1989 F150 Stalling problem
 

I have a 1989 F150 with the 6 cylinder and 4sp/od. 125,000 miles

I have had a stalling problem for several months but it was only occurring infrequently and I have been ignoring it. It is occurring much more often now and is cause for concern.

The stall usually occurs while driving but recently has included stalls shortly after start up. It is as if the ignition is turned off. No jerking, missing or other indications that it might be fuel related.

When it occurs on the highway the only light on the dash that initally comes on is the Check Engine light. The speedometer also immediately drops to zero.

I coast to the side of the road and if it does not start immediately it so far has started within 30 seconds and not more than one minute. I am then on my way and it may not occur again for a week or more.

The truck is driven infrequently but has always been a quick starter and has no bad habits other than this annoying stalling.

It has been doing it more often and yesterday did it twice within 10 minutes while working at moving some items around my property. It also did not want to start again quickly like it had in the past. Just letting it sit and coming back in five minutes was enough for it to start right back up.

The truck was purchased used a few years ago and as far as I know has mostly original ignition components (other than cap, rotor, plugs and wires).

I am mechanically capable, but have no experience or understanding of the ignition system on this truck.

Any suggestions on probable suspects to start to look for a solution?

Thanks, Randy

the ignition switch would be the 1st thing i would replace. for the speedo to drop like that i cant think of anything that would cause the engine to turn off AND the speedo to go to zero. the reason i say this is that if your going down a hill and turn off the engine and then just turn on the ignition the speedo will work.

re: ignition switch
 

Thanks, that does make sense. I will look into that possibility. I hope there is a decent aftermarket switch available and that it is not a nightmare to access.

Randy

Vector,
I would check into the check engine light. There are many issues that can effect the simple operation of the vehicle.

See the read-me first at the top of the forums. There is a simple procedure for testing the computer for codes if you do not have the code reader. All it involves is a voltmeter, a pad of paper, and your trusty truck.

The nice thing about this method is that you can find all the stored codes in the computer and most likely the culprit will stick out right away.

Many times electrical connections will get lightly corroded or loosen over time, start with the code diagnostic and use the resulting error codes to find the related components to inspect.

I hope this helps, and am eager to hear your results.

OBD codes
 

Thanks for your response.

Pulled two codes using the “key on engine off” count the flashing check engine light:

32 EVP circuit has intermittently failed below minimum voltage of 0.24 volts
67 Neutral safety circuit failure

It has been a long time since the battery has been disconnected and my plan is to do that now and then check for codes again immediately following the next stalling incident.

Randy

In an effort to clear the codes thrown by the OBD I left the battery disconnected for over two hours and when I came back and connected the battery and checked for codes again I still have the 32 and 67 stored.

Suggestions on how to clear these codes?

Thanks.

Randy

Run the KOEO test again and when the codes are starting to register on the check engine light, unplug the jumper.

If the condition is not cleared the vehicle will still show the code next time the process is performed.

If your vehicle has a relearn procedure, you may need to do this. After removing the battery for more than 5 minutes the Keep Alive Memory is cleared, and the vehicle will not perform the same for a period of time as it 'relearns' after power is restored and the engine is turned back on.


What type of transmission do you have?

Randy,
It sounds like you 'could' have a short to ground causing the reference voltage to drop. [code 32]

I recently found various exposed wires causing my F-150 to behave erratically as well. There is I believe four connections in the wiring harness which are typically wrapped in an older type of insulation which breaks down over time.

It's a good idea to check the point of connection for any moisture in the connector, as well as following the wires and looking for any frayed/burned wires.

Randy I have an 89 F250 that I recently used a code reader on and pulled a code 67 among others but discovered later reading the book more closley that this code will appear if you run the test and don't shut the air conditioning off before hand which I did not.

I saw that as well but read it as being a factor when doing the test with the engine running. I went back and check and although the AC has not worked in years the selector was not all the way to the left in the OFF position and it might have been a factor.

I did not have time to run the tests again and will not until perhaps this weekend. I haven't had the time to clear the existing codes at this point either. I want to start next time with a clean slate.

Thanks for your response.

Randy

Stalling problem persists
 

This problem of stalling seemed to go away for months and then today it is back. In a ten mile run for lumber it stalled three times. As in the past it started either immediately or within a couple of minutes.

Reading back over my original posting I see I said that the speedometer immediately drops to zero when the engine quits. I realized today that the speedometer continues to register speed as the truck coasts down.

It is the tachometer that immediately drops to zero. It registers zero even though it is coasting in gear and the engine is still being turned over by the momentum of the truck (manual 5 speed).

I am familiar with Bosch fuel and ignition management. If this was one of my Volvos I would say it was a bad crank position sensor.

Does my Ford have a crank position sensor or something similiar?

Thanks for your thoughts.

Randy

randy i do beleive they have the crank shaft sensor im sorry i just cant remember where it is located right now

Vector if you have since fixed your truck Id be very interested in what you did. I have a 1989 F150 6 cylinder doing the exact same thing . Ive already replaced the TPS and am going to replace the ignition switch tomorrow. Any help guys would be appreciated.
Rick

if the tac drops then its a ignition problem. no power to the coil

I ordered a new complete distributor this morning. Ill install it tomorrow and Im hoping the problem will be solved. We will see.
And yes the tach does drop out when it quits. Im thinking its the PIP in the distributor or maybe the ignition module but either way Ill get both birds with one stone.