[6D6GOAT]

trying to get my holley TBI fuel injection dialed in. she runs great up untill 4000 rpm and then starts bucking from that point on. i called Holley and the rep told me he thought it was RF interference and that i needed to find the source....i feel as if i am about to embark on a wild goose chase.

Has anyone had this problem? my set up is: Holley 900 cfm, vortech blow thru.(6-7 lbs boost) mallory MAGNETIC pickup style distributor (no spark control). the ECU is mounted under my dash to the left of my steering wheel.

also, at what AFR does an engine begin to fall flat/miss at WOT? I cant get my AFR richer than 13.1 at WOT (that with the boost coming in)


help, my baby wants to stretch her legs

[Hammered]

The RF diagnosis sounds like BS to me. The electronics are in a sealed metal case that you should have grounded.

[krisr]

What coil and ECU is it?

I tried to setup an MSD HVC2 Blaster coil on mine and for the life of me I could not get it to work properly with the ECU firing a 6AL. It would have a miss/stumble at any random point in time and could not diagnose it, except for when I put the old Blaster 2 or Blaster SS coil, the car would be perfect.

A miss can be diagnosed as lean AFR as you're sending alot more oxygen out the exhaust than you normally would be. You would have to have very messy wiring for it to be RFI. To cause the ECU some pain, your distributor pickup wires would have to be 1-2" away from spark plug leads, alternator charge or main battery lead etc... To combat that you should route your cabling perpendicular to any high voltage stuff. I have heard however, that Holley TBI injectors are noisy on the flyback circuit...

What's your spark plug gap?

[6D6GOAT]

the ECU is grounded fine. there might be some validity to the RF interference. i re routed some of the harness and it seemed to help a little bit. i am going to really tear into it later and re route all of it to the drivers side inner fender. away from the distributor, coil, MSD box and alternator wire.

for the tach input for the ECU im using the tach output on the MSD box. i know that that wire runs parallel with the main power wire going to the MSD box for at least 2 feet. i ll re route that one as well.


here is a pic of the datalogger. the crazy up and down blue zig zags are my injector pulse widths. the light blue is the engine RPM. red is MAP. brown is AFR.

[krisr]

I loomed up all my wiring under the intake and cable tied it to the hole in the back of the block that you use to pick the motor up with. My wiring is done like a "spinal cord" right the way down to the coolant/tps/IAC in the front.

Make sure your tach signal wire to the ECU is shielded! Can't stress how important that is and only ground it at one end so you dont get a ground loop which is the hardest thing to diagnose.

[6D6GOAT]

thats pretty much how mine is. Im wanting to the wiring and everything as far away from my distributor and coil. I am going to re route the tach lead and just for fun im installing an inline power filter to the ECU.

when you say just gound it at one end what do you mean? my system has one ground wire from the ECU and it says that the ECU body itself needs to be gounded ( i ran a seperate ground wire for that.)