1990 2.5L Grand Am major problem

[AZCS-B]

I should be able to get a gauge. A friend and I have changed the timing chain on this car once before when the chain tensioner chipped a hole in the timing chain cover so I know there's a chain there. That's been a long time ago though so I don't doubt something could have gone wrong since then.

[I6pwr]

Hope i'm not too late to chime in.

Your accessories are driven from the crank pulley via v-belts, they will turn when your starter is running unless you sheared your crankshaft in half, very unlikely.

The most likely culprit is the crank sensor located behind the ignition module on the back of the motor where the ignition coils are. First thing is to see if you have spark, pull a plug wire and have someone turn it over..there should be a spark jumping out of the boot to the plug.

No spark...either module or sensor, I suspect sensor. Zip tie the wires on each coil together...two per tie, makes it easier to put back...doesn't matter which terminal as long as 1-4 & 2&3 are together on the same coil.

disconnect neg cable
13MM deepwell and standard and possibly a 10MM socket...sorry been a while. Fairly easy to remove just takes patience. Remove the aluminum plate with the coils intact and when all the bolts are out (3 I believe), pull it slowly from the block since the sensor is inside the block and takes a tug to work past the rubber seal.

Once removed you will see the sensor and it's two very small bolts holding it in, replace and reinstall.

Now, if that's not the case you at least have a lesson on if the motor dies abruptly with no warning and will restart when it cools..ask me how I know.

Now if you are observing very minimal compression you may have the old fiber gears for the camshaft and they may have broke. You can replace the gears or chain with motor in car but you need to remove the oil pan first.

If that's the case, send me an e-mail and i'll try to help.

[xeroinfinity]

Thankx for the input I6pwr, but if you read the 1st page he doesnt have any noticeable compression.

Which is most likly the timing chain broke agian.

and Welcome to AF I6pwr !

[I6pwr]

Yeah I know but he said all the rockers are moving.

[xeroinfinity]

I guess the only way to realy find out is pulling off the timing chain cover and going from there.

I have seen rockers move on v6's when the fiber gear broke. Most newer engines use metal gears, which last much longer then those old fiber gears.

Hopefully he'll post back when he figures it all out.....

[I6pwr]

I can't remember when GM switched to the chain, was sometime in 89 if I remember but I don't know what the cutoff month was, I know mine has a chain and it's a 90'.

[AZCS-B]

I was wondering where to go next. I've got a spare car so fixing this has taken a back seat to work and kid running around. I know it's a chain from the last time I had to change it. The small gear came with the new chain last time but I don't know what it was made of. I'll definitely keep you all updated when I get the timing chain cover off.

[I6pwr]

Was the engine making alot of racket near the cover before it stopped running?

Mine started to rattle a bit around 100K so I changed the chain/sprockets and tensioner. About 175K I lost my force balancer and maybe related maybe not, but a piece of my tensioner broke and may have caused the failure of the force balancer...dunno but I replaced the balancer/timing guts again and she's still quiet.

If it's not the fiber gears of years before I feel the tensioner could have been built somewhat better but hopefully you get it all squared away. Before you tackle the job...go get yourself a 12 point 8MM wrench, one of those cover bolts are really in a bad spot and the 12pt box end is a lifesaver with it's short swing.

[AZCS-B]

I finally got around to working on my poor baby. I got everything off except the crank shaft pulley. There is a 24mm bolt it looks like but I didn't have a big enough socket to tackle it last night so I'm bringing one home tonight.

Do I need any special tool to make the pulley stop turning? Is there a special tool for removing the pulley as well? I work in a pawn shop so I should be able to dig up all of the tools I need. I'm just not sure what I need!

[AZCS-B]

Double post, sorry.

[AZCS-B]

I have one more little bugger bolt that's in a hard spot on the timing chain cover but I noticed that I can see the timing chain from where I removed the oil pan. It appears intact and is rotating when I turn the crankshaft pulley bolt. It's been a lot of taking apart to get this far so I'm going to probably change the chain regardless. I just don't know what to do from here. I guess I'll have to get it all back together and actually find a compression gauge. Maybe I didn't do the finger test right or something.

[AZCS-B]

Quick question. Should the timing gear marks both be at the 6 o'clock position or should the crank be at 12 and the cam be at 6? I'm trying to get the chain off but the Chilton's book looks like the marks should be at 6 for the cam and 12 for the crank gear but when I got the cover off, both were at 6 when I lined them up.

[inafogg]

yes i believe crank = 12 & cam at 6 o'clock the 2 dots should match up with each other but if you are 180 degrees off turn crank one revolution & they'll match up
so sounds like the chain is not you problem

[CoolasIce]

Man, it sure sounds like he didn't do enough troubleshooting before ripping into the engine to replace the timing chain.

• Did he ever determine if it's getting a good spark?
• What about enough fuel pressure??
• Is the throttle body spraying fuel?

Let's see what it ends up being, probably not the timing chain.

[AZCS-B]

You're right, I am a rookie when it comes to working on cars. I do appreciate all of the help you guys give though.