Idling Problem!
 

Me and my buddy did work on his 89 supra and we're having an idling prob. We redid the headgasket, upgraded his ct-26 to a 60-1 trim. Port and polished the head, NA cams, 550 injectors with the lexus afm, 250 walbro fuel pump, 3 inch downpipe, full 3inch exhaust with no cat, aftermarket intercooler with piping, greddy boost controller, safc II. Now we can't get it tuned because the idling keeps jumping from 900 to 1400 it wont stand still so therefore we can't get it tuned. We rejected all the wiring and all the grounds, and we checked the timing three 3 times its dead on. Can anybody help us out, i'm sure someone has run into the same prob. Any help is appreciated, thanx.

I think you should check and test the ECT sensor. Also, did you put both NA cams in?

Any codes?

Yea we put both cams in, i'll check on the codes and let you know. Can't remember if there was any.

as a point of interest, when was the fuel filter last changed? If it is plugged up, depending on how the computer is coded, it could be causing your problem.

Lets not jump to any conclusions till we get his codes. People be patient.

It came up with code 51 and 24 if i'm not mistaken. Any idea?

And what exactly is the ECT sensor, i know what the TPS sensor is but i've never heard of the ECT sensor.

code 24

Its your INTAKE AIR TEMP SENSOR which is integrated with your Mass Air Flow sensor, its located right after the air filter housing. So your have to buy the whole mass air flow sensor(or it could be the wiring). The MAF costs around $350-$400 brand new. But you could also look in ebay and get a used one, thats what I did. Or go to supramania.com and post in the wanted section.

Check the link for Code 51
http://www.cygnusx1.net/Supra/Librar...aspx?S=FI&P=28

By what code 51 says, it could also be your TPS which may not be calibrated correctly, your wiring, or the TPS itself. The TPS costs like $110.

i dont think the lexus afm and 550cc injectors are direct plug and play that might be your problem

Why wouldnt it be?

i heard of people having trouble with it, theres something you adjust or something i dont quite remember, somebody correct me if im wrong

whats the timing set at? and the more you build your car, the less its gonna wanna idle smooth

i disagree with that statement

"99 times out of 100, the weak link in the MKIII is the owner."
-Mike Donahue

Now would i have to buy a Lexus IATS since it is an MAF from a lexus, the TPS sensor is calibrated right we checked it like three times.

that wasn't aimed at mkiii supras specifically.. and if you build it, advance the timing and run the right a/f its gonna wanna idle like at 1200, below that it idles like shit cuz the timing

Assuming the Lexus AFM is the same style as the one from a supra. You would have to buy the whole AFM since the IAT sensor is in the same housing as the AFM. The afm and IATS are integrated into one.

The TPS and the IATS chek out fine, any other ideas?

Then check your wiring, your not getting those codes out of no where.

Wiring is good i dn't know what to do anymore.

If you checked the resistance make sure that IATS was at temperature for spec. Cause temperature changes resistance.

I'll try that thanx.