jptaylor

Any of you guys have a spare pair of MAFs they could send me to try??? Of course I would send them back to you if you didnt want to sell them....

Issue I'm having is once im in closed loop my car will stall EVERY time I come to a stop in gear(as long as I'm open loop it runs like a swiss watch)....I have to bump up to neutral and then shift to D and feather to leave a light to keep from stalling. Have had several shops look at it and the issue doesn't even set a code of ANY KIND, even when It stalls. The only thing it has ever shown was on one(and only one) occasion the log looked like one of the MAFs signal cut out for a split second but was then back like nothing ever happened. Since this is the only indicator that has popped up I'd like to throw a different pair of MAFs in there and see if it's the fix or if I need to keep digging.....thanks Guys

skratch77

I have a pair and also selling pretty new ones with my row boxes if you are interested. Also have stock throttle bodies and plate if you need that.

blurred

That sounds more like a transmission problem

If it is maf related you can unplug them to troubleshoot, if the car still stalls in the same low speed/stopped/light accel condition. If the mafs are fine and the transmission isnt causing it you should also look for a vacuum leak, but it sounds like you were already logging fuel trims to make sure they were low?

jptaylor

Everything looks absolutely perfect with every log we've run except for that one fractional blip with the MAFs.....
I'm curious though, does the TCM operate under loop parameters as well???

hachiroku

you didn't state if you have a tune or not. a tune can directly affect/cause this. if you do have. tune, are you able to flash back to stock to double check? aside from the MAF logging thing...if so i'm surprised the computer hasn't thrown a code if it is in fact the MAF.

jptaylor

RaceIQ dyno tune and it's been on board for years now....what gets me is that it is literally PERFECT at startup and up until closed loop, but as soon as it switches controls it does it every time.

And the computer is not seeing ANYTHING out of order whatsoever, NOTHING!!!!

Jasonoff

How old are your primary O2s?

EDIT: Also, if you had a small leak post MAF it would probably run fine in open loop then not once it switched to relying on sensors.

jptaylor

I'm an '09 so that would make them 12yrs old Jason my Friend......

hachiroku

The Motronic 9.7 always runs in closed loop. There is no open loop. If possible if you own a handheld I'd flash back to stock to see if that helps. Otherwise log your O2 sensors as well as MAF, MAP, and throttlek position sensoro and let us know the outcome.

jptaylor

On site dyno tune with Tony so I cant flash back to stock....I'll see if I can find the files but we logged EVERYTHING for prolly a dozen drive cycles and nothing is out of range....I thought that maybe the fuel filter was shot or the pump had gotten weak as when it is stalling out it actually diesels and sounds like starvation but the fuel pressure and flow are both freaking perfect.....

Was at one of the best indy guys shops on the east side of the country for over a month and they could get it to do exactly what I described but NEVER would anything actually flag....and they were using oscilloscopes, STAR and even flux-capacitor smoothing devices and STILL FREAKING NADA ON THE CAUSE!!!!

When Tasos and I talked about it about 2months ago he said that it wouldn't be like I was looking for a needle in a haystack but like looking for A needle in a stack of needles, he's been right thus far

hachiroku

i see...well if we're able to https://datazap.me/ and possibly see any trends with your logs that may help. when my o2 sensors were failing...there was a point where after 20 minutes of driving one of my sensors would become lazy.

as far as the MAF's and signal cut...if your engine stumbles, your MAF values will drop...more than likely its occurring because of another issue and is simply displaying the drop in airflow across the sensor. MAF's shouldn't have dead spots...they'll either be off entirely or not work as expected.

Jasonoff

It could also be an issue with the secondary air injection system. Check all those hoses.

jptaylor

Ok, so now we are getting somewhere....I've had the left and right bank secondary codes for months now....but when I brought it up to everyone I was told that the secondary air couldn't affect it as it only occurred after running for a while and secondary was only a startup issue

hachiroku

if there is a leak with the SAI system...it could possibly cause issues.

jptaylor

Then I'm going to dig further here....

Mr.Tee

I may be wrong, but your symptoms sound like a crack in the intake manifold plate that is inside of the manifold.
However, that does throw a code every now and then but its a moody one. I had a crack, the car would bog and loose power, but
after shifting from D to N to D the car would be alright. Had a torment of finding the issue and after getting fed up
Pulled off the manifold and hiding in the corner was a crack about 1cm wide. Once that was fixed, the power was mad!

skratch77

I have the mafs in the mail today for you.