Engine Howell 4.2 TBI ongoing idle and WOT fuel issues with new system

[CJKen51]

Hello All, I have around 1 hour of actual drive time on my Howell TBI it ran "mostly" well to begin with and I was excited to drive it. Then, it just started leaning out and dying. Was towed home, by my son, that day. That was back in early June. Anyway, I've messed with this forever. The list of tests is a long one.
When I unplug the MAP sensor, it will actually idle. It idles smooth. Granted, it's rich and in a limp mode, which lines up with the service manual that was included in my kit. Plug the MAP back in and back to dying within just a few seconds. Here's the kicker: I've tried two different MAP Sensors. I also picked up an extra computer, since they were $95. Tried both of those and switched the PROM over, of course. I've talked to Troy, at Howell, 3 or 4 times now and I checked and verified everything he asked. Looking for a tip on anything else I could check. Thanks, in advance.

 

[Manic Mechanic]

What's your 02 reading? Also what's your IAC? (Idle air control)

 

[CJKen51]

Hello-
I tested "movement" of voltage O2 sensor in a vice with my torch. Moves between .3 - .9 which, I believe is good.
IAC - only tested with key "on", engine "off".
Lt Blue = 11.47v
Dk Blue = .391 mv
Lt Green = .4 volts
Dk Green 11..47 v.
I have not back probed the IAC while the MAP was unplugged... only time it will stay running.
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[Manic Mechanic]

I've not messed with Howell to much (not as user friendly as Holley sniper or ACES)

But the IAC should be giving you a reading between 1-3% during idle.

Does Howell have a handheld for tuning or diagnostics?

 

[CJKen51]

As far as I know, they do not have a hand-held. I can hear and feel it pulsing (the IAC) when you do a base idle test. That's about it. They give you an ALDL connector which has 3 wires. It's an 80's style OBD1. Engine trouble light, in the kit will flash codes. i.e. 22 or 33 etc.. The only time I've ever had a code is when I unplugged the MAP, which is to be expected.

 

[boney]

I'm not a deep knowledge base on these. I wish you were closer though, I have a BT connector for the ALDL plug and use ALDL droid to monitor my system (I've built a custom ADX streaming file if you need it). It's made by Red Devil River. Not that you want to spend money on that stuff right now. I've had a bad O2 sensor and a bad MAP sensor, but both would throw codes and effect the performance while it was running. Like when you D/C'd the MAP sensor.

The injectors should pulse. That's proper action. The IAC should be (relatively) constant. It should open to keep an idle and then vary in open-ness to keep it. It shouldn't be opening and closing fast enough to feel it, as far as I know. At least, that's not how mine behaves.

Make sure your throttle is closing all the way to the stop. The IAC should open at idle and close once you've revved up a bit. One of the guys I know around here was chasing idle issues for a year, and it turned out that the throttle was hanging open sometimes, and not others. The end of the shaft didn't clear (I'm working from memory) something mounted nearby. The IAC? Maybe the TPS. We caught it because the throttle position sensor would give different readings when we revved it by hand then let it settle. This was leading him to mis-adjust the throttle position sensor, and then get a poor idle every time the throttle closed all the way. Or conversely, a high idle every time it hung.

That's all I've got. I'll ask if he's got any other thoughts. He spent a lot of time chasing things for his issue, so he has a lot of knowledge on it.

In the meantime, Troy is your man.

 

[boney]

Ah yes: I remember now. The throttle position sensor is mounted on the valve cover side. It was mounted too close to the throttle body and it was binding with the throttle shaft. As a field repair, we moved the washers from under the screw heads to between the TPS and throttle body. Don't know if this will help you, but it's worth having a look at, I suppose.

 

[KRUPP]

I had some headaches at first with my Howell install as well. Long stretch of trouble-shooting. Not an expert, but here’s what was the issues were with mine and maybe it can help.
-The MAP Sensor on the rear of the TB: Per Troy, I shortened the vac hose down to about 2”. This seems to help off idle.

-The injectors: Long story short- they were clogged from debris in the tank, even with the filter. I bought some GM replacements, but sent the originals off to be cleaned/rebuilt and they’re spares now.

The system has run fine for the last 3 years.
I too purchased the Red Devil River cables and ran around in the Jeep with the laptop logging data. I see that you’re in Colorado and you can certainly use/have it if you’d like.

 

[CJKen51]

Boney and KRUPP,, this is all great info. First thing I'll try is get the throttle plates back to fully closed and see if IAC makes everything happy. I know for sure it's open about a 1 1/2 turns right now. i used the books directions with the jumper/disconnect IAC etc etc.. to adjust base timing mabye 50 times. So, we'll give that a shot (it's hard to push all the years of Carb knowledge aside and thing about things differenty.
I'll double check no linkage is getting hung up, as well as the TPS. I had no idea there were cables for the older OBD that you could run and collect data.
Krupp, let me work on these other things and it's kind to offer to borrow the cables.

