Non-Stop Serious Idle Surge (Video)

[Clinical]

Ok so I know what a bunch of possibilities are, but figured I'd post here to see if off the bat anyone knows what I should check first.

Just got my new 1g home today, and I need to source this bad idle surge issue it has. It idles fine until it warms up and then it'll do this constantly. It will never idle normal once it's warm.

I just want to see if anyone has perhaps had this identical problem or something so I can have an idea of what to pursue first. With negative temps I don't want to spend more time in my garage than I have too haha.

here's a video of the issue, any advice is appreciated - thanks
[ame=http://www.youtube.com/watch?v=EQ1Ugim901w]YouTube[/ame]

 

[Chad1993]

Video is private.

 

[TallestHERETIC]

This ought to get you started:

http://www.dsmtuners.com/forums/articles-engine-fuel/191137-how-fix-your-idle-surge-problem.html

 

[Clinical]

sorry about that ,video is fixed

I'll be going through the listed things in that link tomorrow. Just was hoping by the specific way it's surging someone would have an idea what to check first since I've had idle issues before that I traced but nothing as serious and consistent as this one.

 

[pauleyman]

That isnt bad, thats just what idle surge looks like if you have it. Well documented. Start with leak tests, biss adjustment etc. Test isc motor.

 

[Clinical]

any other surge I've had was much less intense or not as consistent - maybe I was just lucky.
Will start going through the steps tomorrow for sure.

 

[Clinical]

Well I re-adjusted the biss to no avail.
I checked the ISC coils with my voltmeter and they all appear to be okay, but it just seems like every other person who has had the identical issue to me has been the ISC - so a buddy who works at Advance Auto is getting me one to throw on tomorrow and see if it fixes it and if not letting me return it.

I did a boost leak test, it holds solid to 10psi and then leaks super fast out of the passenger side weld bead on my intercooler. I'm going to be getting a friend to weld that for me on Thursday. However being that the car holds pretty solid up to 10psi I can't imagine that could be my idle issue.

The car does have the throttle body coolant bypassed.

I pulled up dsmlink and if I disable the idle switch or disable TPS adjustments it idles at 3k rpms and doesn't move.

Also here is a datalog with my idle and some revving at the end of it, if anyone wants to open it and tell me if anything just in the datalog looks off.

Thanks for any more help, heres to hoping the ISC fixes it! If not I suppose I might look into the TPS next.

 

[pauleyman]

Isc will not fix it. Wanna guess why it idles at 3k?

can't imagine that could be my idle issue.

Wanna bet?
You cannot add additional air after the mas. Worst case car dies but with small leaks idle rises...then at 1500rpm ecu notices ips is closed and cuts fuel. Idle drops below 1500, catches goes up again....repeat. it is the very definition of idle cycle. Put the coolant hoses back also.

 

[Clinical]

It literally doesn't seem to leak hardly anything past 10psi, so would that really effect it that much at idle? On my old car I had the tb bypassed and massive boost leaks not holding even 5psi and it idled perfect.

I just really dont see how a car that holds 10lbs and then leaks will have such a bad idle issue from it.
It seems like it has to be the ISC/TPS or something.

Edit: just went out and tried to just hold my hand over the pinholes, no change.
Also the car has never stalled or even comes close to stalling.
During warmup it'll just hold about 1800-2000rpm high idle then start doing its surging. 1000-1600/1700

 

[pauleyman]

Youre right, it has to get past the throttle plate. So that leaves only a handful of possibilities. Fiav, isc, gaskets, biss, and isc control. And again, put the coolant lines back.

 

[Clinical]

Well tested a brand new ISC today, no go. Intercooler boost leak is welded now. Just took off the throttle body, gaskets all good. Cleaned the throttle body as well. Throwing her all back together in a bit, heres to hoping she finally will idle normal. If not I'm going to try to source another TPS / Idle Switch to try. I go back to my university Friday, and I know campus police will have a field day over my car idling like this haha.

