Hi

I have a 5.7 ltr Vortec motor (L31) from a 1997 Tahoe in my buggy. I got the motor as a cut out but have no idea as to the reason for them removing the motor in the first place. I installed the motor "as is" and over the weekend I started it for the first time. The motor runs OK, however, when it warms up the idle is erratic and I noticed a little black smoke from the right hand exhaust. It climbs up the rev range nicely when you hit the accelarator however, once off the gas, it idles properly for about 10-15 seconds and then reverts back to erratic idle. I have not tried the motor under load so can not comment on that.

Any ideas as to what the problem could be?

Furthermore, the torque converter seems to be very noisy. Any suggestions as to the possible cause will be appreciated.

Regards

Michael

Further to my earlier post, I unplugged the right hand side oxygen sensor and the engine reverted to a sooth idle. Re-plug it and it becomes erratic again.

Any suggestions as to what the problem is will be appreciated.

Regards

Michael

You could replace the o2 sensor and see if it smoothes out when plugged in..

any chance you have the o2 sensors switched? LH connected to RH and RH connected to LH? A budy had a similar problem and that was what it was.

Don

Thanks Don

It is quite possible that the harness was incorrectly labled. I will try swapping them around and see what happens.

The 02 sensors are both new so they should be fine.

Thanks for the help.

Michael

Further to my earlier query, I have found that if I disconnect the MAP sensor the idle also retuns to normal and idles smoothly.

Any adeas as to why the motor is behaving this way will be appreciated.

Regards

Michael

When you disconnect the sensors it runs smoothly because the computer goes into a back-up mode(as if the sensor failed completly) and just inserts a preset value for that sensor then turns on the ck enging light to alert you to a problem. How many miles on the motor? On of the bigest problem with them is the fuel injection spider leaking raw fuel into the intake ports. This could definetly happen just on the right hand side as each plastic tube goes into and individual port. But with any obdII you need to get a good scanner to read codes....just the .02 good luck man

Thanks to the advise above, we seem to have solved the problem. The wiring harness appears to have been incorrectly labled and the O2 sensors were swopped around.

Thanks again

Michael

Hi



Furthermore, the torque converter seems to be very noisy. Any suggestions as to the possible cause will be appreciated.

Regards

Michael
What does a noisy torque converter sound like? Sorry not trying to be an ass, but I never heard one make noise. But if you think it is making noise, did you check your tranny fluid level? Not that it would probably do much good at this point if the converter is making noise.....Sure something isn't rubbing on the converter or flexplate?:confused: