powering up a 91.0 with the auto trans

[fox]

Ok, the trans has been upgraded, and now he wants more usable power.

I know linkages are loose and out of adjustment for the VE. That will be first to get right. I have a 3200 gov spring, and will turn the fuel screw a turn or so. I think it has a 21 exhaust housing, and I THINK I have a 16 or 18 housing.



Are the injectors ok or should we change them out. BTW, he does tow a camper with it--5th wheel.

I don't think I have seen one of these that was such a dog to drive. The trans really helped it, but it needs power above 2000 rpm!!!

Truck is 4X4 stand cab.

 

[NIsaacs]

Bone stock they will not impress. Especially the early intercooled ones. If that is a pre-intercooler model, 89/91, it should have a #18 housing. In 91. 5/92 they were 21, then again in 92. 5/93 they went back to the #18.



How many miles on the truck? I would not change out the injectors unless they are bad or you want bigger ones.



Nick

 

[fox]

He has 120,000 on it.

I guess I am asking if bigger injectors are NEEDED to get some good power.

Can the fuel screw give enought fuel to make a big difference. ?



Oh, I just remembered that it had a rough idle that we suspect is an injector issue. I will set the overhead too.

 

[dodgenstein]

I just swapped an intercooled 1992 motor into my 1991 D250. With a cranked up pump, Denny T pin, stock HX35 w/12 cm housing, and 4" exhaust it'll hit 36 PSI boost with a 5 speed. While an auto will take some of the performance away, that kind of boost will still be a noticeable improvement.

 

[cerberusiam]

I guess I am asking if bigger injectors are NEEDED to get some good power.

Not really but it helps. Turn the pump up enough if it will go, and they run pretty good. If it has a "lazy" pump not so much.



At that age and mileage a pump refurb with a turn up internally and pop setting the injectors will help a lot.



Is it intercooled or not?

 

[fox]

Yes it is.

 

[NIsaacs]

So is it a 91. 5 truck then?`If it is, like Cerb says they have "lazy" pumps and really require a set of bigger injectors for best results. The fuel screw on these pumps require a complete turn to equal a quarter turn on a "good" pump.



You will need gauges to monitor the changes as you adjust the screw.



Nick

 

[fox]

I made an error on the title!! It should say 91. 5 dodge!!

My mistake.

So, with the lazy VE pump are there any options to correct the pump?

I believe the injectors need to come out because the front cylinder isn't do much work at idle. So i need to get a set of injectors for it.

Where should I call to get them?

 

[cerberusiam]

I made an error on the title!! It should say 91. 5 dodge!!

My mistake.

So, with the lazy VE pump are there any options to correct the pump?

I believe the injectors need to come out because the front cylinder isn't do much work at idle. So i need to get a set of injectors for it.

Where should I call to get them?

The pumps are lazy because of the way they were setup when assembled. A good VE builder can remedy a lot of that with his build and replacing parts that are not functioning as well as they could.



The ULSD tends to have an adverse effect on these pumps especially in the case pressure control valve area. We have had to replace 3 of them in the last 2 years when the pumps just quit working like they should. If the pump has never been touched then its likely time for springs and rollers internally as those are the main wear items.



If you think the injectors are weak work on them first then see what effect some simple tweaking on the pump will have. The New Era tips will fit these injectors and there is a pretty wide choice available all the way up to the 370's. If you have a Bosch authorized shop near you they should be able to get new tips and set the pop pressures. Will be cheaper than a swap most of the time and at least your working with known pieces.