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Knock Knock Knock all day long...

R

rigive

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First post here, hopefully a good one. I've been reading for the last week or two. Think its time I reach out for help.

I'm really posting on my buddy Travis behalf. He recently purchased a 1996 C3500 with a bad motor. Travis acquired a new to him used motor. (actually his third used motor other two had bad cranks) With the little bit of help I gave him he got it running after bolting everything back up.

On to the night her first started it up. Travis filled the fluids, purged the injectors and she fired up after the batteries spent an hour or two on the charger. Motor idled fine, let it idle for about a minute, give it a small rev or two. Motor knocked just a bit while letting off the gas, not at idle. We noticed a bit of a oil leak from the external cooler clip deals. (looked to be less than a quart) Shut her down for the night. Total run time no more than 2 minutes.

Next day he corrected the oil leak issue. Fired her back up, knocks now at all rpms. Few DTC set (didn't note #'s, details noted below). We're not sure where to start... Cylindar balance DTC on 7 & 8, replaced injectors on 7 & 8 (had a few new in the box). Same knock.

I've filled out the 6.5 Engine Diag. Troubleshooting Checklist to the best of our knowledge.

Any help would be greatly appreciated!!
Tks,
Matt

Year: 1996
- Truck model and class (ie: c2500) c3500
- Automatic or Standard _Automatic
- Mileage: (indicate miles or km) 230,000 Miles
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) Replaced motor w/ 605 block from Military Humve______
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? __Turbo Engine______
- Ambient outside temp: (indicate *C or *F) ___80*F
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc)
Good Question... Fuel (presumably diesel :) ) remaining from previous owner / Unknown age
- What fuel additives are you using? _Unknown_____
- Where are you located? __Pea Ridge, AR_____

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter _Looks to be new__
- Fuel filter _Unknown_____
- CDR Valve? _Unknown____
- Coolant – last flushed/replaced at _New________
- Oil – synthetic/regular, changed at _Regular New______
- Batteries – state of charge, (matched set) replaced at __good charge_____
- Battery cables and grounds (removed, cleaned and tightened): _cleaned and tigtened________
- Glow Plugs - how many miles on them? _Unknown_______ What type? __Unknown_________
- Injectors - last changed at _______________


History: (Describe how the problem first appeared.)
- What were you doing when it happened? _Standing around _:smile5:____________
- How was the truck running fine before this problem appeared? _____________
- Has this problem ever happened before? _______________________
- Describe any related factors that might be part of the problem. ______________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) _Y__ And? (didn't write down DTC) something about Cyl 7 & 8 Balance System, Map sensor DTC (replaced)


Diagnostics:

1] Starting:
1a] Does the engine start? Yes
1b] Does the engine crank over? Yes
1c] Are your batteries fully charged? Yes
1d] Have you removed, cleaned, and tightened all battery connections? Yes
1e] Does your Wait to Start light come on for a time? How long? _5-10 seconds
1f] Does your glow plug light come on? __No_____ For how long? _________
1g] Do you see smoke from the exhaust while cranking? What color? No Smoke___

2] Fuel Issues (if not running): Truck running
2a] Can you hear your lift pump working? ____________
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? _________
2c] Loosen the inlet line from the IP – is fuel coming out (Lift Pump on)? ___________
2d] Loosen an injector line and crank the engine - does fuel come out? _________
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? ___________

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) mounted on side of injector pump___
3b] Condition of Extension harness (if used) Vendor or Homemade? _________
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. Look to be good___
3d] PMD Make: Unknown_
3e] PMD Age: _Unknown_

4] Stalling Issues
4a] Do you experience stalling only when hot? _No Stalling_____
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ______
4c] Does pouring cool water over the IP seem to help with restarting? _________
4d] Is stalling momentary (engine recovers)? _________
4e] Does SES light come on when engine hiccups? _________
4f] Does cruise control quit working when engine hiccups? ___________
4g] Does re-starting seem to reset engine, restoring cruise and power? _________
4h] Changes to dash lights or instruments during stalling events? ___________

5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? _Unknown______
5b] Any bubbles or oil film in coolant overflow tank? _Unknown___
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? __No_____
5d] Excessive white smoke from exhaust on cold start? _No______
5e] Excessive black smoke from exhaust under hard acceleration? _No_______

6] Performance Issues
6a] Do you have gauges? __Factory____
6b] Maximum boost under load? _Unknown_______
6c] Have you added a performance PCM (reflash) or Chip? _Unknown_______
6d] Have you changed exhaust / downpipe / crossover? ___No___________
6e] Wastegate – mechanical or vacuum? __Unknown_______

7] Temperature-related Issues: No
7a] Single or dual thermostats? ___Dual______
7b] Have you replaced them lately? Manufacturer of replacements? __No_____
7c] Have you pulled and cleaned Radiator and coolers lately? __No________
7d] Have you replaced the fan clutch? Manufacturer of replacement? __No_____
7e] (winter) Have you tested your antifreeze? Good to what temp? __New______
7f] (winter) Are you using a winter grille cover? ___________
 
Have you "run" it out ? It takes quite a while to purge air from the nozzles. The ecm tries to balance the motor thus cutting fuel. You either have to IIRC disconnect the OS or just drive it out assuming it's fuel related. If it's real loud maybe check oil pressure. It took a good half hour of driving before mine quieted down after new injectors.
 
Acesneights1 said:
Have you "run" it out ? It takes quite a while to purge air from the nozzles. The ecm tries to balance the motor thus cutting fuel. You either have to IIRC disconnect the OS or just drive it out assuming it's fuel related. If it's real loud maybe check oil pressure. It took a good half hour of driving before mine quieted down after new injectors.
Click to expand...

