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Problem when the engine is cold!!!

SkyHyeR34

By SkyHyeR34,
in Engines & Forced Induction

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SkyHyeR34 Rookie

SkyHyeR34

Posted
Posted

I hav a problem with my car ever since i installed da apexi s-afc II...ok da problem is wen i start da car wen da engine is cold it starts but da rpm reads only 400-450 and its like its gonna stall but doesnt and wat i noticed id that da boost gauge is reading boost on 0 but da car is only on idle how could da boost gauge read 0. i thought it was da apexi s-afc II but i had it tuned n da problem is still there.

ok wen i drive da car n da engine gets warm da problem goes away. its only seems 2 happen wen da engine is cold. can anyone help????

my mods r:

hks bov

full exhaust

pod

apexi s-afc II

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Duncan Grand Master

Duncan

Posted
Posted
I hav a problem with my car ever since i installed da apexi s-afc II...ok da problem is wen i start da car wen da engine is cold it starts but da rpm reads only 400-450 and its like its gonna stall but doesnt and wat i noticed id that da boost gauge is reading boost on 0 but da car is only on idle how could da boost gauge read 0. i thought it was da apexi s-afc II but i had it tuned n da problem is still there.  

ok wen i drive da car n da engine gets warm da problem goes away. its only seems 2 happen wen da engine is cold. can anyone help????

my mods r:

hks bov

full exhaust

pod

apexi s-afc II

Yes! I can help.

The word is "the", not "da"

"Hav" should have an "e" on the end

"gonna" should be "going to"

"wen" should have an "h" in it

"doesnt" has an appostraphe to indicate that "not" has been shortened.

"wat" should also have an "h" in it

"id" should be "is"

There should be a comma after "idle", and a question mark after "boost gauge read 0"

Sentences should start with a capital letter

"i" should also be a captial

"2" should read "to" in this case

"r" should be "are"

Hope that helps :(

riceline Community Regular

riceline

Posted
Posted

translation

I have a problem with my car ever since I installed a apexi s-afc II...OK the problem is when I start the car when the engine is cold it starts but the rpm only reads 400-450 and seems that it is going to stall but doesn't and what I noticed is that the boost gauge is reading boost on 0 but the car is only at idle how could the boost gauge read 0? I thought it was the apexi s-afc II but I have had it tuned and the problem is still there.

When I drive the car and the engine warms up the problem goes away. It only seems to happen when the engine is cold.

can anyone help?

my mods are:

HKS bov

full exhaust

pod

apexi s-afc II

blind_elk Grand Master

blind_elk

Posted
Posted
It can't be the fuel mixture because I got the Apexi S-AFC II and I had it tuned on the dyno.

It must be something else....but I have no idea what!

Do you have any other suggestions?

If you "have no idea what", then why can't it be a fuel mixture problem? You don't tune "cold start" fuelling on a dyno. It appears to be a cold start fuelling problem.

Is the boost gauge supposed to read anything less than 0. If not, then it will always read 0 at idle - boost doesn't generally happen until at least 2000 rpm, and then only when the car is being motivated. (It's possible to actually rev the engine to red line in neutral, and get no boost.) If it is supposed to read something less than 0, then it could be some sort of air leak, but I expect that an air leak that produced no vacuum in the manifold would prevent the engine from running at all.

It could be the cold start valve not opening up when cold. It's located under the throttle body on RB20DETs, and under the inlet manifold on RB25DETs.

Duncan, riceline,

Thanks for the translation

(oh, and it's "apostrophe")

2rismo Grand Master

2rismo

Posted
Posted

elk, boost guage should be reading vaccuum at idle - i.e. negative not "0".

Go to another tuner and ask them to fix it the following morning. i.e. leave it with them over night and get them to check what sounds like cold-start fuelling compensation problems.

Adrian

xRHETTx Mentor

xRHETTx

Posted
Posted

Maybe the hose from the manifold to the boost guage has come off? That won't help idling much, there is air being lost that the AFM has already taken account of. THis happened with my R32, the hose had split and blown off.

joh21m Collaborator

joh21m

Posted
Posted
If you "have no idea what", then why can't it be a fuel mixture problem? You don't tune "cold start" fuelling on a dyno. It appears to be a cold start fuelling problem.

Is the boost gauge supposed to read anything less than 0. If not, then it will always read 0 at idle - boost doesn't generally happen until at least 2000 rpm, and then only when the car is being motivated. (It's possible to actually rev the engine to red line in neutral, and get no boost.) If it is supposed to read something less than 0, then it could be some sort of air leak, but I expect that an air leak that produced no vacuum in the manifold would prevent the engine from running at all.

It could be the cold start valve not opening up when cold. It's located under the throttle body on RB20DETs, and under the inlet manifold on RB25DETs.

Duncan, riceline,

Thanks for the translation

(oh, and it's "apostrophe")

how do you get this cold start valve to open? do you have to clean it out or something?

blind_elk Grand Master

blind_elk

Posted
Posted

I think it's actually open, and then closes. Current is supplied to a bi-metallic strip that causes a "door" to gradually close off.

/edit: had a look at one on a spare manifold, it's normally closed, and will open when current is applied, just like a choke on a carburettor.

blind_elk Grand Master

blind_elk

Posted
Posted
...there is air being lost that the AFM has already taken account of...
No, it's actually pulling air that the AFM doesn't know about, causing leaning out of the mixture. Generally when cold, the engine needs to run richer - that's what a choke does in a carburettored engine.
SkyHyeR34 Rookie

SkyHyeR34

Posted
  • Author
Posted
Maybe the hose from the manifold to the boost guage has come off? That won't help idling much, there is air being lost that the AFM has already taken account of.  THis happened with my R32, the hose had split and blown off.

I have checked the hose from the manifold and its fine. I knew it wasn't the hose because my idle is fine. I think I will just get the Power FC because it will fix my problem and give me MUCH more performance out of my car. Plus its an excuse to modify my car..hehehehe

:P

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