Mass Air Flow Signal Error

[Mistermorgan]

Originally Posted by Bdc101

Have you ever gotten the "fuel trim exceeded" errors? Or just a MAF signal error? My guess (and it is indeed a complete guess) is that "MAF signal error" means there is something wrong with the signal getting to the DME (since you have replaced the MAF). The typical MAF problems tend to cause fuel trims to be exceeded and not cause the throttle to become unresponsive.



Do the throttle problems associate 1-to-1 with every "MAF Signal Error" code you get? Or do you get that code even when the car is driving fine?



Are you sure the throttle itself is not a problem?



Just brainstorming here - I really have no idea. I agree with 80stech, check continuity of all the wires in the MAF connector back to their source.

Sorry - realised I didn’t reply.

The throttle problem does associate 1-1 to the error code being triggered.

Ie - car is driving fine, then the throttle pedal will become unresponsive, like you can push the the floor and it won’t respond. EML light comes on and the code is triggered. Throttle will work ok but sporadically die.


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[EODguy]

Originally Posted by Mistermorgan

Sorry - realised I didn’t reply.

The throttle problem does associate 1-1 to the error code being triggered.

Ie - car is driving fine, then the throttle pedal will become unresponsive, like you can push the the floor and it won’t respond. EML light comes on and the code is triggered. Throttle will work ok but sporadically die.


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Use your foxwell to see what the throttle potentiometers are registering as you could have a dying one on the low side and when the full depression (high side) registers it could confuse the computer causing it to lug the engine.

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[Mistermorgan]

I’m now confident it’s a pedal issue.

Fixed up the VANOS and everything else. Took it for a drive with the scanner hooked up.

Pedal goes intermittent so I put my foot to the floor and it’s reading 15% throttle position. I can get a replacement used part for $100 so going to give thet a go.
Out of interest thiugh does anyone know normal voltages for a working pedal?

Mine is
Pedal position 0%
Pot 1 0.71V
Pot 2 0.36V

Pedal position 100%
Pot 4.69V
Pot 2 2.37V


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[80stech]

Maybe check the wiring/connector. If it is that (I would be surprised), then there must be something (ground, supply) causing readings from both pots to fail at the same time to cause a problem especially without throwing a code.

What happened with VANOS code?

Your throttle cutting out might just be the DME going into failsafe and not really a symptom of the problem itself.

[Mistermorgan]

Yeah I think it could be the connector or some wiring at the pedal. I had a throttle controller connected before and the wires were wedged down he side of the pedal, this issue coming so soon after I replaced the brake booster and was again fiddling around in the footwell could mean I’ve put more pressure on the wiring or damaged wiring at the connector - maybe I’m just being optimistic though, if that is the case and wiring is damaged on vehicle side then a new pedal won’t fix it.

I pulled all the VANOS solenoids and cleaned the connectors, some of the cabling had cracks in it so I’ve taped and heatshrinked the connectors and put it all back in. VANOS codes went. I think this might have just been coincidental timing.

Whilst driving yesterday the throttle issue was happening but wasn’t triggering any codes and EML didn’t come on. It was just a lack of response on the pedal, foot down and WOT and the foxwell telling me I’m at 15% open but this time no code or EML

I don’t think previously it was going into fail safe either though, I was just getting EML for maf sensor signal and intermittent throttle being unresponsive. If it was in failsafe I usually get that message on the display and the throttle being limited wouldn’t be intermittent


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[Mistermorgan]

Just to update for those still here the throttle is not the issue - after a week of fine driving the issue has returned and I’m now investigating the CCV hoses.

I know a MAF code will trigger if unmetered air is getting through anywhere but would his explain the throttle response issue?

The order is - throttle response issue then MAF error, which makes me think it’s not the latter causing the former.

Either way. I’ll pull the hoses and pressure test, these are the newer, insulated hoses so visually inspecting for leaks is not possible.

If there are any other suggestions out there I’d love to hear them


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[80stech]

Any air leakage should result in a mixture code as well so I don't think that is your problem. I would double/triple check the wiring to the MAF and to your throttle pedal AND grounds. Not too often the DME sets a code for a particular signal and that is not the problem. Mixture codes on the other hand can be almost anything.