Green Mesa XJ

Wrong pump or blocked thermostat then? Sent from my iPhone using Tapatalk Pro

I think that diagram gives the wrong impression. This is a picture of a compressor belt bypass. If this is correct then you should be fixed flipping the belt around. Sent from my iPhone using Tapatalk Pro

Hummm, you may be perfectly correct only pictures I could find had the position of the alternator and compressor reversed to where you have them, with the alternator on top and compressor underneath it. Those belts ran from the alternator to under the water pump. These guys were bypassing the compressor by using so the pictures may not be correct. Sent from my iPhone using Tapatalk Pro

I don't think that belt is correct . Because the ribbed side is on a smooth pulley. Hang on I look it up Sent from my iPhone using Tapatalk Pro

Oh. there is a kit for adapting the newer alternators to the old systems. I've been thinking of updating the crappy gm alternator for some time just wanted to see how it went for someone who's done it. For the thermostat You can just pull the thermostat and reseal the water outlet, but I wouldn't run it on the road without it. Not having it will cause problems later on, from over cooling to over heating. Sent from my iPhone using Tapatalk Pro

Is the water pump any good? I'd pull and replace the thermostat and verify the belt set up for the 94 Camaro engine accessories you are using . I see you're using the 94 set up, nice. How did adapting the 90s alternator go? If the front of the jeep is lifted to a slight angle so the radiator is the highest point it should self burp, that might help get some air out. Sent from my iPhone using Tapatalk Pro

Does the block have coolant in it? If it's not the reverse flow pump affecting anything, I'd probably try the thermostat. But I can't think of why the block would be climbing past 180 degrees in minutes. Maybe get an accurate temp see how hot the block is actually getting. Do you know if the water pump is circulating? I think you said the catalytic converter was new so it shouldn't be a blockage. If everything else is fine maybe the radiator is FUBAR. Not a easy radiator to find now I notice a lot of cheap aluminum radiator and very few of that old fashion design for sale. Out of curiosity What finally got the carb working for you? Sent from my iPhone using Tapatalk Pro

I was sure the 2.8 mechanical fuel pump has a input, output and return. I do agree with all those suggestions they are the quickest way to get it running and running reliably. Too many things are just wrong or different compared to Original Factory Setup to diagnose it online. I've no idea why the PO thought the 2SE was a tunable improvement unless he had a E2SE to begin with. Either way it is a POS carb that nobody bothered with 30 years ago. Sent from my iPhone using Tapatalk Pro

Yes the mechanical pump had a return line built in. Look at the instructions for the regulator, you can set up it up to return the fuel to the tank. I don't use that on my set up cause I still have the mechanical pump, but do have the pressure gauge and regulator set up near the carburetor which is where it has to go for this kind of set up. Maybe as a kludge fix use the old 2.8 pump as a way to route the return line temporarily. Probably a bad idea, you need a regulator or at the very least a way to gauge the pressure . If you have this then you know if the electric fuel pump is working or not. That carburetor calls for 4.5 to 5 psi fuel in the specs, but as long as the fuel bowl in the carb is full the engine should run. You said the previous owner wanted that carburetor so he could tune it manually, was it electric computer controlled before? And do you know for sure that carburetor worked on the 2.8? Other things don't look right from the pictures but I'm not sure what you've actually got and what you actually need to make that carburetor work. I think you've got two problems from what you say is happening, fuel supply and probably a bad carburetor. Sent from my iPhone using Tapatalk Pro

I was digging though some saved files on doing a 3.4 swap, here are few of useful links I found. Install instructions for Holley 12-803 fuel pressure regulator (there is a return port) http://documents.holley.com/199r7914-3rev6.pdf Thomas Hardman 2.8 Weber swap with good pictures of the lines and hoses, anyway better than I got. http://www.thomashardman.com/tech/comanche/comanche-weber/ S10 forum has a guy by the name of Jimmykicker who has done the 3.4 swap on a 85 S10 which had the 2.8 w/carburetor, he has a few yourtube videos and s10 forum post about the swap. ericknight from the s10 forum had this summery on fuel supply Other links I think you've already found. Also found two GM diagrams of the Vacuum Lines for the 2.8 carburetor from 1983 & 1984, that might help you sort the lines. Before the swap did it run with that carburetor? Your getting fuel to the bowl, my guess is there is something wrong with it, blocking or clogged keeping the idle mixture off. Even with bad fuel pressure it should run until the bowl is empty.

The lines should still exist, hang on I'll get a picture. This is where it comes out in the engine bay near the fender. One line is already being used to pump the fuel I guess connect the return line to the correct line. I was pretty sure that line with a bolt was vacuum. I don't remember a return line being on that carburetor, it was on the mechanical fuel pump, pretty sure I connected the fuel line to the new carburetor and sorted the vacuum lines out, no return line to cut out. I think the regulator I installed had the option for connecting a return line, not sure it was so long ago. I'm not sure what the electric pumps should do in this set up. some like to add a kill switch in case ending stalls or there's an accident. Some run power from the ignition or something that is only powered while the ignition is on run. Sent from my iPhone using Tapatalk Pro

It should stay pumping. You might need to check where it's drawing power from. Edit: do you have a cut off switch? Maybe that's cutting it off? Sent from my iPhone using Tapatalk Pro

Do they still sell flexible blade kits? Mine never had the factory clutch and blade, it was a spacer with a fan that flexes as the temperature changes. Electric is probably better, but it's another possibility if they still sell them Sent from my iPhone using Tapatalk Pro

