My vlt will missfire really badly at high revs but only when im NOT punching it... It wont miss if im full throttle and hitting boost but if im half throttle and not boosting it will just miss like crazy. Any suggestions what it could be? I can hear a slight vac leak near my plenum which is causing it to idle at about 1000-1500 rpm too. UPDATE: I have replaced my AFM wiring and cleaned the connections, and replaced the in tank pump. The car is now so bad that it idles fine but as soon as i start driving it coughs, splutters, missfires to the point where its undrivable....

running lean, (fuel system fault) plugs are fouled up dizzy cap seen better days spark leads stuffed. blown a hose off under the throttle body btw, VL ECU's don't work to well over 8000rpm

Might be your power transistor. Maybe tape up your air leak with abit of duct tape & see if it makes a difference.

I just went and bought a new dizzy cap because mine is a bit warped on one of the plug nobs because my old cooler piping used to hit it. Ill keep you posted though. I cant actually find the vac leak but i can hear it lol

check the injector seals at the manifold.. they can crack and cause air leaks.. I miss read your original post... "only when not punching it" its due to the air leak for sure. under full throttle, with the extra fuel enrichment and the fact boost is blowing out the air leak and not in to it, the engine isn't running so lean and no missfire.

- Fixed the vac leak - Put new dizzy cap on Runs a lot better but its still missfiring at about 3-4000 revs. It happens when im at about half boost. Im running 10 so it happens around 5psi... I DO have a slight leak on of my injectors, That will be the next thing i try Some original photos have not been recovered yet.

if you r going to take the injectors out, get them serviced so you can get some flow specs on them. since it looks like you are in Sydney, Andy from Australian Fuel Injection in Peakhurst would be a good start. good prices , knowledgeable on VL's. If you call in first he may even be able to do same day service.

fuel or timing My best advice would be get it on the dyno find and fix the problem straight away, get it tuned properly through the rev/power range pin point and pay to repair whats wrong. You could keep guessing but ive done that time and time again and spent large amounts of money on a $20 fix lol

I was going to take it to maatouks today but he isnt in the shop on weekends. I also forgot to mention there has been a couple of backfires this week, one been extremely loud like a gunshot. Scared the SH!T out of me! Will AFI take them out and re-install them too? Or do i need to take off my rail and just leave the injectors with him? Any idea on approx cost per injector? Cheers

I'm not sure if AFI work on cars as I only take them the injectors or buy them from them. It takes less then 20 minutes to remove 6x connectors, 2 bolts, 6 retainers and cut 6 fuel injector hoses and undo 8 hose clamps. If you have the mechanical confidence, I would check this first before taking the car anywhere as you may not make it. since the problem is getting worse it may well be on eof the fuel pumps. AFI charge about 20 or 30 bucks to test them and around 120 or 130 to service them. new seals top bottom, new hoses etc. If they check out, atleast you have peace of mind the are all good. remember to ask for flow test results when you hand them over and I'll help you decide which port to reinstall them in depending on the results.

Yea my daily isnt regod at the moment so i need the VL to get to work. Is that 120 each or for all 6?

Fuel regulator or CAS maybe. A good post here ---> http://www.calaisturbo.com.au/showth...=172136&page=2 (http://www.calaisturbo.com.au/showthread.php?t=172136&page=2)

Got a malpasi rising rate reg. im going to change internal and external fuel pumps as i know my internal is lazy (takes 5 or 6 primes to start in the morning) and my bosch 044 is really noisy. ---------- Post added 18-11-12 at 19:05 ---------- Just changed the plugs and gapped them to 0.8mm today. Also repaired a damaged red wire coming out of the o2 sensor. Runs a lot better but still missing at certain revs/boost... I found the injector leak was just a loose bracket, i tightened it up and it seems to have stopped leaking. Going to try get a tune at maatouks 2moro, hopefully he can find the prob.

Just got back from maatouks. Anthony said i pretty much need an aftermarket computer to fix it properly. He has adjusted the fuel reg to make it safely drivable. Problem was it was just pumping too much fuel in and making it WAYYYY too rich, but he cant make it run lean without making it dangerously lean in high revs. For some reason the car now wants to start by idling/running at low revs really rich then get leaner as the revs get higher, when it should be the complete opposite. MY CAR IS BACKWARDS!

have you been using a pod air filter like a k&n or just the standard one? Did the injectors check out ok? I can diagnose the factory computer system and all its sensors if that is the fault. usually takes about (15mins). If need be the ECU can be tuned to suit your mods, although I think that the MAF/AFM is the cause from what you just wrote, but I still would test the flow rate of the fuel pumps to be sure.

Yea i use a K&N pod filter. He said that putting the forward facing plenum on and moving all the sensors would have caused it, but i did that weeks ago and it was running fine until now. What do you charge to check it out? Where are you located mate?

Malpassi's are ****. Too many fake copies around.

Quote: Originally Posted by swifty! [View Post] Yea i use a K&N pod filter. He said that putting the forward facing plenum on and moving all the sensors would have caused it, but i did that weeks ago and it was running fine until now. What do you charge to check it out? Where are you located mate? Some people just want to sell you a bigger turbo and a microtech to fix it. I have a good idea of the what is causing the fault but if I see the car I can tell pretty quickly. No charge if its what I'm thinking matey. I'd feel guilty. PM me and we can swap some details.

I have replaced my AFM wiring and cleaned the connections, and replaced the in tank pump. The car is now so bad that it idles fine but as soon as i start driving it coughs, splutters, missfires to the point where its undrivable....