My son Tony 5.3 Chevy trouble
 

He put a 5.3 LS Motor in a newer Jeep , used a 4L60 trans, couldn't get it to run good till he unplug the Mass Air Flow. Now it misses at low rpm, any ideas on what to try now.?

Re: My son Tony 5.3 Chevy trouble
 

Tom,
I assume that your son made this swap and is keeping the fuel injection because you talk about unplugging the Mass Air Flow sensor. If that is true ask him to use a scanner to tell us what codes he is getting. There are lots of experts here more capable than me that can help.
I read some of the posts you made recently. I am sorry that our paths never crossed. People outside of drag racing would be surprised at what a tight community we are. I am looking forward to getting back to the community (at 61 years) in Division 1 next year. God bless you and your family. Ray Bassett

Re: My son Tony 5.3 Chevy trouble
 

Tony says :
most of the codes I got were from the transmission faults, I haven't checked since I got it home
thinking of buying a new maf & hook it up
I'm happy with the power.

Re: My son Tony 5.3 Chevy trouble
 

When swapping these types of ECU's it's common to modify the Air Intake leading to and from the Mass Air Meter. this can change the calibration of the mass air. Depending on the ECU it can fail the mass air table and revert to the VE table. The transmission should not effect the function of the mass air meter. Transmission issues typically are incorrect harness or mis matched ECU calibration to the 4L60E.

The mass air issue can be tuned in the MAF transfer function or change the operating system to speed density and tune using the VE table.

I work for Holley so my suggestion is the Terminator X Max. About $1400 complete and has trans control.

Robin

Re: My son Tony 5.3 Chevy trouble
 

I work with this stuff every day. The MAF for the 5.3L truck should be the 85mm one piece black plastic unit, with the five pin wiring connector. Often, engine swaps end up with the older 3 piece MAF, which is calibrated a good bit differently.
With a scan tool, you should see 5 to 8 grams per second air flow from the MAF. Depending on idle speed.Normally, at 750/800 RPM, 8 grams per second is normal for a stock 5.3L to 5.7L engine.

Unplug the MAF, it does not run in true Speed Density Mode, it runs in Backup Fuel Mode. Separate tables in the ECU for that mode. If that ECU even has V.E. tables, there is a binary switch that needs reset (Usually $00 to $02) to run in true V.E. Mode.

Many of those late truck ECUs do not even have VE fuel tables. Just a Backup Fuel Table.