89 Oldsmobile Cutlass Questions

[bpopilek]

Hello all, I just picked up a project car over the weekend and I was hoping I may get some great advice on here like I have in the past.

Like the title says, it is an 89 Cutlass Supreme, and the motor has been swapped out. Originally the car had a 2.8l v6 installed, but the owner I just purchased it from replaced it with a 3.1l because the original motor had died. In addition to changing the motor he got a new computer out of a Pontiac Grand Prix that had a 3.1l engine in it. The car does start and will run, but not very well at all. It spits and sputters a lot, and if you just let it sit there and run, usually within about 5min, the motor just shuts off. What I need is a place to start looking to get this running right. Could the computer not be the right one, and make the engine run badly, or could it be they just hooked a bunch of stuff up worng? I would like to get it running better before I rebuild the motor, to make sure it is even worth messing with.

Also, I drove the car home, barely, and I also noticed that the electronic guages don't all appear to be working right. The battery guage, the RPM guage, and the speedometer are all on, but not reading correctly. The car's speed is actually 15mph slower that the speedometer reads. Is this also related to the new computer that was put in the car? Should I find one of out a Cutlass, or does it matter?

Any help is greatly appreciated! I want to try to get this running right so I can use it as a daily driver to work, my astro van sucks too much gas these days. Thank you!

[GTP Dad]

I would say that the computer is the culprit. The ECM controls almost everything you mentioned and can be causing the issues you describe. I would try to find a computer from another car similar to the Cutlass that had that engine. You may find however that that is impossible to make it work right. Consider changing the engine and computer back to stock or you may even want to try using a computer from a 2.8 to see what happens.

[bpopilek]

I have done a little research and from what I have found is that the cutlass used the same computer for both the 3.1 & 2.8. Luckily the previous owner gave me the old computer as well. I did try to hook up the original computer this evening and I was able to get the car started, but it quickly wants to stall out if I take my foot off of the gas. The other thing I tried was to swap out the computer chip from the new ECM to the original one. This yielded the best results so far, but it still does not run super smooth. Which this may be because I am not sure how well the original owner rebuilt the engine (One of my next tasks to complete). The only problem with the final combination is that the digital display in the center console loses it's settings every time that the car is shut off now, and it does not show the correct information when it is on. Does anyone have any other suggestions? Thank you!

[malletslinger]

Sounds like it isnt getting enough fuel...start by changing the fuel filter and testing the fuel pressure.
Then check the timming and adjust as necessary.

[bpopilek]

Originally Posted by malletslinger

Sounds like it isnt getting enough fuel...start by changing the fuel filter and testing the fuel pressure.
Then check the timming and adjust as necessary.

When I got home this evening, I put the original ECM and it's chip back into the car. It started running and acted like it wanted to stall for about 5-10sec, and then everything smoothed out and it actually sounded really good. The idle and everything was where it was supposed to be. All of the guages were working properly and the check engine light was finally off. The ECM that is in there right now is a model 1227727, and the chip inside it is a Delco ANLB 5079. The problem started when I slammed the passeneger door closed. The engine immeadiately died and I cannot get it to restart. I have checked to make sure that all of the connections into the ECM were secure. The other thing I noticed that in addition to the car not starting now, the digital dash and center console display will not come on. Does this sound like a short or a loose connection someplace? From what I have read on other sites, the original 2.8 and the 3.1 both used this same ECM, but not sure if the chip inside was the same. Any further suggestions are greatly appreciated! Thank you!

P.S. I got ahold of the original owner today and found out that the fuel filter has been changed and also, this engine came out of a 92 beretta.

[maxwedge]

Slammed the door? loose battery/ground connection, btw that pcm was a troublesome unit in those cars, just that number too.

[bpopilek]

Originally Posted by maxwedge

Slammed the door? loose battery/ground connection, btw that pcm was a troublesome unit in those cars, just that number too.

I have checked the battery terminals and they are tight. And when I try to start the car, the starter cranks the motor full force. So I don't think that the ground is loose. What kind of problems are there with this ECM? I have heard of poor solder connections on the digital dash, is the same thing true of the ECM? Thanks for the reply!

[malletslinger]

Have you checked the trouble codes yet? May help shead some light on the subject.
Turn the ignition key to on and connect make a connection between terminal A and B with a paperclip or a peace of wire...then the check engine light should flash.
Each code will flash 3 times and is a two digit #, the first code that comes up should be 12(that means the computer is functioning properly), then have a pen handy and write down new codes as they come up, then when the light flashes code 12 again(after it has flashed other codes) that means it has displayed all the codes...then come back and post the codes you found and I(or someone who beats me to it) will tell you what it means.

[bpopilek]

I tried the paperclip trick, and I do not get any codes at all. The check engine light does not come on at all. I am guessing that the ECM is bad. From what I have read elsewhere, if the car dies with a tap test, ie slamming my car door, then the ECM is no good. Next question, I am going to try to pick up another model 1227727 ECM this week, do I need to keep the original PROM chip for the replacement ECM, or use the one that comes in it? Thanks!

[malletslinger]

Does the light ever come on(like when all the dash lights come on when you first put the key in the ignition) if it doesnt come on then, then the bulb is probably bad.
You would need to keep your prom(there are two removable chips inside the ECM, you need to keep them both)
As it just so happens, I have an extra one that I bought when my 89 2.8v6 camaro was experiencing a short(wanted to have one just incase)
I paid $25 for it(including shipping) and it came from a wrecked car, so it still has both chips in it I tested it in my car and it works perfectly(I didnt even have to switch the chips, but I tried it with both the existing chips, and the chips from my ECM)
I know for a fact it works because I tested it...
If you would like to buy my spare, I can slap a shipping sticker on the Box it came in and mail it tomarrow afternoon. You can send me a private message(or email) if you are interested.

[maxwedge]

Same computer number, same potential for future problems.

[bpopilek]

Well I understand that there is a potential for more problems by getting the same computer. But do I have any other choice? I can't very well take a ECM from another type of car and make it work can I? Or is there a ECM that is pretty much the same as the 1227727 that will work? I know that there is a 1227730, but that is an inside car ECM and the connections are different. Thanks!

[malletslinger]

I dont think mine are the same production # as yours(I can check this afternoon when I get home) but I remember noticing that the # on the ECM in my car and the # on the ECM that I got as a spare were different...
Im shure there is another computer that you can make work, but that would require a lot of rewiring(as well as other work) and even then, it may not work.
The ECM in my car(which is an 89) had been replaced a few years before I got the car so maybe that is why I havn't had any problems with it(the origional ECM in my car would have been the same production year as yours)
However, the extra ECM I have came out of a slightly older camaro, so the ECM would have been a different production year...it was eather an 86 or an 87, I'd have to check.
But when it comes right down to it, you need to replace your ECM, and a new/remanufactured one would be $$$$.
If you want the one I have, you can have it for $28(if shipping is more than I expect then I'l cover it...I have too many spare parts and am running out of space...) You could get one on EBAY, but you would have to wait for the auction to end... You can try a salvage yard, you may get lucky

[bpopilek]

Yes, please let me know if the spare you have is a 1227727 model. I am going to fiddle with it some more this evening, but if that doesn't go well, I may take you up on your offer. Thank you!!!

Also, on another site, someone had mentioned that because of the new engine and the new ECM, I need to do an Idle air speed relearn. Does anyone know how this is accomplished?

[maxwedge]

Get a GM reman for that number, problem over, forget used, given, borrowed!!!