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Car Goes To Stall When I Put Clutch In An Roll To A Stop

BOOZTJUNKEY

By BOOZTJUNKEY,
in General Maintenance

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BOOZTJUNKEY Proficient

BOOZTJUNKEY

Posted
Posted

Hey guys

Had this issue for a lil bit but has got a lil worse since I fitted a 3" ss. Intake pipe I made

What happens is I go to start driving in any gear Iand I'f I put the clutch in the revs drop down like it wants to stall but never does but has come close

I'm leaning towards it being Afm meter related or possibly bov not being plumb back ..

I have no idleing miss or anything so which makes me think it's not the bov and airflow meter related

mad082 Grand Master

mad082

Posted
Posted

most likely due to the atmo bov. what happens is that when you lift off the throttle and the bov opens it sucks fresh air through the bov. this causes the ecu to dump in extra fuel and makes the car stall/amlost stall. putting a plumback bov on will help the situation. if the coils and/or plugs are getting on a bit then replacing them can help the situation as well, but won't solve it completely.

SargeRX8 Grand Master

SargeRX8

Posted
Posted

Not always JUST the bov. When I had my other skyline, I fitted a atmo blitz bov and a alloy intake pipe at the same time. Started the car, started fine, drove it and it almost stalled on the first clutch in. Removed the BOV and fit the stock one on with a rubber return line. The problem got a little better but not right, still evident. I got my pipe remade with the return for the BOV flowing towards the turbo rather than straight down. What was happening is the air from the BOV was hitting the AFM, as mad082 said above, fooling the car into thinking fresh air just hit the AFM and thus putting in fuel to compensate when really it was the same air, just measured twice.

Look at the stock Nissan intake pipe, the breather and return lines are as far away from the AFM as possible and still at a 45degree angle pointing towards the turbo. Its a hint when you go to build your intake pipe.

89CAL Grand Master

89CAL

Posted
Posted

Not always JUST the bov. When I had my other skyline, I fitted a atmo blitz bov and a alloy intake pipe at the same time. Started the car, started fine, drove it and it almost stalled on the first clutch in. Removed the BOV and fit the stock one on with a rubber return line. The problem got a little better but not right, still evident. I got my pipe remade with the return for the BOV flowing towards the turbo rather than straight down. What was happening is the air from the BOV was hitting the AFM, as mad082 said above, fooling the car into thinking fresh air just hit the AFM and thus putting in fuel to compensate when really it was the same air, just measured twice.

Look at the stock Nissan intake pipe, the breather and return lines are as far away from the AFM as possible and still at a 45degree angle pointing towards the turbo. Its a hint when you go to build your intake pipe.

no, the problem with atmo BOV's is that your AFM has seen x amount of air flow through. Then you have an atmo BOV which then makes some of that air disapear. So your car then has (I'll over exagerate it to prove a point) say half the air the AFM has registered. So instead of getting x amount of air with y amount of fuel, your getting 1/2 X with 1 Y

Therefore it runs extra rich, nearly stalls till the BOV closes and the AFM can catch up.

as long as the BOV is plumbed back it shouldnt matter all that much where the air is returned as long as it gets back in before the turbo. As air will always flow towards the turbo (unless your getting compressor surge) so the air from the plumback pipe will flow that way as well..

The problem I'm guessing you had is that you ran the Atmo BOV for a little bit, changed back to plumback and your ECU went weird. I had the same problem. Pulled an ATMO BOV off and it still had all the symptoms of an Atmo BOV. Cleaned AFM, cleaned AAC, did this and that and nothing worked. Reset ECU and ran fantastic.

The ECU's are touchy, I think that might have been the issue and changing the pipe somehow fixed it. Where the air inserts back into the system shouldnt matter to much as long as its between the turbo and AFM. But thats just the way I understand it from what little I know about fluid dynamics.

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