hard rattle on acceleration

My M1008 rattles like dry marbles in a tin can on acceleration. Let off the throttle at any speed or idle and its quiet or at least the rattle isn't there. This does not sound like my M1009. I haven't run the truck much at all probably only 200 miles, I have changed the oil so I know its fresh and full. It sounds like its running dry on acceleration. Any ideas where I should look 1st?

Thanks

Check for an air leak in the fuel lines. Especially the clamps on the rubber fuel hose, post filter block. Make sure they are good and tight. Check injector lines too. Pushing air through the engine via the fuel system can make it rattle.

I should add that the truck starts easily. I didn't think it would start very well if there was a leak and I was getting air in the fuel line. It idles, coasts and decelerates smoothly as long as my foot isn't on the gas pedal. Rattles like hell when accelerating at any rate. I'll check to see its all tight tomorrow. I do know there is no fuel leak showing.

Thanks

Does your cold advance turn off?

doghead said:

Does your cold advance turn off?

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Along those lines, I have a 1009 I got from Barstow that had a rebuilt engine in it and the injector pump timing was JACKED, advanced WAY to far, check the alignment marks on the IP/Engine block. . .

We all have to remember that currently approved diesel fuel has less than 5% of the sulfurit used way back when these trucks were designed and manufactured. Sulfur acts as a lubricant and a cetane improver along with several other ifunctions it improves in the older diesel engines.

I would suggest that you consider adding a fuel additive that includes a lubricant and a cetane booster. I know my dseuce does not "sound right" while running on pump diesel. I add an additive and this goes away.

I may be barking up the wrong tree but it is possible the "clatter" could be caused by low sulfur fuel.

2deuce said:

My M1008 rattles like dry marbles in a tin can on acceleration. Let off the throttle at any speed or idle and its quiet or at least the rattle isn't there. This does not sound like my M1009. I haven't run the truck much at all probably only 200 miles, I have changed the oil so I know its fresh and full. It sounds like its running dry on acceleration. Any ideas where I should look 1st?

Thanks

Click to expand...

My 1009 rattles like H--LL until warm, then is very quiet. Normal?

yes

FMJ said:

Along those lines, I have a 1009 I got from Barstow that had a rebuilt engine in it and the injector pump timing was JACKED, advanced WAY to far, check the alignment marks on the IP/Engine block. . .

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First thing I would check, advancing it further gives more power under some conditions, but causes lots of rattle.

I would check your flexplate. A heavy rattle on acceleration is commonly a flexplate issue.

Mangus, Can you describe what is going on with the flexplate that causes the heavy rattle on acceleration? and what I should check for? The truck starts fine, I haven't had any starter problems or noticed any unusual sounds during startup.

Thanks

He is thinking it may be cracked.

Is your cold advance/high idle, working properly? Are your timing marks lined up?

Need feedback....

Thanks to all of you that responded. I'm going to look into all of your suggestions when I get home this evening.

The marks line up on the IP and housing, but looking at it, where is the cold advance and how is it checked? Is it the green wire? The green wire goes to the IP then to the high idle solenoid. Will unplugging the green wire disable the cold advance? Can the cold advance be stuck on where unplugging it accomplishes nothing? On my M1009 there is the normal diesel rattle at idle but it goes away when the engine revs. The M1008's rattle increases as the engine revs.

I added alot of lube to the fuel but the rattle is still there.

Thanks

Nobody realy needs the cold advance if you are in the truck. This rises the idel from 650 rpm to aproximately 750 rpm. With good oil in the specified grade it is not neccessary even at minus 20° Celsius.
The ratteling noise is not really neccssarily related to the injection system. We found years ago that also a lose starter mount can be the reason. Check the 2 19 mm bolts for proper tightness as well as the starter fix on the other side which is a M12 Screw into the block (1/2 inch wrench works as well) or the nut on the starter where the joint is fixed (11 mm wrench) .
Hope this helps!
Wolf

I disconnected the green wires at the IP, thinking this would disable the cold advance. I can't really tell a difference at idle, but the truck was fairly warm at the time. I'm going to have to take it out on the road to see if the rattle intensity has changed. It still does alot more rattling at idle than my M1009. To check the flex plate, I think would mean removing it which is something I don't have time for right now. Maybe this weekend.

Thanks

If you lay under the truck, while its running, there is a good chance you will be able to tell its the flex plate. Especially if someone can rev it a couple times for you while you are under there.

I read the thread on fuel additives and decided to add more 2 stroke lube. I went with 1 oz per gal of diesel. I went under the truck to hear the flex plate and thought it might be getting quiter. I had disconnected the cold advance and it did idle much rougher at startup and was somewhat harder to start. Temp was about 50. I thought it might have been the cold advance but my next test was driving with the cold advance connected and the hard rattle was getting better the more I drove it. I think my problem is solved. The rattle on acceleration is gone, the engine sounds really good. It was a lube problem as many of you suspected.
I then went with the same ratio with my M1009. It now idles smoother, and runs very well, a noticable improvement. The improvement was noticed by my 2 sons also. Its not my imagination. The cost per tank of fuel has gone up alittle but its well worth it. I was using power service as an additive before, 2 stroke oil is a big improvement, my engines needed the superior lube properties 2 stroke oil provides.

Thanks to all who responded!

Mine would get a rattle sound under heavy load and it turned out to be the inspection plate on the bell housing sitting too far back. This caused the flexplate balancing weight to just barely touch it as it spun and flexed under heavy load. Only did it when I hit the pedal to the floor, but definantly could be your problem. To fix it just loosen the 6 bolts that hold it on and push it as far forward towards the engine as you can and then tighten the bolts. Also could it be bolts from the flywheel and torque converter fallen out and rattling in the bell housing?


Ooops should have read your last post. Well glad to see you figured it out.

I appreciate all the ideas. One reason I like these trucks is that they can be worked on by the owner and with the experience here on this site, just about any problem can be diagnosed.