Hey all, I don't have much internet time, but was wondering if someone could point me in the right direction.
I've got an '89 F-150, 302, 4-spd., 130,000 miles. I was hauling a car this weekend, and my truck started smoking out the exhaust when I put it in 4th gear, until I got up to speed. Driving through town and taking off in the lower gears was fine, but as soon as I shifted into high gear it smoked again. And, assuming my gas gauge is still correct, I used almost a whole tank to go about 80 miles. Any ideas?
Thanks,
James

 

never tow in 4th gear its way hard on the motor and as you can see was causing the motor load up. was it better when you drove in 3rd?

 

Yes, it doesn't smoke in the lower gears, or in 4th when I get above 50 mph. I don't know the gearing in this truck, but in 4th gear, it runs close to 3000 rpm at 65mph. It's the 'work' model, with low gearing.

 

does 4th say od on the shifter at all?

 

no, it doesn't. And, 1st is actually the granny.

 

ok so you have the np435 which is a great tranny. i suspect you have some engine issues then. i would perform a tune up and hook up a mechanical oil pressure gauge so you know exactly what it is. also pull codes www.fordfuelinjection.com explains how using a paper clip. this is also important

 

Ok! Thanks so much for your help. The check engine light has not come on, so I didn't know if checking the codes would tell me anything.
I'll go try it.

 

just because the light isnt on doesnt mean a code hasnt been stored. your truck a 2wd or 4wd?

 

oh, ok! It's only a 2wd.
It's been too cold to check it out, but this weekend looks good and I should have some time.

 

its been freezing cold here to. been in the 30's during the day and teens at night.

 

lol kinda the same here. I think our high for today is 10 deg F. Fortunately, I drive a company truck, so my pickup can wait for better weather.

 

Sounds like something is making it run in closed loop mode maybe........ and thus real rich

 

good call icicle. a bad o2 sensor , engine temp sensor etc... could cause this as well.

 

hey, on that note I need to tell ya some more info. On the highway this truck runs cool. By this I mean the gauge sits at about a 1/4 of the way in town, but drops down to nothing on the highway. The heater doesn't blow very warm air at highway speed either.

**edit** The temp gauge does the same thing when it's 100 degrees outside, but no smoke.

 

ok your air temp sensor and the water temp sensor probably need replaced. I would also replace the thermostat with a 195*.