think i've found the problem, but won't run... figure it might be coil, take spark plug out to check plug, got spark.... dry as bone, like no gas, listen for fuel pump wine, nothing ... replace red relay with black one,still no wine from fuel pump & backfired like sob, what do I do now as fuel pump is expensive and want to make sure thats what it is ?1976 2.7

ossiblue · 07:25 AM

You will need some fuel pressure gauges. Because you did get some backfiring, some fuel is reaching your engine. With the gauge, you can measure system pressure and know immediately if the pump is supplying adequate pressure. If it isn't, you will be 90% certain that is the problem. If it is, you will be headed down the diagnosis road that many here can help you with. No one wants you to throw money at a problem by replacing parts unnecessarily. Find, or buy (good investment) fuel pressure tester and begin your search.

BTW: The fuel pump will not run unless you jump the contacts at the relay. Did you do that? Otherwise, the pump runs while the starter is cranking, and continues once the engine fires. You are right to suspect the pump, but don't assume it is faulty unless you jumped the relay.

crustychief · crustychief's Garage

+1 above
Also you would be looking for fuel from the fuel pump not wine.

enzo1 · 10-03-2009, 10:24 AM

thanks appreciate the advice, can't live without my porsche running..... its an addiction!

enzo1 · 10-06-2009, 02:03 PM

I jumped relay and fp came on, what is the correct place to look for fuel coming from fp..... injectors?

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by enzo1

I jumped relay and fp came on, what is the correct place to look for fuel coming from fp..... injectors?

enzo,

You need a fuel pressure gauge to check your FP or do the volumetric (flow rate)measurement. A good spot or location to do the volumetric test is before or after the FA (fuel accumulator). Doing it right after the FP is probably the best but entails extra work like jacking the car up, removing the skid plate cover, plus the inconvenience of getting under the car, etc.

The advantage of using a fuel pressure gauge (installed in a deifferent location) is that you'll know your control, system, and FP pressures. Either method will tell you about the condition of your FP. Keep us posted.

Tony

enzo1 · 10-06-2009, 03:12 PM

thanks for reply, car is already jacked up &skid pad removed, but the fp has a banjo bolt there & too close to electric connections, will try @ accumulator, have to buy gauges off internet, & was just wanting to see if fuel pump working before I did that

enzo1 · 10-06-2009, 04:19 PM

took fuel supply line to accumulator off, put in bucket, jumped relay, plenty of fuel. took fuel line off fuel injector #4 ... no fuel at all

theiceman · 10-06-2009, 04:57 PM

i think you guys are chasing the wrong dog here .. the reason he is bacjkfiring is beacause he has unburnt fuel ... kepp it simple ,, see if you have spark .. I am betting on a bad coil or ignition module...

just my 2c

Flat6pac · 10-06-2009, 05:08 PM

76, check the dwell on the points, sounds like theyre collapsing.
Bruce

ossiblue · 05:39 PM

Quote:

Originally Posted by enzo1

took fuel supply line to accumulator off, put in bucket, jumped relay, plenty of fuel. took fuel line off fuel injector #4 ... no fuel at all

The injectors will not spray unless the plunger in the intake is lifted. If you've interrupted the fuel flow (by removing the supply at the accumulator, for example) you will also need to "bleed" the system to see if the injectors work.

Turn on the fuel pump. Remove the air cleaner and gently lift the plate in the throttle body. You should hear a squeal from the injectors which indicates fuel is flowing through. If you have one already disconnected, the injector should spray fuel. If nothing comes out, there is a blockage to the injectors. Caution! Do not lift the plunger for more than 5 seconds or so. All injectors spray at once and you will be filling the cylinders with raw fuel.

You stated that you checked for spark. If the fuel delivery system checks out, go back to ignition.

edit: Just a question. When you changed your points, did you remove the distributor or rotate the distributor body?

Paulporsche · 10-06-2009, 05:22 PM

Check those points.

T77911S · 10-07-2009, 03:19 AM

Quote:

Originally Posted by ossiblue

The injectors will not spray unless the plunger in the intake is lifted. If you've interrupted the fuel flow (by removing the supply at the accumulator, for example) you will also need to "bleed" the system to see if the injectors work.

