94 TBI 350 C1500 rich idle help?

**Raksj04** · 08-15-2016

I finally got my new GM replacement motor in my 94 C1500 350 TBI, but it is idling really rich, my wideband 02 was saying 10 to 1.( I borrowed it from another project car.) I replaced the Map and two pin coolant sensor/switch, and it still was idling rich and seems to have overdrive locked out. I have the cable and box to read the information going to the computer and it is saying that the coolant is about 190F and it still runs rich. Did I forget to hook something up? Is there a way to tune around it? I have a Ramjet roller cam in there as well with the stock TBI head.

**ony** · 08-18-2016

are you data logging to see where your maop sensor is running, with a bigger cam it will go up from 30 to 40 or 59 , at idle which will make it rich. please excuase miss spelling my keyboard will not delete. f

**Raksj04** · 08-19-2016

30 or 40 Kpa? I think mine was reading 90? I am not sure. If someone can help me get Tuner pro to record a datalog, i will share it. I am new to the software.

**Raksj04** · 08-23-2016

So I made a data log, however I am not sure how to share it. The map sensor was reading around 70 kpa. I also noticed a week vaccum signal from the map nipple. I removed the TBI and decided to rebuild the TBI.

The port for the MAP was clogged up with a bunch of junk. And the injectors had a bit of corrosion, so I decidedto replace them. Since I really don't want to keep messing with the truck.
Hopefully I can have an update this evening after I get her back together.

**lionelhutz** · 08-23-2016

70kpa is too high for idling, especially with a relatively stock engine. 30-40kpa would be more reasonable. That makes the computer think the engine is loaded so it adds fuel. You'll also likely find the BLM values down at 108 meaning it self tuned out as much fuel as it could.

See what you get once the MAP port on the TBI isn't plugged. If you still get high MAP readings then start checking for vacuum leaks.

**Raksj04** · 08-24-2016

Re installed TBI after rebuilding it and replacing the injectors. Seem to still run rough but, seemed more adjust quicker. so I played with the rocker arms, used Thread tape on the brake booster pipe threads. Cap off the EGR and purge solenoid. She runs so much smoother now. I didn't hook up the laptop to datalog. But she seems to not like to cruise in OD. If I coast it seems to shift into OD. It is hard to tell, the trans was rebuild and I can't feel the shifts.