Problem.....stumped

[1990cavz24]

Alright, in an earlier thread i asked about a 2.8 to 3.1 swap and using the 2.8 ECM to run it. Well, I got everything swapped, 3.1 in the car, everything hooked up, cranked it and it acted like the firing order was off, so I checked, It was fine, next i suspected the Crankshaft Position Sensor, I was pulling it out and....guess what? It broke in half and dropped back down the hole, so I had to drop and pan, push it out, and then installed a new one and put the pan back on, cranked it, still exactly the same problem, ignition timing seems to be off, so yesterday I took the ECM out of my 89 Z24 2.8 went to autozone and bought an ECM for a 1990 Z24 3.1 installed the PROM and then put it back in the car, did exactly the same thing again. Do you guys know anything else that could cause it to do this? I've also replaced coils and ignition module. I need to get this car back on the road..The 3.1 is out of a 1991 Pontiac 6000, all the wiring harness off of my 2.8 has been swapped to the 3.1(yes everything is hooked up corectly)....HELP!!!!!!! !!

[grandprixgtp_91]

what prom chip are you using? is it a 3.1l prom?you should use the prom for that engine.just because the 2.8L ecm will run the engine, that doesnt mean that the prom chip is programmed for proper tuning of the 3.1L , when i was doing tuning on my grand am with a 3.3L , i tried using the code from a 3.1L and it ran like the firing order was screwed up, but the icm controls the firing order. did you check to make sure that you have the wires installed for the year and engine of 6000 that you got the motor for, because the firing order might vary for year and model, just make sure your running the right prom chip though.

Jake

[1990cavz24]

No, I am currently using the PROM out of the 2.8 cav computer, Would the PROM out of the Pontiac 6000 work in the chevy computer? If so I can swap them and see what happens. And I have checked, the firing order is 1-2-3-4-5-6 on both and all the wires are right, Cylinders 1, 3,and 5 are on the front and 2, 4, and 6 are on the back side of the engine.

[grandprixgtp_91]

as long as the prom chips look the same (same plug style) then yes it will work in the computer. use the prom out of the 6000 and im willing to bet all problems will be sloved, unless your cavi has a manual tranny and the 6000 has an auto, then your going to get a service engine soon light from the lack of automatic shifting.

Jake

[1990cavz24]

Alright, i'll check tomorrow. It's an automatic so I shouldn't have any problems there. Hopefully that fixes it, I need to get it back on the road. I've had enough of flames coming out the throttle body. lol I'll post here tomorrow and let you know what happened.

[grandprixgtp_91]

cool cant wait to hear the results!

Jake

[turboD]

Firing order is 1-2-3-4-5-6, but no. 1 cylinder is in the back of the engine (lead cylinder), rear cyl are 1-3-5, front are 2-4-6.
Make sure the egr valves are compatable. 2.8 & 3.1 use different egr's depending on vehicle (A, J, F, W body), and aren't wired/programed the same.
A prom/ecm for a digital egr w/o vacuum is different than a ported egr w/ vacuum. D

[Guest]

First of all, all 660s use the exact same firing order, 1-2-3-4-5-6, ALL of them.

Of course there were problems using a 3.1 PROM to run a 3.3, the crank angle is different, the atual interface between the ICM and ECM is HUGELY different, the 3.3 uses a MAF, where as the 3.1 never did, so those connections were probably throwing the ECM to go "WTF?!".
The ECM is also a different service code and would probably also use a different mask.

There are a lot of 3.1s out ther erunning on a completly stock 2.8 PROM, just as long as the EGR and TB are swapped from the 2.8 onto the 3.1, everything will be just fine.

No, I am currently using the PROM out of the 2.8 cav computer, Would the PROM out of the Pontiac 6000 work in the chevy computer? If so I can swap them and see what happens. And I have checked, the firing order is 1-2-3-4-5-6 on both and all the wires are right, Cylinders 1, 3,and 5 are on the front and 2, 4, and 6 are on the back side of the engine.

Uhhhm recheck that firing order, the odd bank is on the backside of the engine, towards the firewall. You may have just found your problem, correct that and let us know.

[1990cavz24]

lol, the firing order may be the problem. But on the intake on mine it has 2, 4, 6 on the back(firewall) and 1, 3, 5 on the front and that's the way I put it. lol, i'll change it tomorrow and see if that's it. I feel dumb now. lol.

[sharkey]

dont, i did the same thing when we swapped the motor in my buddys 87 cavy. intake runners say 1 3 5 on the front, 2 4 6 on the back, however that is the number of the intake runner (they go across the motor). couldnt figure out for the life of me what the hell i did wrong until i looked in the chiltons book.

[1990cavz24]

lol, thanks guys, swapped the firing order around and it runs....decent, gotta swap alternators coz the one on it isn't charging and fix a small vaccum leak and it should be good to go except for ONE thing....when the car was running yesterday I noticed anti-freeze spraying onto the ground so I looked and found the leak and i don't know that it's fixable. It's the hose that comes off of the pipe sitting on top of the water pump and runs into a metal line that goes back to the firewall and is some sort of a return line, it's rusted through about 2 inches off of the firewall and leaking. I'm assuming I can cut the metal line where it's rusted and replace it with a piece of rubber line and clamp it and it would solve the problem but it seems like it's gonna be pretty hard to get at. Anyone have any tips or have had a similar problem?

[tractorman]

Congradulations on getting it running. Sounds to me like you're looking at a leaking heater core. They ain't too expensive. I don't know how hard they are to change in a cavalier, but it wasn't too bad in the wife's Corsica... as heater cores go, that is.

[1990cavz24]

Cars running decent and has been on the road for about a week now. But I have a minor poblem, the knock sensor plug some how got broken and now im getting an ESC code. Is this hurting anything being unplugged while driving? It won't be long before it's fixed. Also when pulling out from a dead stop it seems to hesitate from idle to about 1500 unless it goes straight to WOT when pulling out. Could the knock sensor being unplugged cause this or is there something else I should be looking for?

[1990cavz24]

anyone????!!!? my problem is getting worse!!! lol now when fully warmed up it wants to hesitate off idle and seems boggy at WOT ONLY when hot, it runs great when cold, fuel pressure is at 40 psi at the test point on the fuel rail and according to alldatapro.com it should be between 40 and 47 psi, so i believe i'm OK there, what else could be causing this? Plugs, the knock sensor still being unplugged, dirty injectors? The car was running way rich the other day so i hooked a scanner to it and got a code 33 MAP circuit voltage to high-low vaccum, found a broken vaccum line and fixed it. Could the running rich be the cause of the problem i'm having now? It started around the time I got the MAP fixed.

[Carlspike]

I had a bad knock sensor on a 1992 3.1 and it acted just like you described. It would idle but when I hit the gas from a stop it would bog down and sometimes even stall. I had the same code for ESC as well. I replaced the knock sensor and it ran fine again. The computer uses the knock sensor inputs to retard/advance the ignition timing, so that could very well cause your ESC code. I would fix that knock sensor plug before I went any further.