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1990 GMC 1500 Jimmy
- Thread starter scpaul
- Start date
The differential housing is plug welded to the axle tubes. It is possible to remove, but not worth the effort.
Fuel-wise, you should have 1 pump in the tank and nothing on the block. I'd pump the tank out and put in fresh fuel. You can reintroduce the old fuel later, mixing small quantities with each tank full of fresh gas, but I wouldn't want to feed it 100% old stuff unless I was desperate. You likely have rust flakes and water in there from the humidity in the air (because the tank wasn't full). My guess is that the rust flakes are what will plug the pickup screen & filter, if anything does. Oil-wise, I would use the normal oil specified for the engine (10W30 if in doubt). Sea foam is good stuff, it is great for resurrecting old engines.
I would replace plugs and wires, lube it up, and see what happens. Rotate the engine by hand to make sure that it's not frozen. Depending on what type of fuel was left in there, the fuel system will probably have varnish deposits on the internals, that's where the sea foam comes in.
I doubt you'll have major problems. As Rob said, the TBI small block is a hard engine to kill. It may not run perfectly right at first, but it shouldn't be hard to get it going.
scpaul
1/2 ton status
Can I gravity feed this TB fuel sys. or is the fuel pressurized from the tank? I'd like to get get it to sputter before I do much of anything. Surely the plugs, wires, cap, and rotor are good enough for that, don't you think? After changing the oil and draining the old gas. How much pressure is there from the pump in the tank, just enough to keep the throttle body full and return the rest to the tank?
It's pressurized from the tank. Fuel pressure should be around 7PSI, IIRC. The truck would probably fire off without replacing any parts. But you had asked what sort of items I would replace, and I would do a general tuneup before expecting too much. At the very least, get the crummy fuel diluted with fresh fuel, as much as you can get in there. Gasoline breaks down, and newer gasoline seems to degrade faster then old gasoline did. And replacing the oil is also a good idea.
scpaul
1/2 ton status
I'm planning on draining and flushing the complete fuel system and definately changing oil and filters. After that is when I want to pressurize the oiling system by pulling the distributor and spinning the oil pump to build pressure and keep it up for a couple minutes to lube everything, I don't know if that will pump up the lifters, some are probably stuck. I just want to hear it hit before I go very far and get my hopes up. That's why I was thinking about having the engine built.
I probably can come up with a way to pressureise enough fuel to just get it to fire. 7 lbs. isn't that much (famous last words). I have access to numerous tanks/cylinders and couldn't I pressurise the tank with air pressure?
The cracks in the carrier, are they usually visable? Is the best way to work on the rear end is to remove the rear assy. what about the front if I need to?
I probably can come up with a way to pressureise enough fuel to just get it to fire. 7 lbs. isn't that much (famous last words). I have access to numerous tanks/cylinders and couldn't I pressurise the tank with air pressure?
The cracks in the carrier, are they usually visable? Is the best way to work on the rear end is to remove the rear assy. what about the front if I need to?
Do not pressurize the fuel tank. Even when new and shiny, it is flimsy sheet metal at best. It will not contain pressure. I'm sure you already know this, but pulling the distributor will throw off your timing, so mark it well unless you want to also be playing with timing adjustments.
You may see visible cracks on your carrier. That is what happened to one of mine, a routine axle seal replacement turned into carrier replacement after the axle was opened up and the problem discovered. The other one failed in service.
For servicing either axle, I would service them in place. Not everyone agrees on this. If you are good at pulling axles and have a workbench to operate on, you may enjoy pulling it and rebuilding it on the bench. But that greatly adds to the workload, as you wind up redoing U-bolts, driveshaft, brake lines, and E-brake cables. Working on the bench makes the axle work easier, though, so it's a tossup overall. For the front axle you also have the steering gear to mess with. Is there any reason to mess with the front axle at this point? Is it leaking or broken in some way?
scpaul
1/2 ton status
At this point, I haven't seen anything wrong with either end, but remember that I really can't get to them very well because of the briars.
I wasn't thinking about any pressure on the fuel tank. I was thinking about a cylinder something like portable air tank that I'd drill, tap, and seal about a 1" to make it easier to put gas in then get a brass barb that screws into the 1" brass fitting. After I add some gas, pressureize it from around the corner of the house with a air chuck that locks on. It's really only drilling a 1" hole, I don't think 7 psi. would be a problem to seal. I could use J-B Weld to give me more of a thread count. I could do it with just 1 barb for the gas in and out. I think that I've got everything here already. I'd probably have to close the return line and then reduce the tank's pressure and bring it up slowly.