Good questions.. Called Travis, he hasn't ran it out since installing the new motor or since the two new injectors. Oil pressure is good according to the IC guages.

When you mention disconnec the OS, what does that mean?

He's a little hesitant to drive it this way, as it doesn't sound the best and he's not wanting to cause any problems.

Watcha think?
 
First, welcome to the site.

A knock could be many things. Pull the serpentine belt off and see if it's still loud. It may also be the harmonic ballancer on the crank.
Could be the vacuum pump...
 
Dieseldad97 said:
First, welcome to the site.

A knock could be many things. Pull the serpentine belt off and see if it's still loud. It may also be the harmonic ballancer on the crank.
Could be the vacuum pump...
Click to expand...

Dieseldad97, Thanks for the welcome to the site.

Pulled the serpentine belt, no difference in sounds. Please excuse my ignorance, but what would that help to identify?

Have a recommendation on how to test or trouble shoot the vacuum pump?
 
You don't need to test the vacuum pump now. The serpentine belt test is used to determine if any accessory is the noise. Alternator, AC, waterpump, vacuum pump etc.

A youtube video of this noise would be very valuable. Good luck to you.

My internet guess is...heat shield loose between the turbo and valve cover.

Again welcome, you've found the correct place...
 
I never did the Optical sensor disconnect(OS) . I just drove mine out. I'm betting you have air in the lines. They can sound pretty ugly when you open up the fuel system. I thought I screwed mine up bigtime. working on larger diesels most of my life I have never seen an engine take that long to purge air so i was in disbelief when GMCTD told me that was the problem, but he was right.
 
Acesneights1 said:
I never did the Optical sensor disconnect(OS) . I just drove mine out. I'm betting you have air in the lines. They can sound pretty ugly when you open up the fuel system. I thought I screwed mine up bigtime. working on larger diesels most of my life I have never seen an engine take that long to purge air so i was in disbelief when GMCTD told me that was the problem, but he was right.
Click to expand...

:iagree:
 
Does the engine miss too??

These things should purge air in short order.

Did you have the injector lines off the engine??

If so there exists the possibility that a couple are mixed up at the IP. This will cause lots of smoke and noises.

Let us know.

MGW
 
Tookie said:
Did you hear the motor run before it was purchased?
It may be the reason it was sold is because it was knocking
Click to expand...
X2, could be all kind of things causing this.
I would crack the inj line nuts one by one to rule bad inj in or out.

other causes would be a bad rod brg or wrist pin,bad lifter,stuck valve or foreign material in the combustion chamber(piece of gasket or tip of glowplug?).
You never know with a "used" engine.

Like Missy said,air usually purges fast after first startup,couple of min at most.
 
bison said:
Like Missy said,air usually purges fast after first startup,couple of min at most.
Click to expand...

I disagree. I thought the same thing until GMCTD chimed in and said "drive it" took a good 20 min if not longer hen was purring nicely. There is a reason something to do with ecm trying to balance out the cyls. I wish I could find the thread but I can't maybe it was over at DP. I think it started" Help, I screwed this truck up bigtime". JD went into a very tech reason of why this happens with DS4.
 
I tried and tried to get all the air out of mine on more than one occasion, -the whole while it was knockin' and clankin' and dropping cyl's (sounds terrible).

Neither my DS, or my DB would clear the air out of two lines until I bled, -and re-bled, -then went out, hit the road and tromped on it, -then she cleared right up.
 
man, they have more adds on that site than they have anything else.

No wonder I refuse to go over their anymore.
 
Wow...Reading it now I feel like an a$$. So much learned since then. Blueburby gots a little attitude huh ? Sin what's happended over there but hope this helps ya.
 
Acesneights1 said:
Wow...Reading it now I feel like an a$$.
Click to expand...

No worse than I did after finding my self distructed air filter blocking the air intake was the cause for my stalling issue.):h

The good part will be that the lessons learned then will help him get the issue solved and you learned from it as well.

Cheers,
Paul
 
As far as feeling like an a$$, -I have you all beat.

I destroyed a freshly built 18:1 motor and broke a mint condition 506 block because a shoprag got sucked into an intake port.

The sound of coolant running into the oil pan on a freshly built engine was enough to literally make my heart hit the ground.

Talk about feelin' stupid, -dat would be ME!!! :mad2:
 
Here is the trick to getting these things up and flying without all the hastle and fight.

On a fresh go round, either a fresh engine or an IP/ injector change.

I always start this way.

Run the Lift pump and make sure I have air free fuel to the IP. Hook the fuel line to the IP. Turn the key to ON then energize the lift pump (not the starter) allow the LP to run for a about 30-45 seconds to fill the IP and purge it out good. (DS pumps will purge right through and get most of the air out of the IP (except pumping chambers)

Next
With the glow plugs removed spin the engine until you have fuel huffing out all the glow plug holes.
The engine will spin at about 400 RPM with the compression relieved.

The IP does not have to fight the compression pressure which will cause the air to remain locked in the system.

With fuel mist blowing out then your ready.
Screw the plugs back in, hook up the wires and lite the fire.

The amount of fooling around, missing, clanking, banging and general Hoopla is cut to near zero time wise.

Once you have the engine running, the final little bubbles will purge quickly and your little creature will purr like a kitten.

The biggy is getting the bulk of that air out without making the IP fight compression pressure.

Compression will be around 400 PSI depending and if the things does fire off then with speed the compression pressure goes even higher.

The IP is then trying to force air into the cylinders and this must exceed the compression.

The fuel oil will go in but air wont and it just bogs things down a bunch.

Next time, give this method a go, Honest, it works quite well and fast too.

Saves a buttload of wear on the starter and the batteries to get it going too.


MGW
 
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