Starting Issue: Need Help

[Johnny V]

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

[Mrmerlin]

I would inspect the fuel pump fuse holder on your CE panel
even the though you may have cleaned the fuse ends the holders get corroded inside the CE panel holder and thus wont pass voltage
look above the CE panel for water tell ales if you see any then a blower box reseal should be on the list

[19psi]

Can you hear the injectors working or tried a noid light on them? The car may be starting/running off the cold start injector. Once warmed up, the cold start injector disables as it should and since the injectors are not working, the car shuts down.

[Johnny V]

I'm going to buy a noid light today to test them out

[Johnny V]

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?

[lfausty]

wow yeah lots of patience and one heck of a thorough understanding of exactely what your car is doing good or bad when it does. and taking a component and knowing everything it involves.

gotta say the pcar knows when a microscopic piece of dust lands on itself. fiiiiickle and itll make you know itself as well as it knows itself, or be cursed. hehe.

do you think someone may have put something in the gas while parked at school..... or you went to a different gas station or the gas station. drain it? bottle dry gas?

o2 sensor? fuel damper carbonized ,air not mixing?

[Johnny V]

At this point, I'm pretty confident the gasoline is not the culprit. It has fresh gasoline and has cycled a few litres of it to the engine and back. I'm suspicious of my injectors at this point, since I think it may only be running off the cold start injector and then dying once it stops spraying. The injector harnesses pulsing my noid light say otherwise, but at this point, I need more testing.

I just wanna drive my Porsche, dammit! lol

[924CarreraGTP]

Did you check the thermo time switch? It can cause it not to start.

[lfausty]

off topic related water pump, tstat , timing belt - have you assesed whats under the black covers there at the front of your engine. nice that you wanted to get driving and have so for some time, yes? maybe time to pay dues. its cryin time again,lol

[jstobo]

First pull your injectors and have them tested and cleaned. Find someone with an ASNU setup or send them off to one of the internet vendors. This assumes your temp II sensor has the correct resistance, your AFC also tests out. You can test the resistance at the computer or at the units directly. Should have the same reading. If not then you have a wiring problem. My guess is your injectors are getting electrical pulses but are so clogged they won't keep the car running. At least once cleaned you will have elimated them as a problem.

[Pete R]

This may seem stupid but how's your gas? Did you get a recent fill up?

[aluminum]

A lot of the tests your doing only show up whats happening on the start up mode
I don't see what year the car is ? But i would just try a known Injector relay / a fuel pump relay / test the coil ballasts ( they are 6 volt ) and look close at the coil wire as well as all the wiring
open and clean the pin connector by the alternator > replace it if its all green and eroded away in places > Sound's like to me the car is starting on the cold start valve and try's to keep running but is not getting power of fuel after the cold start cuts off . my Guess is electrical power to the injectors or fuel pump stops > a relay

[Maleficio]

You got it to start and run a little while after messing with the green wire, right?

Replace the green wire, see what happens.

[Danglerb]

Green wire is a big suspect, you also need to try checking some things "quickly" when it won't start.

I hate to throw money at problems, but not running for two months is too long.

[Johnny V]

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)

[Mrmerlin]

send the injectors to Witchunter and order a new green wire
Inspect the hard fuel lines from the tank to the engine bay ,
there have been a few cases where a jack was misplaced,
and it crushed the line thus the engine would run till it ran out of fuel

[Johnny V]

Witchunter, got it. As far as the fuel lines, I did the fuel return test and got 1.3L of fuel returned to the tank in 30 seconds, which passes the test perfectly. I really think the injectors are at fault and just want them taken care of, lol.

[Mrmerlin]

there is also a feed line to the engine if its damaged then the fuel pump will only pass so much volume of fuel,
once the demand for more is used then the crimped line may not be able to keep up

[Johnny V]

Oh ok, I'll be sure to check the lines throughout

[Johnny V]

UPDATE:

- Removed fuel rails and injectors. They look bad The hoses are all dry rotting and they are filthy. I am going to send them to Witchhunter to see what they say since I'm not sure if those hoses are even replaceable along with the reconditioning they do. If not, I guess I'm going to have to save for new injectors. Here are some pics:




-I removed the temp sensors for testing and I realized the connector on the one farthest back has a resistor on it.. is this normal?



-I also noticed that two ports on my throttle body are capped off. My best guess is these are coolant line ports and the PO did a bypass? Still, looks shoddy and confuses me..



-My pin connector looks in decent shape. I don't see any problems here:



-I removed the shrouds for the timing belt to check it and see if it really was new like the PO said. Seems like he wasn't lying..unless I am judging incorrectly?




-When taking off the timing belt cover on the passenger side, I saw this connector just hanging there. Not sure where it goes or if it was even connected to begin with. Anyone recognize it?