Weird split second profuse engine rattle leaving me puzzled and concerned

[dbrannon79]

Good morning fellas, I have a question about my 93 truck and an odd noise the engine is randomly making. this has happened a couple of other times but I wasn't sure what it was. it happened to me again twice last night while running around town.

The best I can describe it is when driving at in-town cruising speeds the engine will rattle or clatter profusely for a split second, at the same time I noticed that the tach jumped up slightly but there was no jerk or thrust felt while driving. it's almost as if the engine hiccuped or choked on something! the noise goes away as fast as it comes. not sure if this is a sudden blip on the timing advance or my suspicion of it taking a gulp of engine oil down the intake with the blowby it has.

I had heard it a couple of times before I installed the CKO provent and since installing it, it had not done it again until last night. The wife and I were out in it last night and even she heard it and said "what was that" She wants to take a trip for the following weekend to the coast (300 mile round trip) and with this possibly being the engine taking a gulp of oil or maybe an issue with the IP suddenly advancing timing for a split second, I am worried this truck is not going to be up for the trip.

Can anyone help me figure out what this could possibly be? and if it's something I need to be worried about. if I had to count the number of times it's done this since I've gotten it on the road, I would say at least 4 times now in the last 700 to 1000 miles.

as I said, when it happens, nothing is felt driving. Only the clatter and tack movement that last only for a split second.

 

[Will L.]

Any old cell phones lying around you could rig up to record under the hood?
Been looking for an excuse to get a used go-pro that someone sells cheap so they can buy the latest and greatest?

Video of the sound might help. Camera focused on the clear ip hose.

Any changes in oil pressure or fuel pressure or exhaust smoke helps identify.

Could be it jumping in and out of “cold advance”. Just run a jumper wire to it on the ip, from a toggle switch power source- through the window is fine. Then get it warmed up and hit the switch to advance the timing to see if that is the sound you hear. When a db2 6.5 gets over advanced, it will let ya know it’s not happy by rattling your cage, and the neighbor’s kitchen window sometimes too.

 

[ak diesel driver]

I'm thinking injector sticking.

 

[Will L.]

DB2 loves themselves some atf to drink. Can help sticking injectors. Atf can leave some carbon deposits so I follow up with water down the intake like wmi - cleans out the carbon deposits.

 

[WarWagon]

in-town cruising speeds

Below 45MPH the torque converter is not locked and you won't feel any engine RPM changes so much.

In addition to @Will L. advice. Check the lift pump fuel pressure. DB2's knock the engine like hell before they run out of fuel. It's a weird sound you will know if a DB2 pulls up to the fuel pump on fumes. You will also feel running out of fuel if the TCC is locked. I suggest this is the sound you may be hearing.

Clogged tank sock from tank coating coming off, plugged fuel filter, air leaks, collapsing fuel hose...

Checking for air in the IP return ... These pumps return a massive amount of fuel. Way more than they inject to burn. A good way to check for air is to raise the engine RPM while watching the clear return line. Due to an IP governor failure I now recommend a helper in the cab watching the tach and working the throttle rather than reaching over the engine fan to hand work the throttle. The fan is generally stopped by the sudden-like trashed hood on run-away... Just saying it's a very bad habit and shortcut.

Is the CKO provent full of oil?

 

[dbrannon79]

Any changes in oil pressure or fuel pressure or exhaust smoke helps identify.

No change in oil pressure, I disconnected the fuel pressure gauge since it had a live feed into the cab.

Could be it jumping in and out of “cold advance”.

I have the cold advance solenoid on the IP unplugged, only the fast idle solenoid is connected. I didn't like the sound it made on a cold startup.

DB2 loves themselves some atf to drink.

How do I go about feeding it some atf? and then doing a carbon cleanse?

Check the lift pump fuel pressure.

Checking for air in the IP return ...

I will reconnect the gauge under the hood and check pressure as well as look for air, I have the clear line installed

Is the CKO provent full of oil?

the mesh on the filter is saturated and there is a small amount of oil standing in the hose between the CDR and the provent in a low spot of the hose (hose is see-through) I had thought about this thinking maybe some of that "pooling oil" in the hose is making it's way into the provent in gulps where it gets randomly sucked into the turbo. aka like when I use the brake slowing down it sloshes into the provent.

the oil collecting in this hose like this made me think about reversing the in and out connections on the provent since this provent has no check valve in the outlet side. only has a relief valve in the top of the cap.

