1988 Park Avenue Won't Start

Hi, this is my first post. I'm a poor college student, and my car isn't helping me towards my pursuit of a degree. My 1988 Buick Park Avenue will not start. For the last few weeks, the car was hard to start, having to press the accelerator peddle about halfway to get it to start. And when it did start, it would idle very badly, and feel like the motor was hardly turning (about 400 rpm's). Then after 5 - 10 seconds, it would idle and run fine. Over time, i would have to give it more gas to start, and it would take longer for the engine to act right (20 - 30 seconds). Now it won't start at all.

Thinking it was timing related, i have replaced the timing chain, tensioner, timing cam sensor and magnet, crank position sensor, and the balancer. I'm unable to obtain a fuel pressure tester in my area, but i loosened the fuel line and turned on the ignition and fuel came out; if that is any help.

I don't have any trouble codes, but then again, i had to remove the battery so AutoZone could charge it (it died from the repeated attempts to start the car). Any info would be greatly appreciated. The long freezing walks to class are almost unbearable.

Welcome to AF! :wave:

Pushing the accelerator shuts the fuel injectors OFF :eek: usually at about 3/4 travel.

There are several possibilities. i suggest trying some basic good ol fashion diagnostics before replacing any more parts. You need to verify the 3 thing required to run a combustion engine are present:

Spark: nice and blue
Fuel: definately get a hold of that gauge, IIRC s/b in the vacinity of 50 PSI.
Compression: even within 10% acriss all cyls.

Ok, so i got a fuel pressure gauge. I hooked it up to the fuel rail, and i get a steady 43 psi. I even removed the spark plug, left the spark plug wire on, and grounded the plug to the engine to check whether the spark is reaching the electrodes, and it is. I haven't checked the compression, but i just can't imagine that that would be the problem, since after the rough start problem, it would run fine.

So i'm about out of options to try next. Maybe something with the fuel injectors or the ECM? How would i even test those?

Did you check for spark at each of the three front cylinders?
Are the plugs wet?

Which engine do you have?
My book shows 4 different engines available, including diesel.

Right... Turn it over for a few cranks and then pull a plug and check it for gas. If its dry then theres no gas. If wet then theres no spark.

You could get some starter fluid and spray it first thing while cold. If it fires on it and seems to run only when someone is spraying it in the intake then its fuel. If not you have a ignition problem.

If they are very wet you may have dirty fuel injector. When the key is first turned on the

My diagnostics point to first checking the choke system. Your symptoms concur with the choke sticking closed or fuel.

And
If it runs rough and clears.
Injection pump timing.
Injector nossle malfunction.
Air in system.

Hopefully you havent given it more issues.

Good Luck

Thanks for the replies, here is what i've done so far. I sprayed a good 5 to 6 shots of carbureator spray into the throttle body with the throttle valve open of course, but it still wouldn't start. I couldn't check all the combustion chambers for compression because the compression tool hose was bent badly. I was able to check cylinder 1 and it read 90 psi max. It read 30psi at first stroke, 60 on the second stroke, then 90. Is that normal?

I checked the exhaust tip when the engine was turning, so i don't think that it is a clogged catalytic converter. I checked the spark plugs, but it was kind of hard to decide if they were wet or dry. They weren't dripping wet, but they weren't completely dry. I honestly don't even know what to try next. I'm becoming sick thinking about what a garage is going to charge me to get this thing fixed :(

P.S. My engine is a 3800, it says that on top of the intake.

Lets see...need to verify.
Smell the spark plugs immediately..
Should be pretty wet with fuel after ten seconds of cranking without spark.

1. Good spark at proper time to cylinders.
Even if not timed right it would backfire.
2. Good Fuel
3. Good Compression
4. Exhaust/intake clear

Thats about it.

Ok, i ran a compression test on all the cylinders. My chilton manual says that the specified compression for my engine should be 100 P.S.I. per cylinder. I did notice something peculiar though. I removed the spark plugs one by one to see the condition of them, and the number 3 & 6 plugs looked very sutty. One of them even had some crunk inside the spark plug, I think it was the number 3 plug (I'm not sure if spraying carbueator spray into the intake isn't the culprit of that tho). The rest of the spark plugs still look brand new.

I also noticed that the number 3 & 6 terminals on the coil pack are across from each other, at the end of the coil pack. The coil pack is a one piece design, with all the coil terminals (1 thru 6) on one coil pack. Is it possible that i have a cracked coil pack? I don't see any obvious cracking signs, or arching. I already tested the spark on the number 6 plug, and there was a spark at the spark plug electrode. Here are the compression readings from the cylinders if that helps any.

