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post #1 of (permalink) Old 06-08-2008, 05:34 PM Thread Starter
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Howell TBI fuel pump question

Question...Looking for anyone that is running a Howell TBI set up on a 4.2.
Question what is your fuel pressure if you know, and where did you mount your fuel pump?
I'm only gettting about 11 psi, and when it got to 100 degrees today my fuel pressure gauge started bouncing all over the place. I'm wondering if i have mine mounted to far back. I did mount mine per instructions about 18 to 24 from the tank. I was thinking that I needed about 15 psi..

any help..
after searching some posts, maybe 11 psi is not to far off, but still concerned with the the pressure bouncing from 8 to 11 when it got really HOT today +100 . Wondering if I shoudl change to a solid copper line from filter to TBI in place of rubber hose?

83 cj7, 258 .030 over, HEi dist, Howell TBI.

Last edited by rogerscj7; 06-08-2008 at 06:55 PM.
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post #2 of (permalink) Old 06-08-2008, 07:10 PM
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About 12psi is good. Have you thought that the pump may be suckin' air through a pin hole? I've got mine located on the frame rail above the transmission skidplate.

Have you run any fuel injection cleaner through the system? When the pump pressure is bouncing did the engine react differently?
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post #3 of (permalink) Old 06-08-2008, 08:25 PM Thread Starter
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It start to skip and hesitate as I acelterated.
Once I got home i checked my gauge, it was bouncing very very fast between ~ 8 and 11. Once it cooled of later it was fine.. Are you running rubber line all the way?
per my gauge mine is closer to 11 than 12 psi
My pump is much closer to the back than yours..

83 cj7, 258 .030 over, HEi dist, Howell TBI.

Last edited by rogerscj7; 06-08-2008 at 08:28 PM. Reason: spelling
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post #4 of (permalink) Old 06-08-2008, 09:51 PM
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I thought that most TBI's want more than 15 from the pump and then get regulated down to 15.. if your reading under 15, I think you are starting to have a problem. Unless your regulator is just set that low...

What pump are you running?

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post #5 of (permalink) Old 06-08-2008, 10:02 PM
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Sorry Aaron, that's not true for a TBI, it is for an SMPI system.
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post #6 of (permalink) Old 06-08-2008, 10:06 PM
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Quote:
Originally Posted by LEVE View Post
Sorry Aaron, that's not true for a TBI, it is for an SMPI system.
MPI wants 40 to 60, I'm not sure what SMPI stands for...


My 455 TBI uses 15
My 4.3 TBI uses 15
Pat's 401 TBI uses 15
Rickys 401 TBI uses 15

We all run the E2000 pump that is designed for a 15 PSI Ford TBI system.... I guess they are all done wrong....

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post #7 of (permalink) Old 06-08-2008, 10:57 PM
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Sequential Multiple Point Iinjection... it's the real name for Mopar's MPI system.

.. also, IIRC, Ford never made a TBI, their first generation of electronic fuel injection was named CPI, Central Point Injection.

You're correct that the pump puts out more pressure than the throttle body needs. In most TBI systems the regulator (mechanical) is located in the throttle body. All excess fuel is re-routed back to the tank.

Last edited by LEVE; 06-09-2008 at 07:23 AM.
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post #8 of (permalink) Old 06-09-2008, 08:23 AM Thread Starter
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i'll recheck my location and make sure if its not over the trans skid plate, if not i move t. Also since its a push pump, assume being to far back is not good. i'll run some new fuel line hose, sinces its only 12 to 15 psi, reg fuel line hose should work(??). Still do not understand why when it got so hot the in line pressure gauge i have mounted was bouncing so bad as well as running poorly, wanted to hesitate when i started off from a stop.

83 cj7, 258 .030 over, HEi dist, Howell TBI.
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post #9 of (permalink) Old 06-09-2008, 08:32 AM
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Remember that the only thing that cools the pump is the fuel that goes through it. If you've got the pump exposed, it can get coated with clay, dirt, debris of other types and then the pump can't shed the heat. I installed my pump inside a piece of PVC pipe, capped at both ends. It's as clean as the day I took it out of the Howell box.
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post #10 of (permalink) Old 06-09-2008, 08:46 AM Thread Starter
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Cool idea, i try this also.
Are you running std rubber fuel line to your TBI?

83 cj7, 258 .030 over, HEi dist, Howell TBI.
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