I posted on another thread but not much respond so I guess I should start my own.
Here's the story: I just bought a fixer 96 Cavalier Z24 /M5. According to previous owner, the car will crank but won't start. So he let the car sit for 2 years. It never been overheated and engine oil still clear. After tow it back home I started my diagnoses. I tried almost everything and look up GM SI manual over and over. It still crank but don't start.
Here's what I've done:
- Have Kargen check the starter and alternator and both work.
- Check every single fuse in the car and everything looks good.
- Put in a good working battery and check every +/- terminal, nothing wrong.
- Check voltage on all injector and got about 1.5-2v.
- When key on I can hear fuel pump start. Even when I crank I can still hear its running.
- Check all 4 spark plugs with test light and all got spark.
- Pull all spark plug out after a couple crank and they all soak with gas.
- Replaced ICM, two coil packs, coil housing, spark plugs, crank senor, junkyard PCM but none will make it start so put back old ones.
- When put in junkyard PCM it throw code P1629 (Theft lock). Then key on for 20min still no start so put back old ones.
- No code was set whatsoever when old PCM in.
- Everytime when the spark plugs were dry (no gas) it'll run for 2 seconds. Then tried to give it some gas and it just dead.
- Theft light on cluster will light on but never flash.
I'm almost out of idea on what to do next. After searching the forum for 3 hrs, I think I'll take out the fuel filter and take a look. I'll also get a fuel pressure tester to see what happened. Other than that, what else you guys think of?
Just in case if my fuel pump didn't do the job well, can I drop in a Walbro in-tank pump as a replacement? I read in the other thread about replacing fuel pump. And the in-line fuel pump see to be nice. For a 96 what option I can get? A brand new unit cost $240 at www.partsamerica.com.
Just some thoughts form me.
[Everytime when the spark plugs were dry (no gas) it'll run for 2 seconds. Then tried to give it some gas and it just dead.]
--------So it does run--albeit only for two seconds
[Pull all spark plug out after a couple crank and they all soak with gas.]
-------It's over-fuelling?
It obviously fires on the old gas---this means the fuel pump is pumping fuel to the injectors-----it over-fuels----------so the filter is probably clear enough to get---- too--- much fuel to the injectors.
The ECT is common amongst all the following modes of operation---perhaps this is the thing to check next.
1. STARTING
Ignition ON
Fuel Pump Relay energised for 2 seconds to build pressure
ECM checks ECT, MAP and TP Sensors--- to determine how much fuel to send to the injectors
2. ABOVE 400rpm
--in OPEN LOOP------ECM uses inputs from ECT and IAT (Intake Air Temperature Sensors)--- to determine how much fuel to send to the injectors
3. CLOSED LOOP---ECM checks--Oxygen Sensor has varying voltage indicating it is hot enough to operate correctly
---ECT sensor is above a specified temperature
----A certain time has elapsed since starting engine--- to determine how much fuel to send to the injectors.
Secondary check would be the Fuel Pressure Regulator--in case it's stuck from sitting too long
Alont
I'm not sure how much gas in the tank for now cuz the fuel gauge act kinda funny. The fuel gauge shown 3/4 tank but it'll eventually down back to half after a while. Will it because the gas is too old so it won't fire up?
Almost everytime when there's no gas on the plug, it'll fire up for 2 seconds. After that 2 seconds then it dead and not start again. If I keep crank it, it'll flood the spark plugs. Because the spark plugs were flooded, so I'm not sure it's the fuel problem. I didn't take out the spark plugs to check for spark, I just used test light. Should I take them out to see actual spark?
For the first part of your check list, what exactly do I need to check? I'm not quite understand. For the second check, how do I know the regular is stuck?
I was thinking it's the AMOUNT of fuel--for some reason the injectors seem to be receiving excess fuel.
Before you dig into the following try to start the car in the "Clear flood Mode" that is with the accelerator pedal pushed/and held down all the way.
NO fuel should be delivered to the injectors if the throttle is opened more than 62% and the engine speed is less than 600 RPM. See what results you get.
The fact that it does fire means the gas is combusting when the air/fuel ratio is correct i.e. first two seconds, then it floods.---also the old gas is firing ok when everything else is correct.
I would think this rules out the ignition but points to higher than normal fuel pressure at the injectors.
As the ECM uses the Engine Coolant Temperature Sensor (ECT) in all modes I was suspecting this might not be good and is causing the excess fuel problem.
My 1993 info says the ECT should give the following resistance readings at these temperatures:-
5 deg C/41 deg F=7280 ohms
10/50=5670 ohms
15/59=4450 ohms
20/68=3520 ohms
This would be the first part of the check.
And the second part:-
The fuel pump provides more pressure than is required in the system and the excess pressure is bled off at the fuel pressure regulator by diverting some fuel back to the tank via the return fuel line. Normal pressure with key on and engine off is 41-47 psi. With engine idling the vacuum tube connected to the fuel pressure regulator will reduce the fuel pressure (dependant on barometric pressure) but should be less than 41-47 psi.
If you have a fuel pressure tester you could test to see if:-
The fuel pressure regulator is faulty----this can cause a higher than normal fuel pressure.
