86 2.9l problem

[86supercabsxt]

Okay, to start off; it's an 86 Super Ranger STX 4x4. 2.9l 4-spd auto. My main problem is it will run just fine for about 20-30 minutes, going down the road, then it sputters, puffs black smoke, dies and won't run right starting up again until it cools down.

It doesn't overheat. Coils, plugs, distributor, all the fun and easy stuff has been done. The motor only has like 82,000 miles and sounds great. It will run all day long in park when warmed up. It might putter or sputter some but it'll stay running. It does spray some black liquid out the exhaust if you raise the R's when it sputters. I assume this is just really dirty water from the stock exhaust but I thought it was worth noting. Vacuum lines are well past needing replaced and as cheap as that is, I'll be doing so soon.

I've read about similar problems that were caused by a failing O2 sensor or a dirty MAF but there is definitely no MAF sensor on this motor. I ordered a code reader but figured I'd come here for suggestions.

So to sum this all up:
1. Any idea why it's a turd after 30 minutes of typical town or country driving?
2. What gauge vacuum lines should I get?

 

[adsm08]

I'd replace the O2 sensor and see what happens. At 30 years old and almost 100K miles it is due.

Just get the vac lines that fit. I think the stock stuff is 1/16"

 

[86supercabsxt]

Right, certainly can't hurt to put a new sensor on. Appreciate the line size and quick response

 

[rusty ol ranger]

If you find a die hard solution lemme know. My 87 does the same shit.

 

[Pauls 4x4]

Gotta have vacuum sorted on those. Leaks kill all the engine management/ there's only like 4 lines anyways.

So your engine cant do anything to correct itself if there's an issue.

White smoke is more often gas than water. But Black is oil. On a 2.9 coming up when warm it is probably valve seals.
Those older fords were known to wear out valves just as a matter of course.

Leaks oil hot and when you then slow throttle your then getting a sluge fool. Cools and the leak slows/ it can burn off the heavy dinosaur syrup when the engine is correcting to open loop.

Are you using oil?

Proper engine managment might just make the issue ignorable.

You dont get a 2.9 perfect... Just working.

 

[RonD]

TFI module issue, new or not

Maybe coil, new or not, but TFI first

Unplug the O2 sensor and see how it does
O2 makes engine run more efficient after engine warms up and could cause rich or lean running, but could never cause it to not start, O2 is not used on startup

It is possible the capacitors in the computer have started to leak, there are 3 that are a known issue after 20+ years of service
You can pull the computer take off the top and have a look at the circuit board, very easy to spot issues inside

Good one looks like this: http://www.auto-diagnostics.info/ford_eec_iv

You can see the 3 Blue capacitors that start to leak, they can be replaced for under $5

 

[rusty ol ranger]

White smoke is more often gas than water. But Black is oil. .

White smoke is coolant/condensation.
Blue smoke is oil.
Black is raw/unburnt fuel.

 

[86supercabsxt]

Thanks all, the TFI has been replaced and tested. After crawling underneath to find the O2 sensor, I found it broken off at the bolt from age. Managed to get both pieces out without stripping anything. It ran a bit better after replacing one deteriorating vacuum line directly under the throttle body. I've got a new sensor on the way already and will return with the results. I'll take a peek at the computer then too.

Again, thanks all for the info.

 

[86supercabsxt]

Apologies for the late update: Oxygen sensor seemed to make a world of difference. Sputters and dies on cold start but stays running once the needle on the gauge moves. Didn't have any problems driving up and down the road.