Confusing 88 944 No Start, Help Needed!
#17
parts replaced… NO change. If anything it’s trying even less to start! Immediately after trying to start I broke the tail loose to see how my fuel pressure was… and I had nothing. Fuel pressure should stay for at least a bit, shouldn’t it?
#18
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Yes, fuel pressure should stick around for hours. You also said the plugs "have some moisture but not enough for it to be fouled" and that's unusual. This IMO suggests a leaking injector, FPR or damper.
It's also possible you don't have enough fuel and have a lean miss, leading to some wetness on the plugs.
It's easy enough to test giving it more fuel, starting fluid, carb cleaner, brake cleaner can be shot into a vacuum line to see if it wakes up.
It's also possible you don't have enough fuel and have a lean miss, leading to some wetness on the plugs.
It's easy enough to test giving it more fuel, starting fluid, carb cleaner, brake cleaner can be shot into a vacuum line to see if it wakes up.
#19
Yes, fuel pressure should stick around for hours. You also said the plugs "have some moisture but not enough for it to be fouled" and that's unusual. This IMO suggests a leaking injector, FPR or damper.
It's also possible you don't have enough fuel and have a lean miss, leading to some wetness on the plugs.
It's easy enough to test giving it more fuel, starting fluid, carb cleaner, brake cleaner can be shot into a vacuum line to see if it wakes up.
It's also possible you don't have enough fuel and have a lean miss, leading to some wetness on the plugs.
It's easy enough to test giving it more fuel, starting fluid, carb cleaner, brake cleaner can be shot into a vacuum line to see if it wakes up.
Firing brake clean gets it to fire up for about a second, and if I turn the fuel pump off it’ll fire up for a second as well. Still no fuel pressure. I have my old regulator I can test but I believe it’s bunk.
#22
My return line seems to be spraying fuel at high pressure when I power the pump up… unless it’s my to line? But it doesn’t appear to be. Also had a leaky fuel rail so I swapped that out. No change though. Injectors are spraying and don’t appear to be leaking, but I also have next to no fuel pressure still. Trying to upload video of injector spray
#25
Three Wheelin'
Join Date: Oct 2021
Location: Southern WI - 89S2 Megasquirt PNP
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Have you actually measured fuel pressure? If so, what is it? (Third time asking)
This might help (how to troubleshoot fuel supply issues), but first, please measure your actual fuel pressure if not done so (this can tell us many things, like the fuel pump check valve, FPR condition, pump condition, etc)
https://www.clarks-garage.com/shop-manual/fuel-16.htm
https://www.clarks-garage.com/shop-manual/ts-01.htm
Also, in order for the injectors to fire the DME needs to see a running signal from speed/reference sensors. Are you sure you have spark?
You can also test fire the injectors while cranking into small cups by removing the rail - might also be something to check
This might help (how to troubleshoot fuel supply issues), but first, please measure your actual fuel pressure if not done so (this can tell us many things, like the fuel pump check valve, FPR condition, pump condition, etc)
https://www.clarks-garage.com/shop-manual/fuel-16.htm
https://www.clarks-garage.com/shop-manual/ts-01.htm
Also, in order for the injectors to fire the DME needs to see a running signal from speed/reference sensors. Are you sure you have spark?
You can also test fire the injectors while cranking into small cups by removing the rail - might also be something to check
Last edited by walfreyydo; 05-20-2024 at 01:42 PM.
#26
Have you actually measured fuel pressure? If so, what is it?
This might help (how to troubleshoot fuel supply issues), but first, please measure your actual fuel pressure if not done so (this can tell us many things, like the fuel pump check valve, FPR condition, pump condition, etc)
https://www.clarks-garage.com/shop-manual/fuel-16.htm
https://www.clarks-garage.com/shop-manual/ts-01.htm
Also, in order for the injectors to fire the DME needs to see a running signal from speed/reference sensors. Are you sure you have spark?
You can also test fire the injectors while cranking into small cups by removing the rail - might also be something to check
This might help (how to troubleshoot fuel supply issues), but first, please measure your actual fuel pressure if not done so (this can tell us many things, like the fuel pump check valve, FPR condition, pump condition, etc)
https://www.clarks-garage.com/shop-manual/fuel-16.htm
https://www.clarks-garage.com/shop-manual/ts-01.htm
Also, in order for the injectors to fire the DME needs to see a running signal from speed/reference sensors. Are you sure you have spark?
You can also test fire the injectors while cranking into small cups by removing the rail - might also be something to check
#28
Three Wheelin'
Join Date: Oct 2021
Location: Southern WI - 89S2 Megasquirt PNP
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You really need to follow the troubleshooting steps in order instead of playing the guessing game. I linked two very important guides which will walk you through the diagnostic process. Please read them (especially Engine Troubleshooting Guide).
#29
Addict
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Yeah and IMO assuming stuff is what usually gets you. Try the typical testing with a DME relay jumper in place. You did not say specifically if you have a new DME relay but even if you do it might not be a quality part.
If you were getting injector spray then you probably have enough fuel pressure for it to at least almost start if not start and run badly.
Checking spark with a spark checker is an important test also, just looking for a spark that might be too weak to jump in compression is insufficient. If the pressure in the head is 10x then the spark has to be able to jump 10x the plug gap when in free air.
Since the timing belt has been done it's always possible something went wrong there and your cam timing is off.
New rotor might have home loose.
Test your test equipment, test your assumptions, make sure your tests are robust and valid.
If you were getting injector spray then you probably have enough fuel pressure for it to at least almost start if not start and run badly.
Checking spark with a spark checker is an important test also, just looking for a spark that might be too weak to jump in compression is insufficient. If the pressure in the head is 10x then the spark has to be able to jump 10x the plug gap when in free air.
Since the timing belt has been done it's always possible something went wrong there and your cam timing is off.
New rotor might have home loose.
Test your test equipment, test your assumptions, make sure your tests are robust and valid.
#30
Burning Brakes
Its difficult to advise on this as just about every component involved in the fuel delivery and ignition system on the car has either been randomly replaced or disturbed.
Listening to the video clip I am not convinced that this is entirely a fuel pressure/ delivery issue .
Following a proper sequential troubleshooting check and test procedure would have been the best way forward ...however
I would suggest that to at least eliminate the ignition firing order being a contributory feature ...I would suggest that you check the spark plug leads are in the correct position on the distributor and the distributor leads go to the correct spark plugs. and remember the rotor follows a clockwise direction and firing order is 1342.
Next there is a very simple test to check that the engine is receiving sufficient fuel. Start the engine and whilst it is running spray some accelerant such as 'Easy Start' into the intake and note if the engine running improves or not.
Listening to the video clip I am not convinced that this is entirely a fuel pressure/ delivery issue .
Following a proper sequential troubleshooting check and test procedure would have been the best way forward ...however
I would suggest that to at least eliminate the ignition firing order being a contributory feature ...I would suggest that you check the spark plug leads are in the correct position on the distributor and the distributor leads go to the correct spark plugs. and remember the rotor follows a clockwise direction and firing order is 1342.
Next there is a very simple test to check that the engine is receiving sufficient fuel. Start the engine and whilst it is running spray some accelerant such as 'Easy Start' into the intake and note if the engine running improves or not.
Last edited by peanut; 05-23-2024 at 06:35 AM.