LLY: Limp Mode?

[darkone98]

I have just finished a head gasket job in my LLY, everything seems to run just fine; no fuel knock, smoke, or pushed coolant. The problem is now I have is a DTC(s) set, and acceleration is very sluggish, especially up a mild grade, max speed is maybe 35mph, and doesnt seem to want to shift past 3rd gear. The fuel filter is brand new, and unfortunately I do not own a code reader, I should be able to get to one tonight. Does anybody know what might be causing this?

 

[chevyburnout1]

A whole bunch of things... Lets wait till you check the code.

 

[darkone98]

Ok, so my codes were:
P0700 Transmission MIL
P0237 Boost Sensor A Circuit Low

After clearing the codes, the truck has much get up and go and can get it up to 100km/h, but still lacking in power. P0237 keeps illuminating, and If I let off hard, I get turbo bark. My fuel rail pressure is normal, but my MAP sensor reads 33kpa no matter what, I'm guessing this is the issue?

 

[adeso]

Good chance it is a ground or you didn't plug something back in

 

[chevyburnout1]

Check the bale connectors on the driver's side valve cover. Make sure non of the male terminals cannot be pushed in.

 

[darkone98]

Ok, so it ended up being my stupidity and I had forgotten to plug in the MAP sensor in. Plugged it in, reset the codes, and now it runs perfect. Thank you for the advice, I guess my headgasket write-up will come soon!:thumb:

 

[NC-smokinlmm]

Unplug the map and see if it runs better, just don't hammer on it or you will make like 45 psi... Lol...

 

[NC-smokinlmm]

Ok, so it ended up being my stupidity and I had forgotten to plug in the MAP sensor in. Plugged it in, reset the codes, and now it runs perfect. Thank you for the advice, I guess my headgasket write-up will come soon!:thumb:

Huh, last time I had a buddy forget to plug his map sensor in his was over boosting like a mofo. He was making 45 psi almost instantly. And it shoud have not been reporting if it was unplugged. Glad you got it fixed...

Edit, he broke a signal wire instead of not pluging it in...

 

[darkone98]

The scan tool I was using didn't give me boost, thankfully it had rail pressure, I had assumed a fuel issue. It wasn't reporting at all, just stayed a steady 33kpa in any condition which led me to the MAP. It may have been over-boosting for all I know, I got some good turbo bark first time I let off after I cleared limp mode, but you figure it would have had more power instead of none.