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Hi all. I want to start by saying i'm not all that smart or high tech. Ive had my 86 GW about five years and had a few issues but ive been getting it squared away over time. Just turned 90K miles and overall clean truck and its been running well, but wanted to improve cold starts and drivability so others could drive it as its my regular daily car now. I read howell was good reliable and "plug and play"...maybe i shouldve stayed within my limitations as the 2150 was running good but anyway...no turning back now i guess.

I spent Monday doing install after lots of prep work and it seemed to go ok. ive spent the last four days trying to figure out why its running so lousy and really rich.

Ive checked the voltage and connection to ignition/start and its ok
I re ran both fuel line and vent back to tank and checked pressures. pressure into TB was 14 so i opened it up and turned adjuster screw in TB 6 turns and tried it and then 2 more, and not much better but injectors improved. They had been shooting a spray and also a dripping like a faucet in middle of each injector (at idle) and would barely run now mostly just the spray from injectors and will idle but poorly. . no real pressure on return line so that seems fine.
fuel tank top vents are new.

Checked routing and replaced PCV valve and check for leaks.
I replaced the EGR valve and there was no washer (it wasnt original one) so tried it without washer and then with a few different washers and its seems to idle better with a #45 not sure how else to get right size washer.

I have checked o2 sensor and connection although pretty fouled from rich condition i guess.
I have a newer distributer with the Gary Boyd write up ignition upgrade w TFI, and bigger wires etc.
Ive shortened and checked MAP sensor plugged to port on TB back between fuel in and out lines.

im a little confused about white wire to negative side of coil. I check to see if it has current and it does but don't know how to test that one properly for the (tach signal?). Howell tech assistance said to replace ECM which i did and it made no difference. I have called the a few times this week and they've been great but i think they're tired of me now.

Ive gotten 12 code consistently and once got a code 44 but thats gone now.

starts fine. it idles poorly and seems to cycle up and down a bit. it runs really rich blowing smoke from tailpipe. it will rev up but seems to fall apart under a load.

it runs better with one injector unplugged.
could it be a bad O2 sensor even though it was new from them? if i disconnect it it doesnt change anything or show any code.

any help is appreciated thanks.

1986 Grand wagoneer with 360 and automatic transmission.

after reading more on it inow have
-removed TBI and checked gasket on baseplate,
-ran MAP from different pert as test,
-rechecked power/ignition wire,
-checked distributor,
-tried to change timing to get it to run better,
-wired open the exhaust butterfly,
-re-ran and tested fuel line and vent line back to tank,
-disconnected purge tank to make sure not plugged and causing pressure in fuel tank and preventing fuel from venting into tank properly.
-rerouted the vacuum lines and checked for leaks etc.

Intake Manifold gasket is only a few month old so no leaks there.
distributor is not old and was running very well last week with carburetor

any help would be really appreciated. its been a full week now.

anybody?

Call Howell Tec support. I installed one of their units and the pump wasnt turning on--it was a loose connection at a plug. They were very helpful.
If its running Rich/Lean, I'd look at the Oxegen sensor wiring and location in the exhaust.

I’de be interested in what they resolution was there on your instal.
Will likely put one on in the not too distant future.
Did you weld the O2 sensor/bung on the Exh pipe or use one of those pre-made 1/4 round with the bung already welded on it and has the gasket & clamps?
Your Troubleshooting and problem solving is valuable information to others to know about.

Code 12 means it doesn't have a tach signal. A cause of this that is very hard to track down is if the engine is using HEI. HEI has a very weak tach signal, and wont properly drive an ECU reliably.

But, assuming you have a duraspark ignition (OEM setup), this should provide a strong tach signal. Also, code 12 is expected if the engine is not running. But if it is running, and you see a code 12, and you have a duraspark style ignition, I would check the wiring. There is NO continual voltage that goes over the tach wire.

Oh, and if you have an MSD ignition, you need to get a tach filter from howell.

The code 44 means the O2 sensor thinks the engine is super lean, which would then make the mixture super rich if it isn't actually lean. So the first thing to check is the O2 sensor itself. And a question I would have is how down the exhaust did you install the O2 sensor? And, do you have any exhaust leaks? An exhaust leak will pull fresh air into the exhaust and make the O2 sensor think the engine is running crazy lean. The same can happen if you have the exhaust cut off right after the O2 sensor. You need at least 3 ft of pipe after the O2 sensor.

jcpianka, did you ever find out your problem? I am have the exact same issue.

the problem it's a howell system, cobbled together 80-90's g.m. tech

I had an issue with my Howell running well at first start but would run rich and pulse up and down at idle. Turned out to be a bad O2 sensor, also a heated O2 sensor seems to help and the stock one may cool down at idle.

Did you ever get the issue fixed? Try a heated O2?

Kartboy1234 wrote: ↑Thu Apr 25, 2024 9:22 am Did you ever get the issue fixed? Try a heated O2?

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