I managed to pick up a sweet truck today:

1992 D150 short bed. No rust or dents anywhere!

It has the 3.9 and a 3 speed automatic. 112,000 miles.

I met the guy and I already knew that the engine had a miss. This was explained on craigslist clearly. I am ok with that. The check engine light is on. The ABS and parking brake light is on.

The guy drove the truck and met me. I drove the truck and the miss was there. It drove ok, but I had to let off the gas a little at 50 mpg for it to shift into 3rd gear. Otherwise, sweet truck and it drove great.

Anyway, whatever.

The guy picked up the truck a few months ago, and it ran perfect. On the long drive home it started to develop this miss which I am talking about.

He has since changed the plugs, wires, ignition coil, distributor and distributor cap. The miss is still there.

I bought the truck and got it home without any issues. I started looking around. All of the wires and everything he said looks new.

I took the cap off, not cracked, everything great. I made sure all vacuum lines were attached. I took them off the intake just to make sure they were not cracked, then put them back on.

Anyway, I start the truck up and it runs good.
I then put it into gear and it dies. It runs great in park and neutral, but it will die in gear.

Why would it do this? I didn’t change anything. I even took the distributor cap off again to make sure it was lined up. It bolted on without any issues.

Is my transmission a lock up transmission? Could this by my problem?

Anyway, I know my old mopars but I have never had a truck. Why is this truck dying when I put it into gear? Where to start looking?

Thanks,
Eightlitermopar

From what you described with the ABS and Park Brake Light on, I would be checking your brakeswitch (up at the pedal under dash). They are usually problematic on these trucks all the way up to the present. Little plastic gizmo about $20 and 2 seconds to change it out.

The brakeswitch is also the trigger to unlock the torque converter when you are rolling up to a stop so that it doesn't kill the engine by being locked up.

Hope this makes sense to you, the faulty brakeswitch is making the truck think it's rolling down the highway with the torque converter locked up. That's why it dies when you pull it into gear.

That's where I'd start.........

thanks for your reply. I needed a starting point. The brake light has been on for a while (according to the guy I bought it from).

It just makes sense it would get worse as soon as I bought the truck That's just my luck .

So, my transmission does have a lock up converter? I was not sure of this. Thanks for the info. I'll take a look.

Thanks!

eightlitermopar

Yes the brake switch will turn off lockup after it has locked up while cruising. It will not cause the converter to lockup when put in gear. 1st or reverse gear lockup is not possible unless there is something mechanically wrong with the transmission. And yes they did still make 3 speeds in 92.

Update: I am trying to do the simple stuff first.

Brake switch replaced: No change. ABS and E brake light still on.

Disconnected the throttle position sensor: Rough idle but does not die in gear now.

Replaced throttle position sensor with new one: Runs better, no more dying in gear. I can drive it around now.

Still has a miss. Rough idle but doesn't act like it wants to die.

Check engine light is on.

Can I read codes on a 92? I know its not OBDII, but can I figure out WHY the check engine light is on?

The guy I bought it from says the miss started on the longer drive home.

Thanks for the help so far guys! I am learning a lot. Any other ideas?

eightlitermopar

Take it to the local major parts store and have them read the codes for you. Most will do it for free.

OK, update again for anyone who is interested.

It is a pet peeve of mine when someone asks a question then doesn't follow up with what they did to solve the problem, so I am trying to not be that guy.

I was able to figure out how to read codes on the "Check engine light" by counting the flashes.

I did not disconnect the battery after changing the Throttle position sensor.

Here is what I have:
12, 45, 51, 27, 15, 24, 32, 55

According to what I can see online, this is what I have found.
12: Direct battery input to PCM was disconnected within the last 50 key-on cycles.

45: Governor pressure solenoid circuit. **
or
Overdrive solenoid circuit. **
or
Governer mid-pressure malfunction. **
or
Governor pressure sensor volts above rated volts. **
or
Governor pressure sensor volts below rated volts. **
or
Transmission relay circuit. **
or
3-4 shift malfunction. **
or
Governor low pressure malfunction. **
or
Governor pressure sensor. **
or
Overdrive switch low. **

51: A lean air/fuel mixture has been indicated by an abnormally rich correction factor.
Side note here** When the truck was running, I was attaching and disconnecting vacuum lines to see if it made any difference. I think this is why this code was thrown.

27: Fuel injector not responding.

15: No vehicle speed sensor signal detected during road load conditions. **
or
Low output speed sensor RPM, above 15MPH.

24: Throttle position sensor signal does not correlate to MAP sensor. **
or
Throttle position sensor input below the minimum acceptable voltage. **
or
Throttle position sensor input above the maximum acceptable voltage. **

32: An open or shorted condition detected in the EGR solenoid circuit.

or

A mechanical problem found in EGR system (vaccum line leak, defective EGR valve, plugged EGR tube, etc.).

55: Completion of fault code display on Check Engine Lamp. (end of codes)

I think the first culprit to investigate would be the injectors since the truck is having a miss. Anyone agree with this logic?

eightlitermopar

This is TBI or MPI? If it's TBI you can check the injectors with a timing light and see if they are firing, and whether they have a good spray pattern. Code 45 will always show up when equipped with a 3 speed auto, disregard this one. My Ramcharger had EGR problems as well, probably could have been cleaned but I replaced it. That will definitely cause some bad running issues. Start with the free things, EGR can be cleaned with carb cleaner.

This is an MPI fuel delivery system.

I forgot to mention that when the truck is in park and the engine is revved, it revs good and strong but on the deceleration of the RPM's, there is a "POP" like a backfire.

I'll check the injectors today and I can clean the EGR valve. Does anyone know the normal range of OHMS of these injectors? (I haven't got a manual yet).

I'll keep you guys posted. If you have any other ideas, let me know. The plan is to attack this starting with the cheap (or free) things like you said.

eightlitermopar

I think the pop/ backfire and lean condition point to lack of fuel, possible a dying fuel pump (or clogged fuel filter at the least). My 94 318 had a same issue that I chased for a while and a weak fuel pump was the culprit. For me on a cold start it would backfire on tip in. Performance got worse until I couldn't drive 45mph on the interstate.

The transmission often gets the blame when it dies going into gear but it's tuneup related 99.9% of the time.

Another update:

I am doing one thing at a time here.

I think I found a dead injector. I listened to all injectors with a mechanics stethoscope.

I could hear all of them "clicking" away, except the #2 injector is quiet.

Those little jokers cost 129 bucks each , so....is there anyway I can clean out/salvage this injector first?

thanks!

eightlitermopar

The ABS and BRAKE light staying on could be the sensor in the rear differential, or the wiring between the sensor, and the ABS solenoid located on the drivers rear frame rail just before the axle, or the ABS solenoid itself.

On several of my 91-93 trucks I have removed the ABS solenoid from the frame, and plumbed the brakes as they would have been on the pre-RWABS systems. Then simply unplug the ABS relay that is behind the glovebox on the firewall.

This ABS delete is a popular modification, and for myself and several others better braking, and a better non-spongy pedal feel is noticed.

$32 for a stock replacement at Rockauto...

I believe you can upgrade to the blue top Ford 24 lb/hr injectors with 4 holes for better fuel atomization. Those are in junkyards everywhere and also available online. I would replace them all.

$100 shipped to your door...and you get 2 spares! http://www.ebay.com/itm/24LB-FUEL-INJECT...721&vxp=mtr

pull one at the junkyard, if you can't afford rock auto.