V555MAC

iTrader: (4)

Driving my car today and it felt a bit flat when on boost and there was a slight hesitation at 4000rpm ish and then it would carry on. There was no CEL light on, the car ran fine apart from this. My car is a V2 STI '555', it was recently serviced and had the plugs changed and has been fine for about 600 miles since. Could it be the coil packs messing about under hard acceleration?.

I really don't want to drive the car now as it feels slow and I don't want to do any damage!!.

It also has a walbro fuel pump, V5 STI tmic, lightened pulley's, bailey dump valve and an apexi ind kit.

Please help guys

Grant74

iTrader: (10)

Did you check for any codes? Not sure on these as still new, but on some cars it can detect a code, but no warning light

m@t STImulation

iTrader: (3)

sounds like coil packs ive changed mine today and its done a world of good stoped my hesitation. think i still neet plugs as mine dips on idle.

V555MAC

iTrader: (4)

Is it worth buying uprated leads and coil packs?

V555MAC

iTrader: (4)

Any other ideas as to what might be causing my running problems??

I've also checked for fault codes and there is nothing showing!!!

HELP!!

TonyBurns

iTrader: (3)

Was it shortly after filling your car with fuel?

Tony

V555MAC

iTrader: (4)

I only run it on Tesco 99 or Shell V-Power, hav't noticed it doing it before??

widdows

when the plugs were changed were they gapped correctly to 0.7mm?

V555MAC

iTrader: (4)

Forgot to mention that I'm a mechanic and do all the work on the vehicle myself, It's just that I've come from a BMW/Alpina background and I'm still learning about forced induction, when all I've ever had are N/A engines!.

Just don't want to spend a fortune trying to sort what seems a simple problem.

Thanks for your all your help so far guys

PS. I did check the plug gaps

V555MAC

iTrader: (4)

Could the dump valve be causing problems?, it's only a few months old and is a Bailey atmospheric type. I've heard a lot of you guys slating dump valves and was wondering if this was one of the reasons why?. I still have the original, is it worth swapping over?.

Would it be anything to do with heat soak from the Apexi induction kit?, I've got a cold air feed coming out of the inner wing, but again I'm willing to try anything to get my car running correctly!

V555MAC

iTrader: (4)

Checked and cleaned the boost solenoid and all seems well, I even sprayed carb cleaner around the inlet area to see if there was an air leak, not a thing!.

Starting to get really *****d off with my 555!

HELP!!

c_maguire

How about the plug leads? You'll have disturbed them when the plugs were changed and if they are knocking on a bit they may want replacing. Genuine replacements were not expensive for my MY00 so worth doing for peace of mind.
Kevin

V555MAC

iTrader: (4)

I cleaned the boost solenoid valve and the unit above it with contact cleaner and the misfire has now gone, but it still doesnt seem to come on boost as strongly as before, I have fitted RCM lightweight pulleys which have improved bottom end and throttle response greatly, could this be making the step up in power come in more smoothly??

V555MAC

iTrader: (4)

Bump

jeffwrx

iTrader: (50)

Have you tried a resetting the ecu, are the coil packs ok (no cracks) did the sti intercooler fit alright.

V555MAC

iTrader: (4)

The coil packs looked ok, the intercooler fitted fine, but I hav'nt reset the ecu. Is it just a case of disconnecting the battery over night and allowing the ecu back up battery to drain and erase the memory?, the ecu showed no fault codes when I run a diagnostic check with the black plugs, so is it woth re-setting the ecu?

Thanks for the feedback JeffWRX

rezaP1

Id concider a new MAF .... then an ECU reset:

1. With engine at operating temp, turn engine off.

2. Locate the 2 ECU check connectors (under the steering column, consisting of a BLACK male and female and a GREEN male and female connector) NOTE: sometimes they are taped over/together.
With Ignition OFF connect Black to Black, and Green to Green

3. Turn ignition ON (DO NOT START ENGINE) Depress the accelerator pedal to floor and hold for a few seconds, then release.

4. Start engine and drive for at least 1 min keeping road speed above 11 KM/H (this bit is quite hard to do if you live in a busy resident area!)

5. ECU is now reset

6. At this point, the Check Engine light should start to flash the all clear signal (steady 1/2 second interval flashes) If the check engine does not flash, or indicates some other sequence, there is a possible fault present.

7. Stop the engine, and disconnect the plugs under the steering column.

8. It is often advised by some to then take her for a run to 'learn' the boost, and select 4th, gently bring the boost up to around 0.7-0.8bar, hold for a sec or 2, and then floor it to see if boost is restored.