 

[Wreckinball67]

I used to have issues with my battery cables coming loose and when they did the ECM (computer) would not work and the engine would have a loud rattling sound, it was timing I suspect. Once I fixed the cables it was fine. So, what I'm saying is maybe it has something do with your ECM.
Best of luck

 

[dbrannon79]

I used to have issues with my battery cables coming loose and when they did the ECM (computer) would not work and the engine would have a loud rattling sound, it was timing I suspect. Once I fixed the cables it was fine. So, what I'm saying is maybe it has something do with your ECM.
Best of luck

This truck is a mechanical DB2. no ECM to run the engine. not unless there is some things on it I'm not aware of. the factory TCM under the glove box is disconnected at the trans and from 90% of all the engine sensors.

 

[Twisted Steel Performance]

A air leak in the fuel system is possible, a seal on the pump could be suspect, not sucking air all the time sort of thing.

 

[dbrannon79]

ok here is a random thought! how does one of these engines act if a small amount of water gets into the fuel system and manages to make it past the filters into the IP sprayed with fuel into the cylinders? hypothetical thinking here.

I ask this because what's in the tank sitting for 3 years was unknown. I somehow blew out the seals on the FFM and it had started leaking badly a few weeks back. I ended up installing an inline clear fuel filter in it's place as a temporary solution. last I looked at that filter there was some debris at the bottom of the clear section. didn't see any water, but you just never know with my eyes nowadays.

I need to order a filter with a clear bowl like I had put on my 95 but I just haven't done it yet. the truck has already burned through all the fuel it had (50 gallons) and 1/2 a tank of fresh fuel now.

 

[Will L.]

For the atf into system: 1 quart.
Add into the fuel tank is ok. Drain ffm and fill it with atf is more desirable for this situation, pour the rest of the quart in the tank.

You can now run as much fuel lubricant additive as you want.
Pure oil (2 stroke/ atf/ 10 wt engine oil) will retard the timing and smoke because it won’t all burn fast enough. 20% lube should not have any noticeable smoke except full throttle from a dead stop.

Any water ( suspicious of contamination) can damage pump and/or injectors.
How much and beginning condition affects it greatly. But when they get actual damage (instead of debris messing it up) they usually misfire very frequently and worse under a heavier load. The atf will do better at clearing any debris, displacing water, and lube than just a normal additive like stanadyne.

How to decarbon: if you are doing this to a rig with a soot trap/ catalytic converter, begin by removing the catalytic converter temporarily. All the carbon you get off the pistons, valves, etc will build up in the cat. Since you are doing a mechanical repair, it’s legal. Just reinstall after the decarbon and test drive.
This works for gas & diesel.
Some people use a spray bottle- it is safer but takes for ever. A kids squirt gun is a good option. The larger the carburetor or throttle body the more water it can handle at once. On truck intakes if you remove the upper intake so you can squirt water into one intake runner at a time it is better.
I have used a cup like he shows in this video but normally you do it a lot more times than he shows. You will see the dirty exhaust coming out when doing it.
Just keep doing one runner ( cylinder) at a time when possible and let the tpm recover each time. Do it until no more smoke comes out the exhaust. Then hook back up intake / air filter system and go for a test drive of about one mile. Then shut it off.

If at any point the engine dies- do not restart and you are worried Hydrolock is possible. Remove all 8 glow plugs (or spark plugs) and use starter to spin the engine. It will eject any water. I have absolutely drowned a small block ford and chevy to the point the engine died. I didn’t bother pulling plugs just cranked up and kelt going.

 

[dbrannon79]

I have watched the de-carbon thing being done on a gasser using a bottle of water while the engine was hot and revved to the moon while it was poured in. wasn't sure how it was done on our rigs. I like the squirt bottle misting the water in like your saying with the upper intake off better so not to hydro-lock it.

I will have to try both the atf thing and the water mist and see. maybe some good will come out it it like loosening the rings and reducing blowby "maybe" lol.

I will have to get a different fuel filter on there first. one that I can pour in the atf since I have an inline fuel filter on it now. I found another FFM in the parts stash that came with the truck. I think I will go pickup a new filter for it and hope it doesn't leak from the housing.

For now I have put this truck on the back burner. yesterday on the way home from work, the drivers door window motor went kaput. with all the current issues I don't feel comfortable trying to drive it out to the coast carrying the family.

