Deleted user Posted May 9, 2009 Share Posted May 9, 2009 I was wondering if anyone had switched their 4.0 from fuel injeciton to a carb. Were any 4.0s carb or are all of them fuel injected. Sick of dealing with all the problems with my FI system and looking for an easier to work on system. any thoughts or tips would be greatly appreciated Link to comment Share on other sites More sharing options...
Sir Sam Posted May 9, 2009 Share Posted May 9, 2009 the 4Liter FI setup is actually very nice and much less problematic than any carb ever will be. Once you get the problems fixed it will be much more reliable, run better, and give you better fuel economy. So lets start there, what year is your Jeep and what problems are you having? Link to comment Share on other sites More sharing options...
Deleted user Posted May 9, 2009 Author Share Posted May 9, 2009 I'm getting spark at the plugs, fuel at the fuel rail, however I'm not sure the pounds and its not firing, itll crank all day long (until I kill another battery) but won't start. I just bought the think to use as a woods truck and have tried everything i can think of. checked the firing order, spark, fuel pump turning on, bypassing the resistor on the driver's side under the hood (white ceramic thing) and have no other idea why it won't start, any help is appreciated. its a 88 4.0 5spd 4wd pioneer, thats all i know about it.. Link to comment Share on other sites More sharing options...
Eagle Posted May 9, 2009 Share Posted May 9, 2009 All Jeep 4.0L engines were EFI. However, the 4.0L is a direct descendent of the AMC 232/258/4.2L, which was carbureted. If you want a carburetor, pick a nice 2-bbl (or 4-bbl) carb (not the one they used from the factory), get a distributor from a 258 or 4.2L, and go to it. Link to comment Share on other sites More sharing options...
Pete M Posted May 9, 2009 Share Posted May 9, 2009 Did it run at all when you bought it? Did it sit for any length of time? Could be old gas. Link to comment Share on other sites More sharing options...
Deleted user Posted May 10, 2009 Author Share Posted May 10, 2009 eagle--wouldnt i need a new intake manifold? the truck didnt run when i bought it and the previous owner stated it had been sitting for about six months, without being started etc.. Link to comment Share on other sites More sharing options...
Pete M Posted May 10, 2009 Share Posted May 10, 2009 Gas might be toast. :( I would pump it out and fill with fresh before doing anything drastic. By the way, that webpage does have the proper firing order. :thumbsup: Link to comment Share on other sites More sharing options...
jpdocdave Posted May 10, 2009 Share Posted May 10, 2009 efi to carb is a terrible idea. the 4.0 fuel injection is very solid, and not problematic. the carbs during this era however were the worst of all time if you have spark at the plug and firing order is correct you need to know what your fuel pressure is, if the timing is right, and you also need to know if you have injector pulse, and compression. bottom line. and this is identical to a carb other than injector pulse. find that out, and with that info we can figure out what is wrong fairly easily. Link to comment Share on other sites More sharing options...
Deleted user Posted May 10, 2009 Author Share Posted May 10, 2009 have compression, not sure what the poundage is, but sounds decent with the plugs removed turning the engine by hand. What is an injector pulse and how the heck do i check that? Link to comment Share on other sites More sharing options...
Deleted user Posted May 10, 2009 Author Share Posted May 10, 2009 I just noticed something else looking at the diagram of the dist. my cap mounting holes doint point to the #5 cyl they are pointing towards the #1 cyl, is that normal.... assuming the screw placement in the diagram is incorrect, would the #6 plug wire still point between the #3 and 4 cylinders? or is the diagram incorrect? can someone snap a closeup pic of their dist mounting and the cap please and post it on here for me.. i edited the pic of the diagram above but can't figure out how to post it on here... Link to comment Share on other sites More sharing options...
Pete M Posted May 10, 2009 Share Posted May 10, 2009 If you right-click on an online image, you can save the image location. Paste it here, highlight it, then click on the IMG tag right above the text box. Be aware that not every website allows this hotlinking and so it won't always work. To post your own images, see this thread: :thumbsup: viewtopic.php?f=6&t=11077 Link to comment Share on other sites More sharing options...
JeepcoMJ Posted May 10, 2009 Share Posted May 10, 2009 have you had the distributor out of the truck? did you take it out and then have a no-start issue? or did it run bad and then stop running? ....my guess is that one of two things is happening; your distributor is not "indexed" properly (the distributors are non-adjustable to timing, however you CAN adjust it by removing it, turning the gear drive/oil pump key, and putting it back in. OR your CPS is picking up rotation, but not at the right time. that could be simply a failing CPS, or a cracked flexplate/flywheel, or improperly mounted CPS (one bolt missing/lose on it) Link to comment Share on other sites More sharing options...
