Help- Dumbfounded
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Joined: Jan 2005
Posts: 2
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Help- Dumbfounded
I just bought a 86 f-150 with a 302 FI. It will start up run and then die. Then when I try to start it it starts, when I had it the first day. Then the truck was going down the road and it died like it was out of gas, tried to start it and it wouldn't. I came back about 3hrs later and it fired right up. The next day it started right up drove about 5 miles to a family members house and it idled about 5-8 mins then it died, tried to start-it didn't. Came back the next morning and it fired right up. I did a tune up new plugs,wires,cap,rotor,fuel filter,ing. coil,breathing filter,air filter,pcv,cleaned the battery. It started right up it sounded great, but then I heard a loud ticking like a fuel injector, the truck idled for about 10 mins, idling up and down, till it died. I tried again to start it-and guess what nothing
Help! Losing my mind
Help! Losing my mind
Senior User
Joined: Dec 2004
Posts: 230
Likes: 1
one of my uncles trucks did the same thing, i think it turned out to be an air flow sensor, i might be remembering wrong, but it was something that you would never look for and should never go bad, hope you figure it out
Eric
Eric
Senior User
Joined: Jun 2004
Posts: 353
Likes: 3
From: Mid-Missouri
Could be IAC, but I doubt it.
The surging was a problem in this generation of truck. It is not likely related to the problem. It has to do with the EGR system.
It really sound like the TFI ignition module which is mounted to the side of the distributor. Do you have spark when it won't start? Also verify that the spark looks good, strong and at regular interavals. The TFI is known for failing as the engine gets warmed up and not working until it has cooled off again. Eventually it will fail completely.
When installing a new one, make sure that you use the heatsink paste on the mounting surface. You will also need a TFI tool to remove the fasteners that hold it in place.
To get to the fasteners easily, index the position of the distributor on the intake with a paint marker. Loosen the distributor and rotate it so that you can get to the fasteners. Replace the module. Rotate the distributor back so that the marks that you made line up and secure the distributor. You might want to check the timing afterwards.
The surging was a problem in this generation of truck. It is not likely related to the problem. It has to do with the EGR system.
It really sound like the TFI ignition module which is mounted to the side of the distributor. Do you have spark when it won't start? Also verify that the spark looks good, strong and at regular interavals. The TFI is known for failing as the engine gets warmed up and not working until it has cooled off again. Eventually it will fail completely.
When installing a new one, make sure that you use the heatsink paste on the mounting surface. You will also need a TFI tool to remove the fasteners that hold it in place.
To get to the fasteners easily, index the position of the distributor on the intake with a paint marker. Loosen the distributor and rotate it so that you can get to the fasteners. Replace the module. Rotate the distributor back so that the marks that you made line up and secure the distributor. You might want to check the timing afterwards.
Postmaster
Joined: Feb 2003
Posts: 3,441
Likes: 5
From: Muskegon, MI (home)
I am voting on the TFI module. My 84 300 six acted very similar, I had stalling, rough idle, no power. And it left me stranded 25 miles from home! And worse yet I had to get towed home by a GMC pickup! You can get that module tested at Auto Zone and they cost $30 bucks. I replaced mine and the problem was cured! What happens is one the truck is fully warmed up, the module gets hot and it cuts out. This pretty much disables your entire ignition system. Otherwise, you might have a fuel injector going out, or the the in tank fuel pump is going bad. Good luck!
Senior User
Joined: Nov 2004
Posts: 140
Likes: 0
From: Troy, MI
i bet on the air temp sensor. if that doesnt work then maybe an injector or fuel system. check fuel pressure at the rail with a guage.
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New User
Joined: Jan 2005
Posts: 1
Likes: 0
From: Fort Worth, Texas
I have an 86 that did the same thing. Tha dumbest thing was wrong! Since the truck had factory cruise (but someone changed steering collums, i found that out on my own) the armature attatchment had worn and was Pulling the throttle body butterflies closed. Th eengine was trying to keep itself going but was suffocating. Check that real quick its a riding cover that goes on the throttle cable at the top of the throttle body. I also shot the butterflies with some cleaner to knock down the build up that wasn't hepling either.
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