Boost Problem

[JaseYpk]

Car 'Judders' when accellerating & Doesn't Idle

Since the car has been back on the road, she's been through 3/4 of a tank of fresh 99, and had 1/4 of 4 month old 99 in it.. so this may just be dodgy old fuel still in the system, but i'd rather get opinions.

basically, i found a hose flapping about in my engine, coming off a T piece to the right, which i located the place for it to plug into (on the intercooler pipe). So it got plugged back in and cable tie'd up.

But the problem remains (since repair) - when coasting at a set speed around 3500rpm at any particular speed, she quite frequently 'judders' like what happens when the car is about to stall, or bouncing off the redline.

but as soon as i put my foot down, no more juddering.

EDIT - Car judders whilst accellerating gently, but i can floor it and accellerate through it. although this worries me slightly so i'm not doing it anymore

Thats the main problem..

The other problem (which ive had since i got the car), is that it cuts out (usually after driving hard) when i put the clutch down or bring the car to a stop. Basically, it doesnt idle. it goes right down to zero, unless i give it some and manually idle it with my foot around 1000, for a few seconds, then release gently, and itl start idling as per normal.

Any ideas? or is a remap a good idea? I figured it could be fuelling.. hense the remap.

Any help on the juddering or cutting out would be mint

 

[Silverstreak]

The Idle problem could be the idle control valve, I had a similar prob a few years back on a different car.

 

[craig8585]

Do you still have your recirc valve fitted?

 

[JaseYpk]

The Idle problem could be the idle control valve, I had a similar prob a few years back on a different car.

is there a way of diagnosing whether it is this or not? and how much am i looking at for a replacement part?

Do you still have your recirc valve fitted?

yeah got the standard dump valve under the fuse box, havent touched it. thinking of fitting a HKS SSQV when the times right. you reckon this could be the problem?

 

[LuPix_S15]

My car would sometimes cut out when I dip the clutch and the revs drop all the way down until it cut out!!

But this was fixed when I got rid of the Blitz BOV which was the cause of all annoying problems like idling and hunting grrrr. So I'd be surprised if the stock recirc caused problems as you don't have a BOV to atmos setup like I did (and more importantly a BOV on the hotpipe side).


Maybe you need to ensure the boost pipes are deffo all correct and airtight so no leaks etc. Juddering I associate with coilpack failure or... possibly the ECU is not fuelling correctly or there's air in the fuel system but if you've refulled and made sure there's lots in the tank I can't see that being a problem.

Try a reset of the ECU before you do anything else

 

[andeep]

I had the cut-out problem all the time. Just adjust the idle control valve a tad and it should sort it out.

 

[JaseYpk]

Try a reset of the ECU before you do anything else

How do I do that?

I had the cut-out problem all the time. Just adjust the idle control valve a tad and it should sort it out.

Again, How do I do this? lol

I've also noticed a nice black soot appearing around the bumper by the exhaust, and the inside of the exhaust is VERY black compared to how it used to be... its starting to worry me something rotten

 

[andeep]

There's a black plastic screw to the left of the engine at the back on a round thing with a blue label of it. Sorry for the crude description, will try and get a photo later.

What mods does the car have? Black soot in the exhaust is normal, but it may be an over fueling issue.

 

[JaseYpk]

It has no engine mods other than HKS air filter, an aftermarket exhaust (which is very close to standard, twin tail etc. original owner fitted it as he couldnt get a standard one) and a 50mm radiator.

I'l have a look for this plastic screw tomoro when its light. what do i need to do with it? just twist it? how much are we talking about if so?

 

[andeep]

Do you still have a CAT?

Just let the engine warm up fully, then get someone to sit in the car and read you the idle revs as you turn the screw.

 

[JaseYpk]

Oh, it idles fine once i've manually let it rest, its just say 1 out of 3 stops at traffic lights nearly ends in a stall! but when it idles its idling around the right range (800ish)

As far as i'm aware i've still got a CAT.. it might be F'd though.. passed its MOT last week so i'd have thought it does lol

 

[Curryzz]

Have you had the car on a diagnostics machine yet? I had similar things happen to my and the stalling was down to a nakered oxygen sensor in the exhaust

 

[JaseYpk]

nah i havent yet, will any garage be able to diagnose it do you reckon?
edit - the idling problem seems to be solved (sort of) The hose coming from the cold air pipe going to the T piece was bodged with a cable tie, so i put a better fastener on it and now the car doesnt drop off... it sometimes goes right down to 100, battery light flashes, then it starts to idle. without cutting out.

i know how terrible that description was so here's a picture lol

the hose i removed and refitted goes from the two red circles, and the arrow was the end with the bodged connector, which now has the proper one on.

Note to self - check all hoses & connectors before anything else!


The juddering problem however still exists.. any suggestions?