Idle rises than falls on its face...

[BrianC]

I have a 2g with the 1g engine swap. the evo III 16g turbo. engine built. blah blah unsure of what im exactly talking about.. well thats what it seem
bought the car while overseas she dropped her tune so i wentto strictly import motorsports got it retuned. (dsm link 2.5) the had found some boost leaks repaired them and so on.
PRIOR to that the idle would rise as it got warmer and once warm idle would be around 18-1900rpm... shortly follwing the high idle while driving after a while it would just fall on its face and kind of sound like a motorcycle, so i would turn the car off and start it (while rolling)and i would have all my power for a short amount of time till it falls on its face.

NOW since it was "fixed" it has happened again!
so what i found was the exhaust manifold was cracked so i replaced it with a stainless steel manifold that wouldnt crack (courtesy of SIM) and still having the same problem.. I re uploaded the tune just in case it was dropped when i installed my system.
NOTE Strictly import motorsports found a leak at the exhaust manifold the first time which is why i replaced the manifold this time due to a crack

Im new to this i can try to get more info to help anyone help me.

Can someone give me an idea of what to look for or what could be the issue? Is it an obvious boost leak?
CONFUSED

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[Dakota98talon_esi]

could be a boost leak man. because we all know dsm like their best boost and they like it right. i do a vaccum test on all your pipes, couplers everything warm soapy water works great. and let me know how it goes from there. have you checked all your plugs and plug wires? make sure their all connecting good?

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

 

[Dakota98talon_esi]

i just recently dropped a new engine in my 2g talon, i found a forum for all the wiring harness stuff, but do you guys have any idea about all the vac lines and fuel lines where they go and all that bs?

 

[BrianC]

could be a boost leak man. because we all know dsm like their best boost and they like it right. i do a vaccum test on all your pipes, couplers everything warm soapy water works great. and let me know how it goes from there. have you checked all your plugs and plug wires? make sure their all connecting good?

plugs and wires are fine. could bad maf sensor make my idle rise as the car gets warmer? i dont know how i can pressurize the system never done it before. i would like to know a quick way its something i should know.

got a datalog and sent it to strictly imports waiting on a reply

 

[DSM1491]

Good luck on trying to find the problem. Let us know what was wrong when you find out

 

[Dakota98talon_esi]

Good luck bro! And it could be your maf.

 

[BrianC]

Good luck bro! And it could be your maf.

So i cleared all DTC's "mass airflow sensor malfunctioned CEL"
and i do still have the high idle when warm. but it hasnt fallen on its face yet. That CEL must of been messing with the ECU im assuming? if that sounds right. Besides the fact it must be a faulty sensor if it malfunctioned which it hasnt malfunctioned again.... YET

so the high idle (as it warms it rises 900-1850rpms and holds)
should be boost leak maybe something in the throttle body?
you think i could spray down the system with soapy water and drive on it to check for bubbles although un accurate. i dont have anything to pressurize the system let alone really know how to do it or how to make the 8-10 dollar tool.

and for anyone with ecm link that could take the time and look at my log please do its right under my last picture

 

[WES_393]

Before even looking at the tune, you need to be 100% certain there are no boost/vacuum leaks and the idle is properly adjusted. If you don't have an air compressor, you can use a gas station air pump for testing. Your throttle position isn't being logged which could easily be a part of the problem. Check to make sure the TPS is plugged in and there's no obvious damage to the wiring. But your front O2 and MAF sensor appear to be functioning properly, so I wouldn't assume they're the problem. For now just get the TPS working, the boost leaks fixed, and the idle adjusted properly. Here are some links to help you out.

How to do a boost leak test- Testing for Intake Boost Leaks

Where to buy boost leak testers- Intake Leak Pressure Tester

How to adjust idle- 2G BISS Adjustment

 

[BrianC]

Before even looking at the tune, you need to be 100% certain there are no boost/vacuum leaks and the idle is properly adjusted. If you don't have an air compressor, you can use a gas station air pump for testing. Your throttle position isn't being logged which could easily be a part of the problem. Check to make sure the TPS is plugged in and there's no obvious damage to the wiring. But your front O2 and MAF sensor appear to be functioning properly, so I wouldn't assume they're the problem. For now just get the TPS working, the boost leaks fixed, and the idle adjusted properly. Here are some links to help you out.

How to do a boost leak test- Testing for Intake Boost Leaks

Where to buy boost leak testers- Intake Leak Pressure Tester

How to adjust idle- 2G BISS Adjustment

You my friend are my new pocket mechanic. ill let you know what i come up with in the morning.
im gonna go make a boostleak tester ( pvc end pressure gauge and coupler) see what i got going there. as for the TPS im sure its plugged in ill double check ill let it warm and adjust idle.

one more thing if my TPS is plugged in than what?

 

[WES_393]

If the TPS is plugged in but not logging in DSMLink, then I would start by testing the TPS itself. You can read how to here: http://www.dsmtuners.com/forums/newbie-forum/323258-how-do-i-test-my-4-wire-tps.html#post151742361

 

[Colt4G63 also]

I would log TPS, check boost leaks, adjust the biss and TPS, and check your tire diameters.

 

[BrianC]

If the TPS is plugged in but not logging in DSMLink, then I would start by testing the TPS itself. You can read how to here: http://www.dsmtuners.com/forums/newbie-forum/323258-how-do-i-test-my-4-wire-tps.html#post151742361

i dont have a scan tool

 

[BrianC]

Problem solved. did a boost leak test. the iac itself was missing 2 screws. leaking at just 10 psi. Also your gonna laugh... back between the firewall and engine therrewas a 12-10 gauge wire black with yellow stripe....ground?
anyways i reconnected it. adjusted my biss and now its running great.. 21 psi on a winter tune. thanks guys!

 

[Jakes 93GSX]

Yes I had a similar problem. After getting my clutch back in mine would rev real hight about 1700-1900 and drop to normal then surge again. My problem was a bad knock sencer and a few boost leaks

 

[BrianC]

http://www.dsmtuners.com/forums/wel...62262-gsx-saginaw-michigan.html#post153250579