manual computer swap in an auto and running like crap

[RacethisTSI]

my winter beater is a 91 awd auto. i had a few extra parts laying around so i up graded it. swaped a 14b, 450s and an evo fmic into it and the car ran great. 13.7 @ 102. not bad for nothing really done to it. unforntinetly the ecu melted. yay not the first time its happened to me, and i couldnt find an auto ecu. so i had a manuel 1g ecu , swapped it in and the car started up again. but now its running really weird and hitting fuel cut at anything over 7 lbs.(no fun). from what ive read on other threads the only difference was the injector size and the car would run fine with them. Am i missing somthing? im hoping theres somthing stupid im not thinking about... any help would be great.... thanks

 

[SBR Joe]

my winter beater is a 91 awd auto. i had a few extra parts laying around so i up graded it. swaped a 14b, 450s and an evo fmic into it and the car ran great. 13.7 @ 102. not bad for nothing really done to it. unforntinetly the ecu melted. yay not the first time its happened to me, and i couldnt find an auto ecu. so i had a manuel 1g ecu , swapped it in and the car started up again. but now its running really weird and hitting fuel cut at anything over 7 lbs.(no fun). from what ive read on other threads the only difference was the injector size and the car would run fine with them. Am i missing somthing? im hoping theres somthing stupid im not thinking about... any help would be great.... thanks

What year DSM is the ECU from?


Joe

 

[housegsx]

The automatic ecu is for 390cc injectors I do believe, not 450s.

 

[RacethisTSI]

i know the auto ecu is for 390s but the car ran amazing with the 450s so i didnt worry about it. the ecu is from another 91 laser awd i have laying around

 

[housegsx]

Yeah, but have you tried putting the 390's back in to see if it runs good?

The manual ecu isn't putting as much fuel through the same injectors and therefor you may be running leaner than with the 450 injectors and auto ecu. But check for boost leasts if it's hitting fuel cut at 7 lbs. Stock everything shouldn't be fuel cutting though.

 

[dikdiamond]

I did the exact same thing(minus front mount and turbo change)and mine has been running great so far. Did that in September.I did,however,buy a manual tranny fpr. It's about 6-8 psi lower than the stock auto fpr.

 

[RacethisTSI]

no boost leaks, car hasent changed since the ecu was changed. but it has been running leaner

 

[allwheelTSI]

Are you sure it's fuel cut?

 

[RacethisTSI]

yes im sure its fuel cut.ive had enough of these cars to know what it is

 

[GORBS88]

Yeah, but have you tried putting the 390's back in to see if it runs good?

The manual ecu isn't putting as much fuel through the same injectors and therefor you may be running leaner than with the 450 injectors and auto ecu. But check for boost leasts if it's hitting fuel cut at 7 lbs. Stock everything shouldn't be fuel cutting though.

He has 450's in there, like he stated.



Is the ECU you installed a known gooder? There isn't anything your missing since you already have the bigger injectors it should be fine. Mabe the new ECU is bad?

 

[RacethisTSI]

that was my next thought. the ecu is out of a running car but the car in a hack job.

 

[Siral3x]

The Base fuel pressure on a AT is higher then on MT cars, but it should not hurt...
If you swapped 450cc's and a 14B then you got a few things you need to check:
1.Can you confirm that the 'new ecu' is good??got a buddy??try it in his car...
2.Does your wastegate is stuck closed??rusted??or broken/bent arm???
3.Does your whatever boost controler you use works fine??any boost leaks??
4.A logger is a must and it would tell you what's really going on!
How do you know you are runing rich/lean?? Got a gauge?? OR???What have you tested???
Be specific so we can narrow it down!