Finally running again! But not shifting quite right

So, I spent a good 4-5 hours today working on the M1009. It's been parked since around April, due to a bad Injector Pump and my lack of time or money to fix it. Long story short, I got an IP off a guy on Craigslist, got the right tools for the job, and swapped pumps. After just 2 or 3 turns of the the key, she fired right up. Feel like it has a bit more get up and go than before.

However~~~
It doesn't feel like it's shifting like it did before. It used to shift really hard at set speeds. Now, I got it up to 45 and didn't feel a single gear change. Wondering if I need to adjust something. And if so, not sure what. Would it have anything to do with the vacuum pump getting rotated possible not back to its exact position when I put the manifold back on? Or maybe the swapped in vacuum modulator thingy that attaches to the side of the injector pump. I couldn't tell where it was supposed to be adjusted or how.


Anyone got any suggestions?

I think the postition of the vacuum pump may have something to do with it, in the TM it tell you to note the postition of it for reinstall. Someone correct me if I am wrong.

The vacuum pump only produces vacuum, it isn't 'timed'. It is most likely the vacuum valve on the side of the pump, loosen the two screws and move it around a little and then test drive, repeat until the shifting is where you want it. I would say you've got it too far advanced towards the front of the truck, turn it counterclockwise a couple of degrees to firm up the shifts.

If you have a vacuum hand pump and a vacuum gauge, you can precisely adjust it to 8 in/hg at almost wide open throttle. (See page 3-64.1 in the -20 TM for details)

Later,
Joe

Also, do I need to take the truck in to a shop to get the timing checked after a new IP install? It isn't racing or dragging and sounds about like it did before. The idle may be a tad higher but I always thought it seemed too low before.

If it is not smoking and/or acting too different from before, I would say no. If you want piece of mind that it's right, you can get it timed.

Later,
Joe

Glad to hear you are back on the road.

I do not feel my M1009 shift but if I pay attention I can here it. It seems to me not feeling the gear change is a good thing (smooth shifting) although I notice when I get up to 45-55 I keep waiting for it to shift into overdrive/4th gear.

While mine will run 65 to 75 on the highway I can see the fuel gauge slowly but surely moving to the left at that speed so I poke along at 55 to get 19 to 20 mpg.

the rubber hoses could be shot. happen to mine

But if the rubber hoses are shot then it should shift harder, not softer because it's not getting enough vacuum.

Later,
Joe

My bet is the problem is in the Vacuum Regulating Valve (VRV) on the pass. side of the IP. Mine got stuck internally and the truck would wind out to redline before every shift. The VRV can be removed, disassembled, cleaned and relubed with spray. Beats paying $125 for a new one from the GM dealer.

Okay, so I went back and found the pics I took clear back when I first tore the thing apart and rotated the vacuum pump back to where it was before. Still not sure if this matters, but I did it anyway. Then I adjusted the vacuum regulator/modulator thing on the psgr side of the IP. It was already all the way counter-clockwise as far as it would go, so I rotated it about 5 degrees clock-wise, and low-and-behold, between the two, I've got a good smooth shift at 15-25 (Depending on RPMs) and another at 35-45 (again, depending on RPMs). The beast lives!

You guys are awesome. Guaranteed to hit y'all up in the coming months as I replace glow plugs and trace down wiring demons.

Semper Fi!

As far as timing I would suggest getting it timed by a good shop, timing affects fuel mpg and power lvls and the combustion of your fuel. it would be peace of mind atleast but I have taken trucks that many were happy with and timed them and they couldnt belive it was the same truck. Not that you are but in a diesel timing is probably the most ignored maintence issue.