You might also check the fuel is reaching the carburetor and the line is clear while it's out. Eagle what else would fit that intake? Sent from my iPhone using Tapatalk Pro

3.4 Camaro is a reverse rotation water pump. Honestly I have got no idea what that means for the cooling system of the jeep. Plenty of people have done the swap some say use the 2.8 timing coven and water pump others don't mention it. Sent from my iPhone using Tapatalk Pro

I'm confused as to what the previous owners did aside from drop a 3.4 in. Wasn't there something about the water pump direction in later gm 2.8-3.1-3.4 bring different and the timing cover and water pump from the 2.8 had to be used? Maybe this is affecting the cooling ? Sent from my iPhone using Tapatalk Pro

Yep, you have the standard factory carburetor with electric choke or one of those flavors. 2se or e2se Rochester Varajet. Awful carburetor. Here are a few pictures from my 32 year old XJ, your missing part of the factory set up, maybe even the valve covers cause the drivers side cover looks wrong, but it also may not be necessary for all these lines to exist. Also remember I put the Weber carburetor in many years ago and this is how I set it up (following their instruction) some of these lines might be unnecessary. Just uploading small pictures for now, if you need a bigger picture I can upload it later . It's a confusing mess of lines either way. The picture for the firewall specs didn't come out, 700 rpm idle, 1200 rpm with vacuum advanced. Sent from my iPhone using Tapatalk Pro

Yeah, that idea is plenty high enough to keep running. As I remember it needs 700 rpm to idle. I'm going to get some pictures of my vacuum lines, there's a lot it looks like you are missing from the factory set up. I'm leaning towards something clogged or poor fuel supply. Even if the previous owner bought a "new" carburetor it's been sitting for twenty or thirty years, things deteriorate in this time. Sent from my iPhone using Tapatalk Pro

That carburetor like to be 4.5 to 5 psi. You might put a little gas or starting fluid down the mouth of the carb to see it if runs without going through the carb. Carb could be clogged jet, bad vacuum , or comthjng else.

The unpluged is EGR, which I'd leave alone unless you have to pass emissions. Even then it usually screws things up for running smoothly. the other plugged line with whatever that is I'll have to look up. Back of the intake manifold is a splitter that goes to the break booster and splits off the the carburetor, I think, hard to remember this set up after all these years. I believe that rear splitter going to the carb is the most important but I need to look it up. It's a mess of lines for emission crap that didn't do much. Not even going to ask if you still got the AIR pump. Youre also missing some vacuum ports in the front of the intake some of the lines twould go a canister near the radiator drivers side.

The specs looks ok on the fuel pump, maybe a little low. I'll have to look up the minimum spec for fuel psi on the 2.8 later.

Tapatalk stoped wirkjng with this forum so it's kind of hard posting links. I may need to get on the laptop to post all the links. BTW it all should be electric carduretors, I know the factory Chevy/jeep was. I don't know when manual choke died out but most 80s vehicles had electric choke. there is a jeep Chevy Weber 3.8 DGSE kit, it's made for the s10 2.8 but works on the jeep. Comes with adapter plate to work on the factory intake. Only thing is the bolt on the adapter plate for the air cleaner it too long for the jeep hood, I had to trim the bolt so it didn't dent the hood. They may have fixed this by now. those run $375-400 on eBay I bought it much cheaper at another seller but that was a long time ago. Still I'd get the kit number and google search for sellers you might catch a break. the Holley is only for the four barrel adapter plate. edelbrock 3785 is the intake base Edelbrock 3787 is the upper base for the factory and Webber carburetor edlebrock 3789 is the upper base for the 4 barrel Holly the Holley 0-8007 , 4160 390 cfm is the carburetor for the 4bbl kit, all this stuff can be exspensive, but the edelbrock and hollley do come up on auction at eBay from time to time. I bought my intake upper and lower on auction for a good price.

To me if looks like the standard vara-jet 2se carburetor. They came in different flavors for computer controls and ac. Not a lot of options for the carburetor on this engine. Webber or Holley aftermarket is available. Factory set up was limited to the Rochester varajet.. far as fuel delivery, you need 4-6 psi (I think?) to run correctly, not sure what that pump is rated or how it's wired because the 84-86 2.8 were mechanical fuel pumps. Most run a low psi pump and have a regulator in line to keep the pressure correct. If the catalytic converter is good and it should be, temps may be in line with hot summer day, dunno. Maybe take a temp in it with a laser temperature reader or a gauge if it has the correct senser.

how is the catalytic converter? If the old 2.8 died of natural causes then it probably polluted the cat on its way out. BTW the oem fuel filter is at the back of the carb where the fuel line goes in, mine was frozen in place so I added a in line filter.

Honestly you are better off getting a Weber (dgs 38?) , what you got is a junk factory carburetor. The adjusters are in the front center if I remember correctly you'll need a special tool to adjust it, had difficulty finding one 20 years ago. Easy to adjust the idle I think, but that may be the Weber I'm think of. I rebuilt that carb back when I first got the jeep, did a little better but the biggest improvement was the aftermarket carburetor. check the base gasket for vacuum leaks, just some carb cleaner sprayed around the base and other places you think it could be leaking. If you pull it apart to change the base gasket you can ditch the pre heater, it sits on top of the base gasket and plugs into the wiring harness. I've never seen one that works or didn't try to start a fire. Hopefully it's already gone. if you going to keep the carburetor set up then upgrading the intake and carb will help a lot. Weber makes a carb. Holley does as well a four barrel, that goes with the edelbrock 2 piece intake. You can find them on eBay if you wait for a used one to pop up.