Idle problems

Basic tech questions such as future setups, different turbo kits, car diagnosis, etc
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zlatsky
240sx Wannabe
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Joined: Sun Sep 26, 2010 6:25 pm

Idle problems

Post by zlatsky »

I recently did a manual swap along with dropping in a working DE motor but it will not idle correctly. I thought it was the auto ecu but I just swapped it out and nothing has changed. It seems to be like a big vacuum leak as the second the car is started, it'll rev up to about 1.5k and then drop down immediately where it will sputter until it dies. If given gas, it'll be resistant until it hits 1.5k and then it will rev normally. The car's EGR has been completely removed but at this very moment it is running open header as I have not yet had a chance to put the exhaust on.
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Kevin.Burmeister
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Post by Kevin.Burmeister »

Well... from my experience of swapping my trans from auto to manual in my vert, I just took the tranny computer out and threw it away. lol it runs like a dream. When you say that it runs fine above 1.5k then I definately agree that you have a vacuum leak problem. Manifold vacuum gets low enough around 2k in a N/A (and most boosted) engine that it doesn't really take advantage of "leaks" in the manifold. Check the backside if the block/head to make sure all the vacuum lines that go to all the solenoids for the evap system are good. When I pulled my entire system out I still had 2 vacuum sources from the manifold I had to cap off, so if you pulled the egr off make sure you tied up all your loose ends.. and of course having an actual exhaust you can hear vacuum leaks over helps a lot in the process. Happy hunting! :lol:
I am new to this whole trubo KA thing.. so the help is appreciated. >_<
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92' 240sx vert
Manual swap
KYB coilover (junk)
Sparco seats and 4 point harnesses
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zlatsky
240sx Wannabe
Posts: 107
Joined: Sun Sep 26, 2010 6:25 pm

Post by zlatsky »

Thanks for the help man. It's much appreciated.
Mercury_Hg
Dreams of owning a 240!
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Post by Mercury_Hg »

zlatsky wrote:Thanks for the help man. It's much appreciated.
Buy a can of starting fluid and start spraying it around your bay. If your engine revs, you're in the vicinity of a leak. I've got a mild one behind my intake manifold.

I did have a huge one coming from one of my brake booster hoses that I cracked replacing the IACV. Got it replaced from a Nissan dealership and my car doesn't try to throw me out the window at idle anymore.

Also, in the meantime, maybe you could set a high idle with the IACV screw (i.e. 1.5k RPMs). Wouldn't have to deal with the anxiety until you get it fixed.
zlatsky
240sx Wannabe
Posts: 107
Joined: Sun Sep 26, 2010 6:25 pm

Post by zlatsky »

Sprayed around the bay, found a couple of leaks around the intake manifold and fixed them all, but I still cannot get the car to idle correctly. It drives completely fine but idle is still terrible. Sound like bad cam timing?
Mercury_Hg
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Post by Mercury_Hg »

zlatsky wrote:Sprayed around the bay, found a couple of leaks around the intake manifold and fixed them all, but I still cannot get the car to idle correctly. It drives completely fine but idle is still terrible. Sound like bad cam timing?
Could the distributer be off? Check your timing!

Have you tried adjusted your IACV any?
zlatsky
240sx Wannabe
Posts: 107
Joined: Sun Sep 26, 2010 6:25 pm

Post by zlatsky »

I messed with the IACV for a good bit and it did not change anything. Also messed with the ignition timing to make sure it was all right and it was.
Mercury_Hg
Dreams of owning a 240!
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Post by Mercury_Hg »

zlatsky wrote:I messed with the IACV for a good bit and it did not change anything. Also messed with the ignition timing to make sure it was all right and it was.
When you checked your ignition timing, was the car at 650RPMs? Was your TPS disconnected? I dunno how advanced you are with these cars, I'm just a novice.

It might help to upload a video or audio clip of the car running. Someone more experienced would probably be able to chime in.
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Rick
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No... I don't own a 240 anymore!
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"Don't remind me of my failures, I haven't yet forgotten them"
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