UPDATE August 9, 2013: Ian (EVOMS) and Cole (RaceCo) convinced to keep going by so we did a few more rounds of troubleshooting. After loading on a fresh tune the car has been trouble free for over 150 miles. I think we're on the right track now (pun intended).

UPDATE July 24, 2013: Fought the good fight, but this adventure is over.

UPDATE July 8, 2013: Picked up the car from RaceCo and we made it about 25 miles before the CEL was back. I pulled over and tried to talk to the her- see what was going on. She just stared at me. Wouldn't say a word. I've been in relationships like this before... they don't end well.

UPDATE June 20, 2013: New intercoolers have been installed and RaceCo reports the car is running much better. Still trying to determine why the car's sport button is not functional. Attempts to "eat my feelings" have failed repeatedly.

UPDATE: June 14, 2013: Car is currently at Race Co (inside the Miller Motorsports Park in UT). So far they have found a hole in the intercooler. I try to stay upbeat by driving my Matchbox 997 around a 1/24 scale model of the Miller Park I made out of construction paper. Moral is low, but I found an uneaten Oreo on the floor a few days ago and I have been nibbling on it while I "drive." It helps.
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Alright, my first chance to ping the collective!

While I don't have any major issues with my car I do have one small nagging problem. I will describe the symptoms and would be grateful for any insight / help.

1. Unsteady idle. When the car is warming up somethings the RMPs bobs a little (about 100 RMP variation)
2. Idle creep. After driving for awhile the idle creeps from about 750 up to around 790 RMPs
3. When I brake in neutral (while moving) the RMPs climb to about 1400 and then drop again as I come to a stop (EDIT: After more testing it looks like the RPMs climb when slowing even if the brake is not pushed).

I have been talking to Robert at EVOMS (a great bunch of guys, but by the way) and he suggested looking at fuel trims. The LTFT are definitely too positive suggesting that too much air is getting in and the car is adding fuel.



One other bit of info: If I leave the car sitting for a few days and then start it up it doesn't exhibit any of the issues above initially (they start again after awhile).

If I was a betting man I'd say there's an air leak somewhere. Thoughts? Any idea where I should start looking? Other suggestions (i.e. O2 or MAF sensors)?

Thanks in advance,
Cam

UPDATE (5/13/2013): A buddy suggested it might be a brake booster that has a leak. We traced the vacuum line (as best we could) and it looks okay. Short term fuel trim values while braking are pegged at 0 (otherwise they seems to fluctuate normally at +-3). Braking feels normal.

 

Nobody, eh?

I noticed I had a BCM air filter and had read about associated MAF problems. I had a few minutes so I checked the MAF sensors. Car was warmed up. Key on voltage is a little more than 1 volt and engine running voltage is about 1.3 volts. That seems like correct operating parameters (if not, please let me know!). Probably not a MAF issue.

I should have a chance to smoke test everything tomorrow and we'll see if there's a leak.

 

Reads like an air leak.

I'm unfamiliar with the BCM air filter setup.

Generally there can be a problem with some aftermarket air filters, air boxes, in that they can oil the MAF, or can allow hot air from the engine compartment into the intake, or in some cases can interfere with the incoming air obtaining a suitable laminar flow before it reaches the MAF.

Non-laminar air flow at the MAF can cause the MAF to mismeasure the amount of air the engine is ingesting.

If you do not find an air leak, you might consider the intake air filter and air box, etc.

 

At this point, I agree. It's got to be an air leak (didn't get around to doing a test yet). I talked to a shop yesterday who had another EVT 775 with an intake leak. He said the leak was so deep it ended up being an "engine out" job .

No CELs or anything so I don't feel like it's urgent (I'm pretty sure I just cursed myself there...). Long terms fuel trims are high, but they actually went back down to 14.

Oh, whoops- "BMC" is what I meant to write (lot of threads on it). If there ends up being no air leak I'll poke around the air intake again. Thanks for the reply!

Cam

 

Okay, quick update. Robert (EVOMS) called me the the other day. He said other EVT builds had been having similar issues as mine and said they suspected the IPD plenums used in some of the newer builds had leaks around the fittings. On the back of the plenum are four metal fittings that are screwed in (well, one is pressed in). He told me to take out the plenum and JB weld around the fittings to make them air tight.

I'm used to working on my Chevy's so this was interesting (not a lot of wiggle room) but I got it out okay:



I took out the fittings and JB-welded the threads and then, once they were reseated, coated around the exterior. They didn't seem like they would leak but who knows (just bare threads when I took them out- no sealant or anything so maybe).



More interesting to me were the zip ties used on some the hoses going to the fittings. I don't trust zip ties so I replaced them with hose clamps. I also reseated some of the other clamps since they weren't adjusted quite right.

Wonder if it will make any difference? I'll find out later I guess (once the JB Weld sets). I did let the engine idle a bit and it seemed nice and smooth (but these things can totally be in your head- I know). I hate doing things that don't help...

 

This is quite interesting as I have had similar issues with my build that was completed one year ago. My car has been in the shop in Denver for the past couple of weeks for a variety of mods but also to resolve a persistent CEL that would recur every 200-300 miles that seemed to indicate an air leak(s) near the throttle body. They ruled out MAF and O2 sensor issues and now think (hope?) that after multiple smoke tests and adjustments they have it solved. I know they spoke with Robert at Evoms so perhaps they were made aware of the plenum possibility as well but I didn't have a chance to speak to my mechanic as he wasn't around today when I picked up the car. Anyway, I'm driving to Road America in Wisconsin on Wednesday for a 3 day DE so it will get a robust test. I'll keep you posted once I have additional information. Best,

 

Actually Robert mentioned your car. He said your plenum was one of the things that was leaking (based on my recollection). What CEL does your car throw? I hope you can get it resolved- if you do please let me know where they ended up finding leaks.

