Howell TBI

[mr.c]

Howell told me when the tank gets low, and you are going up hills it is
possible to get some fuel not to get to the high pressure Howell fuel pump. I
bought one at a regular auto store, some normal brand that Osburn had
recommended. The only things Ed told me was 1) get one with 4-6 pressure,
and 2) one that if it fails it will still pass gasoline.
I don't remember the brand, but if you want, I can find it. All I remember
was it was about 30$.

I located it just in front of the two tanks, then it goes to a fine filter
prior to going into the howell fuel pump. The fuel is screened by the filter
and then pumpted to the injectors.
Hope this helps.
al

> Al:
>
> What does going up a hill have to do with adding a second pump?? Is the
> first one marginal somehow???
>
> What make and model pump did you install and where did you locate it??
>
> Paul Bartz
>
> From: mr.c [mailto:mr.c]
> Sent: Sunday, January 24, 1999 1:47 AM
> Subject: Re: GMC: Howell TBI
>
> I did add a second fuel pump to keep fuel flowing when I climb big hills.
> That was a recommendation from Osburn and it worked fine. It only puts out
> about 4-6psi and if it fails it does not stop fuel from flowing.

 

[mr.c]

Auto Zone got mine for $69 so I guess that's what you pay for them.
al

> In a message dated 8/24/99 10:41:12 AM Eastern Daylight Time,

>
> injectors that I have seen reported here. I may order a spare or two just
> to be safe. Anybody have a good (as in cheap) source for the Holly
> Injectors??
> >>
>
> I've had my Holley in since 1974 and had no problems until losing an injector
> this summer. I purchased it at Yearwood in Albuquerque for $69.99. The Pep
> Boys shop said they could order it for about $85.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM

 

[mr.c]

Mine is located under the passenger seat. It is just where I can see it if I
glance down at the base of the seat. My wife might just think I am looking at
her, so it serves a dual purpose.
al

> >Where is everyone mounting the check engine light common to the TBI
> >systems??
>
> I used the green "cruse" light. I had disconnected it earlier because it is
> too bright at night. The wire was there right by the cruse module so I just
> attached it to he TBI system wire harness. One of these days I will change
> the green "cruse" filter for a yellow "check engine" filter. But its low on
> the priority list...
>
> Dave
> 73 Sequoia

 

[dave1]

>I would like to hear from all of the Howell guys.
>
>(mine is still in the box)
>
>1 How do you like your system

I like it very much. Big improvement in starting, especially warm starts.
Fantastic idle. Especially when cold. No fast idle, even when cold. Just
starts and runs nice and smooth.

>2 Do you have any problems?

I had a couple problems. First was caused by the fact that I have headers.
I installed the O2 sensor just past where the four header tubes come
together. The problem is that the exhaust cools too much by the time it
gets down there. The fix was to upgrade to a heated O2 sensor.

The other problem I experienced was related to very low throttle operation
when the engine is cold. It would surge slightly as if I was accelerating
and decelerating. It was slight but annoying. I talked to Howell and they
sent me an updated PROM. That made the problem better but it still happens
occasionally.

>3 Would you buy it again?

Yes.
Its costly but very much worth the cost.

>4 Does there need to be any improvements?

There are a couple areas that I would like to improve/modify. One area that
I think could use improvement is the cold (open loop) operation. It seems
to me that it runs way too rich during cold idle. Not enough to make it run
rough or stall but enough to blacken the exhaust pipe and create a little
black smoke. Fortunately the 455 warms up quickly so its not really a big
problem.

One area that I would like to see modified is the mixture set point. When
its in closed loop control it targets 14.7 as the air/fuel ratio. I would
prefer being able to make it run slightly richer in hopes of achieving
longer engine life. I know that 14.7 is the "ideal" mixture setting but it
would still be nice if I had some control over it.

>5 Any other questions?

It runs so much better with EFI. I would never consider going back to
carburation.

I chose the Howell kit because its based on off-the-shelf GMC components.
The exception is the fuel pump and the Holly throttle body. But all the
sensors and the computer are avalable anywhere GMC parts are avalable.

I did not have any problems with the installation. It seemed like the kit
was well documented and easy to install.

>I don't want any urban myths started on this subject ...

One thing that does concern me is the number of failures of the Holly
injectors that I have seen reported here. I may order a spare or two just
to be safe. Anybody have a good (as in cheap) source for the Holly Injectors??

>...since mine is still
>in the box and on the way to installation.;>)

Good luck with your installation. Please feel free to drop me a line if you
have questions. Also I found that Howell has good phone support and was
very helpful when I did run into problems with my system.

