Sachin Misra

Here's the latest...(Before this sounds like a rant, let me tell you I'm pleased with the power, just annoyed with the little technical bugs)

Boost guage has been indicating about 6-1/2 lbs boost max with no intercooler. The blower discharge does get pretty hot (I'm guessing intake temp is around 100-120 deg F. IC design is complete and is being fabbed, it will be ready next week.

Now for the "Issues"................................................................ ....................

My CEL light has been coming on every couple of days, I was geting misfire codes which would trigger the CEL. Got a hold of TPC and they said the increased demands on the engine was stressing the ignition. They assured my tech that upgrading the coils and wires would eliminate the problem.

Changed the ignition coils to the upgraded ones recommended for the 993. Changed the spark plug wires as well. Guess what...! The problem got much worse. Now the car hesitates when you put the foot down, backfired a couple of times.

My tech & I now think that the engine is being starved of fuel. Maybe the fuel problem was always there, and the old ignition just masked the problem. Now, with the hotter coil the fuel just can't keep up?

Questions...
1) Is our assumption of "Not Enough Fuel" correct?
2) Is this something the intercooler will rectify when installed, since the charge air will be a lot cooler?
3) How do I get more fuel to the system...Replace the 7th injector with a GT3 injector and have TPC remap the air/fuel mixtures?
4) Do I get rid of the TPC EMS and install a different EMS, GT3 injectors and an adjustable fuel pressure regulator?
5) Is there a different EMS available? I remember someone in Australia ditching the TPC EMS and using a Unichip piggyback system with GT3 injectors.

Thanks in advance for any help.

JW in Texas

Sachin,
I know it's frustrating but I would wait to make any further changes until the IC is on & you are in the final configuration. Then start chasing glitches.

It's hard to tell if you are maxing out the injectors without a read out of injector duty cycles. I would get the IC first & then try upgrading just the 7th injector to see if things improve any. That should give you some indication of whether fuel shortage is the culprit under load.

Going to a different EMS is an option albeit a pricey one & you will have to get up to speed with it also. I'm running the EFI box & it's pretty adjustable. I would go here:

http://www.efisystems.com/manuals/po...rschePMSOP.pdf

& read the EFI manual. You can never have to much info & you may pick up an idea that will help you out.

This link just gives you a basic rundown of the system:

http://www.efisystems.com/pms.html

My car is fairly docile but it is still a hot rod compared to stock drivability traits. Keep pluging away & good luck

JW in Texas

Sachin,
One more thing. If you get a chance, go grab the latest issue of Grassroots Motorsports Magazine, May '04 issue. It has a great article about fuel injector selection.

MPB993

Sachin, I've not had any of the issues you are experiencing. Even when I was running standard boost. I'm now running 9lb boost on 9.5 compression but with 50:50 methenol/water injection which helps with the intake temperatures. It also killed any knock I had. I watch the afr and know that it is ok all the way to red line even with the increased boost but I had to remap the higher boost fuel settings on the TPC ecu. So the standard injectors and 7th injector provided enough fuel for my setup. The intercooler will help but I decided to take my chargecooler off. I havent looked at a new ECU upgraded injectors as mine seems to work fine in its current form. Not sure what I can add to what has been suggested above.

Regards, Mark.

Sachin Misra

Thx everyone.

Mark,
How did you remap the TPC ECu. Is their software available? Can you shoot me a copy of it?