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'78 K20 - RootBreaker from 1990 - nov 2025 8.1L not runnin

ZooMad75 said:
Are you running a return style fuel rail or return less? The return style will have the pressure regulator on it that you can adjust, the return less won't.

If you do have the return style it needs to come up a lot.
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yup this was it. I was at 45psi!!!!

now the issue.. i got it to 65psi as someone on fb said 55-65psi but his truck likes 68...
sovtook for a drive and stumble gone; however, I did not let it settle.. it actually settled at 72psi!!!! and was chocking itself...
now the engine is from saty west virginia... and adjustment screw was rusty..it stripped going up and I managed to work it back down to 58psi...havent driven it but should be good...
 
little work today...
got intake connected... hope it does well.. got it onnected to my snorkel
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next i jerry rigged exhaust to cherry bombs to get it quieter... till i can get it to a shop for custom exhaust. had to use flex pipe to go around xfer case.

started truck and it was bad...
then it got better but louder...I did not clamp exhaust yet. my truck shat passenger cherry bomb off... so i reversed it and boom good!!!

at MMA now but on way home.. exhaust clamps...

gettin there
 
RootBreaker said:
yup this was it. I was at 45psi!!!!

now the issue.. i got it to 65psi as someone on fb said 55-65psi but his truck likes 68...
sovtook for a drive and stumble gone; however, I did not let it settle.. it actually settled at 72psi!!!! and was chocking itself...
now the engine is from saty west virginia... and adjustment screw was rusty..it stripped going up and I managed to work it back down to 58psi...havent driven it but should be good...
Click to expand...
Dude- I was the one that told you 68 in the 8.1 thread.

If the screw is rusty and you got 58 now, leave it be. Drive it and see how it goes. If you need to replace it, get one for a 2001 5.3 Silverado. Its the same regulator as the 8.1 but for whatever reason easier to get. The replacement might have a dab of paint over the adjustment screw but it's easy to remove to adjust it.
 
ZooMad75 said:
Dude- I was the one that told you 68 in the 8.1 thread.

If the screw is rusty and you got 58 now, leave it be. Drive it and see how it goes. If you need to replace it, get one for a 2001 5.3 Silverado. Its the same regulator as the 8.1 but for whatever reason easier to get. The replacement might have a dab of paint over the adjustment screw but it's easy to remove to adjust it.
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lol sup bud!!!! :haha:

so how does the regulator come off? it looks like it is permanent on the rail?

autozone has the replacement for $75 for regulator that takes an allen wrench...
thought of buying it but didnt know how to remove the old one????
 
RootBreaker said:
lol sup bud!!!! :haha:

so how does the regulator come off? it looks like it is permanent on the rail?

autozone has the replacement for $75 for regulator that takes an allen wrench...
thought of buying it but didnt know how to remove the old one????
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All that holds it in is one snap ring. Which I'm guessing by the barnacles all over your engine is securely rusted in place. Hose it thoroughly with brake or throttle body cleaner to clean any dirt and grime out of the bore before attempting removal. You might be able to see the snap ring then but I doubt it with the rust.

You may be better off not messing with it. If you tweak the adjuster screw to the point where you can't adjust it and it's too high or low and you can't get it out you'll be looking for an entire fuel rail. Which are probably discontinued from gm for the return style system. You'll be looking for a used one.
 
RootBreaker said:
I am all for not messing with it...lol
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Well I did replace it with one from autozone and is not adjustable..for now..

new issue. took truck out and man she wants to go go goooo!!!!
Hawgs cannot grip the street...

Issue now is once she heats up..temp 180+.. it back fires and boggs..runs like crap so.. I think the hot tune I had done has an issue...
 
RootBreaker said:
Well I did replace it with one from autozone and is not adjustable..for now..

new issue. took truck out and man she wants to go go goooo!!!!
Hawgs cannot grip the street...

Issue now is once she heats up..temp 180+.. it back fires and boggs..runs like crap so.. I think the hot tune I had done has an issue...
Click to expand...
well this sucks.. gotta tear it apart. truck caught on fire.. it is bad enough... but not too bad...well from the outside. hope engine is ok.

gotta remove harness and fix few wires..few non engine harness wires... vac line on intake. needs coil packs (why i think it went up) and more...ughhhhhh
 
RootBreaker said:
i think part was i forgot to put oring back under oem regulator..it is too loose as seen in video
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I've just rewired a TON on my Blazer and I'm terrified of a short / fire. I really hate this happened to you but at least you have a good idea of the cause. Not ever knowing the cause would haunt the rebuild forever.
 
That fire extinguisher power is very corrosive, get it off ASAP (I don’t know the best method).
 
