95-6.5 Turbo - Heavy white smoke

[6point5]

After a new pump with new PMD with #6 resistor and new computer with a new PROM on my '95, we barely got the truck started. Once it did start, there is so much white smoke that you can't see the truck. We got a Tech1 unit to set the injection timing. We have a 34 code (stepper motor) and the Tech1 won't let us go any further in the process because of the code. We can't resolve the code by changing the pump position. We ohmed out the wiring, its OK. All checks on the electronics check out (computer, crank sensor, wiring, voltage, ohms). While the engine is running, we get a desired timing reading of 15.9, the actual reading is 0.00 (obviously this is not the real reading) and the TDC reading is -1.10. The factory OEM readings should be 3.5, 3.5 and -.5. We can't find anything wrong and we have no idea of what could possibly make the timing off that far. We double checked the firing order. The engine idles smoother with the coolant sensor unplugged and it smokes a little less and starts better, but still not near right. Also, engine runs real quiet like a gas motor at idle, hardly any diesel noise at all (this is different than it was before the repair). When we try to rev it up some, it smokes, bucks and gets a lot louder diesel noise. We took the pump back off and had it rechecked, it passed all tests (I assume that means the stepper motor worked too). Injectors are new, compression is good (all 350 - 380) leak down test was good.

Could something be broke in the engine and it still run? The only thing we can find in any research is that AllData mentions a shear pin on the cam gear. I hate to take the front off again without it being necessary. Any ideas?

[sixnickel]

White smoke and no rattel sounds like late timing. It should get better with the top of the pump rotated to the left(drivers side) fender. Go as far as you can with it and see what happens? They do make a tool for turning the pump that helps a lot( I made mine)When you unplug the temp sender it thinks its cold and it advances the timing that why it runs better. When I have had pumps off I have always thought about the pump timing gear moving a tooth as it floats around in there. I'ts never happend to me(yet) but I always think about it?Good Luck

[6point5]

I have moved the pump from stop to stop and 15.9 is the lowest timing # we can get. Is that pump gear just laying there? Do you think it could be possible that we did something to cause it to jump and if it did jump, would that really matter since that gear just spins the pump, not change the mechanical engine timing. I'm kind of leaning towards something has happened in the valve train that would change the engine timing, not just the pump timing. Thanks for your reply all suggestions will be appreciated.

[sixnickel]

The IP was a dowel pin for alignment on the gear for proper timing,the gears are timed also. Think about it the pump has to know where the pistions are to inject the fuel at the right time to the right cyl. Why did you change the pump? What was your problum? Do you have a loose timing chain causing late timing also? On a diesel, timing is critical 2or 3 degrees make a big difference whether it will run or not. Not like a gas engine, where timing can be off a mile and it will still run. Put a bar and socket on the front damper bolt and rock the crank back and forth the free movement is the slop in the in the timimg chain. Good Luck

[6point5]

I originally changed the pump because the throttle shaft set screw in the pump came loose and the RPMs couldn't be controlled by the APP, it was either idle or wide open. The day I shut it off to change the pump, it ran perfectly except for the pump problem. Started good, ran good, no smoke. Something happened during that pump change and it hasn't ran since. It definitely has to do with the engine timing. I'm just trying to figure out where something could have happened or broke to cause this situation. I would have thought that id something was broken, the engine wouldn't start & run, but it does. So, I have to find something that could have caused the injection timing to be off about 12 degrees without tearing into the wrong thing.

[sixnickel]

I read your first thread agan why did you have the front of the engine off?? To get to the bolts on the pump gear you take the oil fill tube off and go through that hole. If you took it off(front cover) to get to the bolts and did not line up the timing marks you could be off a tooth. Just thinking!!

[6point5]

I put the cooling upgrade on at the same time I did the pump change and I had the waterpump off. But before I started on the cooling upgrade, I had already changed the inj. pump and had the top all back together. The cooling upgrade would not of caused any of my problems.

