Right.V2 Sti 96. I've recently fitted Harvey's ported headers with matching uppipe, drove the car for couple of days and everything was absolutely fine, spot on, till I decided to reset the ECU. Straight after that car started choking on a low throttle between 1500-2000 revs. The symptoms are like the petrol runs out. It's choking but only in that range of revs on light throttle. Above that range is absolutely fine. If I'll put my foot down is OK. Never happened before !

Any ideas ???

 

Anybody ?

 

If you have fitted ported headers and uppipe then you really need the car mapping, its telling you its not happy with that at the moment

Tony

 

By resetting the ECU it would have cleared all it's 'self learning' and as already said, a remap would be a very good idea anyway

 

Hmm... Cheers guys.
Would faulty/bad coil pack give similar symptoms ?
This is very weird 'cause it only does that at low revs 1000-2500 when just touching acceleration pedal. When pushing it "harder" is OK. To me it looks like something is wrong with ignition.

 

If I only know that resetting ECU will cause such a problem I would never do it :-(

 

Just came back from shopping, driving through town centre in big traffic is a real nightmare. The car behavious like a Kangaroo !!!
Can somebody tell me the symptoms for faulty coil pack and fuel pump ? I've got a feeling it's due to ignition or fueling.

 

did you put the lambda sensor in the new headers, and have plugged it in ? headers wont cause that problem at low/load revs.
If its all as it should be i would test the sensor is working if i were you

 

Hi. There is no lambda sensor fitted from the beginning. As I said it was Spot On after fitted headers till I reset the ECU

 

assuming your on standard ecu ? is your lambda sensor in the top of the downipe then ?

 

Yes, it's standard ECU (6K) with Major_Sarcasm chip. I'm running fully decat system without lambda sensor. I own this car for nearly 3 Years now (with no lambda) and NEVER had such a problem.

 

whats your fuel consumption like ?

 

Believe me or not but it's Very Good. I'm doing 250 miles on a full tank. Mainly going to work and back (5 miles each way). If you'll drive my car without looking at the fuel gauge, you would say that petrol is running out. Everything is back to norm above 3000revs - kicks as normal. Only does it at low range, on every gear. Let say rolling on 4th at around 2000 revs if you want to accelerate it start choking for few seconds and when you reach 3000 is OK.

 

1st, 2nd and 3rd gear are the worst ones. It does it really bad and I think it's getting worst. It feels like running on 3 cylinders for few seconds and then everything coming back to norm.

 

ok im a bit puzzled then, if you have no lambda you should get the cel coming on plus more often that not poor fuel consumption????

 

if it were an ignition or fuel pump fault you would expect it to show up worse in the higher load/boost areas, the lambda is only used in the areas of low load/revs you describe and is ignored above that

 

How did you do the ECU reset?

 

Reset - I unplugged the battery for about half an hour and plug it again.

 

Oh, forgot to say, sometimes when taking foot of the throttle it pops/bang (exhaust).

 

Had a similar issue once when i unplugged a Power FC ecu. Checked everything & all was fine, then i unplugged the fuel pump connector & connected back up & it started working fine. Weird i know, but worth a try.

 

Ok I'll disconnect the battery and see if it help.

 

Hi. I reset the ECU again and... STILL SAME :-(
I also noticed that it doesn't do that when engine is cold. It starts doing it after a few hundred meters when starts getting warm and warmer the engine is, it seems to be worst and worst. Also, the idle is steady, I mean it holds it revs (around 800) but you can feel that engine is not running smooth.
Please HELP !!!
I'm going Wales on Saturday so I need a car in fully working order.

Thank You

 

is it throwing up any fault codes...

 

I had exact same problem just recently, It turned out i had the smallest of holes in the fmic, I got back fire more like antilag, and idle was shot but fine on full throttle, and it jerked in low rev's So if i was you look for a air leak

 

SORTED :-) !!!!!!!!!!!!!

It was a Lambda sensor. Time I was changing headers I unplugged it thinking it was a EGT sensor (exhaust gas temperature sensor) and left it hanging on a side. I thought my car hasn't got a lambda 'cause the hole in the downpipe was blanked off. I didn't know that Classics 93-96 have lambda in headers. So, I plugged it in to the downpipe (luckily the wires were enough long) and my Beauty is back to Live :-)

Every day is a new experience, isn't it ?

Thank You guys for all the replies.

 

il take that as a thank you then

 

:-) P1 Drifter
Yes, Thank You !
I'm so glad it was that, otherwise I'll have to take my wife's car (going Wales next weekend) but definitely NOT same fun and pleasure as going by Impreza :-)

 

That's what I said mate, it must have a lambda sensor as it wouldn't be able to control the afr. At least it's sorted now

 

your welcome glad its sorted mate