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I like to keep it simple...

Bump.

Did you get your high RPM missfire solved? I noticed in one pic that you have D7EA plugs installed. With EFI you need resistor plugs. Get a DPR7EA plug.

Steve

Good eye, Steve. Yes, the resistor plugs were part of the problem, as were the Magnecor wires. The misfire was actually EMI causing the ECU to cycle off and on. I replaced the setup with resistor plugs and MSD wires and the issue disappeared.

We all have had this problem. It is amazing how hard that it is to track down since it only seems to show up under high cylinder pressure.

We are all looking forward to updates on your project when you get a chance.

Steve

Steve Arndt wrote:Bump.

Did you get your high RPM missfire solved? I noticed in one pic that you have D7EA plugs installed. With EFI you need resistor plugs. Get a DPR7EA plug.

Steve

Sorry for the hijack, but please explain this one?

Tony Z wrote:

Steve Arndt wrote:Bump.

Did you get your high RPM missfire solved? I noticed in one pic that you have D7EA plugs installed. With EFI you need resistor plugs. Get a DPR7EA plug.

Steve

Sorry for the hijack, but please explain this one?

EMI from non resistor plugs messes with integrated circuits.

http://www.ngksparkplugs.com/techinfo/s ... sistor.asp

Frequently Asked Questions

Q: When should I use a resistor spark plug?

A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.

In fact, using a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.

« Return to the FAQ main page

Steve Arndt wrote:We all have had this problem. It is amazing how hard that it is to track down since it only seems to show up under high cylinder pressure.

The funny thing was that the EMI became so bad that it was turning off the ECU, even at low RPM and when cranking. You could watch the LEDs on the ECU and watch it cycle off and back on several times. I narrowed that down to a bad Magnecor wire. I replaced those with MSDs and the problem was solved for about 6 months. As the high RPM miss returned, I grew wise to replace the spark plugs with resistor plugs. It's a shame because the majority of headaches I've had with the Tec-II and Tec-GT could probably be linked to those plugs

We are all looking forward to updates on your project when you get a chance.

I'll post up as everything comes back together in the next month or so.

Stripped66,

Just wondering if you have any updates?

Inquiring minds want to know!!

BJ

Stripped, we know you have updates. You only share with the ultimate aircooled group now?

Steve

Tell us about the unlimited street east racing. We have all looked at your gallery already.

I just posted those pictures today.

We want to hear some performance reports. Didn't you run 117 MPH or something insane at your first race outing? Have you dynoed it?

Do you have a picture of your intake plenum and TB setup? It is pretty hidden behind the cooling shroud. I'm testing a set of CB end castings right now instead of the ITBs. I had to change my start of injection event from 390 to 450 degrees to bring things inline.

It ran 7.59 @ 97mph in the 1/8th mile. No burnout, 1.7-1.8s 60', no speed-shifting. My rpm through the traps with my final gear and tire size should have given me 107mph...so, I may have some clutch slippage to address.

Nothing overly impressive, but a good first time out with room to improve. Certainly not 117mph, so I'm sorry to disappoint.

I'm still running the same throttle-body and end-castings as I was before I added the intercooler (there are better pics of those components in my gallery), so nothing has really changed on that side. Yet.