Engine/Transmission (1994 - 1998) delivery valves

[onestackdram]

I have a question for those with higher mileage 12v. ie 95's. But this question is also for the rest.



Can the springs in the delivery valves go bad? Like say after 200k, on a completely 'virgin' truck? I ask this because the truck is missing but the injectors are good, valves are correct, temps are fine, no leaks that can be found anywhere. So we are beginning to think that maybe the del. valves have started to go bad. What do you guys think. For info's sake, the miss is not bad enough to ruin driveablitly its just doesnt have any getty up and go.



Russell

 

[R.ebel]

Sounds like the timing may have slipped?

 

[onestackdram]

we are thinking that as well. I think he is gonna go the delivery valve route first, imho i think he just needed an exuse to step up to better ones, but whom of us havent done that before



Russell

 

[98rammer]

to really tell what's happening with the injectors, they need to be tested on an injector (nozzle) tester. pop off pressures can and typically do vary a lot with stock injectors. i would definately step up



Tom

 

[Missouri Mule]

I think your timing (injector pump)is off a little. As I have read the injector pump timing can slip over time just like gas engines with points (in distributor).



But delivery valves could go too, I guess. I only read about memebers changing them out for increase on fuel output on 160/180 pumps.

 

[Extreme1]

Start by removing the injectors and getting them tested. They do wear out and 200k miles isn't a bad lifespan. If they check out, pull the injector pump and send it to Piers (or Joe D. or... you get the idea). These wear too and should to be rebalanced somewhere between 200-300 k miles to get best performance. The R&R is an easy job and you could tab the KDP while you're at it.



I recommend sending your pump to a performance vendor because they can give you WAY more than a plate kit and have more consistant results for about the same $$.



The timing slip is possible but unlikely unless you've recently changed something that would affect the load applied to the pump gear (like a plate kit or RPM kit). For that to happen, the torque holding it in place would have been on the ragged edge for 200k miles.