Cylinder - P.S.I.
__________________

1 - 93
2 - 85
3 - 110
4 - 125
5 - 93
6 - 90

Sure sounds like the 3,6 coil is bad. It may be sparking but the spark could be weak making it hard to start in the colder weather. Mine did exactly that until one very cold day when it refused to start.

One of them even had some crunk inside the spark plug, I think it was the number 3 plug (I'm not sure if spraying carbueator spray into the intake isn't the culprit of that tho). The rest of the spark plugs still look brand new.
Ah the ol' Crunk problem.. Actually the plugs should look java colored.
Check for proper spark timing while trying to start.
Crank it for a while and smell for gas, exhaust, intake, etc.

So far the engine should run on those pressures.
If you loose the fuel line it should blast out... 45psi during cranking.

As per your mention of spraying with the throttle body valve fully open.. that wasnt good.. shouldnt need to do that. Just spray in there with it at idle and closed.



Good Luck

How do i check for proper spark timing? I think this engine has electronic spark timing. Is there a special tool for checking it?

The Harmonic balancer wheel has the Crankshaft sensor located in it. It sends timing if its working and has not been damaged. Some have put it in and found it later damaged. Some have replaced the harmonic balancer wheel and it wouldnt work right.
To check timing you would have to find the compression stroke TDC on a cylinder, mark or find marks (#1) on the harmonic balancer wheel and mark its position, set up a timing light and crank it. I know of no "special" tool.



Bass

Cool thx, i'll try that next. I actually replaced the crank positioning sensor again a couple of days ago thinking that i had a bad one, but no dice.

So i definiately have compression. For the most part, i have spark (I'm seeing the electrodes on the spark plugs spark). Is it ok to take a fuel injector out one by one and see if it is spraying instead of peeing? It's not gonna mess up the motor when i turn it over with a fuel injector removed from the throttle body intake is it? As always, thx for the replies.

Nah..leave them in. Dont want an unsafe condition..
Peeing just dont let it idle smooth.. that happened back in the 70-80's when they would wear out.
They just get dirty now with the new metals they use.

You got spark? and it wont run?
Then you dont have gas..

Ok, so i got a fuel pressure gauge. I hooked it up to the fuel rail, and i get a steady 43 psi.

Can you descirbe your test method for us?

BTW-Those are some erratic compression numbers. :(

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.

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

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

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

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.

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.

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

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 :banghead:

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.

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.

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.

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.

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?

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.

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.

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?

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.

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

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

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 :dunno:

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.

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.

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

Check your compression dry and wet.

Good Luck

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?

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

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.

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?

It doesnt matter.. (http://www.keveney.com/otto.html)

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)

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 :uhoh: . 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

Just a guess... here. Really.

Oil pressure control valve. .

Bass..

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

I double checked the oil pressure relief valve, to make sure that it was still in it's place, and it was. So the mystery piece in question isn't that. The mystery piece is actually a little bit bigger than the oil pressure relief valve. The oil relief valve is just a spring with a cap over it anyways. The guys at autozone and advanced auto parts are clueless, and recommend i talk to a dealer to find out what it is :screwy:

Edit: Nevermind, it was the power steering pump pressure relief valve. I didn't even know that there was such a thing. Anyway, i'll try to get an PCM tomorrow at the junk yard, and hopefully, that'll fix it.

So i finally got an exact PCM for the car from a junk yard and still no dice. Spring break is about over and i have my bike tires pumped. I did see the noid light starting to work after a couple of turns over, but the light seemed to flash faster than the engine was turning, and after the engine had stopped turning, it would continue to flash for a couple of more seconds. It still backfires through the intake when i shoot starting fluid into it. Also, when the engine is turning, every second or two, it acts like the engine is in a bind.

So after all the the basics of confirming proper compression have still not be determined, no cause of the no start is forthcoming! No compression no start!

I'm wondering if the crankshaft sensor is properly centered between the rings on the harmonic balancer. I'd also give the wiring between the sensor & ICM a careful inspection.

I've tried everything but drain the gas tank. Would water in the gas tank keep it from starting?

Well school is about to start and i'm still riding my bike. Anyone have any new ideas?

I forgot to mention something about the car. Before it died on me, sometimes when i would come to a stop or turn a corner, the car would shut off. It did this for a couple of months, then kinda fixed itself for a month or two before it died.

Also, the steering wheel is extremely loose, the adjustment works, but the wheel can be moved up and down a good 6-8 inches. I don't know if this would cause a starting problem.

I had to junk the car, because I could never fix it. After I sold it to the junk man, my brother said he was working on a car with the exact same problem. He said there is a fuse in the vehicle by the ECM. After he replaced the blown fuse, everything worked fine. I hope this helps someone out in the future.