2.8 almost stalling until it warms up

[cheeseandbeans]

Afternoon all,

I have a few days off so wanted to investigate this issue. When I first start my 2.8 up the revs keep dropping until it eventually stalls. I have to start the car back up again until it gets warm and then it's absolutely fine. Any ideas where to start looking to diagnose this issue? Here's a link to a video I took at weekend of the issue.

View: https://youtu.be/XBkoVSiU9u0

 

[Eddie Zedder]

Air intake rubbers split or camshaft position sensor knackered. Either way bung a code reader on.

 

[cheeseandbeans]

Air intake rubbers split or camshaft position sensor knackered. Either way bung a code reader on.

Will do that this afternoon

 

[Richardrix]

Does that engine have the Idle Control Valve? If it does, try taking it out and cleaning it with brake cleaner. Otherwise, stick in a replacement. I think the one I got from Quarry motors for my E53 was about £15.

 

[Mario]

My money is on the intake boots I had similar symptoms when i originally bought the car both boots had massive splits hidden on the folds.

 

[Oddly Godly]

Sounds like this thread https://zroadster.org/threads/lumpy-idle-possible-misfire-advice-needed.34963/ I had a similar problem on my 2.8 which turned out to be the air hose between the air filter and the engine.

 

[buze]

I have the same exact problem, and it also disappear very quickly once the car has warmed up. Changed Thermostat, Pump, MAF, filter, and I'm /fairly/ sure the intake is not broken (it was slightly unplugged at some point, and the noise THAT makes is quite significant).

I was like 100% sure it was the thermostat, as the car sounds like it 'believe' it's warm enough to reduce the RPMs when idling/cold, and actually, realises sometimes too late that it isn't and sometime, stalls. But new thermostat didn't help.

 

[cheeseandbeans]

Read the codes late last night but the output was German using inpa. Will try again later today and translate it. Is there anywhere in the Manchester area I could get a smoke test done?

 

[cheeseandbeans]

Right, codes read and translated. Interestingly when I clear the code the revs drop off similar to when I first fire it up. I'm guessing MAF sensor?? One code logged as follows, the formatting isn't quite the same as I used google translate.

ERROR MEMORY
Date: 03/04/20 13:21:17
ECU: MS420DSO
JobStatus: OK
Variant: MS420DSO
RESULT: 1 errors in error memory!
8 Air mass meter signal
Error frequency: 1
Logistic counter: 40
Engine speed
Throttle valve angle
Duty cycle idle actuator
LMM voltage value
occurred before (rel. BZ)
704.00 limine
5.15 degreesDK
12.89%
0.02 BC
0.00 h
Signal line short circuit to ground or open circuit
CARB error
Errors saved after debouncing
Error currently present
static error
Error code: 08 72 01 28 16 0B 21 01 B4 85

 

[colb]

Error code pointing to the Maf, could try cleaning it with Maf cleaning spray, see if that cures it, if not then spend your money on an oem Maf dont go for cheap pattern parts, been there done that etc.

 

[NZ00Z3]

Signal line short circuit to ground or open circuit

Error currently present
static error

Check the connection and wiring to the MAF looking for a short or open circuit

 

[Sean d]

I had this on a 2.8 tu that i recently sold, read the codes and nothing, so I warmed it up before the buyer picked it up, worked a treat

 

[Lee]

I had this on a 2.8 tu that i recently sold, read the codes and nothing, so I warmed it up before the buyer picked it up, worked a treat

Jesus Sean I hope you kidding.

@cheeseandbeans unplug the Maf and see if the car runs better, very likely it will. You might get an engine light doing this but don't worry the car defaults back to a richer mixture to protect itself.

 

[Bazza]

WHAT

 

[Sean d]

Jesus Sean I hope you kidding.

@cheeseandbeans unplug the Maf and see if the car runs better, very likely it will. You might get an engine light doing this but don't worry the car defaults back to a richer mixture to protect itself.

He got it cheap

 

[cheeseandbeans]

Jesus Sean I hope you kidding.

@cheeseandbeans unplug the Maf and see if the car runs better, very likely it will. You might get an engine light doing this but don't worry the car defaults back to a richer mixture to protect itself.

Is it a better idea to run it unplugged while I sort a part out?

 

[colb]

It will run on default settings, might be down on power and not as responsive, but ok to run it disconnected in the short while.

 

[buze]

Had my intake disconnected for a while (accidentaly) the car sounded fantastic! Like a bloody old style F1 when booting it

 

[cheeseandbeans]

Slight update to this. I also have a 2.0 on my drive so I took the MAF from that and swapped with the 2.8. It seems to have sorted the cold start issue I think but the fault is still present when reading the codes?? The 2.0 doesn't sound the best starting up now and that MAF is definitely dodgy as when I hover my hand in front of it the car stalls! If I put my hand near the working one on the 2.8 it nearly sucks my hand off (for want of a better phrase). Strangely enough though there is no code logged on the 2.0 with the suspected dodgy MAF.

Not sure where to go with the logged fault on the 2.8 now? I've tried clearing the codes but it comes straight back. Also clearing the codes replicates the drop in revs?

 

[NZ00Z3]

Did you check the connection and wiring to the MAF looking for a short or open circuit?