1987 ford f150 with a 302 while going down the road it acts kinda like the ignition just suddenly goes of for less than a second at a time normally. and it normally kind of does it in batches, 3 or 4 times. Although sometimes it will just die In the road when it happens but normally will start back up fairly easy. seems a light worse on rough gravel roads.

It also has a slightly rough idle you can't really hear it but you can't feel that it's not really running a smooth as it should, smooths out pretty well after 1500rpm. but weirdly it seems to smooth out soon as soon as it's in gear. I can't find a miss pulling wires of at the distributor. It doesn't always idle the same speed but doesn't surge. but it doesn't always idle the same rpm.

It doesn't tend to start well when hot. If you start it back up within 15 minutes or so it will start ok, if you wait any longer than that you have to crank for way to long, and it seems to run very rich for a few minutes after it finally does start. It takes like 4 hours before it will actually start well.

Should probably note I pulled the codes the other day and got a 33, 14, and a 44
smog system has been deleted
kind of wonder if it is possible that all those are somehow connected.


new parts
-fuel tank
-in tank fuel pump
-fuel filter
-fuel pressure regulator
-all 8 spark plugs
-plug wires
-cap and rotor
-coil
-o2 sensor
-tps

 

I would check the ground cable that runs between the battery negative terminal and the front of the engine block and frame. The ignition is grounded through that cable, via the distributor and engine block.
Look for corrosion at the cable's terminal ends and the surface of the engine block and at the battery terminal.
Also, do you have these two small gauge wires coming out of the engine harness, near the upper passenger's side of the radiator? They need to be connected to the negative battery terminal.


While you're there check the battery positive terminal connections for corrosion too, and the wires to the fender mounted starter relay (aka solenoid).

After that, I would pull the ECM and check it's circuit board for damaged capacitors and burnt traces. The ECM is behind the driver's side kick panel, near the emergency brake pedal and pulls into the cab to remove.
There are three blue capacitors that fail in these years of trucks. They're pretty easy to replace with basic soldering skills. Sometimes, the blue capacitors will be swollen or leaking, and have obvious damage. Mine didn't look that bad, but replacing them solved a chattering fuel pump relay issue I was having.

Have you had any symptoms of a loose ignition switch or having to jiggle the key to get the truck to start? The ignition switch that's mounted on top of the steering column and actuated by a rod, from the key cylinder linkage, could also cause the symptoms of shutting off randomly.

 

I do have those two wires and i recently put new ends on them, there good.Where do those smaller grounds go?

The main ground wire doesn't look great gut it doesn't seem like that would be it because nothing else is affected when the engine cuts out, all the gauges lights and the radio

Forgot to put it in the list but the ignition switch is new the original split in half.

I have read that the tfi and the pip can sometimes fail in weird ways, and was kind of wondering about them because of the code 14 Ignition pickup (pip) was erratic

 

I would make sure that engine block ground is good.
Yes, the ignition control module (aka TFI) can cause those types of symptoms. Grounds are critical to the Ignition Control Module and replacements can be unreliable.
I would look at the computer circuit board next.
The small grounds are the power grounds for the ECM. I would look at the ECM after verifying the engine block ground.

 

I'll look into the main ground, may just end up cleaning it up and putting new ends on it.

I will note the two smaller grounds are not the same on mine they don't run through one plug like in the picture, there are two separate wires with separate plugs. It was running without one of them for a while before i noticed it and fixed it but I didn't notice any difference after.

just looked up a diagram out of curiosity the one that was broken may have been involved with the brakes,wonder if that's why the abs light was on? I don't know if it went of, I installed a new gauge cluster and took that bulb out because I was tired of it being on. I wanted to fix it for a while but I wanted a code so I had some idea where to start, but instead of flashing a code the abs light just flashed consistently until I gave up on it.

probably will pull the ECM and look at it when I get the chance. Also the ECM has definitely been out it has a tag on it for either a repair or reman service.

 

As long as those small gauge grounds are connected at the battery negative, it doesn't matter what type of connector they run through. Just verify by wire color that they are the pin 40 and 60 power grounds.

 

Just to clarify my earlier post about "replacements are unreliable" I was referring to replacement TFI modules.
I figure from a troubleshooting standpoint, that engine block ground is relatively easy to check out and clean or replace.
I've read on these forums, that people have gone through more than one TFI module before getting a good one.

 

Also, I've never tried this, but I've heard of people using a small bag of ice or a wet rag to cool the TFI module, when the truck is showing the hard hot restart symptoms.

 

I figured that was what you meant about the replacements being unreliable.
I found this on another thread, talking about ground wire locations, is it posible that one of the two wires on mine splits into two a little further away from the battery?

I might try that one day to see if cooling the module helps with the hot start, might be a bit of a pain to get something on it being on the distributor, but I'll try it. If that works I guess that would be a good sign that there is something going on with the tfi.

 

Yes, it might be spliced in the harness from the factory. I wouldn't worry about it as long as the colors are correct at the battery negative terminal and they both have a good connection.

 

the one that was broken I believe had a white stripe on it.
I didn't notice stripe on the other one, but I wasn't really looking for it.

I wish It would have died and not started back up months ago so I could have found the issue already, I hate tracking down intermittent issues.also doesn't help that I'm not the best with electrical issues to begin with.

 

Just be methodical. Eventually you'll find it. I go for the straightforward stuff first, like ground connections. Then go to the more complicated troubleshooting next.
These forums have most of the information you'll need.

 

are there any more connections between the battery and the ecm or would it just go straight to the plug at the ecm.
Is there a good way to test it with a multi-meter, maybe test the resistance while moving the wire around to see if it changes.

It would also help to have a good detailed set of wiring diagrams and all. I do plan on getting a Haynes manual soon, hopefully it will have most of that in it.

 

​​​​​​I would recommend verifying the colors of the small gauge wires and clean the engine block ground, then move to the ECM.
I base that on what the problem most likely is. It's not very likely that a factory splice inside the harness failed, and it would be difficult to find that splice.
It is very likely that there's a corroded ground connection at the block or frame and failed capacitors are also very common in these ECMs.
I would move to the distributor mounted TFI module last, based on the fact that the truck restarts within 15 minutes of shutting it off. The problem may be the TFI module, but it seems like it would not restart at all until it cooled off.
If you get to the point of pulling the ECM, you could check the resistance of those ground wires then, if you want. I'm pretty sure they're pins 40 and 60. But if it were me, I'd keep moving to the TFI module, after verifying the ECM is ok.

 

Thank you, I'll work on the ground soon as I can and see if it helps if not I'll look at pulling the ecm