1999 Gen VI EFI to Q Jet 4L80E

[Road Trip]

FWIW I have both the Doug Roe and Cliff Ruggles book. I have been sucessfully building Q-Jets for more than 20 years myself. I have the Thorxen tool set for the CCC ones too. I once had a source for chips to reprogram the CCC computers, but they have long dried up.

Funny, the only auto/truck forum I've joined on the internet is this one,
and given that the GMT400s did not come from the factory with a carb (?)
I didn't figure that I'd end up rubbing keyboards with some fellow Q-Jet tuners.

Here we are in 2023, and I feel like I have finally found my peoples! :0)

Good stuff. FWIW I've done a little EFI tuning a long time ago (TwEECer,
dialing in a 331ci 5.0/5-spd 'stang with a cam, GT40 intake & heads,
intercooled Procharger set up for ~14 lbs of boost, Snow water/methanol
injector indexed off the Litening MAF, 19lb>60lb injector upgrade,
added a knock sensor from a F150 while at the machinist, forged flat top
pistons, blah blah blah.) We put this together with high hopes...

Once we got it moving under it's own power, well after maybe 30 minutes we
had the full-throttle A/F ratios where we wanted them. SO much easier than
iteratively changing out brass bits in the carb!

And after 2-3 full days of test/tune/change parameters/save/loop on error ad
naseum...we finally got the part throttle calibration where the car drove as
nice, clean, & responsive (closed loop) as when it came off the showroom floor.

Had to translate all my old carb terminology to a new EFI lexicon (accelerator pump
became plenum volume, etc.) But man oh man, I was the oldster working
on this, and I think I appreciated what a tunable EFI setup allows you to do
more than anyone else on the team.

Here's a youtube video by the owner, who I was mentoring on F-16s
during the day, and we continued the fun after hours spending his
money on something he really wanted to learn. (Caution: This video
was done back in '07, video technology has come a long way since
then. (Skip to 0:45 to get to the twEECer stuff.)

xc_hide_links_from_guests_guests_error_hide_media

After it was all said and done, what previously felt like a whale of a
convertible now felt like an ultralight. The push in the seat at
full boost was most gratifying. It was just plain stoopid. :0)

(many years pass)

So, now I'm watching you guys dialing in your bowtie EFI systems, and
although I'm a huge old-school Q-Jet fanboy, I am also looking forward to
adding EFI tuning on GMT400-style vehicles to my repertoire.

What can I say? This stuff *never* gets old. You guys rock!

 

[df2x4]

Here we are in 2023, and I feel like I have finally found my peoples!

This forum is pretty amazing IMO. All kinds of skill levels and areas of expertise across the member base, and everyone generally gets along and keeps the discussions very civil. I've been a member of a few different automotive forums over the years, but never one as pleasant and informative as this place.

What can I say? This stuff *never* gets old. You guys rock!

Agreed, yourself included. Thanks for joining and contributing!

 

[Schurkey]

I have one I need the rubber seal for the hot idle compensator on. Some of the kits once included the little rubber cone button seal for the compensating device, but seems impossible to find.

If these guys don't have it, you'll have to fabricate something.

Products – Cliffs High Performance Quadrajets

Quadrajet Misc. - Carburetor Parts & Kits for Carter, Ford Motorcraft, Holley & Rochester Carburetors

THE CARBURETOR SHOP/PARTS FOR ROCHESTER

 

[HotWheelsBurban]

If these guys don't have it, you'll have to fabricate something.

Products – Cliffs High Performance Quadrajets

Quadrajet Misc. - Carburetor Parts & Kits for Carter, Ford Motorcraft, Holley & Rochester Carburetors

THE CARBURETOR SHOP/PARTS FOR ROCHESTER

Be sure on your rubber parts in carburetors, to get parts that are ethanol compatible if available. Most gas anymore has at least 10% ethanol content and the older carbs don't like it. Many of the guys on GMSB have been talking about this (lotsa squares have QJs , most of mine did).

 

[amrush2112]

Pull the engine because the distributor is stuck???

You must be registered for see images attach

Brutalize it a bit with a wrench.

You must be registered for see images attach

It IS possible to break the distributor housing...but you'd have to work at it, and even if you do...you were planning to pull the engine anyway.

It is pretty tight back there on a Pontiac 400 in a 68 GTO. The motor is broken free and turns over with the starter. It was seized and sat for 46 years (since 1977) but after 5 gallons of diesel fuel down the valve cover and sitting 24 hours it broke free! I have a bunch of rust on the cowl and dash that I have to cut and replace the dash but the rockers are good. 4 speed is shifting and the clutch is working (don't know if the disc is seized to flywheel but probably). I am not planning on rebuilding it as it only has 83916 miles on it and has good compression. All valve train is working so it just needs to have gaskets replaced, water pump replaced and timing cover cleaned out, and maybe a camshaft changed but probably not. Just planning on getting it to fire off and then back in the car. I like the idea that it is 100% all original. Trying to keep it that way but will go to a hydraulic roller eventually. Stock bottom end though. I have a 65 GTO that is a lot wilder. Has a 428 motor with H beam rods and more good stuff. Lol.

