Hard start, then lots of smoke

[moparguy]

Details; '95 5.9, 300k miles, 215 injectors with about 300k miles, homemade #10 plate installed about mid point, fuel heater removed. NAPA fuel filter about 1 year old, 10k miles on it.

Truck is in south Arkansas so not cold environment at all.

No changes to the engine/fuel system this year.

Truck is in the shop, won't be able to dive into it for a few days and hoping to get thoughts of possible causes for the recent VERY hard start condition. Over the past couple months, if truck cranked every day, truck would start next day at the first hint of the engine turning over. Would start great all day.

However if left sitting for a week or so, it takes lots and lots of cranking and when it does finally start TRYING to crank it's like a gasser that's flooded with the choke engaged. Lots of missing/rough running with black smoke both once it starts trying to fire AND for the first two or three minuted of running. Have to hold accelerator down about 1/2 way to get it to start. Again, Once started no problems for the rest of the day.

Well the last couple days, the above hard start is a daily event not just if sitting for a few days. It's getting worse fast.

It is still cranking fine the rest of the day once cranked in the morning.

Preheaters are not working (working on that) however;

Outside temps don't matter, hooked up the block heater for a couple hours when it was 70 degrees outside, no difference.

I haven't replaced the return line in a few years but with all the black smoke, I'm thinking problem isn't due to a leak.

I have backed off the smoke screw (preboost screw back of afc housing) a couple turns, no diff.

Current plan it to back the preboost screw off a couple more turns. Pull the diy #10 plate and reinstall a old TST #8 plate while looking for any problems.

Anyone have thoughts on what's going on here?

Thanks for reading and any/all advice.

RonR

 

[dieselshadow]

You’re losing fuel prime to the injection pump. Most likely the rubber hoses under the intake manifold are leaking air. This is the most common failure point on a 12v P pump engine. Replace those hoses with the best marine hose you can put your hands on. And replace them every few years.

Also check your fuel heater. Personally I’d delete it. It serves almost no purpose but the connector is another failure source.

 

[crabman]

I had a 95 and replaced those fuel lines.
The fuel lines that are leaking air into your system and making it hard to start are located behind #6 and slightly toward the drivers side. The hoses are only 6-8 inches in length (different sizes 3/8 & 5/16?) and they connect the frame hard lines to the engine hard lines. They absorb the vibration & engine movement. You will have to lay on top of the engine with your head against the firewall (just so you can see them) to replace them. You will need a good light, 1/4" socket set, lots of patience and a first aid kit.
Hence: Buy the best marine hoses you can get.

 

[LandShark]

Had the same problem with my 95. Replaced all fuel lines to and from fuel tank to the engine, with rubber lines. Took care of the problem totally. Do a search and you will find my write up from years ago.

 

[moparguy]

Well, to close this chapter on the long term (24 years and counting) Dodge Commins test. All’s good now.

Being very aware of the fuel hose leaking issues that was my first thought. However the excessive black smoking while attempting to crank was throwing me off.

I’ve changed the return line twice, last time about 10 or so years ago. That time I used a high pressure fuel injection spec'd hose recommended by Joe Donnely. It was still in excellent condition! What I found was both 5/6th worm gear clamps were loose and the stinking fuel filter was loose.

This was all after I was waist deep into replacing the old line with a new hose from Larry B. Well, at that point nothing to do but complete the job. I'd pulled the starter and the fender liner for the job. Eventhough I've changed return lines 6 or 7 times (wife's '98 12 valve dually and lit'l bro's truck along with friends trucks) it's never fun and thanks to advise here, pulling the liner did help a bit. At 68 years young my shoulders need all the advantage and help possible. I did most of the job from the bottom but was able to access and loosen/tighten the top/front clamp from the top.

HAPPY to report that after cranking, a test drive and letting it set for a week the old truck started on first revolution, just like it should.

I had planned to replace the original supply line but after fighting the return line my shoulder and back talked me into doing it some other time. It does still look good and that lower factory band clamp did not look like it was not going to go without a fight.

As mentiond the Dr. Joe spec'd hose was still in great shape. When I'm back in the shop I'll get the number and share it if others want to go that route.

Thanks for all the advice, it's greatly appreciated, oh and I did solve the heater grid not working puzzle. Somewhere in the fuzzy past both hot leads to the solenoids got on one solenoid. Fixed that and all's good.