Car running in limp home mode!?!?

[BLACK6PACK]

Ok, I posted this a couple of weeks ago. I installed Max Effort, Direct Scan and SMC EGT. I started it up and took it down the block and it had no power. It would just cut out and stumble at anything more than 1/8 throttle. I got it back home and stuck in a regular chip - no change. I then unhooked Direct scan from the ECM and reset the computer. It worked fine after that. So I put the Max Effort back in, still ran fine. So I figured that the pins on the ECM weren't clean enough, so I spent another 2 hours cleaning the pins off. I hooked it back up and started the car and it idled fine and I was getting normal readings across the board on the laptop. I didn't have time to take it for a test drive so I shut her down and didn't mess with her.

Friday night I go to take her for a cruise. I fire up the laptop and everything seems to be fine. I get to the stoplight about 1/4 mile from the house and she starts searching for an idle speed. I pull away from the light and she runs fine. About 1/4 mile from the light it felt like she went into limp home mode. I had to drive a couple of miles before I could get turned around an go back home. Again anything more than 1/8 throttle and she would chug and spit. Took about 4 minutes to get up to 35 mph. It isn't throwing any codes and everything on DS and Scanmaster are in spec. Whats going on?!?!

 

[BoostKillsStres]

Not sure what the problem is, you might work with the DS connection just to make sure its totally clean. You will also want to check your oil level for fuel contamination. My car did this once and in the 5 miles it took me to get home, I had a quart of fuel in the oil and your injectors are even larger.

 

[Steve Wood]

sounds like typical DS problems....reclean the contacts on the ecm board and don't push the DS plug all the way onto the ecm board. YOu may have to make a spacer to push over the ecm terminal to prevent the DS plug going all the way on.

REad the trouble shooting part of your DS book for more..

 

[BLACK6PACK]

I didn't quite finish the story. Since I was a couple miles from the house, I pulled over and unhooked the DS cable at the ECM, and reset the computer (this worked last time). It didn't help. Without DS hooked up it still was in limp home mode. I just got a message from Steve Y and he suggested the MAF may be bad. I did the maf test and it didn't stumble. How hard do you have to tap it? It wouldn't suprise me if the maf is bad since it is the stocker and has 206,000 miles on it, but it is still giving good #s.

The first time I hooked up the DS the maf #s were locked, but after I cleaned the pins again it showed real time maf #s.

 

[BLACK6PACK]

WoooooHoooooo!!!

I fixed it! Steve, as usuall you were right the first time it did this, it wasn't reading MAF #s so it ran in LHM. This time though it wasn't DS.

It was the loose nut behind the wheel. Somewhere along the line I didn't get the up-pipe hose tight enough and it blew off. When I took it for a joy ride on Friday night it was midnight and I was in a hurry, so when I looked under the hood I didn't see that the pipe was offset.

Looked under the hood today, and BAM right there in my face. I'm a happy camper!!!!