SideWinderGX

Hello!

First off, the issue: while driving at either wide open throttle for extended periods of time or going to downshift (I say mostly because it happens at part throttle occasionally) the tach goes to 0, throttle response is non existent, basically the ECU has quit telling the coil to fire (or the coil isn't telling the ECU what's going on)...BUT quickly resetting power to the ECU allows the car to come back alive while it is still moving. During this time the car does not lose power, but the tach stays at 0.

I understand this is a weird issue, so here are some details on the car:
-1995 Integra with P75 ECU
-gutted to the bone with a cage, currently being run in a local race (don't want to disclose too many details )
-no more main relay, no more main wiring harness, nothing. Everything important going to the ECU is working. The ECU/power for injectors/power for IACV is run off of one switch. Power for the fuel pump and radiator fan is run off of a second switch. Gauges are run off of a third switch (voltage, fuel, tach, oil pressure, water temp).
-Tach is spliced into the yellow/blue stripe wire going to the ECU from the coil. Again, everything works except for this intermittent cutting out issue.

New parts we've thrown at it:
-new rotor and cap, new plugs, new plug wires
-new ignition coil
-new ignition control module
-fuel pump is good and the sock is not clogged
-ran a ground for the two ECU grounds directly to the battery

Possible fixes:
Another team running an Integra said they had the same issue and had to wire in the stock speedo cable/dash cluster because the ECU *needed* the VSS signal and would do EXACTLY what we are describing without it.

A mutual friend of the teams thinks the ignition coil is heating up too much from extended time at WOT. He suggested leaving the coil cover (the square thing behind the rotor) off and drilling a few holes in the back of the cap to vent some air and cool it down. This sounds like a good idea, but before I go drilling holes in anything I'd like to see if someone has run into this issue before and knows/has a solution. edit: Another Integra guy said we should run a ground from the thermostat housing ground to the body somewhere.

That's the end of my speech, any help is much appreciated. Thanks!

tamboo

i'd double check the ignition stuff just to verify they werent bad out of the box, it happens more often than you'd think. tach issues usually mean bad icm.

http://www.team-integra.net/forum/bl...eshooting.html

SideWinderGX

Awesome thread! I'll go through that when I see the car next, thanks!

Small update: we left the dust cover off, ran a ground from the thermostat grounds to the chassis. The car ran great and didn't experience any issues for approximately one hour of driving. Driver change, and the issue is back, stalls maybe once every 2 to 3 minutes of driving. For the next few hours the issue persisted.

After driving it for an hour and looking at gopro footage, it backfires most of the time the split second before it stalls, and almost every time its when we're hard on the brakes or shifting.

GannyX

it pointing to grounding it spark out... had the same issue but ( rb25 so bit different) it was my coilpack jump a spark to the head instead of the plug

holmesnmanny

Are you using shielded wire ? You must use shielded wire for all vital sensor wiring or they will pick up radio interference. This has been confirmed to be true by myself with regard to knock sensor wiring.