MAF issues at idle

[steven_esi_bui]

So ive got a 92 talon with a 4g63n/a and im having some issues with the MAF. If the MAF is connected it has horrible idle and it sputters and doesn't rev past 2500 RPM, now if I disconnect the MAF it idles some what better and doesn't sputter and revs freely. The ECU is fine (I've opened it and checked for leaky caps) the MAF is new I've tried 3 other MAFs and still same issue, I checked the voltage of the connectors and all checkedout fine. I also changed the temp sensor and the plugs along with wires and coilpack and transistor. Now im stumped with this car since it doesn't throw a CEL. Can any one shine some light on this issue?

 

[Dsmkauai]

Check your grounds, but sounds like the ecu if you've tried several mafs and the wiring is fine. Doesn't have to have leaky caps to have a bad spot. Might wanna get the ecu checked or try another.

 

[pauleyman]

Mas is a symptom not the cause. Car ran better with it unplugged because you changed the situation. Maf is likely fine. Stop replacing parts willy nilly. did this happen all of a sudden or gradually over time? What have you done to the car lately or directly before this started happeneing? Have you ruled out basic maintenance, wires, plugs, timing belt issues etc?

 

[coloradotuner]

My brothers DSM had the same issue rough idle but revved freely and smooth, a new IAC seemed to do the trick.

 

[steven_esi_bui]

The car is completely stock and Ive done the basic maintenance to it already, this would be the 2nd ECU Ive tried so far (both came off good running cars). And as far as the grounds Ive sanded and cleaned off every ground i can possibly think of, i was thinking about adding a ground to the MAF connector and see if that helps. But other than that i have no clue what else could it be.

 

[pauleyman]

You answered some of the questions. Need more info

 

[rough]

Do you have a way to check fuel pressure?

 

[steven_esi_bui]

No not at the moment but the Fuel pump+filter and Injectors are new the only thing that hasn't been replaced is the FPR.

 

[Mauispyder]

Check sp wires.

 

[steven_esi_bui]

Check sp wires.

that was a part of the basic maintenance all that was replaced like a week ago.

 

[steven_esi_bui]

You answered some of the questions. Need more info

It started happening a week after i bought it (car ran fine before). i came home from a ride around, parked it and the next morning it had a rough time starting up and when it finally did it was sputtering and wouldn't rev past 2500 so i disconnected the MAF and it seemed to get way better but still not suitable for driving. So i went off and bought a new MAF and still and that's when i started doing the basic maintenance.

 

[pauleyman]

Pull the pkugs and see if its one cyl or all. If its one check inj harness and plug wire. All id say its a control issue with what ecu sees or dvu itself. Could be leaks, temp sensors, harness, baro sensors etc. Datalogging would help.

 

[rough]

If you had a turbo I would say boost leak

Do you get any cel codes?

Are the timing marks lined up when you pull the timing inspection cover?

Do you have a multimeter ?"get down and dirty and start testing sensors" Coil packs should be first!

When you rev it, does it feel like the motor get's tighter and quieter, like it just cant breathe? Could be a damaged/failed catalytic converter.. Have someone rev it to what it can and see if exhaust comes out forceful like it should!

 

[steven_esi_bui]

If you had a turbo I would say boost leak

Do you get any cel codes?

Are the timing marks lined up when you pull the timing inspection cover?

Do you have a multimeter ?"get down and dirty and start testing sensors" Coil packs should be first!

When you rev it, does it feel like the motor get's tighter and quieter, like it just cant breathe? Could be a damaged/failed catalytic converter.. Have someone rev it to what it can and see if exhaust comes out forceful like it should!

No check engine light and timing is dead on with the marks and coil pack is new. The only thing I haven't checked is the cat.

 

[pauleyman]

Just did spark plug wires.....hmmm.did you check them anyway? You should. Please dont start two threads with identical text.

 

[steven_esi_bui]

Just did spark plug wires.....hmmm.did you check them anyway? You should. Please dont start two threads with identical text.

Yea just swapped out the plugs and wires this morning with new ones and still does the same BS. I also added a ground wire and double checked the voltage on the MAF harness plug and everything checked out. And as far as the double post i tried deleting it but no luck. If you can, do me a favor a delete it.

 

[pauleyman]

Well...I wasn't suggesting you go get another set. I meant make sure there are no errors. What did the plugs look like? Are you using an nt computer? Are you sure? Did it come from another running nt car? Did you swap injectors? What I'm getting at here is you had a failure and I want to make sure you didn't Fix the root cause but inadvertently cause another problem by swapping in the wrong parts. I'm leaning towards an ecu problem still or a leak at the throttle body.