cold engine problems

[johnny_08]

hey pple,
I've recently had my car looked at by an efi specialist, (timing advanced to 20 deg and running rich problem solved) now the car has problems going when its cold.
pretty much if i try to accelerate the car will go no where and sound like its dying (like trying to go forwards in 2nd on a flat road) and it backfires in the intake when reved. what could this be and how could it be solved?

PS: the car is running a bit too lean, and the car is fine once its warmed up

[Gunner]

sorry to start on the questions, but u kno how it is lol.

how much throttle are u givin it for it to die?
is your warm sequence any different, does it idle up?

[slide86]

i gather its a 4age?

so by advancing the timing it fixed your over fueling issue?

the lack of power and poping out the intake sounds like the timing is really retarded

[johnny_08]

its a bigport, it idles up fine, and i can pretty much put my foot down before about 2000 then it starts to get power ( or keep it revved at 2G and then go like that)
And nah the over fueling issue was due to high fuel pressure and a broken map sensor hose, they guy said it was at 20 deg advanced tho, it feels good when warmed up tho, just the cold starts?

edit: i had to turn up the idle to keep it from stalling, would this casue too much air to go into the throttle body?

[Nikkojoe]

MAT (Manifold Air Temp) Sensor, had the same problem on my bigport. Try giving it a clean or swap it with another one.

One coldish night i started the car, began to exit car park by going up an incline and car began to miss and pop back through intake. Let the car warm up, it ran better but still would have periods of extremely uneven power delivery and extremely delayed throttle response. Replaced it with the spare mat sensor off my old intake and never had a problem since.

[dustyae86]

<div class='quotetop'>QUOTE (Nikkojoe @ Nov 29 2007, 01:04 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=444051)</div>
MAT (Manifold Air Temp) Sensor, had the same problem on my bigport. Try giving it a clean or swap it with another one.

One coldish night i started the car, began to exit car park by going up an incline and car began to miss and pop back through intake. Let the car warm up, it ran better but still would have periods of extremely uneven power delivery and extremely delayed throttle response. Replaced it with the spare mat sensor off my old intake and never had a problem since.[/b]

hmmm sounds like what my car does once it's cold? try to put your foot down when it's cold and it farts and or trys to rev then revs

[johnny_08]

weird how it mostly happens on an incline, i'll try that, should i get a catch can to prevent it from gettin crap on it again?

[Driftspec]

I too would suggest a sensor hasn't been plugged in properly, or isn't working. Especially if work has been done on it.

[trd16l]

Usually its the map sensor / air flow meter but a tps not positioned correctly may also have some effect.
Some wreckers might let you try the part out, around the block to test it just to see if thats what is is.Anything to make a sale :P

[johnny_08]

so that MAT sensor is the one with the yellow plug going into it with a probe on the end? u reckon replace this, cause mines clean still, or just give it a go yea. and the efi guy said he adjusted the tps so dont think that would be the problem

[Nikkojoe]

Try replacing it with another (if you can). Try unplugging it and see if it goes better.

[johnny_08]

hey i unplugged the MAT sensor and seems to run better now, should i still replace it or just keep it unplugged?

[Nikkojoe]

Replace it, the engine will just run a default fuel map otherwise (shit economy).