Bunch of questions which might all be the same thing!

[RedM]

Firstly, the huge amount of replies about these makes it really hard to find a definitive answer.

 

Second, I'm asking becuase I too get a drop in revs when at junctions. Yesterday I must have been down to 350-400 at one point but car hasn't stalled yet!

 

Car is JDM auto TT with NO mods.

 

so:

Idle Control Valve. I understand it can be cleaned. Where is it?

 

AICV. (Air Intake Control Valve, am I right?) Is this the same as above? If not, where is it and can it be cleaned?

 

MAP/MAF? The Jspecs have one of these. Could this be the problem and what do I do to get it working etc?

 

Thank you.

[Simon]

IIRC and bear in mind that my mind is going mushy, the jdm uses MAF and this is in the intake pipe near the filter housing. You could blow some air back through the system in reverse (not too high a pressure) which could blow some cobwebs away, otherwise I await the more knowledgeable answers like you.

[LeeT]

IIRC and bear in mind that my mind is going mushy, the jdm uses MAF and this is in the intake pipe near the filter housing. You could blow some air back through the system in reverse (not too high a pressure) which could blow some cobwebs away, otherwise I await the more knowledgeable answers like you.

the jdm supe uses MAP not MAF. the idle air control valve is towards the end nearest the bulkhead of the intake manifold on the left hand side. two 12mm bolts to remove it. take care as there is also 2 coolant pipes attached from underneath

[tbourner]

I would think if it was a MAP signal problem it would cause more major issues than the revs dropping when you pull up. Is it overfuelling or lumpy as well? Do the revs stay low or does it just not catch the idle point properly?

[Ian C]

A low/struggling idle when coming off the throttle is usally a sign of overfuelling. On a MAP based system it's not going to be an airleak as any leaks are still measured and fuelled for - you get a high idle instead.

 

You can overfuel if the MAP sensor's vacuum pressure reference hose has come off, but it would go lean on boost as well. Overfuelling can seem like normal running when you aren't idling as an engine will run across a wide variety of air fuel ratios, so are you sure it's fuelling OK at all other times...?

 

-Ian

[Whitesupraboy2]

You can overfuel if the MAP sensor's vacuum pressure reference hose has come off, but it would go lean on boost as well.

 

-Ian

 

Just out of question, was this what came off on Jake's VVTI and caused that big failure, (you may not remember?)

[RedM]

My idle is usually just above the 500 rpm mark although RLTC puts it at 640 rpm.

 

Sometimes, and it is only sometimes, the needle drops just below the 500 mark and then moves back up to it's normal position after a few seconds. So, like Trev suggests it's like it just misses it's idle point.

 

As for overfuelling at other times, how would I know? What do I look for?

[supra_surj]

Hi guys im getting the same problem. Looks like its missing the idle and revving low around 350.

 

Can anyone point me in the right direction please?

 

Surj

[paul mac]

My idle is usually just above the 500 rpm mark although RLTC puts it at 640 rpm.

 

Sometimes, and it is only sometimes, the needle drops just below the 500 mark and then moves back up to it's normal position after a few seconds. So, like Trev suggests it's like it just misses it's idle point.

 

As for overfuelling at other times, how would I know? What do I look for?

i have never heard of RLTC effecting the idle, is the car running rough when at these low rpms does it feel like it wants to cut out, i know after a ECU reset mine allways goes through a phase of trying to idle real low as the ECU relearns

[RedM]

RLTC isn't affecting the idle. I measured the idle using the RLTC software.

[Jake]

Just out of question, was this what came off on Jake's VVTI and caused that big failure, (you may not remember?)

No mate. It was the vacuum hose to the fuel pressure regulator that caused my first blow up