1988 924s

Hello Porsche family! I need some serious help from other Porsche 944 and 924s enthusiasts. Last week I decided to fire up my 60,000 mile beautiful and charished 924s and it started up and ran pretty rough . It would barley keep an idle and would not rev past 3k rpm. 30 minutes after it would not start at all... I am scratching my head at this one and here is why.
fuel pressure at rail was 36 -38 psi
sprayed some starting fluid into airbox and the car did catch and briefly run until the ether was gone.. This is telling me obviously that I am having a fuel delivery issue
I then checked for spark at all 4 plugs and had sufficentspark
I DID have tach bounce
Changed spark plugs for the hell of it
Jumped relay and the fuel pump came on
Put a noid light to each injector harness and each harness showed proper signal
I decided to change the fuel filter , in tank strainer , and fuel pump check valve.
Compression test cold showed 180 psi on 3 cylinders and I90 on the other.
I then decided to pull up the fuel rail and watch the spray pattern of each fuel injector while my pops tried to turn over the motor and each injector did spray, but the spray pattern appeared very weak, did not fan or mist . it was like they were almost pissing excuse my language ! My question to you guys is that can weak injector spray cause a motor to not start? I thought the car would at least catch or run slightly with weak injector flow. Im pretty sure this is my issue since the car did run on ether. I will be ordering some brand new injectors from 5.0 motorsports hoping that this is my issue. Thanks guys any advice or thoughts will be gladly appreciated.

John_AZ

On Jan 5 you posted you had the belts changed.
After this you have had problems.
Do you have the knowledge to check the installation?
I am assuming the car ran OK prior to the belt change?
J_AZ

1988 924s

I had all belts done at my local Porsche mechanic shop over a year ago along with a new afm put in. I am still having the same no start issue . Im am honestly worried about it possibly being a timing issue or a dme issue. Im trying to decide on sending my injectors to get clean or rebuilt or get new ones. Wow! John az replied to me! I am honored . I have been reading threads on here for years and always looked for your answers on here. You seem to have a lot of knowledge about these cars. John, have you ever seen week flow cause a no start? The car will not even burp unless I hit it with starting fluid

Coloradoguy

Just a shot in the dark but could your wiring to your speed or reference sensors be wonky?

John_AZ

1988 924s,
I reread your old posts and have a couple of suggestions.
You have tried the 3 wire "jumper" ---do you have a new OEM Stribel Fuel pump relay? Never URO or off brand.
Have you spent a couple of hours and cleaned all the grounds on the 924S--especially the 2 electronic grounds by the timing mark? ( cover the timing mark hole if you clean )

924S ground points thanks to 944 Ecology

Take off the timing belt covers and check the gear marks.

Did you get a rebuilt AFM or new?

You might have a bad ignition switch----easy to change about $8 to $10 (they crack)

ADDED: Also look for a massive vacuum leak...
http://forums.pelicanparts.com/9377136-post11.html


GL
John

PPo

Check the AFM box... although when closed the DME should notice and adjust accordingly, but you never know what is going on. I have opened a few and had to clean the contacts to get the car to run again. Since the car would not rev over 3K when it was running, I would suspect the AFM box. Clark's garage has a pretty good write up on how to deal with this, if I remember correctly.

-P

PPo

Also, check your ground on the fuel pump. (Seems strange, but after spending 2+months trying to chase down a cutout issue at the track, it turned out to be the ground to the fuel pump. Car would start and run, but fuel pump couldn't keep enough pressure to maintain full throttle at certain points. It was really weird.)

-P