cchant

Another update. I retested everything and still got pretty close to the same numbers as before so I was still pretty stumped. I figured since I broke that part in the AFM that there was something that I missed on the resolder that I didn't connect just right.

Well, I was perusing craigslist and ebay over the weekend for parts since none of the parts yards around here are open on the weekend and stumbled across someone on ebay selling the AFM from a '94 pickup.

After it was all said and done, I won the auction for 32 bucks shipped. Not a bad price I think. Hopefully it will be here before Friday. I will update once I have it on and tested out.

cchant

Well I got the new AFM yesterday. I got home last night and started in on the truck. I pulled the EFI fuse, then replaced the old AFM with the new one. Double checked the hose and the plug to make sure I got it all in there tight. I replaced the fuse and then checked for engine codes. I got all the same codes again: 22, 24, 31, 41. I decided to pull the negative battery cable to make sure the codes were fresh. After waiting about 15 minutes I put the cable back in and started the truck. It had a very rough idle and after a few minutes it started to blow white smoke and it smelled like gas. I decided I would just see how well it drove.

Backing out of the drive way and going in to first gear seemed fine, though it didn't have near the pep it usually does. After I shifted in to second is when I really noticed something was wrong. When I first get in to second gear, it revs and picks up a little speed then it will instantly bog down. The engine won't die but the RPM's drop very low. If I keep up on the gas it will eventually surge forward and bounce foward. It got a little better as the engine warmed but not much. I drove it for about 15 minutes. I had to keep downshifting to keep from bogging down to a complete stop.

I pulled back in the garage and lots of white smoke and the distinct smell of fuel filled the air. I'm at a complete loss at this point what is wrong. ECU?

Kiroshu

Unless its dumping an ungodly amount of fuel in then the white smoke indicates coolant in combustion chamber.... this is not good.... you can try the ECU slap test. its a very old test but will tell if its bad. You know where its at right? Right kick panel, take panel off with truck running and just give it a slap and if the truck changes how it runs then you got a defective comeputer.... unless slap ing it fixes it which it prolly wont but this will rule out ecu

cchant

Thanks Kiroshu. It seems all my trouble codes also mention ECU. I've measure the resistance on all the parts and they are now all within specification according to the FSM. I've not tested the ECU directly yet. I'm going to print out EG1-141 through EG1-158 from the FSM to test out the ECU soon and see if that leads me any where.

I did some searches on what a lot of white smoke means and a lot of the threads pointed at the head gasket. That would truly suck.

cchant

Well another update. I did the slap test, which didn't really seem to make a difference when I test drove it. I followed the FSM in the Engine - MFI section on checking for continuity. Everything checked out. I had continuity every where I was supposed to. I did not open the ECU so I don't know if anything inside is fried but it looks very clean, there was no rust or corrosion anywhere and the terminals and connectors looked good as well. I went ahead and double checked fuses, under the hood and under the dash. While digging around in the driver kick panel I found a wire that had been cut. I don't know what it is but I went ahead and put it back together. Any one know what it is? Either way it didn't really seem to help my problem.



Should I check the grounding points in the engine bay? If so, where are they? I double checked everything again while I was working on it. Just to make sure, I pulled the EFI fuse then put it back in and checked codes once more. I got the same 22, 24, 31, 41 all over again...

corax

dumping too much gas for the engine to burn, chances are the engine oil may also smells like gas (fuel washing down the cylinder walls into the crankcase) - the main bits that control fuel are the AFM and the TPS if that helps at all. when you test the individual components, it's best to test at the ECU through the harness to take into account any resistance through the wiring. also check for any shorts to each other/ground/power at the AFM connector

cchant

Just wanted to bring this back from the dead to update it for any one that ever happens to have the same issue. I ended up replacing the ECM on the truck and it fixed all the engine codes and the truck is running good now.