[sixnickel]

Ok a'm still thinking!? Have you run this by Walt?

[Husker 6.5]

I think sixnickel is on the right track with your being off one tooth with your IP. That would be like dropping in a SB Chevy distributor one tooth off, you could get it to run, but the distributor housing would be rotated two plugs off the firing order to get the rotor to line up.
One tooth off on the IP would be about 12*, and that's approximately the difference between the book setting and what you're getting. You can't rotate the pump far enough to compensate because of mechanical limitations. I know it's a giant PIA to pull the IP, but since everything electrically is checking out, it has to be mechanical, and the only variable is the IP.

[6point5]

The gear that the IP bolts to, how would i change that gear by one tooth and how would I know which way to go, are there marks on the gear to line up? I assume that I would have to pull the cover off of the front to change this gear setting. If anyone knows the procedure, let me know. Thanks!

[sixnickel]

You are going to have to pull the timing cover off the front of the engine. The IP gear is driven off the gear on the cam shaft behind the timing chain. There are timing marks on the gears that must line up. There are timing marks also on the timing chain sprockets that must line up also. If the engine has high miles on it I would put a new timing chain and sprockets on it at this point because pulling the cover is 90% of a chain job. I believe the timing marks should be at crank sprocket 12 o clock, cam sprocket 6 o clock, cam gear 12 o clock, pump gear 6 o clock. Hope this helps!!

[Husker 6.5]

You are going to have to pull the timing cover off the front of the engine. The IP gear is driven off the gear on the cam shaft behind the timing chain. There are timing marks on the gears that must line up. There are timing marks also on the timing chain sprockets that must line up also. If the engine has high miles on it I would put a new timing chain and sprockets on it at this point because pulling the cover is 90% of a chain job. I believe the timing marks should be at crank sprocket 12 o clock, cam sprocket 6 o clock, cam gear 12 o clock, pump gear 6 o clock. Hope this helps!!

Hey, Doug, before 6point5 pulls his timing cover I was thinking. The stepper motor controls injection pulse timing and duration. If it is not working properly could that be causing the injection timing problem. If the elastomer in the harmonic balancer failed, the CPS signal would be all messed up, it would be close to right at idle, but would become farther off the higher rpm got, and it would be sending bogus info to the stepper which would be trying to compensate for false engine timing. Is this possible? Easy to check the harmonic balancer to see if it's going or gone.

Allen

[sixnickel]

Allan I hear what you are saying but he said the engine ran good before changing the pump with no timing issue. I guess it was a throttle problem. Also he did not think the pump gear was a timing issue all it did spin the pump!That's why I think it could be off a tooth. At this point you can not assume and thing and go back to basics check the timing marks and eliminate basic timing being off. We all know what happens when you assume in this business!!!

[6point5]

to update my situation, we found that the camshaft gear key was bent, but not sheared. I put in a new woodruff key, it started right up, no smoke runs great!!! In a couple of minutes, I got a code for the wastegate. Checking my gauges, I have 20# of boost if you floor it. What is this all about???? What controls the boost that would give me so much??? Any ideas??

[sixnickel]

If some how the vacuum hoses at the waste gate solenoid get reversed you will get full pump vacuum at the waste gate all the time. Also check with the engine off free movement of the lever on the waste gate. If these check out you might be due for a waste gate solenoid. Glad you got the timing problem straightened out. I know it was a lot of work pulling off the front cover be sometmes you have to go back to basics.

[6point5]

Once we set the inj. timing correctly with the Tech tool, the boost went back to normal, it runs about 12 now when floored.

[6point5]

Just in case anybody is researching this same problem, the ultimate cause turned out to be a sheared cam shaft gear pin. It wasn't entirely sheared but enough to change the timing so it was off about 12 degrees. $1.25 fixed it right up, it only took several months to find it!!! Better luck to you.