That sucks dude. I'm pretty sure you learned something from the fire, but I'd say once you get all the damage taken care of it would be good to pressurize the system first before lighting the engine off. Look for leaks.

In my time at Workhorse we did have a recall from GM to perform on the returnless style fuel system on the 8.1's. They had a pressure dampener that looked really close to the pressure regulator the return style systems ran. They had a clip that retained them. The clip was the fail point we had to replace under the recall. But our instructions in the recall were very clear. To avoid problems the tech was instructed to de-pressurize the fuel system. Not doing so would allow the dampener to launch out of the fuel rail, spraying fuel all the way. Keep in mind access on a RV was inside the coach by pulling the doghouse cover off. So if you launched the pressure dampener you sprayed fuel all over the inside of the coach and there was enough energy for the dampener to hit the opposite wall. Not good.

The other caution we gave in the bulletin was that if the dampener did come out was to not just stuff it back in but to replace the o-ring it sealed with. Not replacing the o-ring usually brought trash with it when you stuffed it back in or it would twist or roll, all of which causes it to leak.

We replaced thousands of those stupid clips without a problem. Hell, we did 100 alone at a Workhorse owner's club rally in a park. None leaked if you followed the procedure. Then one of my dealers seemed to completely disregard the instructions. Pulled the clip without taking the pressure off or holding the dampener in place. Shot the stupid thing across the coach spraying fuel all over the carpet, furniture, and the walls. He then stuffed the dampener back in the hole and closed it up without rechecking that it did not leak or letting a shop foreman or manager inspect his work. The coach was given back to the customer and they were planning on taking a small trip right from the shop. 20 minutes from the shop the driver (retired fireman BTW) noticed an odd smell. He told his wife they would get off at the next exit to look for the source of the smell. He didn't make it to the next exit. The smell got greater and smoke could be seen so he pulled to the shoulder and told the wife to grab the dog and get out now. By the time they got out flames were coming out from the front fender wells above the tires. Your basic fire extinguisher was not putting out this fire. Once the local FD got on scene and put it out the flames had burned through the floor up through the dash to the roof and was moving rearward burning the coach from the top down.

The unit was a total loss. The cause of the fire was found to be the leak at the fuel dampener allowing high-pressure fuel to spray over the driver-side exhaust manifold as an ignition source. I interviewed the tech and the service manager to find that none of the steps in the bulletin were followed. I had to inform them to call their insurance company as we were not taking responsibility since they did not follow the procedures outlined in the bulletin.

Point is, any time you make changes to the fuel system, always pressurize without starting to inspect for leaks.
 
I have to say after these instances and talking to Jeff while he went through this experience I'll be double checking my fuel rail before I fire mine up this weekend. Any pressurized fuel system for that matter. It is unnerving how this could easily happen to anyone after performing injector changes or regulator changes. (which I have)
 
well i found the culprit and woulda happened on the road making the truck a total loss...

so my return line, is yough to get too and i did not get it tight. it is finger tight now so definitely the fuel issue.

still no idea on what supplied the spark...

fixed rear harness as elec fuel pump is in there...

dual tank wiring is shot so gonna haveta source that...
20211116_104641.jpg


the engine harness... removed it to ship out
20211116_103938.jpg

but after inspecting it.. turns out loom took the blunt.
cleaned it up.. electrical taped the wires together and re loomed it.. think it is ok.

20211116_111838.jpg

now i need to hookup a line for my manual vac gauge...had plastic but a bud told me to do copper. gotta find one..

replace a coil pack

put harness back in... 2 wires for harnes do need to be fixed but they are connected to wireblock.

oh both starter wires burnt...

that seems to be it...

but gotta figure out how to get in there and tighten the fuel lines...grind wrenches down i guess
 
so my new coil packs arived and wow...
cheap, as i like bargains..but thought I would share..look to be exact replacements. wont be firing it up for a while but still... fingers crossed.

bought them after reading this reviewer...

ENA Pack of 8 Ignition Coils Compatible with Chevrolet CTS Avalanche Camaro Corvette Silverado Yukon Firebird V8 5.7L 8.1L Replacment For C1144 UF192 12556450 12558948 https://www.amazon.com/dp/B01M3P8AQM/

Screenshot_20220106-140421_Amazon Shopping.jpg


here is more ...
Screenshot_20220106-140138_Amazon Shopping.jpg

Screenshot_20220106-140133_Amazon Shopping.jpg



so i should of replaced them to begin with... mine are nasty. was gonna get swap done, bugs worked out and a year or 2 rebuild..
well i got new coils...

20220106_131421.jpg

20220106_135452.jpg




installed

20220106_140017.jpg
 
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