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Cold Start Problem... Again!

Mumbo#5

By Mumbo#5,
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Mumbo#5

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Posted

Hi all

I just wrote a huge post about whats happening but the f**kin forum shit itself :laugh:;) So its getting late and im going to shorten it

Problem: In the mornings, cold starts are a bitch, only when cold.. the engine starts fine when warmish/warm. When you preceed to start the car in the morning, it tries to start, stalls, tries to start, stalls does this around 5-10 times depending on how cold it is. When you blip the throttle to try to get it to start, and when once started, it goes into cold start mode (idling at 2000-1500rpm) perfectly.

Things I have done to try and solve the problem:

Cleaned all electrical things (AFM etc.)

Cleaned Injectors (sonically)

Changed sparkies (coppers gapped at .8)

Changed the coolant temperature sensor (is working fine according to my carmanscan pro, when you do the actuation test and lower the temp the computer see's, it retards the timing so its working fine)

Cleaned throttle body and components on manifold (fully cleaned TB and AAC valve (pulled the AAC valve fully apart and cleaned).)

After doing all of these things, its still doing it. One thing I did notice to be very strange is that when I disconnect the plug completely off the coolant temp sensor, it starts like it should (sends the computer into a default mode) which indicates to me that the sensor was frooked, but its not as it has been replaced.

Is there anything else to do with the cold start side of things that I can test/replace/clean????

Im really really stumped, and so is the rest of the workshop I work with.. ;)

I was doing some searching but didnt find a solid answer..

PLEASE PLEASE HELP GUYS!! I'm getting quite distrought about this... if a god damn V6 commodore can start in the morning first hit, why can't my skyline:(

Any help would be muchly appreciated.. Thanks guys..

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Modena Grand Master

Modena

Posted
Posted (edited)

Dont know if this is of any help but check ALL your hoses.

My car was stalling for a while and I was gobsmacked... I checked fuel filter, changed spark plugs and checked coils coils, checked AFM...then we spotted a hose was off the carbon canister which vacums air inside... its all good now.

Edited by Sir-D
Mumbo#5 Collaborator

Mumbo#5

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Posted

there are a few people suffering the same problem.. and no-one knows a real answer.. thanks for the replies guys, i dont have any vacuum leaks (rebuilt the engine, replaced nearly all hoses)... and done the ecu reset many-a-time no good.

OK.. this might sound stupid.. but after i got the injectors cleaned.. it was good for about a day.. then it started again.. I guess next thing is to replace all the injectors... damn thats gonna be a big hole in the pocket.. and if its not that im gonna cry :|

4drlvr Proficient

4drlvr

Posted
Posted

Hi Guys, Im getting the exact problem. I turned the idle screw a little bit up and it start for about a month and then when it started getting colder it started doing the same thing.

However saying that I know approximately how many turns the engine should start in, so what ive been doin the past few days to get over the problem at the point where i know it is meant to start, at that very moment i step on the accelerator to the floor and it starts fine.........

Just though id share this info

Mumbo#5 Collaborator

Mumbo#5

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sorry off topic...

how much did it cost you to get your injectors cleaned?

for me? about 130 bux.. BUT I did all the work myself (apprentice mechanic).. its approx 20 each injector plus seals and maybe pintle caps. So ur looking at around 3hrs labour I would say at around 65-85 bux depending...

dan22 Enthusiast

dan22

Posted
Posted
cold start solenoid is ur problem thats what fixed mine

could u pls tell me where abouts its located, and also, any idea how to test whether this solenoid has given in.....cuz am having the same problem, and couldnt figure out what was wrong........

BH_SLO32 Proficient

BH_SLO32

Posted
Posted

It would be worth checking that the air regulator is operating correctly. In addition to the AAC valve the air regulator is also used to bypass additional air around the throttle body when the engine is cold. Whereas the AAC is controlled via the ECU the air regulator operates independently of the ECU and is a somewhat simple device which has a 12V feed. When cold the air regulator will open and gradually close when the ambient temperature rises. It should be closed when the ambient temp gets to about 60 degs.

The air regulator maybe blocked with crap or not operating at all.

I have attached a photo of what it looks like. On the RB20's it is located adjacent the injectors under the throttle body and on the RB25's it sits on the underside of the intake manifold directly above the oil filter/oil cooler.

Hope this helps.

Cheers,

post-16836-1150094326.jpg

post-16836-1150094377.jpg

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