91 Suburban V2500 - Tow/Weekend Rig - Build Thread

[Big Ray]

+1 on the fuel pressure...


I don't know enough about wideband sensors to say...but IMO their is unused power in even a stock motor that a reprogrammed chip will let come through...


I need to reread the thread...is the motor reworked or just have add ons?

 

[dhcomp]

From what I understand that's correct - since the stock O2 sensor is essentially only dealing in rich, lean or stoich condition and not a true AFR there's not a lot the ECU can or will do to compensate.

Even then, if the info from CFM tech is to be believed it sounds like a lot of times the factory FPR is running so low that these engines can spend a lot of time in a borderline lean condition as it is. In that case you're actually making the the ECU less inclined to try to compensate.





Did you ever end up turning up the fuel pressure? You mentioned before you were running at 13psi; CFM Tech recommends 14-14.5 when "slightly modded" which includes all the stuff you installed. At 13psi you may still be running a little lean. When I do these mods my expectation is to be running 14 minimum. I think you'll see some decent gains after a little tweaking and tuning - if not in butt dyno power for sure in driveability.

Yep, you nailed my understanding of the factory lean condition.

I forget where CFM tech said anything about recomendations. Definitely not in the instructions. 13 was meant to be a baseline, so maybe i'll crank it up.

Thanks!

 

[AJMBLAZER]

Suddenly I'm reminded of that guy in SoCal on ORC back in the day with the 93 or so Chevy shortbox that he was setting up as a 4x4 prerunner. Was modifying the wee out of his TBI setup and tuning it all the time.

 

[Big Ray]

pm member Dave w...he is a real efi guru...

 

[cuervo]

pm member Dave w...he is a real efi guru...

Or better yet, just come join us in the Injection Section here! Both Dave and Mark are great guys and do like to talk injection.

 

[Big Ray]

Or better yet, just come join us in the Injection Section here! Both Dave and Mark are great guys and do like to talk injection.

yeah, what he said!!^^^

 

[dhcomp]

Or better yet, just come join us in the Injection Section here! Both Dave and Mark are great guys and do like to talk injection.

Thanks for the tips.

Truthfully, I went with the CFM tech stuff thinking I wouldn't' have to do too much more.

I've never read in the Injection section on here, but will in a while.

Right now, i've got bigger fish to fry.


So, picked up another 14ff from a guy on Pirate.

Gear markings say 87, so probably out of an 88. Way clean, 4.10's, Gov lock, newer style backing plate with clip in ebrake cables, and useable brake hardlines. I'm stoked. It cost me, but glad to have exactly the one that will make this swap easy.

The other 14ff will be for sale, along with the 3/4 ton 3.73 set when i'm done.

Picked up wheel cylinders and a hardware kit for the rear brakes, plan to reuse the shoes, but will know for sure when i take a look at them.

All i'm missing is my Ruff Stuff stuff (on its way), and a conversion u joint.

Gonna tear down the axles in the next couple days, then swap over the weekend. Stoked!

 

[dhcomp]

Huge thanks to DocFeelsGood for helping me unload axles again with his cherry picker.

Showed up with a couple hours notice with a picker, no idea how i was going to get them out without him!

 

[dhcomp]

Tore down the 10 bolt!

Found a mysterious pin in the axle tube, hope its not part of the center section.

Posted in the garage to discuss this part
http://coloradok5.com/forums/showthread.php?p=3007688#post3007688

 

[dhcomp]

On a ****tier note, RPM Offroad waited almost a week to ship my lubelocker gaskets.

And i think they shipped UPS ground from TN.

If i don't get my $50 worth of gaskets, and have to use RTV again, i'm going to be pissed.....

Yes, RTV works ok, but I wanted to use these trick gaskets!

 

[cuervo]

On a ****tier note, RPM Offroad waited almost a week to ship my lubelocker gaskets.

And i think they shipped UPS ground from TN.

If i don't get my $50 worth of gaskets, and have to use RTV again, i'm going to be pissed.....

Yes, RTV works ok, but I wanted to use these trick gaskets!

And there is a holiday in there too!!

 

[imiceman44]

Thanks for the tips.

Truthfully, I went with the CFM tech stuff thinking I wouldn't' have to do too much more.

I've never read in the Injection section on here, but will in a while.

Right now, i've got bigger fish to fry.


So, picked up another 14ff from a guy on Pirate.

Gear markings say 87, so probably out of an 88. Way clean, 4.10's, Gov lock, newer style backing plate with clip in ebrake cables, and useable brake hardlines. I'm stoked. It cost me, but glad to have exactly the one that will make this swap easy.

The other 14ff will be for sale, along with the 3/4 ton 3.73 set when i'm done.

Picked up wheel cylinders and a hardware kit for the rear brakes, plan to reuse the shoes, but will know for sure when i take a look at them.

All i'm missing is my Ruff Stuff stuff (on its way), and a conversion u joint.

Gonna tear down the axles in the next couple days, then swap over the weekend. Stoked!

So is your 3.73 set an 8 lug set or 6 lug?
If 8 lug, is the rear ff or sf?
I might take them off your hands if they are 8lug, ff rear.

 

[dhcomp]

So is your 3.73 set an 8 lug set or 6 lug?
If 8 lug, is the rear ff or sf?
I might take them off your hands if they are 8lug, ff rear.

1991 8 lug, 3.73, 10 bolt front, SF gov lock rear.


Also will be selling a 78ish 14FF, 4.10's, open diff.

PM me if interested. I'll post up a for sale post when i get this beast back together.

 

[Big Ray]

1991 8 lug, 3.73, 10 bolt front, SF gov lock rear.


Also will be selling a 78ish 14FF, 4.10's, open diff.

PM me if interested. I'll post up a for sale post when i get this beast back together.

too bad you're on the wrong side of the country

 

[imiceman44]

1991 8 lug, 3.73, 10 bolt front, SF gov lock rear.


Also will be selling a 78ish 14FF, 4.10's, open diff.

PM me if interested. I'll post up a for sale post when i get this beast back together.

Well I have a couple of those in SF.
But I might be interested in your 14bff 4.10
PM me when you are ready to sell, and if you need anything in trade.

 

[dhcomp]

Well, its back together.

Holy crap that was a big project. My Dad got dragged into at least 2 1/2 days worth of work with me.

I'll post up more later. I'm exhausted, and hurting.

Took at lot of time to disassemble/reassemble the front, replace axle shaft u joints, etc.

Took it for a spin, need to work on some vibes i'm getting. Thinking its from the rear.

Going to take the bearings apart, and maybe run them a little looser this time.

Also found a massive oil leak. Think my rear main is leaking

Overall, its together, but not done. Frustrated...

 

[y5mgisi]

What all exactly did you do?

 

[dhcomp]

What all exactly did you do?

Tore down "new" 4.10 geared 10 bolt. Changed axle shaft u joints.

tore down old 10 bolt. Pulled old 10 bolt out of truck. Installed new 10 bolt.

Reinstalled shafts/outers.

Tore down 14FF. tore down brakes, lubed, reassembled/adjusted.

Removed old 14SF. Installed 14FF. Hooked up brakes, ebrakes, vent.

Bled brakes.

 

[y5mgisi]

Interesting. Just curious what might have given you the new vibe.

 

[dhcomp]

Interesting. Just curious what might have given you the new vibe.

Me too. Going through it in my head, going to reset the rear bearings first.

It could be driveshaft related, but this axle was supposedly out of a burb, so it should be the same stock pinion angle as my old one. And i didn't even need a conversion u joint, as i had a 14sf before.