4.0 sluggish acceleration and stalling

[Joebronco]

I'm not sure how to measure flow (cfm). But the tank is new, pump is new and filter is new. I've only filled the tank two times. Seems like there'd have to be an awful lot of trash in the 30 gallons of fuel I put in it to clog a filter that quickly.


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Yup, sometimes new stuff has oils and trimming still in it and can clog a filter fairly quickly. But like lumpy said above- 3/8" line is the way to go with fuel injection.


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[Hog Head]

Hmmm ok thanks, I better check that. Appreciate you guys.


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[Hog Head]

Ok friends, just checked and the rubber line connected to the tank is 5/16 connected to 5/16 steel line to 5/16 rubber line into filter and outa the filter is 3/8 converted to 5/16 into the fuel rail. The 3/8 to 5/16 conversion was on the filter when it came with the in tank pump. Rookie here left it like it came.


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[Lumpy Grits]

We know what you'll be do'n.......
LG

 

[Redcolt88]

hey man,

were you able to run the 3/8" fuel line? I'm pretty curious if that solved your problem.

cheers

 

[Torxhead]

With fuel injection, a larger fuel return line is critical also. Although the oem CJ return nozzle at the fuel tank is only 1/4" though. I have 5/16" line to the tank, some guys have 3/8".

 

[Hog Head]

To date I've not changed the line, still 5/16. I met a local guy, now a friend of mine who was a jeep mechanic instructor for his entire carrier. He's given me a lot of help and even had my CJ7 in his shop for a once over of my build job. Anyway, he told me 5/16 was fine for fi. And after running some injector cleaner through it, it does run and idle better. I still have no top end speed and with oem 2.73 gears, it should run 100 mph. I do remember bending the ss fuel line back by the tank and ended up putting a pretty good kink in it. This could be the volume problem I'm having. What's you guys opinion on that?


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[Belizean]

Just tossing this out there. Is the exhaust system new or something really old ? I've seen 3-4 different times over many years where the catalytic converter gets clogged from a rich mixture and the vehicle runs with little power because it just can't breathe correctly

 

[Hog Head]

It's new, I had it put on in a local muffler shop. No cat converter


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[Joebronco]

To date I've not changed the line, still 5/16. I met a local guy, now a friend of mine who was a jeep mechanic instructor for his entire carrier. He's given me a lot of help and even had my cj7 in his shop for a once over of my build job. Anyway, he told me 5/16 was fine for fi. And after running some injector cleaner through it, it does run and idle better. I still have no top end speed and with oem 2.73 gears, it should run 100 mph. I do remember bending the ss fuel line back by the tank and ended up putting a pretty good kink in it. This could be the volume problem I'm having. What's you guys opinion on that?


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Opinion? I fought with my FI system and was plagued with problems until I went with a 3/8" line. Same with the other 20 or so guys that run the same system on the other jeep forum I'm on. (Edit/add) - it also only cost $50 to do so it was cheap insurance. I still need to do the return line.

But I'm sure your mechanic buddy has more experience rebuilding FI systems in CJ's than all of us or you wouldn't have taken his advice. What kind of FI system does he run in his jeep?



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[Hog Head]

Thanks for the reply friends. He and most all his friends are running cherokees with the same 4.0 that I have. They invited me to wheel with them a couple of weeks back at a 4 wheel park in gilder tx called barnwell mountain. It was my first experience at wheeling. The trails are marked 1 to 5 diamonds. And we rode a couple of 4's and a lot of 3's. at the end of every trail was a really steep uphill or downhill, slippery boulder filled run. I'm telling you this 63 year old's heart was pounding away. There were four other experienced drivers (some in their mid 70's) that really helped me out with driving tips and winched out twice. I got the hang of it after lunch and did much better. Initially I was worried about breaking my newly built jeep. But after I got the hang of it, just drove it like I stole it[emoji23]. At the end of the day, only had a small coolant leak and a huge power steering leak because the pressure line just loosened up at the gear box. All in all, a good day and dang proud of my first build. Things I learned I need: lockers front and rear (have Limited slip in rear now), about an additional 4" lift (have 2" now), larger mud grip tires (have 32" all terrain now), lower gearing maybe 4.10 or lower (now have oem 2.73's), now don't laugh at this one, air conditioning (scorching Texas heat above 100). The Cherokee guys were running a/c and automatic trannys. They were staying cool and listening to jimmy buffet climbing these boulders, and I was pinching up seat cushions with my clutch and non locking 2.73's.
Long story short, jeep performs well and will be better with the aforementioned changes. Just need some acceleration on the pavement at top end.


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[Hog Head]

Gilder should read Gilmer. Darn spell check


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[Bill D]

Thanks for the reply friends. He and most all his friends are running cherokees with the same 4.0 that I have. They invited me to wheel with them a couple of weeks back at a 4 wheel park in gilder tx called barnwell mountain. It was my first experience at wheeling. The trails are marked 1 to 5 diamonds. And we rode a couple of 4's and a lot of 3's. at the end of every trail was a really steep uphill or downhill, slippery boulder filled run. I'm telling you this 63 year old's heart was pounding away. There were four other experienced drivers (some in their mid 70's) that really helped me out with driving tips and winched out twice. I got the hang of it after lunch and did much better. Initially I was worried about breaking my newly built jeep. But after I got the hang of it, just drove it like I stole it[emoji23]. At the end of the day, only had a small coolant leak and a huge power steering leak because the pressure line just loosened up at the gear box. All in all, a good day and dang proud of my first build. Things I learned I need: lockers front and rear (have limited slip in rear now), about an additional 4" lift (have 2" now), larger mud grip tires (have 32" all terrain now), lower gearing maybe 4.10 or lower (now have oem 2.73's), now don't laugh at this one, air conditioning (scorching Texas heat above 100). The Cherokee guys were running a/c and automatic trannys. They were staying cool and listening to jimmy buffet climbing these boulders, and I was pinching up seat cushions with my clutch and non locking 2.73's.
Long story short, jeep performs well and will be better with the aforementioned changes. Just need some acceleration on the pavement at top end.


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Glad you had a good first outing. Lockers are great as is a regearing of the Transfer Case . A total of about 4" lift is about all I would want on a CJ. More is really going to start complicating your life. 33" Mud Terrains would work well with that combination. Sounds like you are starting to get it all figured out though.

 

[Belizean]

I've heard of that ORP. Yeah good ole southeast humidity. Drinking plenty of cold ice water is what is required!