'99 Silverado 4.3 to 5.3 Swap with 4L80e bonus

[stutaeng]

Well, today was probably the most counter-productive day of this build. I had bought an LM7 intake manifold a while back to swap. Recall the slightly rich condition (LFTM are around 15% for both banks.) It is due to the L59 injectors having different flowrates than the LM7. The ECU was tuned to base LM7.

I figured intake swap was easier than swapping fuel rails. I took the time to resplice the original LM7 injectors from the harness. Even did heat shrink. Put it back together and the darn thing didn't fire! I was going crazy (fuel pump bad, etc., LOL?!!!), then just decided to do the basic diagnosing...

I checked and had spark, fuel pressure and injector pulse. What the heck!?

Then it dawned on me to pull the fuel rails...with my son cranking I saw absolutely no stream of fuel coming out, neither side. I double checked injector pulse and connections and all was good. Bingo, now what? It's pretty late by now.

I decided to swap back the L59 fuel rail assembly. Screw it, just cut again the respliced injectors and put electrical tape! She fired right up! Went for a drive and everything is back to were I was! LOL.

I don't know if those other injectors are bad, clogged or what.

Option B is to adjust the tune flowrates with HP Tuners.

Truck runs good. Seems like ECU is still able to make adjustments at this fuel trim. I suppose Option C is to just keep on truckin'!

 

[stutaeng]

BTW, does anyone know how to adjust the cruise control clip that goes into the throttle body butterfly thingy? I spent like 30 minutes trying to figure it out and I gave up.

If I hook it up it revs the engine. I need more slack. I thought it was maybe because of the other intake, but this one does the same. Mine kinda looks maxed out though...

 

[0xDEADBEEF]

Well, today was probably the most counter-productive day of this build. I had bought an LM7 intake manifold a while back to swap. Recall the slightly rich condition (LFTM are around 15% for both banks.) It is due to the L59 injectors having different flowrates than the LM7. The ECU was tuned to base LM7.

I figured intake swap was easier than swapping fuel rails. I took the time to resplice the original LM7 injectors from the harness. Even did heat shrink. Put it back together and the darn thing didn't fire! I was going crazy (fuel pump bad, etc., LOL?!!!), then just decided to do the basic diagnosing...

I checked and had spark, fuel pressure and injector pulse. What the heck!?

Then it dawned on me to pull the fuel rails...with my son cranking I saw absolutely no stream of fuel coming out, neither side. I double checked injector pulse and connections and all was good. Bingo, now what? It's pretty late by now.

I decided to swap back the L59 fuel rail assembly. Screw it, just cut again the respliced injectors and put electrical tape! She fired right up! Went for a drive and everything is back to were I was! LOL.

I don't know if those other injectors are bad, clogged or what.

Option B is to adjust the tune flowrates with HP Tuners.

Truck runs good. Seems like ECU is still able to make adjustments at this fuel trim. I suppose Option C is to just keep on truckin'!

They can get stuck from sitting. You can take a 9v battery to them and keep working them until they start clicking, or just send them out to be cleaned/tested.

 

[stutaeng]

They can get stuck from sitting. You can take a 9v battery to them and keep working them until they start clicking, or just send them out to be cleaned/tested.

Thanks! I suspected something about them sticking when none of them worked!

I found this YT video on a DIY test/clean procedure. I think I'm going to order that little pulser gadget. It's the one for doing injector balance testing! Super handy diagnostics tool.

xc_hide_links_from_guests_guests_error_hide_media

 

[0xDEADBEEF]

When I LS swapped a CJ7 I had 6 that I got working, but 2 were just frozen. I found a local high-end euro motorcycle shop to do them and they got them all working and balanced. I think it was about $10 per injector, but that was probably 7 years ago. I'm sure it's more now.

 

[stutaeng]

I finally took a better look at the axle I bought for the rear. Earlier this week I took the cover off and looked like an open differential. Doh!

I looked around and it is in fact a 9.5" differential, but now they call it a 12 bolt (diff cover has 12 bolts.) For lockers, it's the same as the old 9.5" 14 bolt, with some spacer sold specifically for this.

Today I spun it over it looks like a G80/3.42...I guess it's my time to learn the voo-do regearing magic. Wish me luck!

I haven't decided if 3.73s or 4.10s

 

[Supercharged111]

I finally took a better look at the axle I bought for the rear. Earlier this week I took the cover off and looked like an open differential. Doh!

I looked around and it is in fact a 9.5" differential, but now they call it a 12 bolt (diff cover has 12 bolts.) For lockers, it's the same as the old 9.5" 14 bolt, with some spacer sold specifically for this.

Today I spun it over it looks like a G80/3.42...I guess it's my time to learn the voo-do regearing magic. Wish me luck!

I haven't decided if 3.73s or 4.10s

Is that off of a GMT900?

 

[kennythewelder]

A 10 bolt, a 12 bolt, a 14 bolts refures to how many bolts are on the ring gear, not the diff cover, although, they are usually the same amount of bolts on both.

 

[stutaeng]

Is that off of a GMT900?

2KXX. This is the 9.5, but they also made a 9.76. They are cast with a number on the differential

The GMT900 had an axle called AXN with the 6.2. I think it's the same axle, but not sure.

 

[stutaeng]

A 10 bolt, a 12 bolt, a 14 bolts refures to how many bolts are on the ring gear, not the diff cover, although, they are usually the same amount of bolts on both.

These are hybrid axles, similar to the 9.5" 14 bolt 6 lug of the GMT400 trucks.

The carrier is 9.5" "14 bolt", but the axle tubes are closer to the 10 bolt? I think that's what I read. And the cover has 12 bolts, so that's what the name that's been adopted: 9.5" 12 bolt.