If I'm not mistaken the small block distributor is a slotted drive. Use a slotted screw driver and drill to prime the lube system. The timing would be right or 180* off, unless they have changed how they drive the distributor. right? I'd mark where the rotor is and the distributor body too.
I wasn't thinking about any pressure on the fuel tank. I was thinking about a cylinder something like portable air tank that I'd drill, tap, and seal about a 1" to make it easier to put gas in then get a brass barb that screws into the 1" brass fitting. After I add some gas, pressureize it from around the corner of the house with a air chuck that locks on. It's really only drilling a 1" hole, I don't think 7 psi. would be a problem to seal. I could use J-B Weld to give me more of a thread count. I could do it with just 1 barb for the gas in and out. I think that I've got everything here already. I'd probably have to close the return line and then reduce the tank's pressure and bring it up slowly.
If I'm not mistaken the small block distributor is a slotted drive. Use a slotted screw driver and drill to prime the lube system. The timing would be right or 180* off, unless they have changed how they drive the distributor. right? I'd mark where the rotor is and the distributor body too.
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Wow. Slow down guys. Sounds like a bomb is getting made if you pressurize a cylinder fuel of fuel. Unless you have a way of plumbing that thing into the fuel system you won't be doing anything more than pouring fuel down the throttle body. It won't be going through the injectors at all. Being a stock TBI system there is a jumper wire right off of the fuel pump relay you can use to force the pump on.
Priming the oil system is fine but dont use a screwdriver. Get another distributor and cut off the end where the rotor is attached. Chuck that into your drill. Spin.
I need to go back through the other issues brought up, but I'll do that when I get back from work.
Priming the oil system is fine but dont use a screwdriver. Get another distributor and cut off the end where the rotor is attached. Chuck that into your drill. Spin.
I need to go back through the other issues brought up, but I'll do that when I get back from work.
scpaul
1/2 ton status
I was wondering how long it was going to take to have someone say something about the potential danger of pressurizing a cylinder with a fluid whose fumes are more explosive than the liquid. And the fact that rapid decompression will cause the fluid to become a gas almost instantly depending on how quickly it is decompressed.
That's why I wanted to add another valve where it wouldn't have to be messed with after the pressure is started. I also intended to plumb it into the fuel system and through the fuel line to the throttle body. I've seen and had it happen to me years ago when you pour fuel into the carb and have it backfire. That's also why I made the referance about pressurizeing it from around the of the corner of the house(brick, no windows near by).
Oh, by the way, I'm also planning running the pump and tank to ground rods that are already there. I see why ZooMad said what he did. Basically I'm just making a very small fuel tank (about 1 quart of gas to start it should be enough) and using LOW air pressure, just enough to move the fuel. I could just fill the fuel line and put air pressure to it. I'm thinking that if the system operates at 7 psi. then if I restrict the return line to real fuel tank (with the cap off so no pressure buildup) that I probably wouldn't need but 3 or maybe 5 psi. I've always been a little apprehensive about an electric pump and fuel gauge potentiometer(?) in a tank that could have 30+ cubic feet of fumes in it. It does seem to work ok.
If it sputters I'm planning to take the tank out and clean it. Clean/flush the fuel and return lines, in other words, clean the fuel system from 1 end to the other if it shows any sign of life. I don't like to do something but once, so I try to do it right and completely. That's why I've been asking about that throttle body being able to handle an engine making more H.P. than stock.
I didn't mean to scare anybody, and I'll try not to do anything stupid, I Promise, Paul
That's why I wanted to add another valve where it wouldn't have to be messed with after the pressure is started. I also intended to plumb it into the fuel system and through the fuel line to the throttle body. I've seen and had it happen to me years ago when you pour fuel into the carb and have it backfire. That's also why I made the referance about pressurizeing it from around the of the corner of the house(brick, no windows near by).
Oh, by the way, I'm also planning running the pump and tank to ground rods that are already there. I see why ZooMad said what he did. Basically I'm just making a very small fuel tank (about 1 quart of gas to start it should be enough) and using LOW air pressure, just enough to move the fuel. I could just fill the fuel line and put air pressure to it. I'm thinking that if the system operates at 7 psi. then if I restrict the return line to real fuel tank (with the cap off so no pressure buildup) that I probably wouldn't need but 3 or maybe 5 psi. I've always been a little apprehensive about an electric pump and fuel gauge potentiometer(?) in a tank that could have 30+ cubic feet of fumes in it. It does seem to work ok.
