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· SC400 Newb
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Discussion Starter · #1 · (Edited)
Okay, so today was a rather hot day outside and I noticed something crazy about my idle. I was idling at 6- 700 and it was running 13.0~:1 A/F. It sounded quite different and not normal so I decided to pull the EFI and reset the ecu. So, I do this, come back, drive around for a while to try to let the ecu do its stuff, and I come back to let it idle, and it does not idle one bit.

So, I try and restart the car and am sitting there cranking away for 5 seconds or so. Nothing. :ugh2: I let it sit for a second, turn it over again, this time giving it a little gas, she starts, runs, but still won't idle. So I review everything under the hood, look for vac. leaks and IC hose couplings that might of fell off. Nothing.... I check wiring, seems to be all firmly in place.

So I drive it where I need to be, pull the efi again and go do my business. Come back and its the same as it was before......... So I cripple drove it home and here I stand. I checked a few other threads and a few ideas have come up.
1)My MAF took a shit dive
2)IAC - Cleaned, but still may be bad alltogether.
3)CPS jumped a tooth or two
4)My ECU took a shit dive with me pulling the fuse 1 too many times (my idea)
5)Spark Plugs - Checked and cleaned

Any and all ideas or comments welcome. But otherwise the car drives alright.....

Thanks,
Ryan
 

· SC400 Newb
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Discussion Starter · #3 ·
DrBowser3 said:
I may be wrong, but a friend of mine had a similar problem, pull the I-ac valve, and clean it.

Thanks :bigthumb: I shoulda thought of that. Needed a reminder. I'll give that a try tomorrow.


I wish it wasn't doing this to me now though haha. I was taking it in the morning for some work to be done on it so I could setup my MAP ecu hehe.


Also, anyone else with ideas, lmk. Open to try things.
 

· SC400 Newb
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Discussion Starter · #4 ·
It was a no go. I tried cleaning it and it looked ok, but I cleaned it anyways. Sometimes it wants to start, but doesnt. Like it wants to ignite but won't. Maybe my plugs are shot?
 

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Try pulling a vaccum line off the intake manifold when its off and then try to start the car. If it gets worse its probably a boost leak, if it gets better then you have a blockage in your IAC somehow.
 

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what does IAC stand for and what does it do? i searched, didnt find much.
 

· Super Moderator
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Idle Air Control - its that funky black round thing on the intake manifold right next to the coil packs with the 6 pin connector.
 

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oh thank you. i thought that was called idle speed control. is there one of those too? i feel stupid today. :lol:
 

· SC400 Newb
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Discussion Starter · #9 ·
Wreckless said:
Try pulling a vaccum line off the intake manifold when its off and then try to start the car. If it gets worse its probably a boost leak, if it gets better then you have a blockage in your IAC somehow.

Will try that and let you know

I did pull the plugs, they looked bad, so I was happy and got em looking pretty, and I put it all back together, and nothing still. When I kept it running it ran badass, but, it does not idle one bit still. Real low RPMs when I keep in the gas a bit, it sputters bad... Maybe that will help in ideas.
 

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Discussion Starter · #10 ·
I pulled the vac line, and tried to start it. Nothing happened still.... Hrmmm :rolleyes: Getting irritated at IT!! lol
 

· Your mom goes to college
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Spoolme said:
oh thank you. i thought that was called idle speed control. is there one of those too? i feel stupid today. :lol:
You thought right. It's called the ISC Valve, meaning Idle Speed Control Valve. Although it doesnt really matter, you are all talking about the same thing here.


Ryan- You said you "cripple drove it home." What were the problems along the way other than a poor idle? Have your vacuum readings changed at all? Some cracked or loose couplers can be easy to overlook. Common culprits include the ic hose coming off of the turbo, and the coupler between the 3000 pipe and throttle body.

Problems caused by leaks or an inoperable ISC valve typically cause either a low or high idle (sometimes fluctuating back and forth). Your idle speed of 600-700 rpms is ideal, which makes me think both your ISC valve and your ecu are working just fine. I'd give it about a 50/50 toss up of being either a large'ish boost/vacuum leak or an electrical problem. At this point it sounds like it could be either one. I know you said you've looked, but double check for loose/cracked couplers & hoses and also check your wires (including your grounds).
 

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Discussion Starter · #13 ·
highonoctane16 said:
You thought right. It's called the ISC Valve, meaning Idle Speed Control Valve. Although it doesnt really matter, you are all talking about the same thing here.


Ryan- You said you "cripple drove it home." What were the problems along the way other than a poor idle? Have your vacuum readings changed at all? Some cracked or loose couplers can be easy to overlook. Common culprits include the ic hose coming off of the turbo, and the coupler between the 3000 pipe and throttle body.

Problems caused by leaks or an inoperable ISC valve typically cause either a low or high idle (sometimes fluctuating back and forth). Your idle speed of 600-700 rpms is ideal, which makes me think both your ISC valve and your ecu are working just fine. I'd give it about a 50/50 toss up of being either a large'ish boost/vacuum leak or an electrical problem. At this point it sounds like it could be either one. I know you said you've looked, but double check for loose/cracked couplers & hoses and also check your wires (including your grounds).

Hey sup bro?

I "cripple" drove it as in I had to baby sit it at the stop light, and low speeds. I found out its the tps, and its real screwy. I got it to idle, but it idles real shitty, and wont rev past like 2k or so.
 
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