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Howell GM TBI Fuse Issue!

Howell GM TBI Fuse Issue!

jzak

Old Time Jeeper
Posts
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Location
Pittsboro, NC
Vehicle(s)
1981 CJ5/258 4.2L I6, Tremec T-176 4-speed, Dana 300, Power Steering, Howell Throttle Body Injection System, Warn Locking Hubs, Warn Rock Crawler front/rear bumper with Tire Swing Carrier, Full Roll Cage, Pro Comp ES9000 shocks
Hey!

So I was driving my CJ5 today, and the engine abruptly cut out, and then I couldn't start it. I checked the fuel hose going from the pump to the TBI, and no fuel was coming out. I checked the fuel pump fuse, and it was good. Then I checked the ECM fuses, and the fuse box. All were good. The last fuse I checked was part of the TBI kit. It had two orange wires coming out of a harness. When I opened the harness, I found the 20 Amp fuse was broken. I replaced it, and now it's working fine.

Having that fuse break on me is troubling. My experience has been that fuses break when there's a short, or too much of a load. I've never had one break on me while I was simply driving down the road. It was during the day, so I didnt have my lights on. I had the heater blower going, but i've been using the heater for the past couple weeks now.

Is this a sign, that i've screwed something up, and i'm going to see that same fuse break on me in the future?

Thanks!
 
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I am pretty sure that is the fuel pump fuse, since it is located next to the fuel pump relay. Many issues with the Howell conversion relate to the external fuel pump system. Have you had any fuel pump related issues before? How many volts are you getting at the fuel pump when it is operating?
 
I am pretty sure that is the fuel pump fuse, since it is located next to the fuel pump relay. Many issues with the Howell conversion relate to the external fuel pump system. Have you had any fuel pump related issues before? How many volts are you getting at the fuel pump when it is operating?

Well, I followed the black/red wires connected to the fuel pump up to a harness with the fuse in it, and that fuse wasn't blown. This was a entirely separate fuse harness with orange wires coming out. The PO put in the TBI kit, so i've got no idea where those wires are going out to. The ECM has a fuse box with three 5 amp fuses, so it can't be going to that.

Any ideas?

I can take some pics if that helps!

Thanks!
 
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O.K. so there is also another fuse holder with red wires going to the area around the fuel pump relay also with a 15 amp fuse in it. Maybe that is the one you are referring to? I wish I had a schematic for that system, but I do not think they are available. From personal problems and all the info that I have got from the net, the fuel pump can present its problems due to clogging of the fuel pickup sock, fuel tank vent inoperative, low voltage to the pump, fuel filter issues, just to name a few. My first guess would be that blown fuse might be tied to the fuel pump which got overloaded somehow due to something clogging it or it overheated because there was not enough fuel getting to it. Another guess would be a wiring short somewhere.
Edit: Checking the fuel pump to feel if it is warm to the touch during operation can help indicate if it is not getting enough fuel to it. The fuel pump cannot suck fuel to it very well so it must get fuel delivered to it through a siphoning process.
 
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Either you cracked fuse then a short or fuse had moisture in it and exploded. Never heard of one breaking glass usually just blows link.
Orange fuse controls more then FP.

Here is diagrams from Chevy.
 

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