VetteBabe1

Hey everyone....yes, it's me, a blast from the past for those of you who remember and were around when I used to frequent the forum.

My "old man", LPDesRoche, has been tinkering with my 87 which I bought in 1996, sold in 2001, and subsequently bought back cross country in 2006. Long story, and sounded like a great idea, and I love the poor thing (it has tremendous sentimental value)...Unfortunately it has come with a host of problems which it didn't have when it left...and I've put about 300 miles on it since I got it back in May of 06.

I was wondering if anyone had any ideas about the newest problem. Lee is about to pull his hair out and what's still left is going gray. I've had the car for over a year but driven it for 2 weeks total. We've fixed a no-start problem (fuel pump died, then starter, all at once), a supposed electrical problem which turned out to be a faulty taillight bulb (after tearing the car and interior apart down to the metal), and while it was apart for that, it did something weird. That's where I am stuck now. Of course for 5 years it was the most reliable car I ever had, and I PUT 120,000 miles on it...it sold with 186,000 and now has 206,000. So, I try not to chalk it up to the poor thing being old (original motor too) but I know the age must be a factor.

New problem: Seemingly out of the blue, it would start and immediately stall. Repeatedly...but never continue to run. Battery was getting low so hubby puts battery on charge. But, not low enough to not turn over and catch only to die right away. In the meantime he fools with the wiring stuff some more trying to find electrical problem which is causing courtesy light fuse to blow and then backfeed when brake pedal is depressed. Takes battery off charge and lo and behold, car starts and runs perfect. Not sure now whether but some strange phenomenon it was the battery (batter has been killed about 100 times lately) or whether it was something he touched in the wiring, or pure coincidence. Electrical problem is then figured out and fixed (stupid *** bulb) and car is still starting and running fine.

So we go to put the car back together Wednesday. Prior to starting assembly we start it up, starts and runs fine...we are paranoid because we never understood the problem and are afraid it will strike again. Put car back together - I am psyched because I haven't driven it in 6 months. Get in to go for a drive and voila, iiiittt's baaaack! Catch, die. Catch, die. Then won't catch at all. Of course I want to puke at this point...

We pull a spark plug and it's getting spark, at least until it dies of course. We smell a ton of fuel and fuel pressure gauge is reading 48 to 50 psi. So, any ideas why it will catch but immediately die? I swear I will send a gift to whoever helps figure this out. Is something telling it to die? Is it a stupid sensor? Is it something in the wiring in the dash? Lord help me.

I would so appreciate anyone's ideas. I have a few of my own but cutting to the chase would be great if anyone has experienced this. I doubt there is any way a battery w/ enough juice to turn over and start (reading 11 volts+ on dash) could cause this... Thank you so much for reading!!!

- J

94z07fx3

What a nice narrative! Welcome back.
My suggestion is to pull every fuse that is not directly related to the running of the engine. See if the problem persists. If not, add them back in until it happens again and then trace down that circuit.

_twisted_

pull every fuse but what is needed to run the car, then re install on at a time - when the problem comes back attack that area

VetteBabe1

Wow, must be good advice - got it twice in a couple minutes!

So if I take the fuses out, should it start and run if one of them is causing the problem? And when I replace the "bad" one it will quit again? Am I understanding correctly? :o

VetteBabe1

Ok, talked to hubby on phone (he's on the way back from SC with a 2002 Z06 on the trailer - dashing any hope of my car ever getting fixed!!)...

He said car is NOT starting and subsquently dying, I say it catches maybe one revolution then you let go of the key thinking it's started and it's not.... but he says it's only lighting the fuel that's blowing by (whatever the F that means LOL). So basically it's a no start problem. Something is keeping it from catching and running! Ugh.

And he said the electrical problem (which ended up being a bulb) involved the tail light fuse, not courtesy lights... wwwhhatever, just work, dammit!!

I could potentially post video of what it's doing if that would help!!

_twisted_

take only the fuses not related to engine running

Jims1988C4

Have you tried replacing the IAC valve in your throttle body ??I was having starting problems also,and replaced the IAC,it was all carboned up and now shes fine........Good luck

VetteBabe1

I had thought about IAC, and TPS potentially but have done nothing yet. Is there any way to check the IAC prior to replacement or just get a new one and see if it works then?

What gets me is that this has been intermittent to some degree...

engle1147

Ohm out the pick-up coil. Ohm across the pick-up coil and from the pick-up coil to the distributor body. Below is a link which explains the tests in greater detail.

Good luck!


http://www.autozone.com/az/cds/en_us...es.htm#hd1-1-1

94z07fx3

Please jump in and correct me if I am wrong but if it were IAC wouldn't you be able to start the car with say 1/4 throttle anyway?

CFI-EFI

The IAC wouldn't prevent it from starting and being able to keep it running by playing with the throttle. Don't throw money at the problem. Has the car been checked for codes?

RACE ON!!!

engle1147

Looking at the sensor's connection with the clip catch pointing up its:

The top left pin is "A" (red)
The top right pin is "B" (black)
The bottom left pin is "C" (green)
The bottom left pin is "D" (yellow)

IAC test link:

http://content.madirect.com/pdf/601088.pdf

Jims1988C4

All I know is that it worked for me,$70 isn't that much.

VetteBabe1

Thanks for all the help so far. I will have to enlist hubby to help...though pulling him away from his new toy will not be easy. Not fair that he has one that runs and I don't

Yes, if you depress the gas, it still will not start. But you smell fuel big time.

cv67

If you are smelling fuel Im also wondering about the condition of the injectors, have you ohm'ed them out also?

vader86

The IAC has nothing to do with this problem.

However, taking the TB apart, cleaning it and checking the TPS voltage would be good maintenance.....but it wont fix this issue.

So the engine gets spark initially and dies? I'd start by checking the coil, then the ignition module.
Then go through the ignition system component by component....and check the cables.

89onlyZ51

Is it throwing any codes (have you done the paperclip procedure?)? It could be any number of sensors preventing it from starting. Even though you're experiencing other problems in the electrical system, I wouldn't jump to the conclusion that it's causing your no-start problem just yet.

Hold the starter on for 5 seconds or so and see if it seems like it's running (don't do it too long or you'll burn the starter). There's a seperate start program and run program. The fuel will be cut off if the computer thinks the engine is not running.

jfb

When you start a C4 the fuel pump comes on for 2 seconds and turns off. If the engine starts, oil pressure builds up and turns on an oil pressure switch at 4 psi which turns the fuel pump back on. I think you have a defective oil pressure switch causing the engine to start and then stop when it runs out of fuel pressure due to the fuel pump being off. You can force the fuel pump to stay on if you jump 12v to the fuel pump fuse by inserting a small wire under one of the pins of the fuel pump fuse. If the engine starts and stays running, you have a defective oil pressure switch.

VetteBabe1

Well - the car has 206k on it, original everything except tranny and rear....so the injectors have probably seen better days...

It's been a LONG time - how do I do the paperclip test again? Which holes does it go in?

jfb

Use a paper clip or a piece of wire to connect the top right two pins together on the ALDL connector with the ign sw in run (engine not running). The SES (service engine soon) light will flash a 12 three times [flash.......flash flash and repeat two more times] followed by any stored error codes, just count the flashes.
If you do have a defective oil pressure switch, no error codes will be stored.