Timing or fuel causing problem????

[Rampage139139]

I have a 1994 Camaro Z28 with the 5.7 liter Lt1 motor
The other day on the way home from work the car suddenly became very sluggish. After pulling over it would start but never run correctly it would just chug along for a second then die.
Once I got the car home I took the fuel lines off and checked the pressure coming from the fuel pump. It came up to 80psi right as u turned the key on. Then would slowly fade down to 20psi and hold there. I also reset the ECU by disconnecting the battery for a while.
Also I am not sure whether this could also help but right before this problem came about. You could not just turn the key and start the car you would have to turn the key wait a second or two then start it. It would always fire but not easily. After it started it would run just fine.
Please if you can help me out I would GREATLY appreciate it.

[Krypt0]

Sorry to say your fuel pump may be on it's last leg. It will run like that for awhile before it lets go completely. Check your fuel filter also. I'm not sure what the fuel PSI suppose to be so I can't speculate there.

How long since the plug wires, cap and rotor have been replaced?

[Morley]

Replace the fuel filter.

The 80 PSI you got (they way you did it) is correct, it is dead head pressure. The bleeding down to 20 is a problem, but just a minor one. The checkvalve in the pump is leaking, letting the pressure bleed off after the pump stops running. This will cause the engine to crank a couple of seconds longer than normal to start but won't cause the problem you are seeing.

[Krypt0]

[quote=Morley]Replace the fuel filter.

Morely, did you mean to say fuel pump?

[Wiriza01]

[quote=Krypt0]

Originally Posted by Morley

Replace the fuel filter.

Morely, did you mean to say fuel pump?

Filter 7$, time 20 min. If you have not changed your filter in a long time I would agree with morely. Worth a try before proceeding it won't hurt.

[Morley]

[quote=Krypt0]

Originally Posted by Morley

Replace the fuel filter.

Morely, did you mean to say fuel pump?

No, Always go with the cheapest & easiest component first (filter in this case). The pump change is always a last resort.

[Rampage139139]

I guess that I am up to what it is not.
It is not the fuel pump.
I just replaced it last weekend.
Not the computer
Swapped it for another identical car in all aspects.
Doesnt appear to be the spark plugs or wires.
They looked brand new and I cleaned them.
BUT I did notice that the spark plugs were covered with gas.
Fuel filter was just replaced a week before this happened.


I am wonder what happens if the auto-spark or whatever goes out could this be the problem.
Also somebody at work said there was a sensor on the crank shaft that can tell the position of the crank shaft. So the computer can adjust the timing. Could this be the problem.

[Morley]

Originally Posted by Rampage139139

Also somebody at work said there was a sensor on the crank shaft that can tell the position of the crank shaft. So the computer can adjust the timing. Could this be the problem.

Cam position sensor, usually when these go out the car won't run at all. If the plugs are covered in gas..could be an injector or more stuck open.
All I know about the opti-spark ignition is that it is expen$ive to fix and isn't nearly as reliable as the old distributors they replaced.
If the opti spark isn't working the PCM shouldn't be firing the injectors..so the plugs shouldn't be getting wet.

[89IROC&RS]

your opti took a turd, take it in to have it checked out by someone who is familiar with them. My guess from right now is that your going to need a completely new unit, not just a "cap and rotor" like old distributors. a new distributor costs around 650 from the dealership. www.gmpartsdirect.com has it for around 370.

[89IROC&RS]

also in regard to the fuel pressure bleed down, this is normal. the 80psi spike is for priming the fuel system, then if the engine isnt running the pump stops and fuel gradually passes through the pressure regulator, fuel logs, and back down the return line. operating fuel pressure should be on the level of 45-55psi.

[dolluper]

Am I missing something here i taught the 94 chev Cam Z 28 5.7 was a MPI [p] engine with a standard dist and an ingnighter please fill me in what you guys are taking seems left field If the distributor is behind the water/p it is opti-spark There would be no crank sensor unless it was swapped to a 1996 engine I agree get the codes I'm guessing you will end up with 41 or 42 if it is an opti-spark

[Morley]

LT1=opti-crap.

[dolluper]

LT1 Vette,Roadmaster,Caprice[copper] didn't know they stuck them in Camero anyways opti-spark dist from 92 to 94 did not have vents to get rid of condensation a 95 had 2 in the bottom and 96 went with a vac vent the seal by w/p was always a problem ,so this 94 would have no vent unless it was a late production ,if it was an early production it might not have a mass airflow sensor If and when you pull your codes you get 41 it's your EST system [electronic spark timing] has a short or grounded If you get 42 also EST check circuit ground The EST system goes from computer to module then module fires the coil Your computer determines your spark from sensor info like engine speed ,throttle pos.coolant temp ,rpm, park/neutral switch pos,knock sensor cond,vehicle speed ,engine load

[Rampage139139]

Update on progress
The timing seems way off.
There is a orange dot and an arrow on the crank shaft pulley that should indicate top dead center. Well it seems that cylinder 1 is firing at about 90-115 degrees after that mark.
I am no rocket scientist but this is bad huh?
Next what could cause this problem.......
Could it be the crank shaft sensor that I mentioned above.
Could the timing chain of skipped a link or something of that nature.
It does appear to get spark.....(aka timing light)
If it is enough to fire I dont know.
Please help?????