a friend of mine just got a 94 6.5 5 speed crew cab dually for $4000.....with a miss in the motor. the owner was ready to big block it, and my buddy Ted got it before it was butchered.

he said while running at idle for 30 minutes and exhaust manifolds dont even get hot, you can touch them with bare hand, they are very warm, but not hot. he said it would not bubble up water if you splashed some on there.....it almost sounds like the motor is not getting enough fuel to make it run.

white smoke does exhaust when you rev it up, but not at idle. the oil pressure is 40-45, and runs great other than the miss in the motor.

what is an easy way to check and see if youhave bad injectors? or test to see if you have good injectors?

Could be low compression is keeping cylinders cool.

Mr. Taillight,
Have you/they checked the lift pump? Maybe the OPS?
I had a similar problem a while back, changed them both and no more white smoke.
I've got other issues now but not related to this.
Just a thought.
Mark

also, what kind of miles?

it has 194K on it.

have not looked into the pump yet.

Ted just called and said he pulled 4 injectors and they were very dirty....VERY dirty! looks like factory AC Delco injectors, this may be the problem? (bad used injectors that is)

he is changing them with a 60K set of injectors at this point.

injectors really can do that especially with 194k.
Mark

Don't tell my dad, he has 250,000 mi. on the stock set. Other than the random hard start and bad fuel milage (14 down from
`17) it's hard to tell.

Lol

Wow! 3MPG diff?? ALL of Reno's fuel goes through a pipeline from Concord and it broke today. $2.79/gal $50 maximum. 18 wheelers too.....

3MPG would add up in a serious hurry. Hrm.. I didn't wanna do injectors yet....

Mr. Taillight,
Have you/they checked the lift pump? Maybe the OPS?
I had a similar problem a while back, changed them both and no more white smoke.
I've got other issues now but not related to this.
Just a thought.
MarkMark, what is the OPS?

Ted did change all the injectors and it gets alot hotter on the manifolds now, and not near as much smoke out the pipe. i wonder if a bad injector let a cylinder go dry? as far as rings and it is letting the oil through?? just wondering?

if anyone has any other ideas, lets hear them!

Mark, what is the OPS?

Oil Pressure Switch...
It controls your lift pump as well as your oil pressure. It may show normal on the gauge, but you may be running off of your IP alone and can cause your symptoms. I only say this because I had the same problem.:eek:
Mark

found the problem!!!
after several attempts to get it fixed, it would just not be right.

so my buddy Ted dropped the pan and started looking. found a cracked piston! also afound cracked heads on both sides.

after replacing with different heads, a new piston, high dollar head gaskets, it is running even more quit than my 197K mile suburban! still a great deal for the truck he got.

Cool.
Mark

cracked pistons and heads are survivable with a little work and parts money. Glad to hear it's working!

Wow, man your way too excited from finding broken parts ;)

Its motors like that one, that with one new piston, will last 375,000 miles. But the one you get completely rebuild only lasts 150,000. Usually the way it goes. Cool to hear it was fixed.

i think Ted was even moe happy, he got a heck of a deal for little coin in the end.

How big of a job is it to drop the pan and replace a piston from the bottom end?

TDG, piston still has to come out the top, so head(s) has to come off. I hope you inspected the rest of the pistons very carefully. The last time I had a cracked piston in a 94 6.5, I decided to pull all of them and inspect them and I found 4 more pistons with cracks starting at the top of the wrist pin bore-:t and I must have missed one, because it failed 50,000 later and wiped out the bore, but it didn't matter much, because on further inspection I found the main webs had hair line cracks at the outer bolt holes.:( The only point I am trying to make, is that rarely is only one piston going to fail without the others showing signs also, so look very carefully.:exactly:

your right, if one is bad, chances are others are on the way as well. Ted was happy to find only the one was bad. he did shave the heads 30,000