pcmhacking.net

Hey everyone,

I'm currently pulling my hair out trying to figure out what is going on with my car, just finished the conversion, and the issue is as follows...

When I turn the ignition on, all data updates in realtime, tested with the TPS sensor (pushing accelerator down) and acts just as it should, as soon as i start the car, start getting errors coming out my ass. I can write to and from the NVRAM, no problems, its the live tuning thats causing issues as it craps out as soon as I start the car, and starts going haywire. Current setup is as follows.

VR V8 Auto (4L60e) '424 with $11p OSE 1.0.4
New Ignition module
New distributor
Edelbrock vic jnr single plane hi rise
edelbrock 1250cfm quad throttle body
New Dissy cap and rotor button
New MSD Blaster Ignition Solid State
New Low resistance aeroflow x pro leads and resistor spark plugs (I decided to check these before posting)
NVRAM and ALDL USB Cable from Antus (ferrite bead on USB cable)
Speedhut gauges and VSS is hooked up to gauge with a 4.7k inline resistor as per instructions.
Changed latency in driver settings to 12ms to see if that helped, no change
High impedance 440cc injectors (15ohm)

I've attached a log below, there is data of me pushing down the accelerator cable before I start the car, the revs go up and then the data errors start which you will notice. Transmission data starts doing all sorts of stuff as well, got me buggered why its going haywire.

I've disconnected the wideband from the fusebox, pulled out the 12v wire from the OBD port (I wired it in, thought it may cause issues so removed it, so far nothing has changed, still getting data issues flat out)

Really getting stuck on this now with what to do. Any help will be really appreciated as I'm just trying to dial the tune in now as its a bit rich ATM. I've literally calculated the change in fuel injector size, put it in the tune so it wont flood it, kicked it in the guts and thats pretty much it. Car starts but runs like a dog and on idle falls on its face eventually. This is a conversion in a 1975 HJ which is a twin turbo setup. Currently running NA ATM with a stock 1 bar map sensor and no turbos on the car so I can get a base map down before screwing with boost.

Could be the msd driving it nuts with rf interference if it's close to wiring or a capacitor on the positive of the coil to earth to stop surges up the 12v feed line

Cheers Delcowizzid,

I had my suspicions about the MSD Solid State Coil, only replaced it due to the OEM being faulty and thought I may as well upgrade it for a better one. I'll try a capacitor on the coil and also on the alternator as well. I've pretty much replaced everything on the car with new aftermarket parts. I was hoping it was something simple like the wideband but after disconnecting it no change, just put another ECU in as well (have 4 as backups) and the same thing happens, I thought it may be the ECu but unfortunately not.

The ecu's have the 1k pullup removed as well for the wideband, I read they can cause issues so I removed it anyways. The wideband is a Innovate DLG-1 but I'm only using the LC-2 part of it as I dont require the rest. This shouldnt cause any issues should it?

Ok so upon further inspection I've come to the conclusion something defniitely isnt right.

I've changed ECU's, changed computers, installed a capacitor on the coil, moved the coil away from the rest of the wiring and I am still having errors.

I've tried to initialize hardware to see if the computer can recognize $11p after starting and no dice, tells me its not found, but if I just have the key on and the car isnt running it will find it easily.

I'm really running out of ideas here on what to do. The only time i can get reliable logging done is when the car just has the ignition on and not running.... which is absolutely pointless.

Does your USB cable have a ferrite bead on it? All required grounds in the engine bay good and present?

I have had RFI issues with aeroflow leads

Hey Antus,

Yeah my cable had a ferrite bead on it, it was the one I got off you when I ordered my NVRAM, I decided to go over to Officeworks and on the off chance try another cable as this one was new... BAM can now log with minimal errors... It was the cable that was knackered which has me dumbfounded. The only cable I could find at officeworks was a 5m one and I was very hesitant buying it due to the length, and also no ferrite bead. But now that it works I'll be installing one onto it...

Thanks everyone for the assistance, if anyone runs into these issues in the future definitely try a new cable first and foremost.... I just pulled my entire dash apart and went over my entire loom for nothing lol

Ok great that you got it sorted! Im not sure why the cable would have failed as I test them all on bench before I send them out and they dont usually degrade. The test proves they can handle the GQ-4x power requirements when I do the initial nvram flash and the test run on the bench sending the data though, though I didnt try it on a car. None the less Im glad you tried that and got the result you needed. Send me a PM if you want me to send you another cable.

Nah its alright about the cable, I have a working one now so no problems at all. Yeah I dont know what would have caused it to fail but its ok now, I'm just happy I can finally start getting the tune sorted. Its running around 11:1 on idle so you can imagine how much my eyes are stinging atm in the shed

Do you get ignition pops on the car radio when set to AM?

Joe.