JohnnyV

Hello 928'ers

For about two months now my 928 has been sitting in front of my house, motionless. It all started when one day things were fine and I turned it off to go to class, then when I came back, it wouldn't start. It cranked over, but wouldn't fire. Since then, here is what I have done:

-New fuel filter (AdvanceAuto)
-New fuel pump (928Intl)
-New fuel line from pump to filter since mine had a kink in it (928Intl)
-Checked fuel pump relay and even did the jumper trick
-Checked injector relay
-Cleaned ground points (The ones I could get to without a lift)
-New battery
-Took apart upper intake and cleaned everything
-Took out the fuel level sensor and looked inside at the in-tank filter. Seemed fine.

At this point I don't think it's the fuel system since it will sometimes start and idle for about 3 minutes, and then die. After that initial start, it will start for a second or two and die, almost as if it only tries to stay on when the car is cold. I looked at my throttle body and my throttle cable is a little loose, but I doubt that has anything to do with it. Also, there are two sensors by the cables; one that gets pushed when the throttle is full open, and another that seems to get pushed at closed throttle. They look like little gates with arms that get pushed down to hit a button. Anyway, the one that I'm assuming gets pushed on closed throttle isn't being depressed far enough down to hear that "click" of the button push..I don't know if that has anything to do with my issues, but I figure I'll mention it.

I know I need air/fuel/spark for startup, and I am pretty sure fuel is fine at this point, as well as spark, so my suspicions are on the air part of the equation.

Any help would be GREATLY appreciated as I hate to see my car just sit there

waynestrutt

PM sent

borland

Have you replaced the ignition green wire?

https://rennlist.com/forums/928-foru...reen-wire.html

Randy V

Secret fix?

Post it here for the archives, dude .

JohnnyV

thanks wayne.

thanks borland, i will check it out tomorrow

waynestrutt

YES

12-07-2006, 07:45 PM
https://rennlist.com/forums/928-foru...reen-wire.html

JohnnyV

UPDATE:

- Checked the injector harnesses with a Noid light and all 8 checked out fine.
- Checked to see if the plugs were getting spark with an inline light, and they checked out fine as well.
- Tested fuel system by jumping the pump relay and checking how much fuel gets returned in 30 seconds. I got 1.3L of fuel returned to the tank, which is right on.
- Checked the vac lines on the fuel regulators, and none of them smell like gasoline
- Checked the connectors for the MAF, temp II sensor, and cold start injector. All are intact in visually fine.

After all of this, I cranked her over and after 2 tries, she started and seemed to hold idle well. I timed it, knowing it would die soon, and one minute and 40 seconds later, she sputtered and died. Cranked it over again, ran for 20 seconds and died. After this, the car will just crank over but not start. All of this is just as it was since I started diagnostics over a month ago.

I checked the green ignition wire and the insulation at the plug is gone and I see some corrosion on the wire (see picture below).

I forgot to plug it back in and tried starting it, which was a complete failure. I plugged it back in and it started for a few seconds and died, as usual.

Also, I unplugged the temp II sensor to check if the CS injector was working, and the car started but it idled as if it were running on 1 cylinder, SUPER rough. I plugged the sensor back in, and it started and idled well for a few seconds, and died.

Luckily, I'm learning to approach this whole thing with more patience. I'm glad that I have confirmation that my fuel system is running strong, and that all the plugs and injectors are getting pulsed. I'm planning on buying a new green ignition wire since I have been replacing a lot of old stuff anyway, and that is never a bad thing.

Comments?

Lizard928

With injectors plugged in can you hear the injectors firing?

JohnnyV

I haven't been by the engine when it does run, so I haven't been able to listen for them, but I assume they would be firing since it idles fine when it does start. Is that an incorrect assumption?

Lizard928

It can start and run on the cold start injector.....

JohnnyV

Yea, the symptoms seem to point to that, but all 8 injector harnesses are pulsing.. I'll have to try and listen for the injectors next time.

Lizard928

A noid light has almost no load where L-Jet inj have a large load.
A bad ground could allow the noids to work but the injectors not to

928porschemangreg

Just one more on fuel, crack the gas cap open when starting again. see if it runs longer.

soontobered84

I posted this for you on the OC website, but I'll post a copy here, too:


Johnny,
You say you checked the fuel injection relay. It may just work intermittently.
Use a three-pronged jumper to bypass the fuel injection relay. This will remove all doubt as to the relay. Jumper terminal 30 to both terminal 87's to bypass.

Please let us know the results.

JohnnyV

Hey fellas. Here's the latest. I actually posted her for sale for a bit, then regretted it and decided to forge forward, lol.

My next step is to get injectors out of the question. AFAIK, they are original injectors, and I've been replacing/renewing so much, that I want these to be done too. My question is, where do I send these out, or do I just buy new ones (pricey)