DobsZ28

iTrader: (2)

I posted in the Western Forums but there wasn't too much response, and I'm praying someone in here will maybe know the problem.

My car is an '02 Z28 with 72 thousand miles. Normally, the car drives and starts absolutely fine, something like...49/50 times. But on that 50th time, it just won't start. IT'll try to turn over and turn over, and nothing will happen. If I try and start it a good 10 or 11 times, it sometimes will turn over miraculously.

I've taken the car to 6 shops now. I was originally advised it was VATS, so I had JBA disable it and followed up with CMS, who said it had been properly done. I've had the fuel filter replaced at a different shop, and then took it to another shop just the other day because the car died on me while I was driving. I was cruising at 55 mph, and all of a sudden, the engine just seemed to lose power and died.

When I got the car towed over to the shop, it started just fine, and drove fine. I was so pissed, but I left the car at the shop, hoping they'd replicate the problem. They did. They said the fuel pump was fine, and it was probably the crankshaft position sensor. Had that replaced, and then they calleed and said the car had done the same thing. They then said it HAD to be the ignition security system, and I should take it to the dealer. I told them I had it tuned out, they said it probably wasn't done right.

I've already spent so much money just trying to figure out what the problem is, and I'm honestly worried to drive on the highway. It's my daily driver and I love the car to death but I'm worrieda bout it just dying one day on the highway.

If anyone has any ideas, please feel free to post them, as nobody can figure this out and it's just gotten depressing at this point.

Thanks in advance.

O2Form

Does the engine turn over but not start? OR does it do nothing?

DobsZ28

iTrader: (2)

Turns over but doens't start. I've been doing some reading and a lot of people have said they've had similar problems with the fuel pump relay...

mike171562

iTrader: (4)

do you hear the fuel pump kick on when u turn the key and it doesnt start?

rwb

Try changing your ignition relay. You can just swap it out with a fan relay. Just make sure that you put it back in like you took it out.

TurboStangJON

iTrader: (27)

At this point it could be anything considering the age of the car and parts. However, I'd recommend taking it to a dealership because it seems like these other shops are just throwing on parts. I get a lot of these situations where the customer has been to several other shops who can't fix the problem. In the end it's usually something simple that was overlooked or the shop didn't take time to duplicate the problem. If you want to fix the car yourself I'd start with running a pressure gauge off of the rail so you can see if it doesn't have fuel pressure when the problem occurs. Also, I'd keep a spark tester handy and as soon as the car dies pull an easy wire off and check for spark. Furthermore, I'd keep an injector node tester handy and also pop and injector plug off to check for injector pulse. Depending on what the outcome is it should get you headed in the right direction. Good luck!

sjsingle1

iTrader: (1)

i would suggest a trip to the dealer instead of throwing parts at it

DobsZ28

iTrader: (2)

I went to Autozone, replaced (both?) fuel pump relays and so far, after about ten starts, no problems so far...

If it ends up being the relays and all those shops couldn't figure out what it is, I'll of course be stoked but god damn...

TurboStangJON

iTrader: (27)

Yeah, it's about the age for relays to start acting up. I hope it works out for you and it doesn't surprise me that a shop couldn't figure it out. In all honesty they probably didn't get the car to act up and just started piling parts on.

msydow

had a similar problem with my 02. hope it was just the relays. replace them all of the time at work. good luck....

DobsZ28

iTrader: (2)

Man, I've had this issue for MONTHS now, and have spent a decent amount of money between diagnostics, having the VATS removed, fuel filter replaced, countless tows...I'm really hoping this is it.

The Bronx Bull

Hopefully it was the relays. As a precautionary measure, maybe put a fuel pressure gauge and some starter fluid in the garage next to the car, and in the event that the problem emerges again, you can do some very simple troubleshooting.

1) Turn the ignition off and back on. Listen for the fuel pump. If it primes for two seconds, go onto step 2. If not, check the fuel pump relays (which you've already done at this point), in addition to the fuel pump fuse.

2) Turn the ignition on and test the fuel pressure at the rail. This will give you some detail on the problem, but will not pinpoint it exactly. It'll let you know if the fuel is getting from the pump, through the filter, and into the injectors. Regardless as to whether the pressure is adequate or inadequate, move to step 3.

3) Open your lid, and have a friend spray a small amount of starter fluid into the intake manifold as you are cranking the starter; if the engine starts up momentarily and then dies, you know your spark and compression are good - and that the fuel is the culprit. If not, you're in the spark and compression realm - narrow down the problem from there.