Turn on the fuel pump. Remove the air cleaner and gently lift the plate in the throttle body. You should hear a squeal from the injectors which indicates fuel is flowing through. If you have one already disconnected, the injector should spray fuel. If nothing comes out, there is a blockage to the injectors. Caution! Do not lift the plunger for more than 5 seconds or so. All injectors spray at once and you will be filling the cylinders with raw fuel.

You stated that you checked for spark. If the fuel delivery system checks out, go back to ignition.

edit: Just a question. When you changed your points, did you remove the distributor or rotate the distributor body?

about time.

you said it backfired. did you remove the dizzy to replace the points? if so, you could have it in 180 out.

get the ignition straightened back out and do what was said above.

when the car does not start, try lifting the plate like above and see if that helps.

do you have a popoff valve?

could still be the ignition- CD, coil or wires from CD to coil/dizzy. the wires are old and crack. if it is intermittant, it is hard to TS without swapping parts, the spark you see may not be consistant enough to make it run smooth.

enzo1 · 10-07-2009, 07:36 AM

i took the distributor cap off, replaced points, rolled it up on the cam pad & adjusted w/feeler gauge..... tried to start, nothing 20 seconds it backfired, then checked spark by taking out the spark plug & grounding it, got spark, thought it might be fp, but have fuel to the accumulator, it doesn't even try to start.... nothing but a backfire after 10- 20 seconds on starter

T77911S · 10-07-2009, 08:05 AM

pull an injector(or2) and jumper the FP relay to make the FP run. do not lift the sensor plate. make sure fuel is not coming out of the injectors

enzo1 · 10-07-2009, 08:25 AM

I removed fuel line from injector & jumped the relay for about 5 seconds, no fuel, but I have not tried lifting the sensor plate

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by enzo1

I removed fuel line from injector & jumped the relay for about 5 seconds, no fuel, but I have not tried lifting the sensor plate

enzo,

There are too many variables that could cause your current problems. While you have checked your ignition and sparks, go check your fuel system. Hook up a fuel pressure gauge and avoid the quessing game. Verify that the FP, all six (6) injectors are spraying mist-like fuel, control and system pressure within spec, and lastly the dreaded vacuum leak.

This is the time of the year when a lot of CIS cold start problems become prominent. It is a process of elimination and verification. The simple question about your problem is which component/s is contributing to your no-start trouble. Then an analytical approach is required to find the culprit/s.

All the components and specs for our beloved CIS engines could be checked and inspected. Either it is working, barely working, not working could be determined by some simple DIY test procedures. Your problem might not be the above so locating and identifying the culprit/s is crucial. Keep us posted.

Tony

T77911S · 10-07-2009, 11:00 AM

nice setup tony. i just set 3 big cups on each side of the engine to check my pattern and volume. if i did it more often i would make something like you have. are the caps screwed to to the board? BTW, i found a bad fuel injector line when i checked mine.

just trying to eliminate a stuck plunger.

perhaps a big air leak?
you did not say if you have a popoff valve.

it sure sounds like crossed ignition wires, but that does not fit that it was running good one day and bad the next.

do you have a bosch CD or a permatune? when mine went bad it would cut off then back on with a backfire, but it was very quick until it got to the point it would cut off for longer periods of time.

like tony said, there is sooo much it could be.
here are some ideas that may confuse you more.

electrical:
CD unit
wires from CD to dizzy and coil
coil
ground connection from engine to body. more directly, engine to CD unit.
did you remove the wires from the dist cap? could you have put the cap on 180 out.

fuel:
stuck plunger- not likely since you have no fuel coming out of lines with FP on
stuck or sticking plunger not letting enough/any fuel to injectors. check as osiblue said.
big air leak. makes for a lean condition causing backfire. cracked air box if no poppoff valve.
high control pressure. again, makes it lean causing backfiring. usually when WUR's go bad, it is the warm CP that is not right, too low

enzo1 · 11:46 AM

updating: Paulporsche and flat6pac were right... replaced plug wires dizzie rotor points, she runs a lot better, thanks to all who replied, I feel a lot better also a friend let me drive his 2008 turbo cab, it was sweet