1988 Park Avenue Won't Start - Page 3

Jakal · 03-04-2007, 09:42 PM

The fuel injectors are just not firing. I changed the ECM, even swapped the prom, still no dice. The cam sensor is brand new, i just don't get why the injectors are not firing. The one time i got the injectors to get going, the engine backfired through the intake, and i'm pretty sure that i put the timing chain on correctly.

Bassasasin · 03-04-2007, 10:35 PM

Thanks for posting.. Ive been very interested in this thread.

BY MY 94' BOOK.. It says to disconnect the CAMshaft sensor to see if the engine will go into a different fuel pulse mode and will run anyway but not efficient.

Correct me if I'm wrong but if the Cam/valve timing is off will you not get optimum compression?

If the Crankshaft sensor is disabled will you not get Fuel Pulses.. oh yah! You did say you had spark..

Honestly .. GOOD LUCK

Mickey#1 · 03-05-2007, 04:21 PM

One wire (brown?) going to each injector always has 12 volts while the key is on. Have you checked for power to each of these wires?

The ECM grounds the other wire for a fraction of a second to complete the circuit & fire the injector. The ECM will not ground the injector when the gas pedal is pressed ¾ of the way or more. This is referred to as the ‘Clear Flood Mode’. A faulty throttle position sensor can turn this mode on even though the gas pedal isn’t being pressed. A sticking throttle plate could also cause this to happen.

If you need more info to eliminate these three things let us know. You’ll need a voltmeter.

Mike

wrightz28 · 03-06-2007, 11:38 AM

Don't give up just yet.

When I bought my 87, it took me 3 weekeds in a row, pulling, tearing down, ispecting and rebuilding the enigne each weekend until I got it to run right. Didnt' help it was my first time with EFI but

It took me a while to break the habit of "good enough" that worked on carburated/vacuum controlled motors, is not good enough when you have a electric brain box that only works in certain parameters. Point being, think outside the box, try to see wht teh system wants to see to fire those injectors.

Remove the cam wiring as suggested and see if she fires.

Jakal · 03-07-2007, 09:29 PM

I tried to start the motor with the cam sensor unplugged, but still nothing. I did notice something odd tho. I turned over the motor with a freshly charged battery, and it threw some fire out through the intake a couple of times. I swear it acts like it has jumped timing or something, but i'm 95% sure that i put the new timing chain on correctly. How would i diagnose the engine if it indeed has jumped timing? As far as everything connected to the PCM, it says that everything is OK.

I haven't had a chance yet to see if it is getting fire to the injectors with the key on. I couldn't find my test light.

wrightz28 · 03-08-2007, 02:09 PM

Yeah, it's either running way lean or the vavle timing is wrong.

Bassasasin · 03-08-2007, 02:31 PM

Check your compression dry and wet.

Good Luck

Mickey#1 · 03-08-2007, 05:01 PM

IIRC the cam gear has 48 teeth so the least you could be off is 7.5 degrees. Pull out a spark plug & see if you can see inside the cylinder with a mirror & flashlight. If you can see enough to tell when the piston gets to TDC then you should be able to pull a valve cover & check when the valves are opening & closing in relation to TDC. Anyone know if this will work?

Bassasasin · 03-08-2007, 05:44 PM

Gee Mickey! Which gear do you think it jumped?
I still like the compression check.

Jakal · 03-10-2007, 03:39 PM

Ok, so i pulled the timing cover off to check the timing chain and it is still aligned correctly. The gear for the cam and crankshaft only go on one way, and the marks on the gears are facing each other. I guess i'm a find a junkyard and try to find a matching PCM this monday. I'll try checking the compression more this monday also.

Mickey#1 · 03-11-2007, 12:51 PM

The crank turns twice for every turn of the cam. If the marks are lined up properly & the crank is then rotated 360 degrees the mark on the cam will now be off 180 degrees. How do you know on which turn of the crank to align the cam sprocket or doesn't it matter?

Bassasasin · 03-11-2007, 04:37 PM

It doesnt matter..

The camshaft chooses which cycle the cylinder/crank is in..
The ignition fires on both the exhaust and power strokes.
Both the crankshaft and camshaft gears are keyed to the shafts.
The balance gear is keyed and also alligned with the marks on the camshaft. (3.8L)

Jakal · 03-11-2007, 05:53 PM

Ok, this is weird. I was emptying the oil pan that i had used when i put in the timing chain, and i found a piece of the motor in it

. I'm not sure what it is though, and if it is even a piece that fell in the pan when i was working on it, and not from a previous work-on. It has a spring in it, that i can see through the small hole opening, and on the end, it is flat, with a small bump in the middle. On the other end, there is a metal mesh screen, i'm assuming for the outlet or inlet of oil flow, to be coming in or out of the small opening at the other end. I'll try to get a picture of it soon as possible, and post the link to it. It's not the camshaft thrust button, and i'm 99% sure it is not the oil pressure relief thing.

Ok, here are the pics.

http://img294.imageshack.us/img294/2042/pic2lh4.jpg
http://img294.imageshack.us/img294/6679/pic3ww0.jpg
http://img294.imageshack.us/img294/4191/pic4js6.jpg
http://img474.imageshack.us/img474/2025/pic5zk9.jpg
http://img474.imageshack.us/img474/4361/pic6en6.jpg

Bassasasin · 03-11-2007, 07:02 PM

Just a guess... here. Really.

Oil pressure control valve. .

Bass..

Mickey#1 · 03-11-2007, 07:17 PM

Isn't the pressure relief valve part of the oil filter adapter?

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