84' cj7 ,Howell TBI wont idle

[Redcolt88]

NIKE!, VICTORY!, EUREKA!

Problem was a bad wire to the fuse block, it had a 4 volt drop from the battery to the fuse block power so I ran a wire with a 5 amp fuse inline directly to the fuse block from the battery and instant fire, no chugging no drama.

Lesson learned I should have started with the trouble shooting guide rather than going rogue.

I do sincerely appreciate the suggestions and advice.

 

[Torxhead]

Thanks for the update. I see per the Howell troubleshooting guide that there is supposed to have .5 volts max difference between the battery and the Howell ecm fuse block which is wired from the inside of the CJ cab fuse block and voltage is lost as volts pass through the CJ fuse block from the engine compartment. Although 4 volts is quite a bit, this can affect other items on the inside of the CJ like gauges and the oem computer. I ran the #2 red wire from the alternator which is also called the "Sense" wire to the hot line on the fuel gauge under the dash. Now I get full battery voltage throughout the CJ.

 

[thundley57]

I ran the #2 red wire from the alternator which is also called the "Sense" wire to the hot line on the fuel gauge under the dash. Now I get full battery voltage throughout the CJ.

Hey Torxhead,

Would you mind elaborating a bit on this mod? I'm having similar issues with my 83 CJ7 Howell TBI engine and wondering if I should do this. I started a thread back in Feb or March on my issues for which you and Posi helped me tremendously. It's been a couple of months since I updated my post as it's been too hot to work on the Jeep in the brutal Bakersfield sun but I finally was able to get it started and idling normal yesterday after installing the 3rd distributor pickup coil. I'm still not convinced that the problem isn't intermittent though. I think you were the one that recommended checking all of my grounds which I've done but still not convinced it's not an intermittent grounding problem. I definitely would like to try this wire from the alternator though.

Thanks, Tom

 

[Torxhead]

I got that mod years ago from another forum, a guy who now calls himself "Team Rush" who has even made a few posts on this forum. I noticed that the voltage under the dash was on the weak side and I think there is a problem where the electricity passes through the CJ junction box. On the oem alternator wiring, in the back there are three wires, two red and one brown. The main red wire goes into the starter solenoid through a fusible link. The other red wire, goes from the #2 location on the alternator to that main wire location on the alternator. This is called the "Sense" wire. So I have sent this sense wire from that #2 location into the back side of the junction box at the red hot line to the gas gauge also using a fusible link. When I start a cold engine the voltmeter reads around 15 volts and then drops down to around 14.5 as it warms up. I have also increased the size of the main wire going to the battery from the alternator along with increasing the size of the fusible link. I hear it is better just to double up and add the same size main charge wire, a #10 and a #14 fusible link. I do run a 94 amp alternator to power the electric fuel pump and Warn winch when needed. Clear as mud? if so let me know.
Edit: Oh yeah, the voltage is checked from under the dash, with the engine running of course. Redcolt has a pretty good solution also.

 

[thundley57]

Thanks for that Torxhead! In regards to Redcolt's solution, doesn't that cause the ECM to be powered up all the time as opposed to only when the key is on?

 

[Torxhead]

Redcolt, could you go into a bit more detail on the wire you replaced?

 

[Redcolt88]

Redcolt, could you go into a bit more detail on the wire you replaced?

I will take pictures and put a more detailed solution in the first post.

 

[Redcolt88]

Skip to bottom to get straight to the point.

This will be a more detailed follow up now that some time has gone by and the problem hasn't come back. I won't go into detail about the diagnostic process because there is plenty of that on the net so I will focus on the problem I had once I discovered it. I have very Limited experience and I'm not a guru by any stretch of the word, but if you want my .02 on a problem you're dealing with PM me your situation or direct me to your thread and I will help however I'm able.

Most important part of this post/thread...
IF YOU DO NOT HAVE THE SERVICE MANUEL TO YOUR HOWELL SYSTEM YOU NEED TO GET A COPY OF IT FROM HOWELL OR SOMEWHERE ON THE NET
I say this because I could have saved myself 2 weeks of agony had I started with the diagnostic troubleshooting section of the manual in the first place.

