1985 King Cab Sputters Loses Power When Accelerating

[Grit]

I have a 1985 2WD King Cab with auto trans, stock carb, and maybe 2 year old vacuum lines. Dunno when the fuel filter was last replaced.

 

So Erie just got hit with like a foot and a half of snow. Oh god the rust...

Anyways I'm trapped and am trying to get back to Cleveland.

I was driving down the interstate, couldn't' see more than 20 ft.. in front of me in a blizzard and next thing you know I can't accelerate.

 

I pulled off at the next exit and did some very light troubleshooting.

When in drive I can get to probably about 20 miles an hour, sometimes more sometimes less.

If I give it any significant amount of gas it starts to sputter and all power is lost.

With my window open I could hear it sputter and sound almost like a backfire but not nearly as loud.

In neutral I can rev it and it sounds and feels pretty normal.

 

So I shut it down started it back up, same deal.

 

So I shut it down jiggled the plug wires, took off my air filter cap looked at the carb for about a second, jiggled the plug wires a little more, put the airfilter cap back on, and started it up.

The truck was now behaving normally. I decided that I shouldn't be driving in this storm with a sick truck so I turned around and went back Erie.

 

Within 15 minutes the problem returned. I made it back to safety, but I'm now snowed into a parking lot with over a foot of snow surrounding my 2 wheel rear wheel drive truck. (No sand in the back)

 

Based on everything I told you above I've determined the problem could be anything, but if anybody sees something obvious I'll go try and check it out.

Of course since basically all the surviving 720's are out west I'll probably not get an answer for another 3 hours.

 

[datzenmike]

1/ My guess is carb icing. Is there a 2" to 3" metalized hose between the air filter snorkel down to the warm exhaust manifold? If not this is the problem. It allows the motor to draw warmed air in and mix with the cold to prevent moisture, even just high humidity, from frosting inside the very cold carb. Most auto supply shops will have some of this and a couple of hose clamps.

 

2/ If there is a black flex hose from the snorkel forward to the rad support, pull this off so the snow isn't sucked into the air filter. This is just for fresh air and will work using air from behind the rad.

 

3/ The wiring on the Z24 is very close together on the cap and if they are not in good condition and they get wet from flying snow.. you can get sparks jumping between wires. Try to keep them dry from flying snow... the coils too. In a pinch you might try an ignition spray that drives away the water and coats them. WD-40 is usually pretty good but there are others.

[Grit]

Thanks mike.

 

I am familiar with Items you mentioned; I will check them all out when I find my key's...

 

I wish there was a face palm emoticon,

 

I may have dropped my keys in the snow...

[Grit]

#1 would make a lot of sense by the way.

 

I have had slight stalling issues in the past during high humidity conditions and I know for a fact that the "hose" is poorly secured on my vehicle.

[datzenmike]

I had problems with my 620 years ago. Freezing rain or fog with melting snow. The hose and metal shield around the manifold had long since rusted off. I cut and wrapped a Maxwellhouse coffee can and stovepipe wired it on and clamped a replacement pipe to the air filter. Worked like a hot damn. The next summer I got the real thing and replaced it all.  

[Grit]

Still haven't found my keys... 

 

Good thing my brother still had an old style wire coat hanger.

 

Really glad I used a free harbor freight screwdriver coupon and left the screwdriver in the truck as well.

 

Also glad the steering column lock has soft metal security screws. They didn't have a slot for a screw driver so I unscrewed them from the side with a flat-head and brute force.

 

Unfortunately I don't have my service manual with me to find the ignition wiring diagram.

I guess it should be laying around google somewhere...

[Grit]

Didn't have to splice wires since I got the whole ignition switch off. Just unscrewed the switch from the column lock and turned with a flathead.

Started right up. Guess my brother will have to keep and eye out for my key's once all this snow melts.

 

The engine is now behaving normally.

 

I'm pretty sure you were right on point number 2/ Mike.

Especially since the only two times the issue started were on the interstate when cold wet snowy air was being forced fed into the snorkel.

My metalized hose to the exhaust manifold was still intact and reasonably secured. I should still get hose clamps for it though since as of right now it's only held on by the plastic flex ring things.

[datzenmike]

Yeah in heavy snow it will wet the air filter and act like a choke. Just leave the fresh air hose off in the winter months.

[Grit]

The weather wasn't nearly as bad today but I disconnected the snorkle and got back to Cleveland alright.

 

Can't thank you enough Mike. You really helped me get through one of the worst ever of "those days"

 

 

For future reference to anyone that permanantly loses the keys to their 720.

 

If you take the plastic cover off from around the steering column and wiper/signal controls (Requires removal of a couple phillips head screws) you can remove the ignition switch assembly from the steering column by removing 4 bolts.

 

Two of the bolts are phillips head and the other two lack slots for a driver; for security purposes I'd imagine.

These two bolts are soft enough that you can dig a flathead screwdriver into the side of them and force them to unscrew little by little.

 

Once you get these off the ignition switch assembly will fall away from the steering column and free the steering wheel.

At this point you can remove a phillips head screw from the back of the ignition switch to remove the switch from the locking mechanism.

 

Then just turn the switch with a screwdriver to start.

The whole process takes a lot more time and effort than just brute forcing the steering lock and hot-wiring but shouldn't cause any permanant damage.

[datzenmike]

I used a hack saw to cut slots in mine for the screw driver. Even re-used them again.