LS swap 3100 truck HELP!!

[akalshaikh]

Hi

I am working on a 6.0 swap chevy 3100 truck, stock ECU out of 05 GM truck with painless wiring. MAF sensor was deleted and all the codes were set off and MAF failed. The car runs decent for half a min then starts to shake and does not pick up throttle then dies. I noticed it backfiring into the intake as well sometimes and its struggling to keep running.

Its my friends truck that I am helping out with the tune. I have forced it into open loop and disables O2 sensors since he cancelled them. So the car basically has no MAF sensor and no O2 sensors.

He says it used to run good but did not pick up throttle at all and another tuner tried to fix that but actually got worse (car dies). I managed to get the throttle to work and pick up RPM's for short time but can't figure out why its struggling to keep idling or keep running.

Lastly, it's mechanical/cable throttle body not drive by wire.

I have attached the tune file and some logs for the issue we're facing. Is there anything I am missing out or done wrong?

[blindsquirrel]

If there are no O2 sensors (dumb) then the DTCs need to be set to No Error Reported, too. Same for all the ETC codes still active. Same for... well, it's a mess.

[blindsquirrel]

Do you have the right PCM service number with the IAC drivers inside to do this conversion? Why would you not log the IAC/idle stuff if you're having idle problems?

[5FDP]

You need to wire in a IAT sensor as well because you deleted the MAF.

He failed the MAF wrong too. They are set to no error reported, they need to be set to MIL on first error for the DTC codes. It can't run off the VE table if it won't fail the MAF sensor.

Open loop EQ ratio must be 1.00 at operating temps, it can't be 0.95 because that will throw your fueling off when tuning.

[akalshaikh]

If there are no O2 sensors (dumb) then the DTCs need to be set to No Error Reported, too. Same for all the ETC codes still active. Same for... well, it's a mess.

I'll download a stock 05 tune file and start from scratch i think i am better off this way.
Reason i did not check the error codes or did not oay attention to them is that i did not get the MIL or check engine light related to them. Thought previous tuner already did that.

Do you have the right PCM service number with the IAC drivers inside to do this conversion? Why would you not log the IAC/idle stuff if you're having idle problems?

Yes, I'll log IAC and idle related stuff and try my luck with this tune file first before going from scratch. I'll post the logs later today.

You need to wire in a IAT sensor as well because you deleted the MAF.

He failed the MAF wrong too. They are set to no error reported, they need to be set to MIL on first error for the DTC codes. It can't run off the VE table if it won't fail the MAF sensor.

Open loop EQ ratio must be 1.00 at operating temps, it can't be 0.95 because that will throw your fueling off when tuning.

I am getting IAT readings, I'll go through the DTCs all over and see what has been changed. P0101-02-03 all should be set to MIL on first error or just P0103?

[5FDP]

I am getting IAT readings, I'll go through the DTCs all over and see what has been changed. P0101-02-03 all should be set to MIL on first error or just P0103?

No you aren't. The channel is stuck at -38 degrees. That is the default number for a not working sensor. The 5 wire MAF sensor has the IAT built into it. Now that it is removed, it no longer works. I don't think Bahrain ever actually sees freezing temps or north pole like cold lol. People there would probably never function if it did.

Just set all 3 DTC's to MIL on first error.

[akalshaikh]

No you aren't. The channel is stuck at -38 degrees. That is the default number for a not working sensor. The 5 wire MAF sensor has the IAT built into it. Now that it is removed, it no longer works. I don't think Bahrain ever actually sees freezing temps or north pole like cold lol. People there would probably never function if it did.

Just set all 3 DTC's to MIL on first error.

If it did you won't even find people to check weather functioning or not.

Thanks for the input for some reason i was seeing it 39 degree and was not noticing the (-)

[akalshaikh]

UPDATE:

So I disabled the MAF sensor (properly ) and went through all the DTC's & did the open loop EQ ratios the car runs great and keep idling not struggling thanks to everyone who helped me through this.

Another issue now is that at idle, when revving it up it hold the rpm for sometime then drops it. Tried changing throttle decay and IAC stuff with no luck although I noticed the desired IAC stays up for sometime. Tried increasing and decreasing the IAC values by 50% with no luck (Trial and error). intake sound like a procharger. My guess is that the IAC port and the hole on the throttle plate is too much for it to idle or lower the idle RPM since its cable driven.

You'll notice on 'running 2' log that it gets almost perfect but that only because i kept my hand on the throttle body trying to reduce air in. So once i restrict air flow to the throttle it gets all nice and sweet.

Attached is another log and the updated tune file.


Thanks

[blindsquirrel]

So adjust the throttle plate stop screw to allow it to close more, letting less air in. IAC counts, after it's warmed up and idling, should be between 40 and 60. Lower than this and the blade is open too much and passing too much air (or you have a vacuum leak), higher and it's closed too much and not allowing enough.

[blindsquirrel]

Actually, scratch that. Don't adjust anything else either mechanically or in the tune until you have a working IAT. Didn't realize that fundamental issue hadn't been fixed yet.

[akalshaikh]

Actually, scratch that. Don't adjust anything else either mechanically or in the tune until you have a working IAT. Didn't realize that fundamental issue hadn't been fixed yet.

Ok, They are already working on it to hook up the IAT. Will post an update soon.

Thanks

[akalshaikh]

UPDATE:

IAT sensor hooked up and done a street tune to it. all is perfect except a bit of high idle a bit which was rectified after the tune. Thanks for all the inputs.

Face one problem only in VCM scanner that i couldn't get to log my wideband as an input to the scanner. only this truck the rest were fine. like its not a supported parameter by the ECM

[5FDP]

Looks like it's out of fuel injector too, it's pushing past 100% duty cycle pretty easy. The intake must be sucking in a ton of hot air too if it's a jammed engine bay, that's hurting performance and likely removing a lot of timing. On good fuel you should be able to see 20 degrees of timing at full throttle.

Commanded AFR is a bit rich too, raising it might gain you back a little injector headroom but it won't really be enough. I'd aim for 12.2ish AFR instead of 11.8.

[akalshaikh]

The design of the intake is bad, they made it in a way that sucks in air from the engine bay it self as there is no room. I kept it on the rich side because of the hot air.

The truck will never be raced or anything. Just barely a weekend car or a show car.

Performance is not what they are aiming for and they are using regular 87 Octane fuel.

Edit: Fixed fueling at WOT it hits 97% and Wideband shows 12.4.
He's in for fuel pump soon i guess.