Electric fuel pumps can do strange things. One thing to remember is that they cool themselves with the fuel in the tank, so if the tank is always run low, the pump has a greater chance to fail. It also has a filter on it that can clog, the bearings go bad, etc. Check your fuel and return lines from front to rear for pinhole leaks, cracks and kinks.

 

I haven't had the time of money to make any more repairs, but I wanted to add that I time the beast and now it has a very hard time starting. It will take two or three long cranks before it starts. I don't give it gas, as I am afraid of flooding. I don't even know if TBI floods. Anyway, I finally got a new code. I'm sure it's because I cut out the Catalictic Converter. It's code #21. O2 sensor problem (oxygen sensor), upstream of down stream. I cut out the Cat, but have not plugged the return line yet. Should I plug it? As soon as I get the cash for a new fuel pump, O2 sensor, and Coil, I'll post more on status. Thanks to everyone for your Ideas.

 

Did you remember to disconnect the Coolant Temperature Sensor when you checked the timing?

Adjustments

NOTE: Check curb idle speed and adjust if necessary before proceding to the
following procedures.
Place transmission in neutral and turn OFF all lights and accessories.
Connect timing light to number 1 cylinder. Refer to timing light manufacturer's
instructions for proper connecting procedures.
START engine and allow to warm up to normal operating temperature.
Disconnect coolant temperature sensor electrical connector.
The CHECK ENGINE lamp on the instrument panel should illuminate once this sensor has
been disconnected.

Check timing by pointing timing light at the front crankshaft pulley. If timing is
within 2° of specifications do not adjust. If timing is incorrect, loosen distributor
hold-down bolt and rotate distributor housing until correct timing specification is
obtained. Refer to Ignition Timing - Specifications - Electrical See: Specifications
Tighten distributor hold-down bolt, and recheck timing. Reconnect coolant
temperature sensor electrical connector, and erase any fault codes that may have
been set.
Recheck idle RPM.

NOTE: There is an additional socket next to the timing scale, it is a socket for a
magnetic timing probe. Do not set the timing through this socket with a standard
timing light. This socket is positioned 10 degrees ATDC and will yield inaccurate
timing specifications if used with a standard timing light.

 

Yes, I followed the book down to the "letter"! Since I've cut out the cat. it's been running better. But, now I get the "real" feel that the fuel pump is plugged. It sure acts like it. What concerns me more, is after about 20 minutes with the lights on, on the road or at idle, the head lights start to blink off and on until the completely give out. I'll let the truck sit "Off" for about 10 minutes and start up again and again 20 minutes down the road, it will do the same thing. Kinda scary when you're doing 75 down the highway.

 

Sounds like you have a melted connector or wiring terminal in the headlight circuit. Check the connector on the headlight switch first. Then the dimmer switch.

 

Also check the headlight relay wiring.

 

I replaced the head light switch which took care of the head lights blinking on and off when it got hot. I still have the bogging problem, although it's not that bad since I pulled out the catelictic converter. I have a feeling it's going to be the fuel pump (clogged).

 

Well, I replaced the fuel pump. That was the problem. It runs great now with lots of power. However, about 4 days ago, it started giving me problems again. It's done it twice now. Once it died during idle and the other time I shut it off and tried starting it about an hour later. Well, both times, it wouldn't start. It cranked and cranked with lots of juice, but it just won't jump to life. Well, after a couple of minutes the first time and two days the second time, I got in and turned the key, and it started right up like nothing was wrong with it. I'm starting to think it's going to be problems with spark. I was thinking it may be my distributor cap, rotor, etc. The plugs and wires look good and aren't that old, but that doesn't mean they aren't. Anyway, suggestions anyone???

 

if you replaced the fuel pump and it ran great, but then it started dying again, maybe the gas is getting dirty? try putting 1 inline filter on the carb and 1 the gas line. If that doesnt work do a full tune up like you said. Distributor cap, rotor etc... Ive also got a 1978 ford truck that im restoring, I just got it running and it was doing the same thing, runs great then at times its starts bogging, maybe your float is getting stuck? Next time it happends try and wack around the bowl in the carb. Try a high volume fuel pump? Good luck

 

i had the same problem with my 91 d150. i put summit racing headers on it and forgot to put the O2 Senser back in and it would run fine just sitting there, but if i started to drive it i would drive fine for a couple of mins. but then **** would hit the fan. put the O2 Senser back in and it ran like a champ again.