M928A1....to scrap or not to scrap...that is the question.

[mcshooter79]

Yeah I looked under the front two valve covers and I didn't see anything obviously wrong, I still need to look under the back one.

I think the geometry will work out to allow the piggyback. It was actually harder than you would think to get the bed close to the ground when I was looking for a a good ditch to load my pickup into the back even with all of the overhang.

Speaking of overhang I noticed that when I pulled a trailer with the 928 that I didn't have to worry as much about taking the corners wider because once all of the overhang had swung the other way it pulled the trailer with it so that the trailer actually tracked right about where the rear tires of the truck did. I could right next to a curb without having to worry that the trailer would run over it (M105 trailer).

 

[wrenchturner6238]

I Agree don't scrap it. Was it smoking heavy in a white or gray color while knocking? It is possible it could have a bent push tube or valve train causing your knock.

 

[Hainebd]

If you don't want I will take. Pm me if we need to talk.

 

[Suprman]

I had a knocking sound coming from the intake and the engine was running all wrong. One of the arms had loosened and slipped off and the valve was not opening. It was on the first bank under the farthest cover.

 

[rchalmers3]

The issue may not be obvious to you through a visual inspection, for example a loose valve seat. However using the normal compression testing and leak down methods should guide you to a diagnosis.

I am am another vote for saving the rig and encourage you to diagnose the problem and let us know what you find.

rick

 

[Jeepsinker]

Fix it!

 

[Ferroequinologist]

I am 80 miles from Walterboro. I have the space and the equipment to recover and do an engine swap or repair. Would at the least save you in storage fees.

Thought I'd offer.

 

[mcshooter79]

Well by far the popular consensus is to keep the truck. At the very least I think the best thing to do is drag it home and open it up to see if I can get a better idea of what happened. I hate to see it go to scrap so if the time comes I will post a classified add and weigh the monetary options and hopefully see if we can't get her to another good home where someone has more time and some heavier equipment. One problem is that if I decided to get rid of it it has a number of parts that I would like to keep for my other trucks and after I have removed those I don't know that anyone would give me more than scrap value for what's left and if I don't remove them I don't know if I can get that much more for it than the parts would cost me.......For now as long as the wife will support it I'll try and fix it.

The smoke was pure black in my opinion. The knock would change in volume depending on how much load I put on the truck and now I think something is being knocked around in the bottom end so I don't know if that points to a valve train issue, although at this point I rule nothing out. The more we talk about it the more curious I become. I will definitely post a follow up with pics when I get there.

As for compression and leak-down.....where do you even put a compression gauge? Do you pull the injector and screw it in there?

Ferroequinologist (horse whisperer?) Thank you sincerely for the offer, in the coming days my wife and will evaluate our financial situation and my time and all things will be considered. I wish you were 80 miles closer to me instead of farther away.

 

[Recovry4x4]

The rear overhang dragging the ground can be compensated by suspending the fwd rear axle as high as possible. Note avatar, I have some experience!

 

[TacticalDoc]

I have a spare truck that I took the winch and hard top off. It needs a head gasket and trans work. I'm pulling off all the spare parts I may need then selling the axles/tires. Then scrapping the rest. Its not worth it to fix when you can buy one for so cheap. The amount of hours and parts expense just doesn't make it worth the time.

 

[mcshooter79]

Recovery, yeah I had the same thoughts after towing my 931s home. I think that may be the trick to getting the rear end up higher.

Tactical, I agree, it's a numbers thing and if it were a standard 923 or 925 I would lean more toward scrapping it and doing precisely what you are doing...as is...I'm torn. I think the big factor will be what I find when I open the engine. If I can fix it in place for less than $1000 then maybe keeping it doesn't seem like such a bad option. The truck otherwise doesn't need anything major. But in the end if reality says I end up with more money and less headache by scrapping it.....well then I guess that's life.

 

[quickfarms]

How much fuel was in the truck when you picked it up?

What did the fuel look like?

Was there any poly wigs or water in it?

Did the mechanic check the fuel?

A injector or injector pump problem caused by bad fuel can make these engines sound like they have a knock.

I would check the fluids for contamination. If the fluids look good I would have the pump and injectors tested. If they have issues they can be rebuilt. If they have issues I would also dump all of the fuel, have the tank cleaned, clean out the lines and replace the filters before restarting it.

I have to warn you that a stuck injector or water in the fuel could bend a rod.

 

[98G]

I seem to remember the GL ad missing a fuel cap.

 

[CBR Metalworks]

I seem to remember the GL ad missing a fuel cap.

That was the truck I bought. I got it home, let the water settle (it actually froze which turned out to be nice), siphoned about 30 gallons of diesel out, drained the tank, installed a new fuel filter and all was good to go. I did have to add engine oil and transmission fluid because they were bone dry.

 

[mcshooter79]

There was about 30 gallons in the tank, I would guess, when I picked the truck up. I probably burned about 10 gallons of that before I filled it with fresh diesel and added a diesel fuel additive to the tank.

