91.5 slow return to idle

[cumminstogetya]

My girlfriend's truck is an intercooled 91. 5 5 speed and I might buy it from her. I am not very familiar with the VE pumps, but I know that the truck has been turned up a little by the previous owner. When you free rev the truck it takes several seconds to return to an idle. I wasn't sure if this is a common problem or some fluke thing with a simple fix (hopefully). I don't think it is hurting anything, but it is really annoying. Thanks in advance.





John

 

[Greenleaf]

I laymen's terms;



The governor is near an imbalance state. The springs and weights are fighting each other. The full fuel screw imposes a lot of tension onto the governor through lever(s) and spring(s) thus by mearly turing this screw in will net increased tension and tgend to slow down the reponse.



It's some folks way of increased fueling as opposed to modifying the internals of the pump. Back out the full fuel screw about a quarter of a turn each time and test run untill the inbalance corrects it'self.



GL

 

[paccool]

GL- question about this. Is your answer the polite way to say the pump is at a near run away condition or does this just slow down the response time when coming back to idle?



I'm not trying to start a war or anything like that, I just don't know and was wondering.



Stan

 

[Greenleaf]

Others could better answer that question. I have had both run-a-way (no doubt there ) and a slow to return. I have never had both at the same time. However our good reverend/doctor Bob has said that one will cause another. I have not found that to be true, but I guess anything is possible.



I have limited experience you understand.



Scott

 

[paccool]

The reason I asked is I will be doing some major tuning in a few weeks and it would be good to know if a run away is getting close. I'll have to remember to loosen the inlet clamps so I can get a piece of plywood in front of the turbo in a hurry!

 

[cumminstogetya]

I will try that. By runaway pump, I assume you mean never returning to idle?



John

 

[paccool]

Going to full throttle and not being able to shut it down with the fuel shut off lever on the pump. Only shutting off the air will stop it.



I've seen the "emergency shutdown boards" hanging on the wall at a couple of shops. One was at Piers.



Stan

 

[Greenleaf]

Bill's pump worked and seemed fine... ... ... ... ... ... untill it decided to run off into outter space while we headed into town for a test drive. It was not responsive to the throttle nor did it respond to the shut-down solenoid. The manual shut-off, if I recall correctly, would shut it off or slow it down.



Again, this was after it seemed fine operating at various speeds in the shop and parking lot. His pump had just undergone reconstructive surgury and I figure it was rejecting the "doner" parts



Be careful with them fuel screws. They will bite.



BTW, turning Bill's fuel screw out 1/2 turn solved the problem.



Scott

 

[Den_FL]

Also check that it's resting on the low idle screw when returning to idle. Sometimes when the linkage is adjusted it will return but not rest on the screw. Then the vibration or a quick snap of the throttle lets it rest on the screw.



Worth a quick check.



Den

 

[Paychk]

The reason I asked is I will be doing some major tuning in a few weeks and it would be good to know if a run away is getting close. I'll have to remember to loosen the inlet clamps so I can get a piece of plywood in front of the turbo in a hurry!

I don't know... I think if it was me & mine, I would have the inlet hose completely off and a 10 lb. CO2 extinguisher aim at the turbo with the safety pin all ready pulled.



PS Maybe even make that a 20 lb. bottle

 

[BMote]

Easy Fix Maybe

Oo. I had similar problem with my 91. Very simple problem eventually. Disconnect the injector pump rod from the throttle cable where they connect on the transfer shaft. Now determine if pump is not returning,or is it the throttle . You can take that transfer shaft assembly apart, and might discover rust and crud causing it to bind. Clean thoroughly, grease lightly and re-assemble. Voila, problem solved.