Edit: Threw it back together after cleaning TB and went ahead and put on a new throttlebody gasket. Still surging, blah.

In DSMLink, it is selected to simulate idle switch from TPS - should that mean the idle switch isn't doing anything anyway? Unplugging the idle switch physically does nothing. Unplugging the TPS it just revs to 2700-2900 and holds there.
So i'm essentially leak free. I'm pretty much down to the TPS or Idle Switch from what I can see. This thing is driving me nuts.

I've had coolant bypassed on my last two project DSMs and have never had issues. But I suppose I can go ahead and pick up a couple new hoses and try setting it it back up with stock coolant to the TB again. I know I've heard it can cause issues during warmup but never have heard of it causing any non-stop constant surge like this.

Adding to this, when I put the throttle body back on and went to drive it - for the first time I had a check engine light come up for a split second and when I went to take off I had almost no throttle, it just kind of would rev barely and then go back to idle surge if I gave it any gas.
Pull up the DSMLink and shows TPS malfunction. So I'm really getting a good feeling now about the TPS being the issue all along. New one will be here tomorrow, lets hope this does it.

 

[EGLTAWLN]

why does he need to put his coolant hoses back on?
could you give us a reason?

 

[spyderdrifter]

Just as a possibility, maybe check you bov. I was doing boost leak tests on mine a few months ago and found my fuel pressure regulator line would pop off the fpr at 12psi. So I fixed that and then since that didn't leak, pressure built to 15psi then my bov did the same. Found the bov to be weak so I replaced it. No surges after, even though I thought it was something major.

 

[pauleyman]

Fiav doesnt work properly without hoses. And no you are not leak free. Car couldnt idle that high with the throttle plate fully closed. Isc, biss or fiav have to be letting air past (its their job) but it must be controlled. Rght now yours isn't.

 

[xuberantz]

You have a vacuum leak, had a similar issue that didn't show up under my initial boost leak tests but turned out to be a lower injector seal.

 

[TSI_AWD_FTW]

It sounds to me like an electrical issue, since the car runs fine cold, and only has issue after the engine is hot. try swapping out your cas with a known good one. It sounds like your timming is way off by the video.

 

[Clinical]

Just as a possibility, maybe check you bov. I was doing boost leak tests on mine a few months ago and found my fuel pressure regulator line would pop off the fpr at 12psi. So I fixed that and then since that didn't leak, pressure built to 15psi then my bov did the same. Found the bov to be weak so I replaced it. No surges after, even though I thought it was something major.

Well with my intercool welded the system holds good to 20psi. I'd hope my BOV wouldn't leak since it's a Dodge Modded 1g haha. Always that chance but at a 20psi system I'd say shes pretty good.

I took my throttlebody off again tonight and read on how to test my TPS. It seems I have a dead pin in it that I'm getting no reading off of. The other pins are not giving anywhere near correct readings when I go closed->open throttle, they are only somewhat accurate at closed throttle.

Really is looking like TPS is the culprit.

Fiav doesnt work properly without hoses.
If And no you are not leak free.

I was referring to boost leaks. Also, my FIAV is essentially eliminated as it is..
I'm just confused by the whole needing to run my coolant hoses again, because a lot of people eliminate their FIAV to get rid of idle surge in the first place.. If I'm correct, if the FIAV was an issue I would be having warmup idle issues, not constant - am I wrong?

You have a vacuum leak, had a similar issue that didn't show up under my initial boost leak tests but turned out to be a lower injector seal.

I haven't actually checked for vacuum leaks yet, this will be my next step tomorrow if the TPS doesn't fix it - lucky my car actually has

It sounds to me like an electrical issue, since the car runs fine cold, and only has issue after the engine is hot. try swapping out your cas with a known good one. It sounds like your timming is way off by the video. few vacuum lines left (for a turbo car) so shouldn't be hard to check them.

