1986 Hardbody V6 4x4: Very rough running; Stalls regularly

[markmdz]

If anyone could help me out, it would be greatly appreciated.

I bought an '86 hardbody V6 (4x4) from someone locally up here in CT last year. When I bought it, the previous owner did explain to me that it had a strange problem of not wanting to start right away if it's been running for a while, then I shut it off. He went on to say that if it sits for a few hours after it's been running, it usually starts right up without issue. (Example: If I drive to homedepot (about 20 mins from my house) and get a few things, unless I figure out a way to kill a few hours in the store, I'm SOL on starting it unless I pop the hood, remove the air cleaner cover, and open the butterfly on the t/b for a while to let some air in.)

So it seemed to me that there might be a bad (leaky) injector, or faulty fuel pump.

As soon as I mentioned that to the old owner, he told me that the fuel filters and pump had just been changed, as that was his suspicion as well.

I don't know of a way to check the injectors without actually pulling the top of the motor off, which I would rather not do considering the time and effort needed to do that.

There's a million other little 'maintenance' items I replaced as soon as I bought the truck too, and the problem is actually getting worse, not better. Now if it's just been idling for anything more then 5 mins, and I go to get on it, it stalls (then I get into the 'can't start it' situation described above) out or spits and sputters, burps (not a backfire) and takes off like a bat-outta-hell until the next stop.

As it stands right now, I consider it undriveable as it's too unpredictable, and stalls regularly.

Any help anyone can provide is greatly appreciated.

Thanks, -Mark D.

[MaximA32]

Any vaccum leaks? Any ground wire issues?

[markmdz]

Kenny,

Honestly (and here's where my ignorance shines through) I wouldn't know how to check for vacuum leaks if I wanted to. Same with ground wire issues for that matter.

Care to shed some light on those ones for me? ..or is it something better left to a seasoned pro?

[MaximA32]

Just look under the hood for things that are disconnected.

[markmdz]

Well, as far as I can tell, there's nothing that's just disconnected. I also don't notice anything that sounds like an air leak/sucking sound. (I only mention this b/c I did have an older car that had a vacuum leak, and you could clearly hear it sucking air into the hose at the break point)

I should add, when I mention above that the thing burps then takes off, that 'burp' is like a bad smoker clearing his throat. The thing spits a few times, with small puffs of black smoke out of the exhaust (clearly very rich in unburnt fuel), then a good 'ol puff, then buckle up b/c it takes off. Etierh that, or it chokes on it's smoke and dies. Lately, it's been doing more dying then taking off.

Also, the other parts I have replaced with new so far:

Full exhaust from cat-back.O2 sensor (the whole thing, not just the sensor and splice the wire)Cat w/ return hoseTemp sending unit

I suspect the stat needs to be replaced, but I snapped a bolt in the housing, and have a new housing, cover, and stat, but don't have the full day that I'll need to replace it due to the piss-poor positioning of the damn thing.

[nismopu]

Well when you have that day, make sure you replace the CHTS and all your problems will most likely disappear, as it sounds like a bad CHTS or CHTS harness. When you take off the T-stat housing you will clearly see the sensor bolted into the head right behind it. A 3/4" socket will remove it quite easily, or if you don't want too you should at least OHM it with a volt meter. peace.

[MaximA32]

Please elaborate on CHTS. It's an acronym I'm unfamiliar with.

[nismopu]

Cylinder head temp sensor. It does the same thing a coolant temp sensor does and is just as important. peace.
Modified by nismopu at 12:29 AM 4/15/2008

[markmdz]

Well guys I'm sorry to bring this thread back from the dead, but still have the same problem, and sadly still have yet to replace the t-stat or CHTS.

Were these things prone to leaky injectors?

Have any members replaced the top of this motor (ie. t/b, manifold, etc) with that from an actual fuel injected V6 from a newer hardbody? If so, how involved is that swap/upgrade?

[rico808]

try throttle position sensor,air flow meter,ficd solenoid all these are mounted on the carburetor,kinda pricy though, im trying to convert my 86.5 nissan 4wd to a carburetor and putting a weber on there. im doing that to eliminate all the vacuum lines and all the sensors on my truck.sounds like something like mine spits black smoke ,dies out idles rough too but on highways while driving lots of power gtood luck

[markmdz]

Rico, that's an awesome idea that I'm all for. Please keep me in the loop on this project of yours as I'm interested in doing the same. I also considered going the other direction and pulling the EFI setup from a newer hardbody/pathy motor. I know it can be done, but it's a HUGE undertaking because it'll require swapping out the entire harness, ECU, etc.

Were you going to do something like the 36/38 DGEV? ...or something more extreme like IDF's or DCOE's? (I have a pair of DCOE45's on an old Honda of mine, so I'm no stranger to those big bastards, just the price and tuning aspect of those scares me).

[rico808]

going to go with the 38 weber from redline redline says thats the one i should be running for my particular motor

[markmdz]

do you have the Z24 or the VG30?

[rico808]

its the Z24 regular cab D21 hardbody napz 8 plugs