 

[Scooterwrench]

Mine will be getting the 355 and Q-jet soon,my 305 is dying quicker than expected. Oil pressure hit 0 yesterday. Got about 4 knocks this morning till the little bit of oil pressure it has came up.

 

[amrush2112]

Funny, the only auto/truck forum I've joined on the internet is this one,
and given that the GMT400s did not come from the factory with a carb (?)
I didn't figure that I'd end up rubbing keyboards with some fellow Q-Jet tuners.

Here we are in 2023, and I feel like I have finally found my peoples! :0)

Good stuff. FWIW I've done a little EFI tuning a long time ago (TwEECer,
dialing in a 331ci 5.0/5-spd 'stang with a cam, GT40 intake & heads,
intercooled Procharger set up for ~14 lbs of boost, Snow water/methanol
injector indexed off the Litening MAF, 19lb>60lb injector upgrade,
added a knock sensor from a F150 while at the machinist, forged flat top
pistons, blah blah blah.) We put this together with high hopes...

Once we got it moving under it's own power, well after maybe 30 minutes we
had the full-throttle A/F ratios where we wanted them. SO much easier than
iteratively changing out brass bits in the carb!

And after 2-3 full days of test/tune/change parameters/save/loop on error ad
naseum...we finally got the part throttle calibration where the car drove as
nice, clean, & responsive (closed loop) as when it came off the showroom floor.

Had to translate all my old carb terminology to a new EFI lexicon (accelerator pump
became plenum volume, etc.) But man oh man, I was the oldster working
on this, and I think I appreciated what a tunable EFI setup allows you to do
more than anyone else on the team.

Here's a youtube video by the owner, who I was mentoring on F-16s
during the day, and we continued the fun after hours spending his
money on something he really wanted to learn. (Caution: This video
was done back in '07, video technology has come a long way since
then. (Skip to 0:45 to get to the twEECer stuff.)

xc_hide_links_from_guests_guests_error_hide_media

After it was all said and done, what previously felt like a whale of a
convertible now felt like an ultralight. The push in the seat at
full boost was most gratifying. It was just plain stoopid. :0)

(many years pass)

So, now I'm watching you guys dialing in your bowtie EFI systems, and
although I'm a huge old-school Q-Jet fanboy, I am also looking forward to
adding EFI tuning on GMT400-style vehicles to my repertoire.

What can I say? This stuff *never* gets old. You guys rock!

Nice Vert! Looks like a Saleen! I remember those back in the day.

 

[amrush2112]

Be sure on your rubber parts in carburetors, to get parts that are ethanol compatible if available. Most gas anymore has at least 10% ethanol content and the older carbs don't like it. Many of the guys on GMSB have been talking about this (lotsa squares have QJs , most of mine did).

Yes we have QT gas stations here that have 91 Unleaded that is 100% no ethanol. Pricey but it runs good on it. Don't know about my 10.75-1 400 though. I am sure that with a stock cam (the HO motor had a bit of a lope but not much) I am going to have to back the timing down a bit. I've run 11.8-1 with 93 super but that was way back years ago. It did ping quite a bit and would have to run a can of 105 real lead octane booster and it was barely acceptable. That was in a 455 with a BIG solid cam that bled off a bunch of cylinder pressure. Don't think the stock 400 would do the same.

 

[amrush2112]

Been busy for a while but thought I would update on direction. So I have decided to make a big change on the suburban. I have pretty much resolved to find a complete and running Cummins 24Valve and NV5600 out of a dodge. I have swapped already in a 2002 GMC and its actually easier in the GMT 400 chassis. Going the route of the P Pump and manual trans because this is going to be more of an oveland build. The 454 will come out and get freshened up and used for probably a chevelle or a camaro or something. The 4L80E will go in my 93 that has a broken parking pawl. My suburban is getting a solid front axle and swap setup so it will be my toy rather than my daily driver. I have a 93 K2500 with a 350 that will be my daily D. With the cost of fuel getting higher and higher and us moving out to farmland it just makes more sense to have something a bit different for what I need. If I keep going with the 454 in the Suburban it will just get more miles and worn out. Lets face it, the 454 would be a heck of a lot more fun in a convertible Chevelle and a T56.

 

[Scooterwrench]

Been busy for a while but thought I would update on direction. So I have decided to make a big change on the suburban. I have pretty much resolved to find a complete and running Cummins 24Valve and NV5600 out of a dodge. I have swapped already in a 2002 GMC and its actually easier in the GMT 400 chassis. Going the route of the P Pump and manual trans because this is going to be more of an oveland build. The 454 will come out and get freshened up and used for probably a chevelle or a camaro or something. The 4L80E will go in my 93 that has a broken parking pawl. My suburban is getting a solid front axle and swap setup so it will be my toy rather than my daily driver. I have a 93 K2500 with a 350 that will be my daily D. With the cost of fuel getting higher and higher and us moving out to farmland it just makes more sense to have something a bit different for what I need. If I keep going with the 454 in the Suburban it will just get more miles and worn out. Lets face it, the 454 would be a heck of a lot more fun in a convertible Chevelle and a T56.

Oh HAIL Yeah!!!!