[Curt Reinhardt]

I had the Howell system (bought new from Howell) installed two years ago on my 78 CJ5/304 and it’s never worked correctly. Three competent mechanics and Howell’s tech dept (Howell has been very supportative) have never been able to figure it out. I’ve installed new chips, new computers, new throttle bodies, new idle control modules-everything we can think of has been tried and no success.

The problem has to do at idle. Sometimes I start it and it will idle reasonably well. Other times it floats up and down 100-150 rpm at idle. Actually there have been times it would swing between 900-1200 rpm according to the Jeep tach. Often - but not always - I turn it off and restart it and it corrects. Off idle it performs flawlessly.

It’s only thrown a code one time (maybe #22) and seemingly it was a bad connection at it idle control but that was a year ago.

I’m ashamed (almost) to say I’ve got thousands into trying to fix it (not including the original cost) and my heart has given up. The sad thing is it ran perfectly before I switched to fuel injection!

So here’s my question - Which carburetor is better for my purpose? It’s strictly a DD. It will never go off-road as long as I have it. I know…I know but it’s a pretty low mileage (now 55k) , original condition CJ5 - original carpet (worn), original seats (also worn), dealer window sticker, owners manual , all that stuff. There are not a lot of 5s running around and I want to take care of it. It’s got a couple small rust spots but very small and they’ll be fixed this winter.

Back to my question - it’s got a Edelbrock Performer manifold on it. Should I go with a Holley or Edelbrock carb.

Thanks for any help or recommendations!

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This may be of no help at all because you and Howell covered it.

I am buying a 350 TBI complete this Saturday and while reading the Affordable Fuel Injection website, I noticed the FAQ repeatedly stated that vacuum leaks were the #1 problem with the Chevy TBI system. In fact, the first item to check in the diagnosis section for every problem was almost alway's vacuum leaks.

Also, do you have engine to frame and frame to body ground straps?

I hate to see anyone go back to a carb, especially in your case when you made the decision to spend over a grand. If you are finished with the TBI, I would use an Edelbrock Performer 600 cfm on a Holley Street Dominator 300-Z manifold. The 300-Z was designed by Duntov specifically for AMC V8's, it's a single-plane small runner manifold with excellent low-end throttle response.

[Curt Reinhardt]

I sincerely appreciate your reply.

I'll get up with the shop to see about vacuum leaks and grounding. What bothers me is nothing is consistent. I don't understand why it may run much better after I turn it off and back on and it's done the same thing with different ECM's. If it starts and idles reasonably well it stays that way until I shut it off. If I start in and it idles erratically it also never changes until I shut it off.

I don't think the vacuum leak possibility has been aggressively pursued so I will check on that.

Thanks again for your carb/manifold recommendation.

Curt

[1979CJ7]

I have the same thing on my 304. My jeep idles high all the time. Its normally at about 900. I need to make it go back down and I vaguely remember having to mess with the port with a paper clip and setting the idle that way. I would have to go back and look but thats what I remember doing.

Vacuum leaks would be a good area to pursue. My vacuum port caps became dry rotted and I was leaking every where. It ran all right with the leak until i discovered it.

[Cherokeester]

So your Jeep will never go off road, so why did you spend thousands on fuel injection? Just curious. As for carbs, I have had very good luck with the Holley truck avenger. It is an off-road carb but it really runs great all around. Get the 470 cfm unit for your application.

I am sure you have checked everything, but O2 sensors are the number one issue with fuel injection systems.

[Curt Reinhardt]

Hi Cherokeester-

I'm retired and wanted to have some fun.

I thought about a Porsche (which I love) but would lose my license over speeding tickets or reckless driving charges. I thought about a HD Sporster but my reflexes are not what they should be any more!

I wanted to try to make a low mileage CJ5 as reliable and modern as possible and use it for a daily driver. I live at the beach and only drive it when it's above 60* and sunny. I didn't want a new Rubicon because they're all over the place.

So far I have not been successful but I'm still working on it.

Thanks for the Holly recommendation. To be honest the one thing that has never been replaced is the O2 sensor.

[Cherokeester]

Originally Posted by Curt Reinhardt

Hi Cherokeester-

I'm retired and wanted to have some fun.

I thought about a Porsche (which I love) but would lose my license over speeding tickets or reckless driving charges. I thought about a HD Sporster but my reflexes are not what they should be any more!

I wanted to try to make a low mileage CJ5 as reliable and modern as possible and use it for a daily driver. I live at the beach and only drive it when it's above 60* and sunny. I didn't want a new Rubicon because they're all over the place.

So far I have not been successful but I'm still working on it.

Thanks for the Holly recommendation. To be honest the one thing that has never been replaced is the O2 sensor.

Yep, I would check that O2 sensor, I bet your problem lays there.

[Curt Reinhardt]

Originally Posted by Cherokeester

Yep, I would check that O2 sensor, I bet your problem lays there.

Hi Cherokeester-

I'm going to try a new O2 sensor Thursday morning (I think) and see if that corrects it. If it doesn't I'm going to have a carburetor standing by!

Thanks - Curt

[CJ83]

Sorry to hear that, I've been runnning a Holley carb but don't take it off road much. Let me know if you'd want to sell your Howell setup. I might be interested in giving it a shot.

Clint

[JeepHammer]

Originally Posted by Curt Reinhardt

Actually there have been times it would swing between 900-1200 rpm according to the Jeep tach.

So, no one told you not to use the factory tach?

Did anyone tell you to solder all the electrical connections?

Did you ground the exhaust so the O2 sensor can give an accurate reading?

