99 4.8 swap to 02 6.0, Issues
10-29-2015, 10:41 PM
#31
To the OP it should be withen + or -3 from 0 when running correctly.
The 4.8 MAF readings are different from a 6.0L and can affect the fueling.
10-29-2015, 11:12 PM
#33
We used HPTuner to re-program the computer with a stock 6.0 tune. Once the tune was installed the truck would not crank, if we left the 4.8 tune it would crank. We ended up installing the 6.0 tune but replacing the MAF table with the 4.8 to get the truck to crank and run.
Neal
The amount of air you pull through the MAF on a 4.8 Vs. a 6.0 is different. If you skew the tables you will have fueling issues just like your describing.
10-30-2015, 08:04 AM
#34
On The Tree
Thread Starter
10-30-2015, 08:12 AM
#35
On The Tree
Thread Starter
I'll check with the guy that put the tune in but I think he said he only used the firring order of the 4.8 but everything else is the 6.0 tune. This is the part that has me stumped as the firing order should be the same. He said it was a known issue when doing this swap and had read about it on the internet.
I have never tuned a motor nor used that type of software so I'm a little behind on this but he did offer to let me use HPTunners to look around in the PCM.
10-30-2015, 05:19 PM
#36
On The Tree
Thread Starter
I ran the injector balance test on the Denali, when I turned each injector off the LTFT went over +25% on all injectors (+25% looks to be max).
I'm going to replace the injectors on the 99 and see what that does.
thanks for all the help,
I'll update when I get them replaced and see what the scanner says
I'm going to replace the injectors on the 99 and see what that does.
thanks for all the help,
I'll update when I get them replaced and see what the scanner says
10-30-2015, 08:31 PM
#37
+ or -3 on the fuel trims? (just to make sure I follow you)
I'll check with the guy that put the tune in but I think he said he only used the firring order of the 4.8 but everything else is the 6.0 tune. This is the part that has me stumped as the firing order should be the same. He said it was a known issue when doing this swap and had read about it on the internet.
I have never tuned a motor nor used that type of software so I'm a little behind on this but he did offer to let me use HPTunners to look around in the PCM.
I'll check with the guy that put the tune in but I think he said he only used the firring order of the 4.8 but everything else is the 6.0 tune. This is the part that has me stumped as the firing order should be the same. He said it was a known issue when doing this swap and had read about it on the internet.
I have never tuned a motor nor used that type of software so I'm a little behind on this but he did offer to let me use HPTunners to look around in the PCM.
11-06-2015, 01:37 PM
#39
On The Tree
Thread Starter
We replaced the injectors with the injectors from the 4.8,
Bank 1
Injector 1 off +13%
Injector 3 off +13%
Injector 5 off +22%
Injector 7 off +22%
Bank 2
Injector 2 off +13%
Injector 4 off +15%
Injector 6 off +25%
Injector 8 off +25%
the LTFT is now +2.3% both bank 1 & 2 while this is a change form -8.6 and -6.3% with the old injectors.
The front section of the engine looks to have something going on as the front 4 cylinders are a little off on the injector balance test.
I pulled the vacuum line from the fuel pressure regulator to see if the LTFT #'s would change (+2.3% to -.8%) and they did so that looks good.
still working to get in touch with the guy that did the PCM tunning to see if he can change all the tables to the 6.0 tune to see if this will make a difference.
Gota do a compression test to see if anything is out of the ordinary there.
If there was a vacuum leak on the front section of the intake would it affect the front cylinders more than the back ones?
Need to pull the plugs to see if any look significantly different than the others to get an idea if I need to be looking at a particular cylinder.
Thanks for all the help,
I'll update when I get more info,
Neal
Bank 1
Injector 1 off +13%
Injector 3 off +13%
Injector 5 off +22%
Injector 7 off +22%
Bank 2
Injector 2 off +13%
Injector 4 off +15%
Injector 6 off +25%
Injector 8 off +25%
the LTFT is now +2.3% both bank 1 & 2 while this is a change form -8.6 and -6.3% with the old injectors.
The front section of the engine looks to have something going on as the front 4 cylinders are a little off on the injector balance test.
I pulled the vacuum line from the fuel pressure regulator to see if the LTFT #'s would change (+2.3% to -.8%) and they did so that looks good.
still working to get in touch with the guy that did the PCM tunning to see if he can change all the tables to the 6.0 tune to see if this will make a difference.
Gota do a compression test to see if anything is out of the ordinary there.
If there was a vacuum leak on the front section of the intake would it affect the front cylinders more than the back ones?
Need to pull the plugs to see if any look significantly different than the others to get an idea if I need to be looking at a particular cylinder.
Thanks for all the help,
I'll update when I get more info,
Neal
11-06-2015, 01:47 PM
#40
Yeas a vaccuum leak will affect the cylinders closest to it more so than those further away...compressin test is probably best plan of action at this point.... Make sure you disable fuel so you arent getting false readings or filling the cylinders with fuel....