I have just fitted T04S etc. However when attempting to tune the car with the wideband the car seem to be 'missing' kind of breaking up when I got to about 0.7 to 0.8 of a bar.
We thought it was running to rich and missing because of this, although we have run it in the tens elevens and twelves and nothing changed, it still seemed to be breaking up when reaching about 0.7bar. Although the car is fine below these boost levels, if I hold the car at 0.5bar it feels great.
Any ideas guys, definetly not the plugs or leads would any of these things give this problem throttle position sensor? map sensor? coils?
Thanks in advance Ross. UK

 

I would start with the ignition system. It may be any part of this, the coils, wires, or plugs. You said it was not the last 2 so I suspect you have swapped them. If this is the case and you still have the problem it could be the coils or it could also be that your charging system isn't keeping up. Since you are in the UK you are more than likley running over 93octane so that will only aggrevate a weak ignition system.

Daniel

 

Another odd possibility.. could it be that your wastegate is not holding the boost properly? What wastegate and spring are you using? If you have ever seen somebody's dyno graph with a bad boost control system, you will know what I mean... the line gets all wavy like a sine wave.

One more thing, please list your modifications such as fuel, engine management, ignition system, etc.... Where did you get your T04S? Is that the kit from XS Engineering?

Regards,
Brian

 

I had a similar problem, I am running a haltech, I had to ground the sheilding wires for the ignition harness, after that, no problems at all..Max

 

Thanks for the replies guys appreciate it.

Dont think it is the wastegate, I have been monitoring the boost whilstit happens, nothing odd there.

Apexi Power FC and Commander. Extended Intake and Exhaust Ports, Garrett TO4S, Panspeed Manifold, downpipe, mid-pipe and back box, HKS Racing Wastegate 45mm vented to atmosphere,Trust Modified SMIC , HKS Remote Oil Filter. Systec Fuel Pump, systec RRFPR, Power Cone Filter+heatshield. FEED Plug Wires. Re-Amemiya Underdrive Pulleys.Trust Hard Pipe Intercooler Kit. SFS Silocon Radiator Hoses. Battery Relocated. Air-Con, Air Pump, AST, Double Throttle, etc, removed. Loom simplified and wrapped

 

Where are the sheilding wires ??

 

They are the bare wires in the haltech cas harness, they pic up stray voltage if not grounded...Max

 

Always try the grounding fix. Check all your factory ground points and add a few more in various spots. An ignition upgrade will help also. I had that problem all last Summer.

 

umm, you should check your timing values, you might be too advanced!

 

I had the same problem with my T04S turbo running above 12 psi for awhile. It's ignition related. Add ground straps and check your plug wires and coils, change all new plugs. The problem should go away. It's apparent because at over 12 psi, the pressure and the extra fuel in the mixture makes it harder to ignite, therefore exposing a weak ignition system.

Fred

 

I have the same problem with my setup also. I'm wondering if it could be caused by a loose plug wire since I recall not being able to tell if my taylor plug wires were completely seated last time I had to pull the coils. I'm also going to test my coils in accordance with the FSM..

 

I have just changed the plugs and put two new grounds in the coil pack area, one going straight to the loom and the problem seems to have gone away.

 

hmm, I put a ground strap going from the bolt on the coils that the harness is grounded on, to the firewall but I am still having the problem.. maybe my problem is not grounding related.

 

Problems leading to ignition misfire are often difficult to find and sometimes you never know what it was that fixed it. Could be a bad connection in a stock harness connector, try plugging/unplugging them several times. Could be an improperly torqued spark plug or a bad set of plugs. Could be a bad coil that tests ok under no load. Electrical gremlins, tuning, ... endless

I fought an ignition misfire for awhile. In the process of playing with connectors and checking every circuit, torquing spark plugs, trying set after set of different heat range and style of plugs, swapping spark plug wires, swapping coils, swapping igniters, and on and on the problem went away. I immediately stopped fiddling and started tuning. Now that the AFRs are right and I have no misfire, I am left with a setup that includes an HKS ignition amp, Taylor wires, stock coils, and NGK race plugs. I'm not changing anything, having too much fun driving!

Good luck.

 

I had the same prob and have associated with persons who have the same problem. Change your plugs! I don't care if they are new, my car has gone through a set of plugs in only 1 day of flogging and tuning. Everytime the car starts to misfire at mid to high revs I change the plugs and all is good. Once the car is tuned properly, plugs should last much longer. I've got nearly 7000km of playful, spirited, "I'm gonna whip yer **** Hyundia boi,so hard yer dealer mechanic will feel it in 2010 u silly ****!!!!!!" driving. Good luck and may the Great God Wankle be with you my son.

 

my problem was just under-torqued spark plugs. d'oh!

 

do you have a way of monitoring your fuel pressure under boost? It's possible your dropping fuel pressure, you should hook your fuel pump up so it see's 12volts at all times.. also if you'd like to send me your map I can take a look at it in fcedit and see if I can find any problems... you can e-mail it to me at dragon@sunny-net.ne.jp also if you list all your mods including injectors, port etc I can probably send you back a map that will put you in the ball park of where you want to be.

I also had my leading lower spark plug wire shooting a arc to the 10mm bolt that holds down the oil filler neak, it was a tiny pin hole and the only way I found it was that there was a small white spot where the arc was jumping out and it only did it at high rpm or under boost..

Chris

 

What kind of plugs are you running? Hopefully not the stock BUR's. Mine misfired up high until I switched to gapable plugs. I even leaned it dangerously out thinking it was too rich until I found the true cause.

s

 

I fought this all last Summer having crapy misfire. I hope that with replacing the main harness and going to full MSD ignition I wont have the same problem. I was going down the same road as Jscott pulling put fuel,and it could be as simple as colder plugs and better ignition. It does not hurt to add grounds, it helped Me.