Weird idle/RPMS in 1st/2nd Gear (Video!)

Eagle96TalonTSi · Dec 21, 2012

[ame=http://www.youtube.com/watch?v=ER_XBC-zCyk]Tsi probs - YouTube[/ame]

Been having this problem for some time now. I believe it to be an accessory to the engine as the engine runs and drives fine and pulls like a scolded dog. Never smokes or anything like that. Turbo has zero shaft play and I have NO boost leaks whatsoever. I fixed every boost leak and have retested twice since then and my boost holds at 15 psi easily.

The video pretty much says it all. I have yet to attain a consistent idle with no misfiring sound or anything like that. Even when the motor is operating temp, it sounds like theres a misfire somewhere. Ive got brand new plugs/wires in so it cant be that.

What I try to explain in the video while driving: That bogging noise that almost kills the car, it happens when I first start and drive the car. When I take it past 1000 RPMs it makes a bogging noise, so I have to push the clutch back in and rev it to warm the motor up a little bit. I cannot simply start the car and let it sit and idle to warm up, because it dips down like the video shows, and I do not want to tear the video up.

Tomorrow I am replacing the front o2 sensor, getting a new/better ground on the battery, and getting a better look at the starter and wiring.

What could it be?

Its probably something simple, because after the car warms up it runs fine for the most part, except inconsistent idle sometimes and a slight misfire here and there.

?!

Riceburning101 · Dec 21, 2012

I had to play with my biss screw to get my idle nice. The cold bog is common turbo cars like to sit a little bit and warm up before they behave. If you have the biss screw backed out to much it will cause the ISC to be retarded and jump all over. As for your drain/weak start we all know DSM's have wonderful grounding issues. Have you checked the voltage at the battery with the car running to make sure your alternator is pushing enough voltage out? After you get the new ground to the battery it might help. I think you need to work with the biss screw a little. here is a good link for the idle that you may find helpful.
Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

citymunky · Dec 21, 2012

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

Eagle96TalonTSi · Dec 21, 2012

So it's idle surge?

I speculated this, but it happens while driving. I guess I will check the plugs/injectors and start from the top of the list.

Anyone know where I can find an oem isc and how much they'll run?

Riceburning101 · Dec 21, 2012

you can test your ISC
http://www.dsmtuners.com/forums/articles-tuning-ecu/386663-dsm-isc-motor-testing-replacement.html
If not dealer, rockauto, tons of supporting vendors carry OEM or used OEM

undefined0000 · Dec 21, 2012

This was my car

https://www.youtube.com/watch?v=e4FCIjTMxCY

I changed the intake manifold gasket and plug wires.

Check the ohmages on your ISC pins, check the ones right next to eachother, so
1 2 3
| | |
4 5 6
| | |

1,2 2,3 4,5 5,6

If any of them show infinite resistance, its a dead coil and you need another one, if you need one, I have like 3 good ones lying around.

wickedtalon93 · Dec 21, 2012

yeah i would first check to make sure you are getting the right voltage

Eagle96TalonTSi · Dec 21, 2012

Seems as if I am not as lucky as you were since I have changed one of the TB gaskets to no avail, and brand new plugs and wires. I have the other gasket for TB to Intake mani but that means ill probably need another gasket for TB> upper IC piping :/

I will take the TB off and do the other gasket and clean the TB top to bottom, check te volts on the ISC and go from there.

undefined0000 · Dec 21, 2012

Eagle96TalonTSi said:
Seems as if I am not as lucky as you were since I have changed one of the TB gaskets to no avail, and brand new plugs and wires. I have the other gasket for TB to Intake mani but that means ill probably need another gasket for TB> upper IC piping :/

I will take the TB off and do the other gasket and clean the TB top to bottom, check te volts on the ISC and go from there.

The one for the elbow should be metal, if not, invest in one. Will save much headache. When checking the ISC, you aren't checking volts, check for resistance.

95TalonTSI4EVER · Dec 22, 2012

Hey you said the N word. Instead say Ghetto rigged. I hope no black dsmers help you

Eagle96TalonTSi · Dec 23, 2012

Took my throttle body off and cleaned it spick and span.

Replaced both TB gaskets with new OEM.

Messed with the IAC I think? Little black thing on the front of the TB with a clip on it. Put it back on as close as I could to the marks I put on it but it seems to be idling a bit high, yet when first starting the car it was so low it almost killed the car. TB was pretty nasty so even though it didn't fix it I'm glad I got it cleaned up for the first time in 15 years. Also the TB > intake mani was a shitty rusted metal one. Replaced it with oem paper one.

I know I have a vacuum leak because the car whistles at exactly 1200 rpm on the way down to idling. Gonna fix that tomorrow, and new o2 sensor, and check the ISC. Also going to check and restore the throttle body idle control sensor thingy to factory. Then continue checking shit off the list.

Anyone know what it is in the intake manifold area that makes the "clacking" noise? Not tick, it's something else. Thanks in advance.

Wish me luck. I will need it and I'm refusing to give up. Just need to get this thing purring like a kitten so I can work on a 14b/accessories and the finishing touches on the exterior and I can sleep happy

undefined0000 · Dec 23, 2012

I had a clacking when my intake manifold gasket was blown.

The thing you messed with was the TPS.

UK-DSM · Dec 23, 2012

Just to add, I had an ISC that was very slow to respond to any changes. Even though resistances read good.

Replacing the ISC I was night and day. The ISC could make fast on the fly changes giving perfect idle.

I would not buy a used one. There's no point buying another old one. Rock auto has a good price. They are under air/fuel.

Make sure TPS is set correctly as the idle switch is voltage dependent not switch controlled.

EDIT: Also, is the fast idle air valve modified in any way? Still have the coolant lines to the TB etc.

Eagle96TalonTSi · Dec 24, 2012

UK-DSM said:
Just to add, I had an ISC that was very slow to respond to any changes. Even though resistances read good.

Replacing the ISC I was night and day. The ISC could make fast on the fly changes giving perfect idle.

I would not buy a used one. There's no point buying another old one. Rock auto has a good price. They are under air/fuel.

Make sure TPS is set correctly as the idle switch is voltage dependent not switch controlled.

EDIT: Also, is the fast idle air valve modified in any way? Still have the coolant lines to the TB etc.

Just put in 2 new TB gaskets and am still getting the clacking noise, but it goes away randomly then comes back.

Gonna try new ISC but I haven't gotten time to check mine. Put in all new trunk panels today because the previous owner cut big holes in my previous ones for a huge system.

Took out all of the wiring and stinger terminals today and replaced with all brand new shit, looks factory and definitely made an improvement. One step closer to cleaning this son of a bi*** up

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Weird idle/RPMS in 1st/2nd Gear (Video!)

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wickedtalon93

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