To be fair I'm thinking it has the issue during warmup too, it's idling above the maximum surge point during idle (so around 1900-3000rpms during warmup) so I think the issue is still present, it's just not noticeably surging because it idles so high while warming up.

I think it's doing this pretty much the whole time.

My problem here is that I don't know anyone with a DSM around let alone a 1g to share parts off of, so just swapping parts is no easy task for me.

If this TPS doesn't fix things tomorrow, I'll start looking into all my vacuum lines and my timing.

Will mention too since I don't think I did already, the car drives absolutely beautifully on the road, although at low rpms it still is trying to surge while I'm driving below 2000rpms. However when cruising around the car is perfect and runs like a dream.

 

[xuberantz]

I took my throttlebody off again tonight and read on how to test my TPS. It seems I have a dead pin in it that I'm getting no reading off of. The other pins are not giving anywhere near correct readings when I go closed->open throttle, they are only somewhat accurate at closed throttle.

Really is looking like TPS is the culprit.

You can use Ecmlink to get a sweep of what the TPS is doing by voltage. You should be getting around .63 at closed throttle (if your TPS offset is set right, or you can physically loosen the screws and adjust). With the accelerator cable properly adjusted you should be close to or at 5v at WOT. It should rise as you press the accelerator. You can do this with the car off. You can also log the idlestopswitch to ensure it's showing 1 when you have your foot off of the gas as you have it set to emulate it based off the TPS.

 

[Darksun280]

Am I way off thinking that it could be your T-Stat or somthing related to coolant temp? If its not working right the car always tries to go for the cold start idle and bounces around. Worth a shot. It's happened to me on a couple cars.

 

[Clinical]

Seems I have a much bigger problem now.

So brand new TPS. Still throwing a CEL code for the "Throttle Position Circuit malfunction".
Also ever since I took the throttle body off and put it back on, and even now - it doesn't register any throttle input. Full throttle it shows no TPS % at all in dsmlink, the car just chugs and goes lean so it's not receiving any signal for the throttle so its not putting in any fuel.

Logging on DSM Link occasionally it'll show about 20-25% TPS input while I'm revving it, but it never shows 100% even though I'm going WOT.

I'm completely lost.


heres a video of it currently
[ame]http://www.youtube.com/watch?v=2hZlteHAY3Y[/ame]

 

[spyderdrifter]

Have you checked your TB shaft seals at all? Just another thought. If you're getting all these issues, I would ignore DSMLink for now and use the traditional multimeter to test each component for proper operation.

 

[Talon64]

is the idle set screw set correctly? I know on my 1g non turbo I just picked up the idle set screw was turned into far. I back it out and runs perfect and yes it had the idle loop like yours. Idle set screw is what you first unplugged in the beginning. Also the iac has a o-ring and they do rot. boost leak I couldn't find it but starter fluid fixed that. If you have a can of starter fluid laying around spray near your injectors and make sure they aren't sucking in air. Just my quick .02 cents

 

[spyderdrifter]

I had the issue with my injector o-rings at one point too. Bought new ones and the leak was gone.

 

[Clinical]

Thanks for the advice all, going to try tomorrow morning going back to step one I guess since I don't know what else to do.
I found a broken wire beneath the wrapping for the TPS sensor which is why I was getting a CEl for it and it wasn't responding to any throttle. Fixed it and it at least is reading the throttle again and I can drive it to an extent.

I need to leave town around 11am to get to my university around 2pm tomorrow and the talon is my only vehicle, so fingers crossed it makes it at least. Shit thing is I have an extreme lack of tools / working space up there so I'm going to try to wake up early to try to do a once over in the morning and pray I find something.

Only thing I haven't checked at this point are shaft seals that I know of. At least the TB is easy enough I can just take it in the house for the job if it is.

 

[spyderdrifter]

Well good luck, hope your Talon works out. Hopefully you'll figure this surge out.