FxRacing282 Posted May 10, 2009 Share Posted May 10, 2009 to check for pulse you can use a test light. pull one injector connector and place one lead to one of the wires, another lead to another wire. crank the engine. the light should flash. no flash, no fuel. it may only be a dim flash but that means its getting voltage. Link to comment Share on other sites More sharing options...
whowey Posted May 10, 2009 Share Posted May 10, 2009 Gas might be toast. :( I would pump it out and fill with fresh before doing anything drastic. I usually get a can of starter fluid to check this... Shoot a little in the air horn. If it fires.. start looking at fuel related causes. Link to comment Share on other sites More sharing options...
Deleted user Posted May 10, 2009 Author Share Posted May 10, 2009 can anyone help me out with the diagram above. On the image above the mounting screws line up to the #5 cylinder, on my truck the line up to the #1 cylinder. If done properly should the #6 plug wire be between the #3 and 4 cylinder or does the image of the distributp cap just need to be rotated in the image? Link to comment Share on other sites More sharing options...
jpdocdave Posted May 10, 2009 Share Posted May 10, 2009 can anyone help me out with the diagram above. On the image above the mounting screws line up to the #5 cylinder, on my truck the line up to the #1 cylinder. If done properly should the #6 plug wire be between the #3 and 4 cylinder or does the image of the distributp cap just need to be rotated in the image? went out and took a couple pics of my 90 4.0 for you. Image Not Found Image Not Found Link to comment Share on other sites More sharing options...
Deleted user Posted May 10, 2009 Author Share Posted May 10, 2009 thanks Jp big help my wires were set off one counterclockwise....now to my next issue, since I thought i had it right last night when i wrenched on the truck, with the #1 cyl set a TDC the button should be at the #1 spark plug and the end that fits into the rotor should be at the #6 plug right? or did i totally screw my self? Link to comment Share on other sites More sharing options...
jpdocdave Posted May 10, 2009 Share Posted May 10, 2009 yes, the rotor points to 1 at tdc. but be careful you could have it 180 degrees off, and still point at number 1. it has to point at number one on compression stroke. Link to comment Share on other sites More sharing options...
Deleted user Posted May 11, 2009 Author Share Posted May 11, 2009 after some wrenching i got the timing set it was 180 off. with a little starter spray i got it to fire. then i went to the fuel pump and it wasnt running, removed it and oh my god...think I'm gonna need to drop the tank. does anyone know how to clean out a gas tank I'm sure its cruddy as all get out... Link to comment Share on other sites More sharing options...
jpdocdave Posted May 11, 2009 Share Posted May 11, 2009 after some wrenching i got the timing set it was 180 off. with a little starter spray i got it to fire. then i went to the fuel pump and it wasnt running, removed it and oh my god...think I'm gonna need to drop the tank. does anyone know how to clean out a gas tank I'm sure its cruddy as all get out... ya, they get nasty. take it down and drain it and clean it as best you can, otherwise there's places that can clean and coat the inside, or find a replacement. was there power at the pump? if the pump had power and ground, and no pumping, then you need a new pump, if it didn't have power, its not the pump Link to comment Share on other sites More sharing options...
Pete M Posted May 11, 2009 Share Posted May 11, 2009 I would start with a fresh tank. :cheers: Link to comment Share on other sites More sharing options...
Eagle Posted May 11, 2009 Share Posted May 11, 2009 My friend who restores old Hudsons deals with an old-time radiator shop that refurbishes and lines gas tanks. For a vehicle for which you can't buy a replacement tank, it makes sense. A new tank for a SWB MJ cost me $150 (approximately) two years ago. The cost to have them open up, clean, and reline the old tank would have been about twice that amount. Link to comment Share on other sites More sharing options...
Deleted user Posted May 11, 2009 Author Share Posted May 11, 2009 no home remedies for cleaning the tank? Link to comment Share on other sites More sharing options...
jpdocdave Posted May 11, 2009 Share Posted May 11, 2009 you can take it down, drain it out, wash it out, water, mineral spirits, flush it a bunch, blow it out with air, and let it dry thoroughly, and it won't be great, but much better. but for 150 i'd just get a tank. Link to comment Share on other sites More sharing options...
Pete M Posted May 11, 2009 Share Posted May 11, 2009 I know I've seen photos of guys refurbing their tanks. Don't know how extensive theirs were in regards to cleaning. You might want to start a fresh topic about that so hopefully they'll see it. :thumbsup: How's the rust in your area? Link to comment Share on other sites More sharing options...
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