KingpiN.SC

iTrader: (1)

I recently purchased a Gs3 with a GTE Aristo Swap.. It had a few problems, but I managed to work most of them out, with the exception of the following:

The car is Sputtering/Detonating at 14psi only on full throttle, with the TTC mod (true twin conversion).. The car will seem like it really wants to get going, and then when I ease into full throttle, it will sputter intermittently at around 4k RPM all the way to redline.

I have done the following:

Changed Spark Plugs
Replaced fuel pump with Walbro 255lph

It still does it, and it seems like it is starting to get worse. I am leaning towards an ignition problem, but I want to get a good baseline on where to start looking first... Any ideas??

GoFastTSI

iTrader: (1)

First off, what plugs and what did you gap them to? Secondly, do you have a wideband O2 to monitor? What do the plugs look like after a wide open throttle run (are the electrodes white or black?). When was the fuel filter last changed? Lots of variables here. I agree, it sounds ignition related but it could very well be fuel.

Kaiser

iTrader: (1)

I'd lean towards fuel with detonation issues. You could also try bypassing the fuel ecu.

147noob

iTrader: (1)

is it factory ecu cause i thought that boost cut one our cars were 11ps1 if u havent bypassed it in some way just my $0.02

KingpiN.SC

iTrader: (1)

The car has a fuel cut defender. Strange thing is, it was running just fine on the same boost before yesterday. I have been troubleshooting all morning, and here are some ideas that I came up with:

- Boost leak somewhere in the piping
- coil ground
- crank angle sensor

I had just replaced the spark plugs with some NGK Laser Iridiums, and left the standard gap. The plugs that I pulled out of the car were some platinum 4 prong junk plugs.

I also noticed that I need to replace my valve cover gaskets, as there was some oil in the spark plug holes. I am staring to think that under full load the coils are arcing..

I decided to put a few gallons of 110 octane in the car, just in case I may have put bad gas into the car. Shook it all up and drove it around out of boost for about 10 min, then tried getting on it, and no luck... the problem is still there.

I have heard about bypassing the fuel ECU, and when I looked at the wiring, it looks like someone has done something very strange with the wiring. I will post up a pic shortly.

Still stumped...

GoFastTSI

iTrader: (1)

Check your coil packs. If you have oil in your spark galleys along with cracked coil packs you will have the same issues you are describing. Also, depending on the year of your GS, you may not have a fuel ECU; my 94 2JZGTE swapped GS300 doesn't.

KingpiN.SC

iTrader: (1)

I do have a fuel ecu, but the previous owner did some weird wiring to the fuel ecu's harness. I am guessing it was because they wired in the Aristo/Supra TT pump. Not a clue though. They also hooked up an ebay fcd, but I am going to order a legit one shortly.

I just ordered some NGK BKR7E plugs, and am planning on repairing any cracked coil packs this evening while I change out my plugs..again.. Clear nail polish and heat shrink tubing for the win! haha. Got a gasket set on order as well, so that should hopefully make the coil packs and ignition system a whole lot happier.

I was definitely leaning towards a spark issue, so I ordered an AEM UEGO wideband kit as well. That should tell me exactly whether the problem is fuel or spark related.

Keep the suggestions commin guys, and thanks for the help thus far!!

KingpiN.SC

iTrader: (1)

Here are the pics of the fuel ecu wiring:

moejz

iTrader: (1)

Use the NGK 6097 plugs - gapped to between 24 to 28 thou... ( its a cooler plug for the turboes and smaller gap will prevent spark blwoout ) . I never run any iridiums or whatever in my turbo cars.

For the coil packs, check for cracks. Even if you don't see any, use some 1 inch heat shrink and cover the coil postst and insulate it. It may be arching.

A good insurance is to buy a Wide band sensor and also get your car tuned. If you are detonating, your engine will not last very long. Better invest in some wideband and at least and SAFC-II or Emanage to tune the car. This is a cheaper route athan rebuilding an engine.

get rid of any no name brand electronics from your wiring harness. especially if you don't know what it does and what the specs for it is.

Kaiser

iTrader: (1)

The black harness is the fuel pump ecu and it has been bypassed. I don't know wtf is up with the red 8 gauge wire tho.

The fuel cut defensor has to be calibrated to the correct voltage. You could always check to see what it's dialed in at.

KingpiN.SC

iTrader: (1)

Thanks guys! Fixed the problem. Changed the valve cover gaskets today, replaced the plugs with NGK BKR7E (properly gapped them), and put 1" heatshrink on each coil pack. It feels great to finally give the car some throttle!!

KingpiN.SC

iTrader: (1)

Thanks guys! Fixed the problem. Changed the valve cover gaskets today, replaced the plugs with NGK BKR7E (properly gapped them), and put 1" heatshrink on each coil pack. It feels great to finally give the car some throttle!!

GoFastTSI

iTrader: (1)

That 8 gauge wire is the 12-volt mod to the fuel pump. Common Supra upgrade. Glad to hear it's fixed!!!!

Kaiser

iTrader: (1)

That 8 gauge wire is not necessary to do the 12v mod. Cut two wires and twist together and done. The 8 gauge is not the right way to do it which is why I question what it was doing there.