10 mpg

[bobbywalter]

wasnt keeping up.


you can use a spray bottle and squirt water around the injectors and intake mating surfaces and listen for hissing and monitor stumble.

seems like vacuum leaks were the issue.

it can be really difficult to install the injectors and rails without janking up the seals.... i always do the soapy bottle spray right away and a week or so later after it heat cycles to make sure there are no vacuum leaks.

it can get frustrating.

 

[HakunaMatata]

wasnt keeping up.


you can use a spray bottle and squirt water around the injectors and intake mating surfaces and listen for hissing and monitor stumble.

seems like vacuum leaks were the issue.

it can be really difficult to install the injectors and rails without janking up the seals.... i always do the soapy bottle spray right away and a week or so later after it heat cycles to make sure there are no vacuum leaks.

it can get frustrating.

The only place there could have been a vacuum leak was at the injectors, but when I did the vacuum test, it definitely showed no vac leak. Once I got to the injectors I definitely smelled a little fuel.

It was a combination of several things. TC was going bad, very poor acceleration. MAF sensor KOEO was reading .15. After pressure washing, a couple of plug wires showed evidence of getting wet on the plug connection, so they were cracking. I believe the coil wasn't performing the best it could. Egr pathway was horribly built up, cleaned it all out, same with throttle body. Injector seals very hard and brittle, and injectors were very very dirty.

Happy to say today I got 15mpg. That's with ac on blast all day, probably about 1 hr total idle time, and carrying about 900 lbs in the bed. I tend to have a lead foot as well haha.

 

[bobbywalter]

The only place there could have been a vacuum leak was at the injectors, but when I did the vacuum test, it definitely showed no vac leak. Once I got to the injectors I definitely smelled a little fuel.

It was a combination of several things. TC was going bad, very poor acceleration. MAF sensor KOEO was reading .15. After pressure washing, a couple of plug wires showed evidence of getting wet on the plug connection, so they were cracking. I believe the coil wasn't performing the best it could. Egr pathway was horribly built up, cleaned it all out, same with throttle body. Injector seals very hard and brittle, and injectors were very very dirty.

Happy to say today I got 15mpg. That's with ac on blast all day, probably about 1 hr total idle time, and carrying about 900 lbs in the bed. I tend to have a lead foot as well haha.

15 cruisin with ac is good enough for me....i would love to have ac....if only...


38 kpa at idle and there is a low idle stumble/burble on the 5.3... two injectors are leaking.... i suspected a flange issue and put the water to it...but it was just the two injectors....on the vac side obviously....

only have a single o2 on that particular engine setup and its on that bank with the leakers. it was actually pulling timing on transition with a wicked correction edge.......so i turned off the learn and loaded the 380 tune for now. still waiting on o rings for the multecs. runs much better on fixed tables though.

the 4.0 did the same thing...but not spending money on that for hp tuner credits...not to mention i would need to put an actual obd2 setup on it. even know it is obd1... it has 2 o2 sensors .... luckily we had o-rings for that. two of the three injectors i pulled were ugly on the drivers side....so that was something i wish i did not see. but the plugs looked real good ... it does still idle rough...but since it runs great under load..... i am not buying injectors...

the vacuum on that went from 17 initially and down to 14-15 in about 7 tanks of gas...

kind of weird...but it was an easy fix.

i am tempted though....to do the obd2 upgrade and data log these non egr early 4.0s, because there is so little data shared. it runs well enough if we get the other rigs in the fleet in better shape before bob beats it up too bad, i might do it..

just rather put that time and money towards a 4 cylinder ecoboost swap.