Need help Chevy v6 with holley projection

[echas9]

Cant seem to find fix to approximate 2200rpm misfire and backfire. Spoke with holley they wont help because its a v6 and says there system is only compatable with v8. is there a work around to fake out computer

[steveo]

need way more details about your engine, what's been done to it, what the misfire is and how you know its a misfire, which holly system, post pictures, send your first born child, etc.

if we have all that stuff im sure we can help you at least tune around it..

[echas9]

Chevy 4.3 v6 Fresh rebuild stock cam, compression, 1.6 rockers, tbi spacer, factory tbi manifold, engine will run slightly rich above stoich if slowely accelerate at approximately 2200 rpms engine falls flat, goes way lean than has backfire. If accelerate hard before misfire engine will rev smooth all way to 5000. Fuel pressure steady at 12.5. Running hei ignition, holley projection 2d analog controller with the adjustable dials. found out after purchasing and installing kit that it is only for v8. thinking that since its v6 that tach signal is confusing the computer and fuel curve causing it to trim itself at break over point. holley 502-20s is kit. found a dakota digital interface that can take a v6 signal and convert it to a v8 tach output signal and then i could modify lean/rich condition. Im open to any/all ideas just need to get the rig moving asap. Thanks guys.

[steveo]

ah, so this is one of those 'kinda self-tuning' systems that doesn't do ignition, does it.

yeah i'm not suprised there's issues

i dont think a lot of guys here have much experience with that particular knob-tuned system

but thinking about it; a v6 tach signal should barely even cause issues with running on a TBI ecm, if it's just doing fuel and not spark, and the ecm isnt presumed to have a correct mapping anyway..

you may be on the right track with the tach signal.

i guess if it was my engine i'd try it

(or maybe get a real ecm)

[Six_Shooter]

No Holley 2D pro-jection is no where near self learning. It's basically an electronic carb, and is worse than a carb IMO.



I have read so many times about people that use these systems they would mount it under the dash within reach of the driver seat so that it could be adjusted while driving...

Best thing you could do is ditch it and go with a GM ECM, or if you must go aftermarket, a MegaSquirt, BS3, SDS, but not any of the "self learning" systems, I have yet to meet someone that is truly happy with them, and there are more than a few people around me and that I know that have been talked into using those systems, namely the FAST version.

[echas9]

Who would you recommend. Could I use stock ecm and then add additional sensors needed. I'm just so far into this kit with wiring and parts hate to just toss it.

[buddrow]

I agree with Six_shooter, ditch that b^&*h and grab a factory ecm and related components. Tuning with a knob is fine for youre stereo, but not so much for your engine.

What sensors do you have in place now?You should count on installing a tbi distributor, knnock sensor and ESC module all of which match your engine(4.3v6?) as they are different between engines and will positively affect driveability. Is this a stock application, meaning did the vehicle have TBI factory or is this a retrofit?

Now with that being said, you can try Steveo's suggestion and alter the tach input to see if it helps, if not, time to do it right(no offense).

Buddrow

[steveo]

that'd be like opening some tuning software and finding one scaler labeled 'fuel'.

i didnt realize it was such a peice of crap

get rid of it, there's no way to make that right

[fastacton]

I think you'd be much happier with stock GM TBI on a 4.3. You can always sell off the system you have to offset the costs. I have a TBI 4.3 in my '51 Ford Panel and it ran great until the head gaskets went (great excuse for the LS swap and there was 300k on the motor). Even with the panel body, much bigger tires and the stock tune, I had great drivability, decent acceleration and good fuel mileage going down the highway cruising at 75-85 mph. I could get you what you need and I'm sure there are others on the site that can as well. Or hit up eBay for pretty much any TBI stuff you need.