GM had a real problem with getting that particular computer to ground, make sure it has a dedicated ground wire to the case.

Back to my question - it’s got a Edelbrock Performer manifold on it. Should I go with a Holley or Edelbrock carb.

Holley will be more tunable, easier to get parts for and doesn't have the 'Issues' the Edelbrock version (which is upgraded) of the Carter AFB.

[Curt Reinhardt]

Originally Posted by JeepHammer

So, no one told you not to use the factory tach?

Did anyone tell you to solder all the electrical connections?

Did you ground the exhaust so the O2 sensor can give an accurate reading?

GM had a real problem with getting that particular computer to ground, make sure it has a dedicated ground wire to the case.



Holley will be more tunable, easier to get parts for and doesn't have the 'Issues' the Edelbrock version (which is upgraded) of the Carter AFB.

Hi JeepHammer-

I will check on the grounding of the exhaust - I'll bet it's not. I'll check on the ground to the computer and make sure it's good.

Per a post from Cherokeester, I replaced the O2 sensor today and there was no change but.......I'm glad I took his suggestion because I found out it actually runs and idles better without the O2 sensor hooked up!!! Why???

What happened was I got the wrong sensor to replace the old. We removed the old sensor so I could take it to the NAPA dealer and try to match it up. I had to take the Jeep so we put a plug in it's place. The darn thing wound up running much better at an idle without the sensor! We replaced it with a new Bosch sensor and it began "loping" again! The replacement wound up being an in-line 4 pin plug from a 1997-1999 Chevy. Anyway, we replaced it and the "lope" came back. We decided to remove it - I drove it about 12-15 miles in stop and go traffic and it idled as well as possible - so well that I never would have thought anything was wrong!

We're going to get up with Howell to see if they have any suggestions but I'd appreciate your thoughts on it.

Thanks for all the help and suggestions, I truly appreciate it - Curt

[jfwireless]

Curt:

Have you checked your fuel pressure at the input to the throttle body. It needs to be rock solid at all throttle positions or you will have trouble. I had the same issue with my 1976 CJ7 (304) junkyard TBI install, ended up being to small a fuel return line to the gas tank causing the fuel pressure at idle to wonder from 15 lbs to 12 lbs, as soon as I gave it some throttle it went rock solid to 12 lbs. Engine ran great at all throttle positions except idle, at idle it would just surge up and down and than just die. When I installed a 15 lb pressure gauge on the fuel input port of the throttle body I could see the fuel pressure moving all around at idle causing the idle problem. Remember the fuel return line was sized for low pressure carburetor, not higher pressure for TBI. Check the size of your return line and see if it isn't much smaller than the main fuel line.

Fuel pressure is critical for TBI engines, setting the proper BPC and than the VE tables is dependant on fuel pressure. If the fuel pressure is not constant you never can get the proper fuel/air mixture.

I hope this helps, it would be a shame not to get you setup running after all you have invested in it.

Jim

[Curt Reinhardt]

Originally Posted by jfwireless

Curt:

Have you checked your fuel pressure at the input to the throttle body. It needs to be rock solid at all throttle positions or you will have trouble. I had the same issue with my 1976 CJ7 (304) junkyard TBI install, ended up being to small a fuel return line to the gas tank causing the fuel pressure at idle to wonder from 15 lbs to 12 lbs, as soon as I gave it some throttle it went rock solid to 12 lbs. Engine ran great at all throttle positions except idle, at idle it would just surge up and down and than just die. When I installed a 15 lb pressure gauge on the fuel input port of the throttle body I could see the fuel pressure moving all around at idle causing the idle problem. Remember the fuel return line was sized for low pressure carburetor, not higher pressure for TBI. Check the size of your return line and see if it isn't much smaller than the main fuel line.

Fuel pressure is critical for TBI engines, setting the proper BPC and than the VE tables is dependant on fuel pressure. If the fuel pressure is not constant you never can get the proper fuel/air mixture.

I hope this helps, it would be a shame not to get you setup running after all you have invested in it.

Jim

Thanks Jim

I know the supply line was enlarged because it starved for gas when I got on it. I'm sure nothing was done to the return.

The symptoms you had sure are similar to mine. The Jeep goes to the shop tomorrow and I'll have them check the pressure out. I'll let you know what I find out.

Thanks again for your reply - Curt

[Curt Reinhardt]

Originally Posted by CJ83

Sorry to hear that, I've been runnning a Holley carb but don't take it off road much. Let me know if you'd want to sell your Howell setup. I might be interested in giving it a shot.

Clint

Hi Clint

Sorry I didn't get back with you sooner regarding selling the Howell setup.

First I'm going to try some of the suggestions that have been made. If that doesn't correct the problem I'll go the carb route.

He doesn't know it yet (he will now I guess) but if I go the carb route I'm going to give the stuff to BESRK (Eddie). I know this forum has two really great moderators (BESRK and jeepskate) but Eddie has posted one heck of a lot of interesting, informative and "fun to watch" stuff that made it worth me becoming a "Lifetime Supporter" to JeepForum.

My thought is there is nothing wrong with the Howell - my CJ is just possessed - but since I'm not 100% sure, I don't want to sell it.

Thanks for asking - Curt

EDIT
I never should have posted this even though it's 100% true. I want to try and get the Howell working! If I can't then I should have called Eddie and privately given it to him. I don't know why I did what I did. Sometimes this forum is like a bunch of guys sitting around BSing. I'm sorry.

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Curt,

It's a different company but you may want to check the FAQ's on Affordable Fuel Injections website.

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