I rolled in the 95 to look at the steering issues. tried to do a hillbilly driveway alignment job last night and it still wanders all over the road. I'm really leaning on the gear box being fubar. it's the only thing I can see with some play other than the swaybar bushing being shot.

 

[jrsavoie]

I have watched the de-carbon thing being done on a gasser using a bottle of water while the engine was hot and revved to the moon while it was poured in. wasn't sure how it was done on our rigs. I like the squirt bottle misting the water in like your saying with the upper intake off better so not to hydro-lock it.

I will have to try both the atf thing and the water mist and see. maybe some good will come out it it like loosening the rings and reducing blowby "maybe" lol.

I will have to get a different fuel filter on there first. one that I can pour in the atf since I have an inline fuel filter on it now. I found another FFM in the parts stash that came with the truck. I think I will go pickup a new filter for it and hope it doesn't leak from the housing.

For now I have put this truck on the back burner. yesterday on the way home from work, the drivers door window motor went kaput. with all the current issues I don't feel comfortable trying to drive it out to the coast carrying the family.

I rolled in the 95 to look at the steering issues. tried to do a hillbilly driveway alignment job last night and it still wanders all over the road. I'm really leaning on the gear box being fubar. it's the only thing I can see with some play other than the sway bar bushing being shot.

I'd replace the sway bar bushings first.

I have a friend that claimed improvements by changing his sway bars.

 

[dbrannon79]

Yeah, on the 95, I noticed the bar to frame bushing banana'ed out on the drivers side. the links to the LCA's are in good shape though. I replaced the steering wheel shaft with one that has a u-joint and got rid of the rag joint a goo while back, but if you jack up the wheels and try to turn the wheels, both tires will move back n fourth a good amount with the column locked (key out) I have rebuild the current gear box twice now since owning this truck. bump steer is also a problem as well as trying to drive with a side wind. when the tires find a rut in the pavement they want to follow it!! I didn't realize just how bad it was until parking it and getting used to driving a different vehicle.

 

[Will L.]

I forgot about your in-line fuel filter. Disconnect the hose after the in-line filter so there is no filter drop that part of the rubber hose into the court of new ATF. Start it and run it until half the quart is gone. And reconnect your fuel line to the in-line filter start it up and let it run again for a couple minutes. Pour the rest of the quart in the tank.

 

[MrMarty51]

Below 45MPH the torque converter is not locked and you won't feel any engine RPM changes so much.

In addition to @Will L. advice. Check the lift pump fuel pressure. DB2's knock the engine like hell before they run out of fuel. It's a weird sound you will know if a DB2 pulls up to the fuel pump on fumes. You will also feel running out of fuel if the TCC is locked. I suggest this is the sound you may be hearing.

Clogged tank sock from tank coating coming off, plugged fuel filter, air leaks, collapsing fuel hose...

Checking for air in the IP return ... These pumps return a massive amount of fuel. Way more than they inject to burn. A good way to check for air is to raise the engine RPM while watching the clear return line. Due to an IP governor failure I now recommend a helper in the cab watching the tach and working the throttle rather than reaching over the engine fan to hand work the throttle. The fan is generally stopped by the sudden-like trashed hood on run-away... Just saying it's a very bad habit and shortcut.

Is the CKO provent full of oil?

My first thought was a lean burn condition.

 

[Paveltolz]

To help clean up the system after filling up with some really bad fuel I did a 50/50 mix of ATF and BG-44 in the FFM a few times until I'd run a couple of good fuel tanks through it. Cleared the stuttering, hiccupping, almost stalling out situation nicely by the time I got to Salt Lake. Pro-tip, don't buy the cheapest priced fuel you can find in Dubois WY, you'll have issued before you get to Jackson Hole.

 

[Stoney]

My first thought is water in fuel. There's been ALOT of bad fuel lately.. yeah I know they test tanks etc. but that doesn't change the fact.. everyone I know that runs diesels has had probs lately.. ironically if ya switch to red coolaid there's no problem.
Second thought is if filters are getting partially plugged.

 

[Will L.]

My first thought was a lean burn condition.

Diesels don’t “burn lean”. Gas engine do because they have a spark plug that will force an explosion with not enough fuel/too much air. Also gas engines regulate the amount of air they get to control rpm.
Diesels always have all the air they can handle. Way too much air hurts absolutely nothing. Not enough fuel just makes the rpm lower. When it gets too low the engine turns off.