Also...

This summer I installed a Westach exhaust mixture meter and their Vac/Tach
gauge. Its probably too soon to have any conclusive data but the gauges
work great. One thing that is interesting is to watch the engine control
computer "learn" the engine. When I installed my gauges I pulled the
battery leads which caused the computer to loose its memory. When I first
started running it after installing my gauges the mixture was all over the
place. But, as I drove it, I could watch the mixture gauge and see the
computer adjust the mixture for each speed and vacuum setting range. After
a thousand miles or so it does a good job of dithering the mixture right
around 14.7.

Fun toys

Dave
73 Sequoia

 

[bartz paul]

Dave:

Did you get the optional knock sensor and ESC (electronic spark control)
module also?? If so, what did you replace your original distributor with?

Paul Bartz

From: Dave [mailtoGMDGM]
Sent: Tuesday, August 24, 1999 10:41 AM
To: gmcmotorhome
Subject: Re: GMC: Howell TBI

I would like to hear from all of the Howell guys. (mine is still in
the box)

1 How do you like your system

I like it very much. Big improvement in starting, especially warm starts.
Fantastic idle. Especially when cold. No fast idle, even when cold. Just
starts and runs nice and smooth.
2 Do you have any problems?

I had a couple problems. First was caused by the fact that I have headers.
I installed the O2 sensor just past where the four header tubes come
together. The problem is that the exhaust cools too much by the time it gets
down there. The fix was to upgrade to a heated O2 sensor.
The other problem I experienced was related to very low throttle operation
when the engine is cold. It would surge slightly as if I was accelerating
and decelerating. It was slight but annoying. I talked to Howell and they
sent me an updated PROM. That made the problem better but it still happens
occasionally.
3 Would you buy it again?

Yes. Its costly but very much worth the cost.

4 Does there need to be any improvements?

There are a couple areas that I would like to improve/modify. One area that
I think could use improvement is the cold (open loop) operation. It seems
to me that it runs way too rich during cold idle. Not enough to make it run
rough or stall but enough to blacken the exhaust pipe and create a little
black smoke. Fortunately the 455 warms up quickly so its not really a big
problem.
One area that I would like to see modified is the mixture set point. When
its in closed loop control it targets 14.7 as the air/fuel ratio. I would
prefer being able to make it run slightly richer in hopes of achieving
longer engine life. I know that 14.7 is the "ideal" mixture setting but it
would still be nice if I had some control over it.
5 Any other questions?

It runs so much better with EFI. I would never consider going back to
carburation.
I chose the Howell kit because its based on off-the-shelf GMC components.
The exception is the fuel pump and the Holly throttle body. But all the
sensors and the computer are avalable anywhere GMC parts are avalable.
I did not have any problems with the installation. It seemed like the kit
was well documented and easy to install.
I don't want any urban myths started on this subject ...

One thing that does concern me is the number of failures of the Holly
injectors that I have seen reported here. I may order a spare or two just
to be safe. Anybody have a good (as in cheap) source for the Holly
Injectors??
since mine is still in the box and on the way to installation.;>)

Good luck with your installation. Please feel free to drop me a line if you
have questions. Also I found that Howell has good phone support and was very
helpful when I did run into problems with my system.
Also...
This summer I installed a Westach exhaust mixture meter and their Vac/Tach
gauge. It's probably too soon to have any conclusive data but the gauges
work great. One thing that is interesting is to watch the engine control
computer "learn" the engine. When I installed my gauges I pulled the
battery leads which caused the computer to loose its memory. When I first
started running it after installing my gauges the mixture was all over the
place. But, as I drove it, I could watch the mixture gauge and see the
computer adjust the mixture for each speed and vacuum setting range. After
a thousand miles or so it does a good job of dithering the mixture right
around 14.7.
Fun toys

 

[bartz paul]

Can we also get responses from those having either a Holley (except Emery!)
or Turbo City TBI installed? Actually Emery you're also invited to comment
if you desire.

Where is everyone mounting the check engine light common to the TBI
systems??

One thing I learned in talking to an owner last night who installed the
Turbo City TBI system in the Fall of 97 is that he asked for and received a
copy of their parts list with GM part number's (I'm told that their catalog
now has such number's) so that you can get parts locally instead of going
back to Turbo City in California. I might add that he also said that he
noticed no improvement in gas mileage, wanted a system that could be trouble
shot anywhere, carries no spare parts for it, mounted the check engine light
on the table over the engine compartment opening, and the power he felt was
lost with the QuadraJet carburetor was restored.

