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Discussion Starter · #1 ·
I picked up my car a few days ago from the shop that put in the NA-T setup. When i picked it up it was idling off the chart lean on the wideband and it was stuttering at around 750 RPMs. The vacuum was also low at around -15 in/HG. I looked around and finally found a vacuum hose on the manifold that was disconnected. After i connected and started it up, it would cold start at around 14.7-14.8 AFR perfectly at around -19 in/Hg. After it warmed up and i started driving it would cruise fine and boost fine. However when i came to a stop sometimes it would idle at -14.7 AFR and -19 in/Hg while sometimes it would start to stutter at a little under 800 RPMs and it would be -17 in/Hg and 16.1-16.9 AFR. Could there possibly be another vacuum leak? spark plugs? reset ecu?

If you have any suggestions let me know, thank you.
 

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TT This
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what do you have for fuel upgrades? Fuel management? injector sizes?

My car has never idled smooth like it did stock and I don't think it ever will again. The shuttering your feeling is most likely the engine being starved of fuel. My car doesn't really smooth out till I'm at about 13.6 - 13.9 AFR.
Your AFR really will change alittle with the temp outside, unless your fuel management can comensate with a air temp sensor.

Also check your BOV to see if it leaks at all, try adjusting it alittle tighter or looser perhaps.
 

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Discussion Starter · #3 ·
I am running the stock injectors with only a walboro fuel pump. I have an SAFC contolling it because the tuner couldnt get the MAP ECU to work.

I dont think the BOV is leaking because sometimes the car idles perfectly like stock but when it is shuddering it is running lean at around 16.5 AFR.

What could be causing this lean condition? It can be the BOV because then it would be running rich, correct? If anyone has any input let me know. Thanx
 

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MkIV Pilot
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Hey man, it looks to me like youre in pretty good shape with your NA-T ..... mine would DIE at idle and when i let off the gas over 4k rpms!!!!

Maybe the best answer to your question is a quote from DaveH:

"This is the nature of the beast..." :D

Prolly about 95% of the Singled Supras that i know around Atlanta have wierd idles.... its not uncommon...

I hope my car runs fine with the AEM... cant wait to get her back!!!
 

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Discussion Starter · #5 ·
mogallo said:
Hey man, it looks to me like youre in pretty good shape with your NA-T ..... mine would DIE at idle and when i let off the gas over 4k rpms!!!!

Maybe the best answer to your question is a quote from DaveH:

"This is the nature of the beast..." :D

Prolly about 95% of the Singled Supras that i know around Atlanta have wierd idles.... its not uncommon...

I hope my car runs fine with the AEM... cant wait to get her back!!!
yea this is true, i can deal with it but i was just wondering if something was wrong that is easy to fix

i look over everything again tomorrow
 

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mfr122887 said:
yea this is true, i can deal with it but i was just wondering if something was wrong that is easy to fix

i look over everything again tomorrow
I have the idle speed set at 950~1050rpm, it actually idles very smoothly . Maybe raising your idle speed might help. I tried to have it set at 600~800, unfortunately the car would just stall and die.
 
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