hi guys I'm new to the group here so bare with me.


I just bought a 96 z28 with the 5.7 lt1 motor 6 speed. car has 111000 miles. the guy I bought it from told me it had been sitting for 2 years, but he would go out and start it up from time to time. the day I drove it home it was great, car drove fine. I stopped at the gas station and put a octane booster in it and topped it off. it drove home fine from there also. I did notice when I test drove it, it did take some time cranking before it would start and the check engine light was on once it started. checked the code and got p0372. high pulse..... 2 days later I got the plates on it and went into town to drive it. car started jerking and backfired after about 20 mins of driving. also the rpm gauge would drop down to 0 rpms while vehicle was acting up. it died but started right back up. but as I was driving it the rpm gauge would drop to 0 rpms when I pushed in clutch and return to the correct rpms when gear was engaged. this is a very clean car inside and out. even under the hood everything is dry no rust or flaking of the paint. no leaks, yet. lol. I am planning on checking res pressure on fuel pump but I don't think that's the prob with the delayed start. memory serves me the crank position sensor would also cause that, but as I read on these post by other members the crank sensor is used for detecting miss fires. I have also read that the code I pulled wont make the car die so that kind of leans me back towards fuel pump. idk


any thoughts would be great. I have read a lot of these threads and most people never respond back on how the fixed there issues.




96 Camaro z28 lt1 5.7, leather, t tops

 

Welcome to CamaroZ28.com ! ! !

"Site Help......" forum is for problems accessing or using this site. So let's move this post to "LT1 Based Engine Tech" where you are more likely to get help.

 

Did you recheck for codes AFTER the engine actually died? P1371 after a total shutdown would confirm a problem with the optical cam position sensor in the Optispark distributor. Total loss of the high resolution pulse signal from the cam position sensor will not shut down the engine. But erratic, inaccurate high res pulse pattern can cause the tach to act up, and rough engine operation.

You may actually have two problems. Extended starting can be the result of a problem with the check valve in the fuel pump, leaking injectors, leaking fuel pressure regulator, or leaking fuel lines. That is easy to spot by using a fuel pressure gauge to watch how high the pressure reaches when the pump primes for 2 seconds (key turned to "run" position only), and watching how fast the fuel pressure drops.

 

I think your right, I did check for codes when I first got the car p0372. cleared them then when it died while driving and check engine light came back on I checked code again and got the same result. it acts like its not holding res pressure over nite. if I start it in the morning, then let it sit for a few hours it will start right up. I will have the fuel pressure check this weekend and get back to you. thanks again

 

If you can pay a shop less than the cost of buying a FP gauge..OK

But you should have one of these in your tool box to rule in/out fuel pressure issues. EXTREMELY easy to use

https://www.summitracing.com/parts/h...e2-_-hypertech

Cars that sit for long periods can have problems from non use. fuel, ignition system, seals, etc.

 

so this weekend I pumped out about 5 gallons of gas from the tank, tank was about 3/4 full when I started. topped it of with 93 octane and a bottle of heet. car ran fine all day yesterday, about 20 miles. no check engine light. drove it to work this morning car had check engine light on after leaving my house. got about half way to work and it died at a stop light but started right back up with no issues. its about a 16 mile commute to work. also I have noticed that the car has not had to crank multiple times before starting. starts right up in the mornings now. but as it has been mentioned before in this forum that the p0372 code will not cause the engine to stall. I will post back this week as to how it is doing, but will only change opti if needed.
thanks guys


96 Camaro z28 lt1 t tops leather

 

After it completely died, did you recheck for codes, and P0372 was the only one present?

Could be a problem with the Opti harness connector(s). OEM part has a short harness extension that starts at the gray 4-pin connector on the bracket for the EVAP solenoid, passenger side of intake manifold. Other end plugs into the Opti. Check both ends, but if there is a problem - damaged wire, damaged pins, corroded pins, broken lock clip - it will most likely be at the Opti end. The MSD, and many rebuilds/aftermarket units now come with the short extension permanently attached to the Opti.

 

rc...

if it turns out to be your opti harness, this guy makes a great product. everything he makes is top shelf

http://innovativewiring.com/?page_id=721

 

thanks guys, I haven't checked the code yet as I am at work. but will check when I get home. most likely its going to be the same one.

 

drove the car home yesterday after work. all highway, and it never died. code still comes back to the p0372.

 

you can wiggle/pull gently on the wires at each end of the opti harness while motor is running to see if it shuts off...which would indicate a "intermittent" aka bad connection in one of the wires of the Opti harness

You can also just unplug this harness and bench meter it while wiggling wires

Backfire through intake......I suspect your Opti may need a look inside. After 2 years of sitting it may be contaminated inside with either coolant or oil from a seal leak on Timing cover or Water Pump. You would need to pull the opti and take the cap off and inspect inside.

Opti can be carefully cleaned and a new cap & rotor installed if it is just crap inside opti. Optical or bearing failure you need a new Opti. AC Delco reman is about as good as it gets now on replacement Optis

 

So I did figure out that I have a bad fuel pump. Car was giving me problems this morning while going to the store. It would not start. So I ended up getting it started. Drove it home and let it sit for about 6 hours. Went out and pop the hood, went right to the Schrader valve on the fuel rail and push down on the needle. Nothing happened not even a drip or drop of gas. Got in the car turn the key forward let the pump fill up the line shut the car off went out and push down on the needle in the Schrader valve again and fuel came out. I will be ordering a fuel pump assembly off of the internet and installing next weekend

 

before you replace the fuel pump...would be good idea to actually check the FP with a gauge

 

I recommended that in post #3, and you emphasized in post #5, but so far advice is either being ignored or rejected.

 

Well if res pressure is not there, that's and obvious problem with the fuel pump.