Erratic Idling

[Dew511]

A friend of mine also has a 1jz and his has an idling problem. On start up it will idle consistantly at 1000-1500rpm. It will do that for about 3mins. Then I guess once it starts to warm up, it starts bogging down to below 500 and then back up to 1200. Almost like its fighting to stay on. If it does ever decide to even out, it will stay around 1500rpms.

We have tried to swap out the TPS. After that didnt change anything, we figured that it wouldnt make a difference anyways 'cause its just a sensor. We swapped map sensors. No difference. We've beeeeen looking for vacuum leaks. Cant find any. Ummm... I think thats it. Im stumped. Dont know what else to do.

He said that maybe its the fuel filter. So I guess thats the next task. Can you guys think of anything else that might be causing this prob. Thanx in advance.

O... and he swears by Supraforums. I tell Supramania is WAY BETTER! Naturally!

 

[Anomili]

Funny, I have the exact same problem on my 7M. I've been trying to solve it for 6 months. I have replaced: ecu, afm, injector o-rings, tps, ispc and tb. I am currently swapping in a t-67 turbo in for my upgraded ct-26 which was leaking oil. I am hoping that the problem was caused by the leak which I figure would dump oil into the engine. This would then cause problems idling when the car's cold start sequence ends and the heat is no longer enough to burn all the oil? My other thought was that the oil (which was dripping out of my intake filter it was leaking so much) was clogging the vacuum hose that attached at the bottom of the accordion hose. Otherwise I have no idea what the problem is.

Dave

 

[Dew511]

Yeah I been talking to some more ppl. Have you changed the fuel filter yet? Thats what every1 is saying. I mean they might have a supra but they said the same symptoms. So thats what we are going to do next.

 

[Anomili]

Hmm, if I remember correctly my fuel filter was changed when I installed my walbro pump last summer. It shouldn't be clogged, but if problem persists I ahve a spare filter at the ready.

Dave

LMK if changing your filter fixes the problem.

 

[Dew511]

Hmmm... well we changed the fuel filter. Got a lil better but the car seems to be in limp dick mode. The check engine light is on. It idles roughly around 600rpm... and I mean roughly! It sputters like crazy. I dont think he can go past 2k rpm either. Maybe his ECU is shot. IONO... Im clueless.

 

[Xtreme]

check your codes

 

[T701jz]

Has this been happening since you made the swap or just recently? What year is the car? It might got some thing to do with the wiring.LMK

 

[Dew511]

My friend took his car to a shop 'cause we ran out of ideas. Turns out they said that 2 of his injectors were stuck open. Now he's in Louisianna helping out down there so I guess that project is halted for the moment. I'll let you know when he gets baq. Thanx

 

[T701jz]

Replace the ECU, But I would be cautious to plug the new one until you find out what shorted the ECU.Did he done any wiring job or sound system in the car? God bless him and if he ever need any thing for parts to fix his problem let me know and I will try my best to get it.

 

[Dew511]

Yeah I asked him the same thing tryin to narrow down the problem. I think the only thing he said he put in was a turbo timer. I dont remember if he said he put in another radio or not. He was sayin that he might as well get an upgraded ECU like a Mines or something if he has to chhange it out. But like I said, hes not around now, hes down helping out with the huricane but I'll keep every1 informed as to what he plans on doing. Thanx