LSXMisfit
04-03-2011, 02:56 PM
I recently bought a 240SX from a friend of mine, for almost nothing. Car works for the most part, some quirks, but nothing absurd. The biggest issue right now is the idle. It doesnt matter if its a cold start, hot start, its idle rough, almost like a V-8 with a good sized cam. It fluctuates between 700 and 1200 rpm. Its like the engine idles then theres a slight hangup where it pauses and torques/shakes for a split second, then back to idle.
And just today it started spiking all the way up to around 2000 rpm when I would push in the clutch prior to stopping, and stay that way until either a short period of time, or I started driving.
Perhaps I should stop here and say, I'm a transplant from the LSX community, I used to drive a 04 GTO, I know nothing about this car.
Anyways, the engine is rattling around quite a bit, more than my LS1 ever did. I did some reading and a few people have talked about the engine coolant temp sensor for the ECU along with the MAF or IACV. I have a new temp sensor, just havent installed it yet, but heres where I'm stumped.
If i disconnect the temp sensor, it idles smoothly for the most part, sounds like maybe an ever so slight cam lope, but its hard to tell. Right around 900-1000rpm, havent looked at the tach to verify, but thats what it sounds like. If I disconnect the MAF, same deal, smooth idle, barely noticeable pause every few seconds. Im not sure where the IACV is, I can get a new one for 45 bucks, I don't know how to tell if thats bad.
And as the final piece, I know the injectors were swapped out at some point, I have the stock set that the guy I bought the car from held onto, no idea whats in there right now. But I dont think its the injectors if the car is idling near perfect with the maf or temp sensor unplugged. Thoughts?
Appreciate whoever is willing to help me out with this.
And just today it started spiking all the way up to around 2000 rpm when I would push in the clutch prior to stopping, and stay that way until either a short period of time, or I started driving.
Perhaps I should stop here and say, I'm a transplant from the LSX community, I used to drive a 04 GTO, I know nothing about this car.
Anyways, the engine is rattling around quite a bit, more than my LS1 ever did. I did some reading and a few people have talked about the engine coolant temp sensor for the ECU along with the MAF or IACV. I have a new temp sensor, just havent installed it yet, but heres where I'm stumped.
If i disconnect the temp sensor, it idles smoothly for the most part, sounds like maybe an ever so slight cam lope, but its hard to tell. Right around 900-1000rpm, havent looked at the tach to verify, but thats what it sounds like. If I disconnect the MAF, same deal, smooth idle, barely noticeable pause every few seconds. Im not sure where the IACV is, I can get a new one for 45 bucks, I don't know how to tell if thats bad.
And as the final piece, I know the injectors were swapped out at some point, I have the stock set that the guy I bought the car from held onto, no idea whats in there right now. But I dont think its the injectors if the car is idling near perfect with the maf or temp sensor unplugged. Thoughts?
Appreciate whoever is willing to help me out with this.