If it sputters I'm planning to take the tank out and clean it. Clean/flush the fuel and return lines, in other words, clean the fuel system from 1 end to the other if it shows any sign of life. I don't like to do something but once, so I try to do it right and completely. That's why I've been asking about that throttle body being able to handle an engine making more H.P. than stock.
I didn't mean to scare anybody, and I'll try not to do anything stupid, I Promise, Paul
If it were me, I would skip trying to build a pressure pot. I would do as others have said , to drain the tank, get some fresh gas, fresh filter ,(buy a couple ) then pull the feed line off of the throttle body , put a hose on it long enough to go to a container outside of the engine bay . Then use the jumper at the fuel pump relay to flush and primer the system . This way you won't put as much old crap into the injectors . I would then feel better about trying to start it.
After hooking up the feed line again! Haha !
After hooking up the feed line again! Haha !
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Paul, I'm all for safety. It just sounded spooky. Watch yourself that's all I will say.
Where is the Blazer at? The back yard or driveway? I think you mentioned it before, but I must have skimmed over that. If it's not really accessible I'd pull it out with your quad and get it where you can get to everything without going on a bushwhacking spree. It don't have to be on your driveway, but it would be best if you could so you can safely jack it up and put it on stands so you can pull the wheels. Messes can be cleaned up. Keep a bag of floor dry or kitty litter handy and soak up the spills. Driveways can be cleaned and it's a lot better than spills going directly into the dirt.
From there you can get the maintenance process started. Pump out the fuel left in the tank. DON'T put it back in even in diluted form. Run it through your lawnmower or find a way to dispose of it safely. Put a few gallons of fresh fuel back in. Pull the fuel filter. Hook up a hose to the pipe that would normally lead to the inlet of the fuel filter. Run the other end of the hose to a bucket. Use the fuel pump prime circuit and get the pump running to cycle that fuel into the bucket. Look for garbage. Rust flakes like Campy noted will probably be most common. Filter the fuel through something like a paint strainer or even a pair of panty hose. You just need to collect the flakes. Put the fuel back in the tank and repeat the cycle until the fuel is coming out flake/debris free. At that point I'd put a new fuel filter in and hook the line back up. After you've changed the oil/filter in the engine, primed and I'd even squirt a shot of oil into each plug hole just to insure the cylinders aren't dry when you crank it over finally. You should be ready to fire it up. With it running I'd watch the oil pressure and water temp.
From there you can go after the drivetrain.
Where is the Blazer at? The back yard or driveway? I think you mentioned it before, but I must have skimmed over that. If it's not really accessible I'd pull it out with your quad and get it where you can get to everything without going on a bushwhacking spree. It don't have to be on your driveway, but it would be best if you could so you can safely jack it up and put it on stands so you can pull the wheels. Messes can be cleaned up. Keep a bag of floor dry or kitty litter handy and soak up the spills. Driveways can be cleaned and it's a lot better than spills going directly into the dirt.
From there you can get the maintenance process started. Pump out the fuel left in the tank. DON'T put it back in even in diluted form. Run it through your lawnmower or find a way to dispose of it safely. Put a few gallons of fresh fuel back in. Pull the fuel filter. Hook up a hose to the pipe that would normally lead to the inlet of the fuel filter. Run the other end of the hose to a bucket. Use the fuel pump prime circuit and get the pump running to cycle that fuel into the bucket. Look for garbage. Rust flakes like Campy noted will probably be most common. Filter the fuel through something like a paint strainer or even a pair of panty hose. You just need to collect the flakes. Put the fuel back in the tank and repeat the cycle until the fuel is coming out flake/debris free. At that point I'd put a new fuel filter in and hook the line back up. After you've changed the oil/filter in the engine, primed and I'd even squirt a shot of oil into each plug hole just to insure the cylinders aren't dry when you crank it over finally. You should be ready to fire it up. With it running I'd watch the oil pressure and water temp.
From there you can go after the drivetrain.
This is a good idea. I don't see what benefit you're getting from bypassing the original pump with the pressure vessel. Sounds like extra work to create a condition that won't be stable even if you do manage to get it safe. The TBI system wants a steady supply of good fuel, not a bursty supply of aereated gasoline, that's asking for rough running (again, assuming you avoid the "I just made a gasoline bomb" aspects of the plan). Ultimately you want it running under its own pump, so I'd start with Rob's suggestion of pumping out the old gas and going from there. I hadn't thought about filtering the gas and putting it back in to flush out the entire tank, but that's a good idea.
