Will your car run with Mass Air meter disconnected

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Will your car run with Mass Air meter disconnected

July 28, 2010, 12:13:06 PM

My car runs really rough the first 1 or 2 mins when I first start it (starts missing really bad). This happens when the engine is both cold and hot. After a few minutes the engine smooths out, runs great and has a lot of power. I have no DTCs, get a 11 for PASS. At first, I thought it was because I modded the engine slightly and have no CATS. As a result, I put a Moates chip on the ECM and have been trying to tune it out for the past year, with no luck.

I'm finally gave up trying to correct the problem with a chip. The more I thought about it, I think my ECM may be bad. For example, when I disconnect the MAF, the engine will died immediately. I would think a good ECM would at least keep the engine runnning. What do you think?

Will your car run with Mass Air meter disconnected

Reply #1 – July 28, 2010, 02:17:15 PM

Mine dies if I disconnect the MAF while engine is running... It will run if I start it when already disconnected, but not very well...

Will your car run with Mass Air meter disconnected

Reply #2 – July 28, 2010, 02:50:53 PM

Quote from: TurboCoupe50;329799

Mine dies if I disconnect the MAF while engine is running... It will run if I start it when already disconnected, but not very well...

X2. That's how mine is affected as well.

Will your car run with Mass Air meter disconnected

Reply #3 – July 28, 2010, 05:56:11 PM

Quote from: turbocoupe50;329799

mine dies if i disconnect the maf while engine is running... It will run if i start it when already disconnected, but not very well...

Will your car run with Mass Air meter disconnected

Reply #4 – July 29, 2010, 08:26:40 PM

Well I tried starting my car with the MAF disconnected, and sure enough it runs, although not well.

I also pulled codes:

81 & 82 - Air Injector Diverter & Bypass failure. These are not surprising because I have the pollution pump and tubing removed.

11 - system pass

I then checked the following:

Manifold Pressure: 17-18inHg at idle
Fuel Pressure: 35psi with vacuum, 40psi without vacuum connected
Ignition Timing: 10deg BTDC at warm idle

All seems reasonable to me, but car still runs rough the first minute or so after start. Doesn't matter if engine is cold or warm. Once it goes though this "cycle" it runs smooth and has good power.

I still suspect the ECM having an issue....I'm not sure what to check next.

maf

Reply #5 – August 04, 2010, 07:37:39 PM

It could be possible that the a9p may not like the maf transfer from the cobra maf sensor.
What kind of software are you using to tune the chip?
If you have a moates quarterhorse, your set as far as the hardware goes. :D

Mike

Will your car run with Mass Air meter disconnected

Reply #6 – August 04, 2010, 08:02:21 PM

have you tried cleaning your MAF?

Will your car run with Mass Air meter disconnected

Reply #7 – August 06, 2010, 11:59:41 AM

I've tried cleaning the MAF and I also had a Moates Chip with the Cobra MAF transfer function for the A9P. I used EECtuner to program the Moates Chip.

Will your car run with Mass Air meter disconnected

Reply #8 – August 08, 2010, 11:10:34 PM

Quote from: 88BlueBird;330973

I've tried cleaning the MAF and I also had a Moates Chip with the Cobra MAF transfer function for the A9P. I used EECtuner to program the Moates Chip.

I'm guessing she might be leaning out with some of cold enrichment.
Can you data log cold start up air fuel ratio with the EECtuner and Moates?

Mike

Will your car run with Mass Air meter disconnected

Reply #9 – August 10, 2010, 11:44:54 AM

Well I found the problem. Seek made a post awhile back about having the same issue. He found that his O2 sensors were reversed. So, I checked my O2 sensors last night and sure enough, I had the connectors switched. I swapped the connectors from left to right. I can't believe that I chased this issue for over a year and it ended up being that simple. It's so wierd that the car would run so poorly, but the ECM would never give me a code, that it was in limp home mode. Well anyway...thanks for the help everyone!

Will your car run with Mass Air meter disconnected

Reply #10 – August 10, 2010, 10:22:25 PM

Just wondering but how did you switch the wires in the first place? I thought they were only long enough to reach one side.

Will your car run with Mass Air meter disconnected

Reply #11 – August 10, 2010, 11:21:06 PM

Never mind I figured it out. The left hand (driver's side) o2 sensor lead has a blue wire and the right hand (passenger side) has a green wire.

Will your car run with Mass Air meter disconnected

Reply #12 – August 11, 2010, 11:30:05 AM

The O2 sensor harness I have runs down the center of the trans bell housing, so it was easy to switch the LH O2 connector with the RH one. When I put the engine in the car, I must not have realized that I had the connectors switched.

Will your car run with Mass Air meter disconnected

Reply #13 – August 11, 2010, 03:27:51 PM

True I guess it can be done. I just taped the harness to the firewall on mine. Then again mine was a 5.0 car to begin with.

Just wondering but what colors are the O2 wires on your car? The LH side on mine is green with a light green stripe and the RH is dark green with a red stripe. I think the LH side wire has changed color over the years;)

Will your car run with Mass Air meter disconnected

Reply #14 – August 12, 2010, 08:38:10 AM

The LH side on mine is Dark Blue with Light Green stripe. RH side is Dark Green with Pink stripe. The colors were not easy to read on my O2 sensor harness either, that's probably how I got them reversed in the first place.