high idle/tps problem

[lilskyline240]

ok i got everything else figured out on my car but this is the last problem. With my TPS calibrated correctly to .45v with the throttle closed the car WILL not idle under 1800rpm. the second i move the TPS to about .2v the idle drops to 800rpm. Very weird if u ask me. Im using a q45 thottle body and TPS sensor. I eliminated the High idle spring on the q45 thottle body so i can get my idle as low as possible. But even with the idle screw all the way in, with the TPS calibrated the idle will not go below 1800!! this is aggrivating me. Any suggestions?

i cant really time the car accurately with this TPS problem

possibly an air leak?

[mott6904]

Me and you are in the same boat. I had all sort of problems such as high idle ,crappy hunting idle, stalling when the e-fans came on then i moved the tps to a lower voltage and it ran completely different. Im still adjusting the tps and timing and idle trying to get this thing dialed in perfect. Im curious to hear what people say about this?

[noodl35]

I'm guessing an air leak. RB26 ITB seals can go bad causing air to escape thus causing high idle issues. I'd do an air leak test.

[S13 240SX]

i'm in the same boat too.

i been trying to fix that same problem for a year now, but i also may have bad maf wiring too or bad maf sooo who knows?

i'm running new maf wiring this week and see what happens.

[lilskyline240]

wow i thought i was the only one that has this problem. hopefully someone can shed some light on this situation

im going to do a leak test tomorrow and will post the results. Im hoping to find a leak

[lilskyline240]

when i time my car and i set it at 15* the CAS is almost all the way to the right which seems odd. Im using the white wire loop behind the coil pack harness for my signal wire and ive heard that it can read double? so maybe im wayyy advanced?

[S13 240SX]

when i time my car and i set it at 15* the CAS is almost all the way to the right which seems odd. Im using the white wire loop behind the coil pack harness for my signal wire and ive heard that it can read double? so maybe im wayyy advanced?

you have an rb20det right?

you should be using the black wire that loops at the back near the inigitor plugs

[lilskyline240]

no i dont rb25det s2

[mott6904]

I have a rb20. My timing is doing the same thing. When ever i adjust my tps to specs or .40 volts with the idle switch engaged it runs like crap. Whenever i adjust my tps at like .50 with the idle switch disengaged it seems to run better. I dont understand it and it has been driving me insane for a while now. Ive check boost leaks also.

[lilskyline240]

im going to take a guess that if its running fine, it doesnt matter exactly what its set at

[lilskyline240]

double post

[SIL-LINE]

i had this problem a while back on my 20..

first check your wirning make sure all wiring plugs are tight and secure .

second look for airleaks , im sure you already have so disregard. but for any one else.

third check both the AAC valve which is usually the one on back of plenum.then check the IACV valve under the throttle body ..( i always try to keep those clean)

if not then try to ask carl h for wiring help , thats what i did ..

i bought a new AAC and carl rewired my harness( i had a real bad one so i bought a new one and sent it to him)

just my 2 cents..

[lilskyline240]

well right now i have an air leak at my TB which when i pressurize my intake system wont let me put more than 5psi into it before it stars leaking out. Im guessing it could be sucking in air at idle