One more thing: when i first fired up the system, it actually drove pretty nice for just an hour or so. I had never cleaned or replaced the fuel return line before hand. If you think debris could have made it past the filter, to the injectors, i may very well have dirty injectors. I took them out, looked at the little screen, and they seamed pretty clean. ..put them back in. Then, I replaced the inline filter, new fuel return line AND MTS fuel tank. I noticed some dripping coming from the injectors when idling, (map disconnected it will idle but it's RICH) Sounds like I have more work to do.

Thank you very much guys

 

[jzak]

Hello All, I have around 1 hour of actual drive time on my Howell TBI it ran "mostly" well to begin with and I was excited to drive it. Then, it just started leaning out and dying. Was towed home, by my son, that day. That was back in early June. Anyway, I've messed with this forever. The list of tests is a long one.
When I unplug the MAP sensor, it will actually idle. It idles smooth. Granted, it's rich and in a limp mode, which lines up with the service manual that was included in my kit. Plug the MAP back in and back to dying within just a few seconds. Here's the kicker: I've tried two different MAP Sensors. I also picked up an extra computer, since they were $95. Tried both of those and switched the PROM over, of course. I've talked to Troy, at Howell, 3 or 4 times now and I checked and verified everything he asked. Looking for a tip on anything else I could check. Thanks, in advance.

You're giving me PTSD buddy! I went through all of this with my Howell TBI. Spent way too much of my time, money, and my sanity trying to fix it. I talked to Troy three times, replaced just about every part of the kit including the ECM and TBI unit, and it got me no where. Eventually I just gave up and got a Carter 2BBL carb. I know there are plenty of owners out there who love thier Howell TBI, but the learning curve needed to properly maintain and fix these systems, goes beyond my skill set, and most mechanics won't touch them with a ten foot pole. Also, If something goes wrong with your carburetor on the side of the road, chances are you can do a patch job, and limp it home. If something goes wrong with your TBI, you're calling AAA.
Sorry! I just had to say it. Best of luck buddy. Hope you get it working.

 

[CJKen51]

Well jzak, sorry for the flash backs. I have a few things to try before I give up. I actually love my BBD. It's a 1979, easy to work on and super efficient. (great milage and no H.P.) It passes emissions with flying colors. The down side is, getting up to camping/4-wheeling between 8500 and 11000 feet, she gets a little finicky and you need a third foot to keep it running/starting on a steep hill. Anyway, if it's not up and running with confidence by May, it's back to the carb and back to the hills! More updates coming.

 

[Manic Mechanic]

Stories like these are why I went with Holley sniper

 

[boney]

Stories like these are why I went with Holley sniper

Those aren't without the challenges either, though I do believe there aren't as many.

Problem is, Holley won't get a CARB cert for them so some of us have no choice but the Howell.

 

[KRUPP]

Those aren't without the challenges either, though I do believe there aren't as many.

Problem is, Holley won't get a CARB cert for them so some of us have no choice but the Howell.

Exactly. I'm required to pass emissions where I reside in Colorado. Consequently, depending on where the O.P. is from in Colorado, he'll likely have to deal with emissions too.

For older vehicles, like my '69 Bronco, it's not an issue and I'll likely get a Sniper for that motor.

 

[KRUPP]

CJKen51,

In the case where you decide to service/clean the injectors, I used these guys. The turnaround time was about 3 weeks when I did it.
New injectors are available on Ebay and other areas too.

Search

Fuel Injector Connection is the leader in high performance fuel injectors from top manufacturers including Bosch, Siemens, and Lucas.

www.fuelinjectorconnection.com

 

[Belizean]

Don’t ever think the Sniper is the end all greatest thing ! When they are working well they are great. I’ve been battling mine on and off for the last couple of years. For a big piece of it burning rich. Then back in October i thought I finally figured that Bish out. TPS wasn’t correct and heard that many were coming out new like that from factory not correct. Got that and another new O2 sensor and it was running like a champ. Put several hundred miles and a 3 day wheeling trip with no problems. Then a couple weeks ago I started having it go lean for the first time. I noticed when at idle the AFR would rise to 14.9 or 15.0 and the IAC would raise from the recommended 8 -12. Adjusted that a few times. Hearing there are lots of problems with the Bosch O2s. Read people were trying NTK. ( NGK ) O2s so I gave that a try. Nope ! Readings were all over the place. Put my Bosch back in and it ran fine. Need to test it again later when the sun warms the air a little. And here I was considering a Howell. Read many a story about the Howell and why I went with the sniper. If it wasn’t for a planned trip to Colorado I probably would have gone back to a carb also except I hear that they are hit and miss now sometimes and the chinee mechanical fuel pumps are junk also. WTF is a Jeeper to do that doesn’t want to spend their times always fiddling and wants to drive it like a modern vehicle without dozens of sensors that go haywire.

 

[Manic Mechanic]

I don't think we can do anything other than just help each other out and figure out everyone's problems

 

[CJKen51]

KRUPP, thanks for the info. I'll get those cleaned up and try the throttle closed (see if the IAC will take care of business) May not get to, until this weekend, but I'll send updates. I appreciate everyone's experiences!