As for dumping it in the lawn mower...poor lawn mower!
Contaminated gasoline is nobody's friend. Many bonfires have been started with a batch of contaminated diesel fuel that I got a couple years back. I decided it wasn't worth running the watery gunk in anything, I can't blame you if you decide your stuff isn't worth running either. I'd base that decision on how nasty it is when it comes out.scpaul
1/2 ton status
This is funny. First, whatever you want to call what comes out of the tank,if it gets used at all it might be used to wipe down the outside of the axle, if that. It's not even good enough to wash non-critical parts. I don't want the fuel pump to turn at all. I plan on pulling the fuse/plug to it.I don't want any of it to go through the throttle body. This mtr hasn't been turned over since it was parked about 8 (?) years ago.
I'm in S.C. We have temperature that changes over 100* over the course of a year. We also have humidity. The lowest that I can think of unless it's below freezing is about 40% and don't ask me how but, the local has claimed 100% humidity, to me, that seems like it should be raining. I think that the stuff that comes out of the tank is going to be some of the nastiest "gas" that anyone has ever seen. I'm planning on siphoning as much out as I can because I don't want ANY going through the pump.
The gas tank is metal on that model, isn't it?
Can I gravity feed the throttle body? If so, How would y'all do it? I don't want the pump to come on at all and I want the whole system including lines cleaned before the pump is turned on. I don't want to mess up a pump or TBI that could be fine.
I'd like to disconnect the fuel line from the TBI and put a hose barb in place of it. I plan on using gas with a good dose of Sea-Foam in it. Then cranking it. If it doesn't crank, let it sit overnight to let the Sea-Foam work and try it again. I do have all the necessary safety equipment including fire extinguishers, one is about 3' tall and a foot in diameter. My whole yard is sand and I have shovels. I do need to get some cat litter.
Someone tell me, given what I want to avoid about the fuel system. Paul
I'm in S.C. We have temperature that changes over 100* over the course of a year. We also have humidity. The lowest that I can think of unless it's below freezing is about 40% and don't ask me how but, the local has claimed 100% humidity, to me, that seems like it should be raining. I think that the stuff that comes out of the tank is going to be some of the nastiest "gas" that anyone has ever seen. I'm planning on siphoning as much out as I can because I don't want ANY going through the pump.
The gas tank is metal on that model, isn't it?
Can I gravity feed the throttle body? If so, How would y'all do it? I don't want the pump to come on at all and I want the whole system including lines cleaned before the pump is turned on. I don't want to mess up a pump or TBI that could be fine.
I'd like to disconnect the fuel line from the TBI and put a hose barb in place of it. I plan on using gas with a good dose of Sea-Foam in it. Then cranking it. If it doesn't crank, let it sit overnight to let the Sea-Foam work and try it again. I do have all the necessary safety equipment including fire extinguishers, one is about 3' tall and a foot in diameter. My whole yard is sand and I have shovels. I do need to get some cat litter.
Someone tell me, given what I want to avoid about the fuel system. Paul
We already told you . ..
Zoomad went to another level, which I thought about ,, but you apparently don't like our idea .
The fuel pump has a screen on it to keep it from sucking up some stuff. The screen won't get tiny particles, but it should be good .
Is there any guarantee that the screen is good ? Not for sure , but it is a good chance .
Zoomad went to another level, which I thought about ,, but you apparently don't like our idea .
The fuel pump has a screen on it to keep it from sucking up some stuff. The screen won't get tiny particles, but it should be good .
Is there any guarantee that the screen is good ? Not for sure , but it is a good chance .
scpaul
1/2 ton status
You are probably right, I'm probably overly protective of the pumps. My history with the in tank pumps isn't good at all. Over the years I'd hate to say how many I've had go bad. I also got a new one that was bad. I guess if I siphon it dry a couple of times that maybe I'll get almost all of the scale out of the tank. Will it damage the pump if I put low pressure air through it backwards, does it have a check valve that would be damaged?
Any other precautions or suggestions?
Paul
Any other precautions or suggestions?
Paul
disenough
Registered Member
I think you should drop the tank to clean it out and check the pump. My burb had sat for 5 years before I bought it.
It had half a tank of gas and to pump had been replaced not long before it was parked. The tank was rusted to the level
of the gas and the pump was shot.