The key is to wait patiently for the one time that it will turn over but not start, and pinpoint why it won't start. I can imagine the dealer's frustration when you bring a problem to him that happens "one out of fifty times."

DobsZ28

iTrader: (2)

Just my luck, car didn't start tonight after basketball. Back to the drawing board...anybody have any ideas?

It cranks and cranks and cranks, and when I let go it feels like the engine is shaking a bit, like there's no fuel (but that's just a guess.) I don't know if it was by chance, but I popped the hood and took out the smaller of the relays (20A), put it back in and the car started.

I knew the relays were too good to be true...

TurboStangJON

iTrader: (27)

I said this up top but I disagree with using starting fluid for any form of diagnosis or mechanical issue. Reason being, after the engine has been running the underhood temperatures are very hot, so mix that with extremely flammable ether and it's not going to be pretty. Just diagnose it correctly and check for spark using a spark tester like I suggested. Not being a jerk but I've seen fires combined with blowing intakes up as a result of flooding the intake tract. I was taught in school that it has no place in the automotive industry and to leave it to the lawn mower industry.

DobsZ28

iTrader: (2)

Anybody have any other ideas??? Any help is greatly appreciated...

TurboStangJON

iTrader: (27)

Have you diagnosed it or followed anyones advice? Its not a new car and it could be anything and that's why you need to track it down. At least give us some clue as to what it's missing like fuel, spark, etc.

DobsZ28

iTrader: (2)

Original shop I took it to replaced the fuel filter, tested the fuel pump and said the pressure was @55psi consistently, and couldn't figure out why it sometimes didn't start. Told me it was the VATS system, and that he didn't have the software to do it. Took it to JBA, who I paid to disable the VATS. Had the same problem a week later, so I took it to CMS and they checked it out and said VATS was indeed disabled. From there, took it to another shop that said it was most likely the fuel pump, then when the car started, they tested it again and said it was the crankshaft position sensor. Had them replace that, then the shop called the next morning and said the car was having the same problem. They told me it HAD to be the car's "ignition security system," and that somebody must have messed up when disabling it. Then I was told to go with the relays, so I replaced both fuel pump relays at auto zone yesterdya, all seemed well, then it didn't start at night when I was leaving basketball.


Today on the highway, the car died. I was in sixth, felt the engine just turn off, but I still had power steering, brakes, etc. Downshifted to fourth, the RPM's jumped up a bit but the when I gave it gas nothing happened, and the car came to a stop. Luckily it started right up, and I got off the highway and took backroads back home.


Hope that helps at all...

TurboStangJON

iTrader: (27)

If the shops couldn't figure it out then why would you trust what they say. You need to start from ground zero and forget what's been done to the car. Rediagnose it yourself or take it to a qualified person who knows what their doing. Simply take it to a dealership and let them figure out what's wrong with the car. If it didn't fix the car why didn't you take it back any one of the shops that you paid? I think every shop is just blaming another shop to compensate for their lack of knowledge. Like I stated before put a fuel pressure gauge on the car and route it up through the cowl and tape it to the windshield. Leave it there until it dies again and watch to see if the fuel pressure falls. If it doesn't than that gets us headed in the right direction or at least eliminates a huge part of the equation. It's going to require someone to get their hands dirty to find the problem and fix it right the first time. I get this type of situation on a daily basis where a shop put 500 parts on it and some hack mechanic wants to explain to me what he thinks is wrong with it. I don't even listen and don't even care because if someone couldn't figure it out then apparently they overlooked something. Most shops have the ability to bypass the VATS with either a VATS box or a resistor and can easily diagnose a VATS problem. Go to a good shop and stay with a good shop until the car is fixed is my best advice.

jim ravencraft

Hi,
sorry to hear of your problem. I would try and obtain a good tech/not a parts replacer. Check the cables and grounds on battery and starter. I have seen some that needed a washer to make proper contact on battery. Check for open circuit with volt meter. Secure all grounds and make sure battery has proper voltage....on occasion the plates in the battery can ground at random creating like issue......wishing you the best and keep your chin up!!!!!jim

DobsZ28

iTrader: (2)

I'll try and give this a shot the next time it gives me a problem at home and I can test it...with the lighter fluid, should I be doing it only when the car is cold? Or will it not matter...