Intercooler affecting idle? Overfuelling issue?

[Jimbob]

I have a problem with my idel at the moment

I can drive the car around happily off boost and fairly ok on boost. It does stutter when the turbo initially kicks in the though.

Also noticed (more concerningly) after boosting I coasted down to a junction and got a lot of smoke out of the back. Couldn't see colour as it was dark but may have been white? My compression is good (if a little high) and even on all four cylinders so not a head gasket issue.

The symptoms are darkish smoke when idling cold, and stalling after the engine is warm at idle. Through revs seem good, much better with the new hotter grade 6 plugs. Has anyone got an idea as to why the car is overfuelling on idle as the plugs are black but car is ok(ish) while driving.

Turned up boost as was hitting a flat spot at about 4.5k running very low boost, and as I coasted down after revving through the revs a whole load of smoke came out and then dispersed once I was ticking over?

The car doesn't want to tick over and it seems as if it is almost overfuelling at tickover?

Could a new intercooler core and increased length of pipework affect the idle in any way?


Any help would be great

Thanks,

James

[TBDevelopments]

sounds like a bit of an air/fuel ratio screw up mate.

You have that intercooler and piping pressure tested to make sure its not leaking/sucking air? Not saying it is but its not really a tested product i would be inclined to fit a standard one to see if it solves the problem.

Also is this the same car you have for sale on ebay?

Tim
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[Wayne]

Did you do an ECU reset after doing this mod?

Let the car get to its peak temperature, then reset the ECU, do this by removing the EFI fuse ideally for around 120 seconds, then refit it and take your car out for a thrash for about 5 minutes for your ECU to cope with the new mod.
You should do this with every engine modification.

[TBDevelopments]

i think he would have done this, but saying that an ecu charge wouldn't cause this many problems.

before doing this i would just check to make sure there isn't any error code for a shagged sensor, but still sounds like something is cuaing an air/fuel ratio mess up.

Tim
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[Jimbob]

Going in to be rolling road tuned 2ms so will hopefully find out then? No fault codes and as far as I can see/test no dodgy sensors.

[TBDevelopments]

i'd be looking at the components from AFM to intake manifold, sound like your getting/losing metered air from somwhere.

We had this on a friends 200sx it turned out to be the worst welding job i'd ever seen on an intercooler kit he had bought from Apex Performance (ment to be specalists), we pressure tested it and it leaked like a siv

Tim
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[Jimbob]

All the fabbed parts are fine.

I have a feeling its a sensor somewhere? Anyway RR tomorrow, so we'll see then

[TBDevelopments]

thats what i asked, has it been pressure tested because without that you can't say that for sure.

It was just an idea and what i would be looking at.

Usually sensor problems would throw up an error code.

Tim
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[Jimbob]

thats what i asked, has it been pressure tested because without that you can't say that for sure.

is 4 bar enough?

[TBDevelopments]

yes that would do that. you could have said that when i first asked.

How did you seal the intercooler ends to pressure test that out of interest?

Tim
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[Jimbob]

Easiest way is to weld end caps and one little stubpipe for the water/air onto aluminium pipes. Just stick them in the ends of silicone connectors on the IC with clamps, and pump it up. Air doesn't require bleeding but creates a lot of stored energy which you don't want if things go pop! Best to use water to give a good visual indicator of leaks too.

[TBDevelopments]

Yeah was going to say, just stick it onto a compressor and for an intercooler that size just stick it into a bath full of water and look for air bubbles.

Tim
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[mr2turbo117]

hi mate,
check your lambada sensor !.
i had the same problem would be fine untill boosting then it would sturggle.

dastek and tunning zone did not find this problem.

it would make the car over feul and not give it enough either.

check both of the sensors on your cat or de cat pipe and this should solve the problem.

[TBDevelopments]

both sensors?

Theres only one o2 sensor, the others just a cat temp sensor and can be totally removed with the decat pipe.

Tim
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[Jimbob]

Thanks for advice, already checked to no avail