I think the ethanol killed the pump, every bit of rubber in the tank had turned to goo. This is an 89 burb with a TBI 350
the same as your jimmy. I found a tank at the junk yard with a good pump. Put the tank in and some gas and it tried to start.
One injector wasn't spraying so a little tappy tappy on it with a small hammer and it started working and it fired up.
It was parked running also, the guy lost his keys in a lake while fishing and had it towed home.
I have been though this a few times. I am cheap and don't drive anything that's not old.
The 20 gallons of gas out of it was filtered with coffee filters and ran thought my K10.
It didn't like it, but was ok. I said I'm cheap. I also didn't how to dispose of it.
It had half a tank of gas and to pump had been replaced not long before it was parked. The tank was rusted to the level
of the gas and the pump was shot.
I think the ethanol killed the pump, every bit of rubber in the tank had turned to goo. This is an 89 burb with a TBI 350
the same as your jimmy. I found a tank at the junk yard with a good pump. Put the tank in and some gas and it tried to start.
One injector wasn't spraying so a little tappy tappy on it with a small hammer and it started working and it fired up.
It was parked running also, the guy lost his keys in a lake while fishing and had it towed home.
I have been though this a few times. I am cheap and don't drive anything that's not old.
The 20 gallons of gas out of it was filtered with coffee filters and ran thought my K10.
It didn't like it, but was ok. I said I'm cheap. I also didn't how to dispose of it.
Now that you mentioned the ethanol, when Larry pulled the tank on mine to swap in the higher psi pump from the TBI unit, the rubber hose that connected the pump to the hard line had turned to goo. I have no idea how long mine sat before Larry picked it up, but I do know he had it over a year.
I agree dropping the tank while a pain is very smart to do. Change the pump while you got it apart. Acdelco pumps for these can be found cheap on Amazon or rock auto. Get the tank cleaned up and reassemble. Prior to putting the the tank back in I'd pull the filter and blow out the line with compressed air. You could pull the line off the TBI and blow that section out too. Then reassemble. Put the tank back in and that system will be ready.
I agree dropping the tank while a pain is very smart to do. Change the pump while you got it apart. Acdelco pumps for these can be found cheap on Amazon or rock auto. Get the tank cleaned up and reassemble. Prior to putting the the tank back in I'd pull the filter and blow out the line with compressed air. You could pull the line off the TBI and blow that section out too. Then reassemble. Put the tank back in and that system will be ready.
disenough
Registered Member
I didn't try to save any part of mine, just swapped in the junk yard tank. You can still find them down here.
I would rather run a used AC pump than the junk from parts stores.
I would rather run a used AC pump than the junk from parts stores.
scpaul
1/2 ton status
Now y'all are starting to think about just about the same things that I'm expecting. I know that years ago we couldn't find a tank for something. We took the gas tank,drained and dried it out and put a fair amount of new aquarium gravel in it. Then
they shook it with something. I don't remember what they used but I remember the viberation being described as comparable to a lawn mower with a blade that was out of balance. I wasn't there for all of this, but the tank looked good inside the next time I saw it. This was 35 - 40 yrs. ago and gas tanks must have had much thicker metal.
It's been years since I've been under it on a lift. It seems that removing that tank looked like a job. It has the big tank on it. It also has the tank guard that is claimed as an option and I was thinking that the pump wasn't that old. That's why I'm trying to save it if I can, but your probably right about it not being any good.
I got the stuff to pressure wash it today. I hope that the washer will crank. I hasn't been used in a year or more, but it has been stored in the utility room.
How hard is it to get a siphon hose in that tank? Will I be able to use a garden hose or an I going to use a small hose, anybody know?
Thanks, Paul
they shook it with something. I don't remember what they used but I remember the viberation being described as comparable to a lawn mower with a blade that was out of balance. I wasn't there for all of this, but the tank looked good inside the next time I saw it. This was 35 - 40 yrs. ago and gas tanks must have had much thicker metal.
It's been years since I've been under it on a lift. It seems that removing that tank looked like a job. It has the big tank on it. It also has the tank guard that is claimed as an option and I was thinking that the pump wasn't that old. That's why I'm trying to save it if I can, but your probably right about it not being any good.
I got the stuff to pressure wash it today. I hope that the washer will crank. I hasn't been used in a year or more, but it has been stored in the utility room.
How hard is it to get a siphon hose in that tank? Will I be able to use a garden hose or an I going to use a small hose, anybody know?
Thanks, Paul
