Update Was MAF problems

[hpjay]

More MAF DME problem

Now I am really getting irritated.

Toolpants…time to put the thinking cap on.

Background 2000 3.2 S suddenly went from running great to no revs past 2K

Replaced MAF with new ($270 from Sunset w/PCA discount).

Newest updated version 968.606.125.01

No change.

Still will not rev beyond 2K with MAF pluged in.

Unplugged, runs as expected in limp home mode.

Disconnected battery to reset all electronics, no effect.

Start car with MAF unplugged, then plug in. Engine takes a big hickhup then continues to run.

Drive for a few miles …just fine but still in limp home mode.

Turn off and restart ...same problem

Measurements 5 v on DME feed, Batt voltage on red/blue feed.

3-4 ohms on sensor term 3 & 5.

Unable to read DME codes until I get a ISO ODB2 reader. My Novus reader can not read ISO protocol.

Open for any suggestions.

Henry Jay

[Tool Pants]

Try again with your part number.

Then, what was the part number of your orignial sensor.

[hpjay]

My original PN was 986.606.125.00

Has been superceeded with

986.606.125.01

Per dealer and Pelican

HJ

[hpjay]

Sorry I have this dyslexia problem with 968 986/

HJ

[hpjay]

Ok more data points

Read manual and followed procedure for power up from "dead Battery"

"turn key on for run 1 minute, turn off for at least 10 sec. to reinitialize DME and e-gas throttle.”

No change..still will not rev beyond 1-2 K with no power.

PPBBer Bill-MA suggested coast @ 15MPH, switch off

Then switch on and bump start.

Seems to come out of limp home mode and run as expected

Until you start with key switch than it is back to the 2K problem

Seems that something in the start mode is causing the problem

What continues to baffle me is

1) Why it will not go into the limp home mode with MAF connected

2) Why no CEL are being shown

Well it looks increasing like a trip to the dealer is going to be required.

[mrmickeymouse]

Someone told you to turn your vehicle off, and then back on while you are doing 15 MPH.

I would steer away from that disaster waiting to happen.

I could see it now, wheel locks up, and you can't turn it OH.... OH ...:(

Maybe on a dyno...

Scott

[Tool Pants]

I spoke to Peter today. He works at my local dealer, is a PCA tech advisor, and put on tech sessions for us local owners.

I told him your car would not rev past 2,000 rpm. You disconnected the sensor and the car ran fine. You then replaced 986 606 125 00 with the superceeded part 986 606 125 01. No reprogram is required for this swap per Peter. You car still has the same problem. Is this correct?

He said your DME/ECU may be bad and it may not be a sensor isssue. You need to have someone with a PST2 check your DME.

He explained why and I sort of understood it. The DME receives signals from the sensor. If the DME is bad then the signals confuses the DME and it does not know what to do. When you unplugged the original sensor then your removed the source of the signal that confuses and the DME goes into the limp mode. This is why you have the same problem with the new sensor plugged in.

You did not say if you unplugged the new sensor and tried the car. But try that to test the seat of the pants theory.

Then you have no choice but to take it to someone with a PST2 unless someone has a better idea. Let us know what it turns out to be.

[hpjay]

I told him your car would not rev past 2,000 rpm. You disconnected the sensor and the car ran fine. You then replaced 986 606 125 00 with the superseded part 986 606 125 01. No reprogram is required for this swap per Peter. You car still has the same problem. Is this correct?[/i]

HJ this is correct

You did not say if you unplugged the new sensor and tried the car. But try that to test the seat of the pants theory.

Same results with either MAS sensor

The most unusual thing is that if you do not start the car with the key (ie do not initiate the start mode) the DME recognizes the MAF and runs fine. I tried this several times to verify. Requires a rolling start using the clutch.

I have an appointment with the dealer next week. Sure hope it is not the DME as I expect this item is very costly.

Henry Jay

[Tool Pants]

I did not tell Peter your were turning the key off, then on, then getting the engine to run properly by push/roll starting the car. Wish I had as he may have had a different thought as to what is wrong.

I also hope it is not the DME as they are very expensive.

[frenchy]

The DME is ~500$ (for a rebuilt one with "core" exchange), a new one is ~1000$.