Paul Bartz

From: MTrovao [mailto:MTrovao]
Sent: Tuesday, August 24, 1999 2:29 AM
Subject: Re: GMC: Howell TBI

In a message dated 8/23/99 2:08:32 PM Pacific Daylight Time,

>

Gene, you know I like mine. Took it to Yosemite, no problems. Took it to San
Felipe, also no problems. The kit was very complete. Instructions were good.
It took me all day to install it but that's because I took my time and fixed
(improved) a few other things.

 

[blank]

>
> One thing I learned in talking to an owner last night who
> installed the Turbo City TBI system in the Fall of 97 is
> that he asked for and received a copy of their parts list
> with GM part number's (I'm told that their catalog now
> has such number's) so that you can get parts locally
> instead of going back to Turbo City in California. I
> might add that he also said that he noticed no improvement
> in gas mileage, wanted a system that could be trouble
> shot anywhere, carries no spare parts for it, mounted the
> check engine light on the table over the engine
> compartment opening, and the power he felt was lost with
> the QuadraJet carburetor was restored.

You don't mention whether he is satisfied with the system. Are there any
areas that it didn't meet his expectations? Which distributor did he use?

Patrick

 

[bartz paul]

Sorry Pat, I meant to also say that he said he would not hesitate to do it
again. I believe he told me he got a distributor from an 85 Olds. I don't
believe he had any unfilled expectations.

Incidentally, can you comment on the status of the archives? He claimed he
could only get them up to January of this year???

Paul Bartz

From: Patrick.Flowers
[mailto:Patrick.Flowers]
Sent: Tuesday, August 24, 1999 11:13 AM
Subject: RE: GMC: Howell TBI

>
> One thing I learned in talking to an owner last night who
> installed the Turbo City TBI system in the Fall of 97 is
> that he asked for and received a copy of their parts list
> with GM part number's (I'm told that their catalog now
> has such number's) so that you can get parts locally
> instead of going back to Turbo City in California. I
> might add that he also said that he noticed no improvement
> in gas mileage, wanted a system that could be trouble
> shot anywhere, carries no spare parts for it, mounted the
> check engine light on the table over the engine
> compartment opening, and the power he felt was lost with
> the QuadraJet carburetor was restored.

You don't mention whether he is satisfied with the system. Are there any
areas that it didn't meet his expectations? Which distributor did he use?

Patrick

 

[bartz paul]

Al:

What does going up a hill have to do with adding a second pump?? Is the
first one marginal somehow???

What make and model pump did you install and where did you locate it??

Paul Bartz

From: mr.c [mailto:mr.c]
Sent: Sunday, January 24, 1999 1:47 AM
Subject: Re: GMC: Howell TBI

I did add a second fuel pump to keep fuel flowing when I climb big hills.
That was a recommendation from Osburn and it worked fine. It only puts out
about 4-6psi and if it fails it does not stop fuel from flowing.

 

[dave1]

>Dave:
>
>Did you get the optional knock sensor and ESC (electronic spark control)
>module also?? If so, what did you replace your original distributor with?

No, I went with the basic system. I upgraded to the HEI ignition from a 75
Toronado, checked the centrifugal curves (they where OK) and changed the
Vac-advance to the correct one for the GMC (10 degree unit).

I made the decision for a couple reasons. First was cash. I really didn't
want to spend the extra $. The other reason is that I have heard that the
knock sensors can fail without being detected. I don't know if that is the
case with the Howell setup but it just adds one more level of complexity
that I didn't care to deal with. Maybe I would get better mileage or cooler
operation with the knock sensor but, in the end, I just decided that I
didn't want to spend the extra money.

Dave
73 Sequoia

 

[dave1]

>Where is everyone mounting the check engine light common to the TBI
>systems??

I used the green "cruse" light. I had disconnected it earlier because it is
too bright at night. The wire was there right by the cruse module so I just
attached it to he TBI system wire harness. One of these days I will change
the green "cruse" filter for a yellow "check engine" filter. But its low on
the priority list...

Dave
73 Sequoia

 

[dave1]

>In a message dated 8/24/99 10:41:12 AM Eastern Daylight Time,

>
> injectors that I have seen reported here. I may order a spare or two just
> to be safe. Anybody have a good (as in cheap) source for the Holly
>Injectors??
> >>
>
> I purchased it at Yearwood in Albuquerque for $69.99. The Pep
>Boys shop said they could order it for about $85.

Emery,

Do you have a phone number for Yearwood?
Also, what is the part number for the holly injector?

TIA,

Dave
73 Sequoia