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1993 6.5TD Bad shake at idle

WarWagon

WarWagon

Well it hits on 7 of 8...
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1993 6.5TD. Vin F not so much as even a kitty... 125K 2500 EC LB 4x4. Just bought.

When I come up to a stop light I have a really bad shake at idle. Seams to come and go. Almost like a miss. Does it while hot. Shakes the entire truck.

LP working and pressure good. (OPS replaced.)
No smoke. Little/no blowby.
Just had trans rebuilt and shook before that.

Damper in fair condition. (Slight rubber swelling on one side. Dealer said it is ok.)
Motor mounts unknown condition.
Injectors unknown: original OEM or changed. (Is there a way to tell? Factory paint marks?)
Glow plugs appear ok as it started well in 20 degree weather. (40 - 70 degrees here now.)
Fuel filter new. Air filter Ok.
No codes - not that this has more than a trans computer...
No pressure in cooling system aka head gaskets holding.
Stanadyne P.F. used in fuel.
Oil sample lab tested good.

Could the cold advance be staying on too long?
Other ideas?
 
If it's got a maual transmission, it's probably the 2 piece flywheel coming apart. I had a '95 do the exact same thing-thought the engine was missing. Chased it for a couple of months before I figured out what it really was.........
 
qwomack said:
I would be cautious of that damper. They are a weak link on these trucks and any kind of swelling is not good.
Click to expand...

+2, it could also be the serpentine belt damper too.

Try this, unhook the TC and see if it goes away, could be a bad torque converter.

A compression test wouldn't hurt either.
 
turbovanman said:
+2, it could also be the serpentine belt damper too.

Try this, unhook the TC and see if it goes away, could be a bad torque converter.

A compression test wouldn't hurt either.
Click to expand...

Can a bad TC produce a rumble or vibration at idle? I have another vehicle that rumbles bad at idle and has other TC symptoms.

Can bad trans fluid also cause a rumble at idle?
 
What is your rpm at warm idle? Too low and you'll get the shakes. Usually low rpm at warm idle is an indicator of other problems.
 
SuperTuscan said:
Can a bad TC produce a rumble or vibration at idle? I have another vehicle that rumbles bad at idle and has other TC symptoms.

Can bad trans fluid also cause a rumble at idle?
Click to expand...

Its possible if the front pump bushings are shot or the pump is torn up, broken/cracked flexplate.

Bad trans fluid, not likely but it would be an indictator of present issues or maybe future issues.
 
If you suspect your balancer at all, check it and replace ASAP if necessary. A bad balancer has been the demise of many 6.5's as they tend to break the crankshafts. They are relatively cheap, under $100 in most cases and easy to check. If I am not mistaken, it is recommended that they be changed at 100K intervals. If you have the big bucks, you can go with the FluidDampr setup from Heath for $415 and you'll never have to worry about it again.
 
That's interesting to know, Kenny. I wonder what Bill Heath thinks of that as he is running a SCAT crank and it wouldn't surprise me if he is running a Fluidampr on his LSR truck.
 
what would be the best way to inspect the damper just visually, kind of hard to see. what are we callin a bad shake. mine is more of a heavy vibrate.
 
I know when my mandrel bent downpipe was touching the frame when i first installed it i got a nasty vibration at idle that went away with any increase in engine RPM.

Could be another possibility.
 
A bad vibe at idle but not elsewhere in the RPM range makes me suspect an injector not popping and or an IP thats failing.

Check to make sure all the cylinders are firing. (pop the lines one at a time)

A bad converter will shake worse as the RPM increases.

You can remove the flywheel cover and then run the engine. If the flex plate wobbles all over, then the converter is likely a rebuilt and the hub/snout was not located correctly when it was replaced. (have seen this several times)

A poorly rebuild converter can wreck an engine and short order due to the shake.

Missy
 
tcihla79 said:
what would be the best way to inspect the damper just visually, kind of hard to see. what are we callin a bad shake. mine is more of a heavy vibrate.
Click to expand...

A visual is a good way. Any rubber that looks different means it is bad. The rubber tends to swell and pop out. Least mine looks like this. So I have it on order...
 
For the most part, you are looking for the rubber ring swelling, cracking and bulging out from between the hub and outer ring. If you see signs of any of those symptoms, it is time to be changed. It is not a big job to remove the upper shroud, fan, serpentine belt and pulley to check the balancer. All you need are basic tools, and an afternoon's worth of time. While you are in there, take some pics and post them up so we can give you some guidance.

Before you change it, make sure you have a good harmonic balancer puller/installer. I have the Proform #778-66514 from Jegs and it worked great. It was about $70 and worth every penny. This is one tool you don't want to scrimp on. This is one case where the tool makes the job. If you don't have the right tool, you will very quickly end up with a big mess. If you can't justify the cost, see if you can rent from somewhere like Advance or Autozone or maybe a friend has one you could borrow.
 
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