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i have just did a 25 conversion into my 32. problem is that when when the car is cold, it is mega gutless and doesnt want to drive properly. it only really revs to 3000rpm and starts to splutter and almost feels like there is something holding the car back.

when the engine has warmed up it seems to be driving normally and will rev normally etc.

any idea on what i can check for and/or fix to help it run properly all the time

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my mates 300zx's throttle body was getting stuck because it was a bit dirty and when the engine warmed up the alloy expanded and it wouldn't stick. fiddle with the throttle body and throttle cable as thats the first easiest thing to eliminate.

i have just did a 25 conversion into my 32. problem is that when when the car is cold, it is mega gutless and doesnt want to drive properly. it only really revs to 3000rpm and starts to splutter and almost feels like there is something holding the car back.

when the engine has warmed up it seems to be driving normally and will rev normally etc.

any idea on what i can check for and/or fix to help it run properly all the time

My old car did the same, was an R33 RB25DE.

Took it to the mechanic about... 2-3 times. Never discovered what the problem was. Only on very, very cold mornings did it struggle. I drove the car for about a year and never had any other trouble, and my mechanic was checking very thoroughly every service that nothing was going wrong.

Get it checked out, if they can't find anything wrong. Don't stress too much. Let her idle for a few min before driving on cold days, and take it easy till she's properly warmed up.

I am a mechanic myself ...

In all honesty it sounds like the engine is flooding ... when cold

If ya have access to a gas analyzer this would be the best place to start ... to check what your readings are when cold ... even hookup a scanner and check for error codes

but a couple things to check if ya dont have access to the above would be

Check 02 sensor and coolant temp sensor by swapping them with replacements and seeing if it makes a difference ...

You might even have the wrong heat range spark plugs for your engine fitted ...

just a couple things to check

I am a mechanic myself ...

In all honesty it sounds like the engine is flooding ... when cold

If ya have access to a gas analyzer this would be the best place to start ... to check what your readings are when cold ... even hookup a scanner and check for error codes

but a couple things to check if ya dont have access to the above would be

Check 02 sensor and coolant temp sensor by swapping them with replacements and seeing if it makes a difference ...

You might even have the wrong heat range spark plugs for your engine fitted ...

just a couple things to check

My uncle is a mechanic aswell and my car does the same on a cold morning (brought this up to him one day) and if i dont tap the accelerator it will stall. My engine has only done 465km (BRAND NEW PISTONS FULLY RECONDITIONED TOP AND BOTTOM END!!!) its not a engine problem he also said like above, it was a 'choke' like mechanism but on a car. There are a fair few problems that have to be trialed and crossed out, simple things like cleaning parts and resetting the ecu and installing sensors will eliminate what it would be but im pretty sure its what i have.

Check tyhe Idle Control valve on the back of the plenum that it is not stuck

http://www4.wave.co.nz/~lakewood/Skyline/IAC.htm

I have just put in a new RB30DE (last week) into a R32 Skyline and forgot to plug in the AAC valve so it would start with partial throttle open but not without. Its the AAC valve that manages idle air flow.

Also the Cold Air Regulator maybe faulty.

http://www4.wave.co.nz/~lakewood/Skyline/ColdAirReg.htm

However I had removed mine on my original RB20DE 2 years ago and blocked off the vaccum lines. I didn't fit it to the new RB30DE.

Nigel

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