The mechanic only "smelled" the fuel and told me it was bad. Apparently I don't have a nose for bad diesel yet.

I already changed the filter in the water separator and the tank was actually clean with no water or any other debris in it.

I think a bent rod at this point would be minor compared to what I'm afraid may have already happened. If I decide to fix the motor I will check all of the injectors as well. Yeah it was the opinion of the Cummins mechanic that the knock that could be heard was fuel related. Is there a way that some kind of injector issues could cause the issues I had?

My engine oil was good but My tranny was also about 6 quarts low.

 

[Suprman]

Its all mechanical adjustments on top. There was a thread with the step by step adjustment procedure

 

[swbradley1]

There are several guys on here that have rebuilt the top end of their Cummins engines. A veritable fountain of information they are.

 

[quickfarms]

There was about 30 gallons in the tank, I would guess, when I picked the truck up. I probably burned about 10 gallons of that before I filled it with fresh diesel and added a diesel fuel additive to the tank.

The mechanic only "smelled" the fuel and told me it was bad. Apparently I don't have a nose for bad diesel yet.

I already changed the filter in the water separator and the tank was actually clean with no water or any other debris in it.

I think a bent rod at this point would be minor compared to what I'm afraid may have already happened. If I decide to fix the motor I will check all of the injectors as well. Yeah it was the opinion of the Cummins mechanic that the knock that could be heard was fuel related. Is there a way that some kind of injector issues could cause the issues I had?

My engine oil was good but My tranny was also about 6 quarts low.

Yes bad fuel can cause a diesel to run like crap and knock. The fuel has to be really bad to smell bad.

The injectors can either become plugged up or they can stick open. Diesel injectors are designed to pop at a specific pressure to inject the fuel. If this is no occurring at the correct pressure or is erratic it can cause the issues you have described. Diesel injectors have many small offices in them and spray the fuel out, this can be another issue if they are not spraying. Multifuel injectors have a much larger office and are referred to as dribble injectors. Additionally multifuel engines have a lower compression ratio tag allows the wider range if fuels to be consumed. This is a diesel and not a multifuel!

Since you say the tank looked clean I take it did not have red diesel in it. The only real way to tell if there is water in a tank that has sit for a while is to drain some off the bottom. The diesel will float in top of the water.

The filters can only deal with a little bit of water. After that they can with plug up or by pass. Did you change both filters and were they complete?

Out of the four engines that we have resurrected in the last couple of years three had fuel issues. The fuel in the pump and injectors was bad and it caused them to run like crap until the good fuel in the 5 gallon can got into the engine. Two needed to have there tanks cleaned. The third needed a new tank. The fourth one had been run with some water in the fuel and the pump and injectors needed to be rebuilt. This is the reason that I have the trucks towed to the shop.

After visually inspecting the engine.

I would pull the injectors and pump and have them tested. You will probably find that at least one injector has issues. Then have them fixed. Before you put them back on clean out all of the lines and change the filters then reinstall the pump and injectors. Run the suction and return line into a clean 5 gallon can of fresh diesel. You need to correctly prime the system before you attempt to start it. If you do not you will kill the batteries and maybe the starter.

 

[mcshooter79]

Quickfarms,
Thanks for the advice. Once I've made the repairs to the motor I will pull all of the injectors and have them tested with the pump. I'm sure I will learn a wealth of knowledge about the subject from searching the posts on here and I will study up before I do any repairs. I only changed the filter that is in the fuel/water separator right in front of the drivers wheel well. It was intact but rusty at the bottom so I'm sure some water had sat in there at some point. I would say the rust only went 2 or 3 inches from the bottom of the filter. The diesel in the tank was very clean looking, no tint and no water "bubbles" or layers that I could see, I pulled the strainer and looked around with a flashlight.

What would a stuck open injector do when the engine was running. Could it have been hydro locked and someone started it bending the rod before I even got it?

 

[quickfarms]

Quickfarms,
Thanks for the advice. Once I've made the repairs to the motor I will pull all of the injectors and have them tested with the pump. I'm sure I will learn a wealth of knowledge about the subject from searching the posts on here and I will study up before I do any repairs. I only changed the filter that is in the fuel/water separator right in front of the drivers wheel well. It was intact but rusty at the bottom so I'm sure some water had sat in there at some point. I would say the rust only went 2 or 3 inches from the bottom of the filter. The diesel in the tank was very clean looking, no tint and no water "bubbles" or layers that I could see, I pulled the strainer and looked around with a flashlight.

What would a stuck open injector do when the engine was running. Could it have been hydro locked and someone started it bending the rod before I even got it?

What repairs are you going to do to the motor?

Based on your description my mechanic and I agree that the probable cause is the fuel system. He actually suggested to try cleaning out the filters and lines and run it off a 5 gallon can of fresh diesel to start.

A reputable shop usually does not charge much to test the injectors and pump.

Hearing that you found rust in the filter leads me to be more concerned about the fuel and less concerned about the rest of the engine.