Here's what happened:

The Howell fuel injection system has a fuse block that is part of the kit and has keyed power supplying it with juice. It has three fuses, if mounted vertically like mine, the top one is keyed power to the ECM, the bottom two supply power to the injectors.

*important note, each injector has its own fuse! that is why there is two of them*

There is a .5v voltage drop tolerance between the battery and power at the ECM fuse block.

**Important note #2, in the Howell install manual, the Howell service manual, and everywhere on the net, "ECM fuse block" and "fuse block" are terms used interchangeably that refers to the black plastic fuse holder that has three 5 amp fuses in it.**

When I checked the voltage at the ECM fuse block on my jeep, it was only receiving 8v. I ran a fused wire directly from the battery to the supply wire that went into my fuse block and the motor started and ran smooth. It idles great and smoothly returns to idle after giving it throttle.

The Fix: I tied into keyed power from the Jeep fuse block under the dash and ran a new wire to the fuse block, making sure that i had was within proper voltage spec.

Do not put battery power (constant power) to the ECM fuse block because it energizes relays when power is sent to it and it will kill your battery in less than an hour. (ask me how I know) The proper way to do this would to energize the fuse block with a relay, but for now I have a couple spare 5 amp fuses in the console and I am waiting till this winter when hopefully I will rewire the entire jeep anyways.

Clear as mud?

ECM fuse block


bonus pic of the sad state of the main fuse block

 

[Torxhead]

Thanks for the fix report.

 

[thundley57]

Yes thanks Redcolt.

 

[Lutheros]

Lets try the overlooked. How old is the gasoline? Gas goes bad. If it is more than a few months old there is a good chance that it has gone bad. The next most likely cause is the injectors have partially clogged from varnish build up due to sitting so long. As for the oil in the distributor, it is most likely due to its bushings being worn far enough to allow excess oil to work up the shaft. You can get away with cleaning it out periodically, but it needs to be replaced.

 

[Lumpy Grits]

Gasoline doesn't go bad in just a few months. Contamination within the fuel system is another world.
If the engine runs fine, and won't idle-it's not the fuel itself.
LG

 

[Belizean]

E10 gas has a shelf life of 90-100 days under ideal environmental conditions. That doesn't mean you can't run your vehicle on 2 year old fuel

 

[Lumpy Grits]

I have had zero issues with CA. gas that has sat in my vehicles for 9+ months.
LG

 

[Belizean]

Maybe at almost double the cost of what we buy gas at, maybe the refinerys in Cali add Sta-Bil to there's

 

[Lumpy Grits]

Well-After Harvey leaves, you prices might be closer to ours-
What's a gal of reg go for where you live?
LG

 

[Belizean]

1.95 last week and for months. Last year at the low point 1.67 a gal. Last September I drove from Oregon through Cali down to Palm Springs and it was in the range of 3.40 - 3.80. I think Texacans will be having high prices. We have several refineries in the area and they are cranking out plenty of fuel here. Even the SPR is here and plenty of LNG also.

 

[Redcolt88]

Lets try the overlooked. How old is the gasoline? Gas goes bad. If it is more than a few months old there is a good chance that it has gone bad. The next most likely cause is the injectors have partially clogged from varnish build up due to sitting so long. As for the oil in the distributor, it is most likely due to its bushings being worn far enough to allow excess oil to work up the shaft. You can get away with cleaning it out periodically, but it needs to be replaced.

Thanks for the input, It did have year old gas in it but that was switched out, the injectors could have been the problem and i didnt clean them or run a cleaner through them but i have since fixed the root problem and the injectors are fine. The distributor had only about 1000 miles on it since it it was replaced. not saying it didn't/doesn't have a manufacturing defect with loose tolerances but in another thread I addressed a high crankcase pressure issue where a clogged breather and busted pcv valve were causing oil to come out of the dizzy, the dipstick tube, seeping out of the valve cover gasket, etc. I have since cleaned it all out and replaced the pcv valve and we have been running like a champ for a while now. The low voltage to the ecm fuse block ended up being the problem. If you're curious about more detail i have a more in depth post about what I did.

cheers

 

[Lumpy Grits]

PLZ-Let's hear the details.

LG

 

[Torxhead]

FYI Redcolt, if you don't already have it, the Teamrush big cap conversion is a great addition to the throttle body conversion.