The fuel return line is crimped or blocked after the fuel pressure regulator-----this can cause a higher than normal fuel pressure.
A new third part:-
All six fuel injectors are stuck OPEN, highly unlikely I would think?
Alont
guessing it means he has the 2.4L Engine and its an inline 4????
I bought
Actron Fuel Pressure Tester Kit from harbor frieght. I'm trying to test the fuel pressure today but I can't find the test port as mentioned in the instruction. Where can I hook the test gauge up? Please help
You can hook it up to a regulator.
Phewes wrote:You can hook it up to a regulator.
Do you mean hook it
TO the fuel pressure regulator? I can't find any opening along the fuel rail or the fuel line inside the engine bay.
I'm thinking the fuel pressure regulator is dead. The pressure might be too high so soak the spark plug therefore it won't start now.
There is no test port on the 2.4L fuel rail. You have to pull the regulator or the line off and check it.
Will it always start, then die after 2 seconds? And the security light is staying on? If so, that's Passlock. The proper re-learn is in the FAQ.
Gives me some more routes anyway even though I've already tried most of these.
After battle with my Transport leaking LIM gasket, return my Grand Prix to stock, I finally got time to work on my Z24. I replaced fuel pressure regular, new spark plug. I tried to start her up. It fired up for the same 2-3 second and dead. What else I should look into? It still crank/turn but won't start at all.
If I want to do a 99 swap, can I use my 96 tranny? Also, how hard to swap the harness from 96 to 99?
I didn't check the pressure yet cuz I dunno where to hook up the check gauge. I'll do that after holiday.
No, it didn't. Everytime it started and dead, it won't start anymore but just crank. Not unless wait for 10-20 minutes.
I'm thinking about either do an 99 engine swap or just sell it.
It sounds like a fuel delivery problem, a fuel pump problem actually... if it starts and dies and then floods your plugs it seems like there isnt enough built up pressure and it craps out..
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So you think the fuel pump is dead? But I hear it starts when I key on. I know the fuel pump is freaking expensive. How can I put an inline pump?
Inline pumps are a stopgap measure at best. It is better to replace the stock pump. As with anything, if you cheap out on something, you will regret it later, especially when you are sitting on the side of the road waiting for a tow truck.
If you turn the key to ON... then you hear the fuel pump prime for three seconds and shut off.... then it's a good pump. Pump is either live or dead... there is no inbetween.... It won't suddenly come back to life when it's dead (unless the problem isn't the pump... but the wiring to it is cut up... that's another story...)
If you're hearing the pump OK... and the car starts but dies after 2 seconds (on 95-99 cars ONLY!!! 00-05 won't start at all).... then I'm 99.9% sure it's your PASSlock shutting it off. Might be as simple as re-learning the R-code... might be related to remote start (if you have it)... might be a bad key or cylinder....
But IF IT STARTS then DIES AFTER TWO SECONDS.... it's absolutely, positively PASSlock shutting it down.
...j
The status is like this; when I start it, it runs for about 2 seconds and die. Then it'll only crank, won't start. The spark plug will be wet also. After the spark plug dry out and try again, it'll do the same thing.
I read that if PASSlock problem, the theft light will flash. But mine never flash, just light up. I buy it from someone. It doesn't come with remote start or alarm (factory nor aftermartket). I did find a switch that kills the starter. Should I take that off? I tried the R-code relearn from GM SI manual, no luck at all. Is there some other way to relearn the R-code?
Thanx.
Quote:
6-99 J-car
1. Attempt to start the vehicle, then leave the ignition ON. The THEFT SYSTEM light telltale will flash for 10 minutes.
2. When the THEFT SYSTEM telltale stops flashing, start the vehicle. Once the vehicle is running, the password is learned.
Whatever you do... don't turn OFF the ignition between #1 and #2. That's the procedure for a 00-05 car, after the third try... but you have a 96... anyway...
The only other way is to do the GM download, but that takes like half an hour, because no GM tech does it often enough to know how.... so they have to look it up... yadda yadda yadda...
The switch (if it's on the front frame rail) is probably the ignition recall relay. If the car starts, then it's working fine. No cause for concern.
Is the key really old and beat up? If so, replace it (go to the dealer, give them the VIN, get a new one cut)... then do the PASSlock relearn again with the new key. If that's doesn't work, it's more than likely to suspect the lock cylinder.
Here's what I just did:
I'm standing out and turn the key to "ON". All lights are on, theft light on too. Then I wait for 10 mins leaving the key at "ON". After 10 mins, the theft light STILL ON. Then I tried to start it, same thing, crank but won't start.
I know of one thing. If that's a PASSlock problem, the theft light will flash. But mine NEVER FLASH at all. So what will it be???
Quote:
If you turn the key to ON... then you hear the fuel pump prime for three seconds and shut off.... then it's a good pump. Pump is either live or dead... there is no inbetween....
Fuel pumps CAN be dead but still pump, if the impellor is shot, mine was, car would start fine, but as soon as I touched the gas it died, if the impellor is toast it cannot maintain system pressure causing the car to stall.
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