In case anyone is curious I test drove my car. My work didn't make a difference . Still have unsteady idle and RMP jumping when I decelerate in neutral. The only saving grace for me is that I don't have any CELs and the car drives just fine (as far as I know).

I had a chance to smoke test the car and I didn't find anything, but the machine I used only went to about 12 PSI. I need to do more comprehensive testing with higher PSI's like THIS. Maybe next month. But mark my words, leak. You can hide but I will find you. And when I do... there will be no mercy.

 

Here's what I leaned after perusing my invoice later today......

"...unmetered air entering after the mass airflow sensors. Performed smoke test of intake system. Found smoke leaking from bolt that holds boost pressure sensor into IPD "y"-pipe. Installed thread sealer to bolt. No smoke leaking after repair. Smoke tested turbocharger intake pipes and intercooler pipe work. No leaks found for bank one or two. Road tested vehicle over weekend. Found CEL after two days of driving. Faults recorded for unmetered air. Removed IPD "y" pipe. Pressure checked "y" pipe with high pressure. Found leaks in aluminum plugs installed by IPD. Installed sealer over plugs to stop air leaks. Reinstalled "y" pipe. Road tested. No faults returned.

I drove the car 150 miles today without getting a CEL. The car ran fine but I'll put on 2500 road miles and 500 track miles this week so we shall see..........Let's stay in touch.

PS My idle exhibited similar symptoms as yours. Today, that seems fine which gives me hope. I don't know what code was thrown.........between PIWIS, Durametric and whatever diagnostic system my shop uses, I think the comparability is somewhat limited. I've purchased an OBD 2 scanner that I'll start using if the CEL pops up again this week. The good news, I think, is that this is a fuel-rich condition. While not optimal, it won't blow up a motor like a lean condition will on the track......

 

That's interesting. Is there any way you could find out how they recorded these faults? I've had my car hooked up to a PIWIS and I've got a Durametric but none of them actually show a fault for unmetered air.

I don't have an IPD Y-pipe, otherwise I would look for leaks there. At least my plenum is air tight

Hope all goes well on your trip!

 

[QUOTE=UTPorsche;3852931]That's interesting. Is there any way you could find out how they recorded these faults? I've had my car hooked up to a PIWIS and I've got a Durametric......

PM sent.

 

The saga continues (I know, I know- I need to do a comprehensive air leak test). Ran a quick errand last night and the car started going a bit nuts. I have driven this car nearly every day- nothing special about the drive last night. Well, except this:

When rolling (in neutral, foot off clutch):


The idle got stuck at about 1100 RPMs too (this is stopped, in neutral, foot off clutch).


I knew what was going to happen next:



At first the OBDII port was totally unresponsive- I could not communicate with the car at all. I locked the car, let it sit for a half hour or so and gave it another shot and it was working (has anyone ever encountered something like that?).

Pulled from a code reader:



And the Durametric info:



I feel like maybe I'm looking at something bigger than an air leak... any other ideas (I will still do the pressure test, but maybe there's something else I should be doing as well)? Anyone seen anything like this before?

Forgot to mention- I unhooked the car's battery last night and then hooked everything back up this afternoon. The car is now running like it was before.

 

Cam...man Im sooo sorry to see you are still having problems. I am eagerly waiting on the outcome of your situation. I have to be honest...my car exibited some of the exact same symptoms STRAIGHT off the truck from EVOMS...so there is a hope that some of the little things thT started y o u down this path are normal. Since the very first time I ever drove my car (after being at EVOMS for 5 weeks) the idle at start up was just a hair eratic...till it warmed up...the idle would also hang JUST SLIGHTLY coming to a stop. Sooooo maybe thats just how they run? I dont know....
What I do know is my equally modified Protomotive tuned 996 GT2 was straight percect as far as the tune and driveability went. Im not a tuner OR mechanic for that matter but I know cars and have owned only modified cars cor the past almost 20 years....fact is some tunes are just better than others. I chalk my "issues" up to tuning.
Just because Im curious. ...im going to ask my local guy (a guy who I have no bad words for and a Porsche fanatic) to give mine a once over...ill post up my findings.

 

Sorry to hear about your problems guys. Is there any chance your tune doesn't "know" that you have the IPD Plenum installed? Not likely but I do recall reading some time ago that if you install the IPD Plenum and larger GT3 throttle body that the tune has to be adjusted otherwise the idle will be off. Just a thought...

 

LOL, it's part of the game! To be totally honest the car has thrown these codes before shortly after I got it. I figured I had done the throttle adaptation wrong. I reset the computer and it drove (mostly) fine for 700+ miles. Then last night- bam! I reset it again and it's running fine (well, as fine as it has run since getting it).

That's interesting. I've talked to a few other EVT 775ers and they don't seem to have these issues.

Agreed. And I don't wait to point any fingers and I've got nothing negative to say about any tuner, but I'm wondering if - like you say - part of these issues are tune related.

That's what I'm doing- I finally found a semi-local place to take my car to and in a couple of weeks they'll go over everything with a fine tooth comb. I DO expect them to find a leak somewhere, but I don't expect that will be the end of all my issues. You never know though.

I think we must like the pain! The tune I have is, as I understand it, adjusted to accommodate the IPD Plenum which is part of the EVOMS build.

I'm just hoping someone hops on here and goes "OH FREAK YEAH! That same stuff happened to me and it was the [magic cure goes here]." I should check my warp core. Something always goes wrong with those.

Cam

 

Maybe you can eliminate the IPD and go back to the stock part to see if that's the problem?