Intermittent LEAN LEAN condition!!

[nicstang]

I would like any suggestions on a problem car I have in the shop. Its an 87 T-type; TE61 turbo, 50# injectors, Impala SS MAF with translator and TT chip. The car had this issue before the MAF and chip. It idles fine for a while with the AF hovering around 13.5-14.0. I tip in the throttle, and it jerks and bucks (even with no load) and the AF shoots to over 19:1. I know the lean condition is causing it, but why? Fuel press baseline is 45 psi. At 10 pounds of boost, its at 55 psi. The car will set no codes at all, and on my scanner, everything looks normal. Of course, when the engine goes lean, the O2 voltage drops, but I expect that.
The owner says the car ran perfect before he installed the turbo and injectors. Injector duty cycle at WOT is at 70-75%.
Any thoughts?

 

[FreeBoost]

Confirm all the injectors are actually working and that the owner didn't cross up or damage the injector leads.

 

[nicstang]

I can hear each injector working, but I plan to check duty cycle on each one today. I will also recheck firing order of each injector. Thanks.

 

[TurboDave]

At idle, warmed up, what are your TPS and IAC values?

 

[FreeBoost]

At idle, warmed up, what are your TPS and IAC values?

I had the same thought last night - if the TPS isn't working, cracking the throttle without adding fuel (TPS not working) would make it go lean.

 

[ijames]

When was the IAC and passageway last cleaned? Maybe it is sticking.

 

[87buickracer]

I would like any suggestions on a problem car I have in the shop. Its an 87 T-type; TE61 turbo, 50# injectors, Impala SS MAF with translator and TT chip. The car had this issue before the MAF and chip. It idles fine for a while with the AF hovering around 13.5-14.0. I tip in the throttle, and it jerks and bucks (even with no load) and the AF shoots to over 19:1. I know the lean condition is causing it, but why? Fuel press baseline is 45 psi. At 10 pounds of boost, its at 55 psi. The car will set no codes at all, and on my scanner, everything looks normal. Of course, when the engine goes lean, the O2 voltage drops, but I expect that.
The owner says the car ran perfect before he installed the turbo and injectors. Injector duty cycle at WOT is at 70-75%.
Any thoughts?

Check your translator settings and maf sensor.Take screen out maf sensor also...what is your tps, Int,blm and iac numbers reading?Owner says car ran fine before injectors and turbo ,so I would start in those areas.chip,injectors,maf,computer and translator..etc..just my .02 cents

 

[Abomb]

nicstang did you figure out the problem? just curious what it was.........