Stalling, The Air Flow Meter And Relearning Process

[tobybromley]

I know this topic’s been covered and seems to be an ‘Achilles Heel’ for the M35 but can someone please help me out with a query I have on this?

My question is, when I perform this procedure (Accelerator Pedal Released Position Learning , Throttle Valve Closed Position Learning , Idle Air Volume Learning ), must the AFM be plugged in or can I successfully perform this relearn with the Air Flow Meter unplugged and then plug it in once successfully performed?

Here’s my reasons for this:

Sunday afternoon, driving in the city 50kms the car splutters, slows and stalls.

Tried to restart it – starts but very low revs in idle, black smoke, stalls when put in gear.

I unplugged the AFM – car starts, idles and drives although very poorly but enough to limp home.

Got home – plugged in a spare AFM – same issue therefore it appears the next step in diagnosing issue is the reset procedure.

Thanks in advance for your insights

[scotty nm35]

Ahh, something isn't right, and no amount of throttle re-learn will fix it. Have you done the flashy light dance?

My guess, if it indeed isn't the AFM, probably a big boost leak. Do you have the ability to make a plug for the intake and pressurise it to check for leaks?

[tobybromley]

Ahh, something isn't right, and no amount of throttle re-learn will fix it. Have you done the flashy light dance?

My guess, if it indeed isn't the AFM, probably a big boost leak. Do you have the ability to make a plug for the intake and pressurise it to check for leaks?

Thanks Scotty,

I took the car to Craig at the weekend and after he plugged the laptop in we got the 'cam shaft sensor' code.

I went to Nissan, bought both sensors for the better part of $400 and after much fiddling was able to replace both of them. I also installed a new AFM, started her up and same problem. Stalls when the AFM is plugged in but will run sluggishly with it unplugged.

Is there something I've missed? the sensors were installed the correct way. What would you do next???

Toby

[scotty nm35]

What afm, one of mine, or a Nissan one?

Did you check for boost leaks by pressurizing the intake as I suggested?

[tobybromley]

Hi Scott

I've got 2 new AFM's 1 Nissan one from Jetwreck. same issue.

I havn't done what you suggested - I don't kno whow to do this.

Do I need to relearn the AFM, etc after I replaced the two camshaft sensors?

Toby

[scotty nm35]

No, you need to pressure test the piping, can you make a bung to fit the intake and get some pressure into it? 20psi works well if it will hold it.

Perhaps I should start making them, or hire my boost leak tester out...

I will call Craig and speak to him about it when I get a chance.

[tobybromley]

No, you need to pressure test the piping, can you make a bung to fit the intake and get some pressure into it? 20psi works well if it will hold it.

Perhaps I should start making them, or hire my boost leak tester out...

I will call Craig and speak to him about it when I get a chance.

Hi Scotty

Thanks for this advise and the car is now in the hands of my mechanic however I will advise him to pressure test the piping. We have changed all 3 sensors, reset and it still has this issue. Is there anything else can tell him? Is it the intake that he must bung off to perform this test? I really appreciate your help

[scotty nm35]

Yep, The intake, after the afm and before the turbo. It's an easy way to see if a pipe has split, it can be impossible to find otherwise.

Have him check the fuel pressure if possible. Should be around 35-40psi at idle.

If that doesn't fix it, all I can suggest is one of my AFM's, the Nissan ones are crap.

[tobybromley]

Hi Scotty

Thanks for this advise and the car is now in the hands of my mechanic however I will advise him to pressure test the piping. We have changed all 3 sensors, reset and it still has this issue. Is there anything else can tell him? Is it the intake that he must bung off to perform this test? I really appreciate your help

Thanks Scotty that was spot on. Asked my mechanic to pressure test and sure enough the intercooler piping had split. All fixed now and I've got your AFM fitted thanks to Craig and 2 new cam sensors which I didn't need but handy to know they're new.

Have a good long weekend

Toby

[scotty nm35]

Great news Toby.