1988 Park Avenue Won't Start

[Jakal]

For testing the fuel pressure, i screwed the fuel gauge end onto the fuel rail fitting on top of the engine. I turned the key to the on position and the gauge showed about 43 psi. I tried turning over the motor, and the fuel pressure was still showing 43 psi. I let the engine sit, and it was still holding 43 psi, i didn't see the pressure leaking down or anything. That's all i did for the fuel pressure testing.

[Mickey#1]

Does it act like it's trying to start or does it seem more like it's dead on all six cylinders?

[Jakal]

It acts like it's dead on all cylinders. I don't hear or feel that it is trying to start.

[Bassasasin]

Do the plugs get wet with gas after trying to crank it for a while?

[Jakal]

This might be my last post regarding my car

My dad sent me a bunch of parts off an identical car he has, and the car ran fine before he took them off. I replaced the Mass Air Flow sensor, the ignition module, with the coil pack, idle air control valve, the fuel rail with all the fuel injectors and fuel regulator, and a brand new o2 sensor. I also tried swapping the ECM, but i'm not 100% sure if it was the exact same ECM. I think the ECM i tried came out of a 91 Buick Park Avenue.

It still won't start up. I couldn't get to the bolt to take the throttle position sensor off, but there wasn't any trouble codes for it anyways. I don't think loosening the catalytic converter off the exhaust is going to help it, that was my only other thing i could try. I'm completely out of ideas.

[HotZ28]

You have fuel pressure, but are the injectors pulsing? You need to test with a "noid light"! You can get a set at AutoZone. If no injector pulse, suspect the ECM.

[Mickey#1]

Excellent idea to check for injector pulse. I've also seen the throttle position sensor disable the fuel injectors.

[wrightz28]

Originally Posted by HotZ28

If no injector pulse, suspect the ECM.

2 things, before going this route:

1-don't overlook the obvious, and make sure the fuse for the injectors is good

2-it eludes me was year they (GM) started using the CAMshaft sensor to determine injection operation, but I know my 87 had one, was pretty useless but it was there.

[Jakal]

Ok, i replaced the TPS sensor, unhooked the exhaust from behind the engine. I put a noid light on the number 1 injector, and started cranking, no light. Then sometimes after it had finished cranking, the light still flickered a couple of times. After a while of periodic cranking, I actually saw the noid light flickering and it acted like it wanted to start, but it sounded like it back fired through the exhaust and intake hard. I did shoot some starting fluid in it though to get that effect.

I tried playing with the relays for the fuel injector, i wasn't sure which one was which, but i kept replacing one with a new one i bought, still no dice. I had before tried a '91 buick electra ECM, but maybe that one isn't compatible? Maybe i could swap the proms? I don't know what else could keep the injectors from firing. I'm pretty sure that i put the timing chain on correctly. Would it still build compression if i put it on slightly wrong? I figured that the ECM is ok, if the injectors are still firing, even though they are firing every once in a while. And when i replaced the TPS sensor, i got a trouble code for that, so i guess the ECM is still working correctly? Anyway, i'm completely out of options now on what to try next.

[Bassasasin]

Proms? .. most likely its ok..
even the PCM may be fine.
But as you say its one of the only things left you haven't changed and would have to suspect it.

I dont see individual relays for the injectors..

Not sure if you get pulses till its running.. I know perhaps it should get a pulse just when turning to start.. as a prime..


The injectors pulse from the PCM.
Wires going back to the PCM theres a Bulk head connector..Might be there but if you got a flash says theres some kind of connection.

Cam sensor tells the Ignition Module.. the ignition module tells the PCM,

The PCM outputs on these wires to the injectors.

1- Black
2- Green
3- Pink
4- Red
5- White
6- Yellow

the PCM goes out to a Bulkhead connector.. the wires then spread to the injectors.. the injectors (Brown wire) have a common #7 fuse in the relay center assembly.

UNDERSTAND the PCM provides the GROUND pulse for the injectors.. the gray wire should be hot in run position on the ignition switch.. if the fuse 7 is ok in the BODY relay center.
The fuse 7 source OF POWER is on your ignition switch and since your starter turns that power is working and ok there.


Perhaps you have lost a ground to the PCM.. BLACK WHITE wires to the PCM on D6.D7, D1 on the PCM.

.


Good Luck.

[wrightz28]

Originally Posted by Jakal

I actually saw the noid light flickering and it acted like it wanted to start, but it sounded like it back fired through the exhaust and intake hard. I did shoot some starting fluid in it though to get that effect.....

....I'm pretty sure that i put the timing chain on correctly. .

As soon as you mentioned the backfire, and I thought back to your compression numbers, I immediately though of engine timing. Plus again, if a 88 uses the CAMsensor for injector pulsing and the magnet is cracked/missing/ yada yada, coul dexplain the erratice noid signal.

Did you replace the enitrre set, gear and all? What brand did you use? Proer installation should have had cyl ! at TDC, the cam gear alignment dot a the 6 o'clock position and the crank at 12.

[Jakal]

I replaced the timing chain, that came with a gear for the cam and the crankshaft. I also replaced the cam magnet that goes inside the camshaft gear on the timing chain as well. I made sure to align the dots (cam gear at 6 and crank gear at 12) before i removed the old timing set, (i didn't make sure that cylinder 1 was at TDC, it doesn't matter right? if the marks align correctly?) and installed the new set. I also replaced the timing chain tensioner as well. The old one was extremely wore out. I'm not sure on what brand the parts were, i just got whatever autozone had on stock.

I did notice that when i was installing the cam magnet button, it seemed longer than stock, would that affect anything? I hate to take everything apart again just to double check my work. Maybe i could remove the cam sensor, and move a piece of metal over it, to see if it fires the injectors? I didn't think that maybe my work was flawed, since it wasn't running when i replaced the timing chain to begin with. But it didn't fix it either. I haven't tried a timing light yet, maybe that would determine if the timing is off?

[wrightz28]

You know, the magnet may be a problem, but double check the CAM and CRANK connectors for cleanliness and connection as well as visually inspect the crank sensor and make sure the shutter on the back of the balancer didn't hit and break it.

[Jakal]

I give up, this car just wants to die. I hope this thread helps someone else who has the same problem with their vehicle. Thanks to everyone who helped by replying in this thread.

[Mickey#1]

Don't give up. Can you give us an update on what the current status is?

In particular:
Car still not starting?
You confirmed fuel pressure
Spark at each of the three front cylinders?
Fuel injectors being pulsed?