hey guys.

I was wondering how responsive the throttle on a 94.5 psd should be.My brother has a cummins and his is just as soon as you touch it,mine you have to push it a little bit this is from idle speed.

 

There are a few things that can be done to improve the throttle response on an early Powerstroke. The first thing would be to bend the tab on the pedal, so the IVS switch is released at lower pedal travel. Be careful in doing this, because if you adjust it too much, the IVS won't be fully depressed when the pedal is released, and the throttle won't operate. Also, don't put any pressure on the IVS itself while making this adjustment. The IVS can't be replaced, you'd have to replace the whole assembly, which is quite spendy.
Another thing would be to shim the fpr to 80-85psi, which will improve low end response.

 

Thanks for your reply.

This may sound stupid but what is a "fpr" and what is this shimming procedure

 

The fpr is the fuel pressure regulator. On 94-97 trucks, you can increase the fuel pressure by increasing the tension on the spring inside the regulator housing. This is either done by putting a BB behind the spring, or inserting a #2 cap screw inside the spring, at the back end. Ideally, the fuel pressure should be between 75-85psi, though many/most trucks are much below that because of the spring's age, and loss of tension.
You check the pressure at the shrader valve on the side of the regulator. If you want to do this, and want/need more details, let me know.

 

I am not sure if your truck has a turbo, however my friend has a 97 powerstroke. He replaced the downpipe and just a straight pipe exhaust, and that made a big difference. He said he noticed a huge difference in throttle response. The stock downpipe is very restrictive.

 

THanks for your reply Quadzilla

Iwould like to know how to check the fuel pressure,where is it located and what kind of tool do you use.Please give me more details,Thanks.

 

QUADZILLA - sent you an email, you probably don't have it yet but I got your webshot instructions for the shimming of the fpr, great instructions. Don't have a pressure gauge and none of the so called auto stores in my area have one. You mention pencil type gauge and it connects to what looks like a normal shrader valve, is the pencil gauge just a normal tire pencil tire gauge???
Also is it measured running at idle or what?
Thanks in advance

 

Once you take off the engine cover, you'll see the fuel pressure regulator on the driver's side of the fuel filter housing. Near the front of the fpr is the shrader valve (valve stem) I mentioned. To check your fuel pressure, wrap a pressure gauge in a rag to avoid getting sprayed, and check the pressure while the truck is idling. A regular tire pressure gauge will work, but since there's some pulsations in pressure because of the operation of the pump, you won't be able to see the low/high readings, only the high ones. That's really the important one for this anyway. Ideally, you'd like to see a reading of 80-85psi. I'll bet you that you won't, though. You'll likely see something in the 45-55psi range instead.
To increase the pressure, turn off the engine, and remove the large brass nut located toward the rear of the truck from the shrader valve. Once you do that, you'll have some small parts that are inside that housing, that look like this.
The spring will have to be removed from the cup, but the cup doesn't have to come out of the housing. Also in the picture are the two most popular ways to "shim" the fpr, to increase tension on the spring, and increase fuel pressure. The first way is to put a BB inside the cup, and then reinstall the spring. Be careful in putting the large brass nut on, to be sure that the nipple on the inside of the nut is centered in the spring, or you can kink the spring. Once everything is tightened back up, check the fuel pressure again. If you're above 70psi, I'd call it good. But, if you're a tinkerer, or your pressure is below that level, you might need to do what I did, and use a #2 cap screw, like the one in the picture. The screw is inserted in the spring, and then inserted into the cup. Typically, to get the pressure up to the level you want, you'll need to add a washer. The ones that I used were nylon. If you're going to use nuts to increase the pressure on the spring, you'll need to file/grind off the corners of the nut, so it will fit inside the cup. The picture shows the finished product.
To get my pressure up to 85psi, I needed to use two nylon washers. One got me up to 76psi, which is really close enough, but I'm a tinkerer.
I hope this helps. If I left something out, let me know.

 

Thanks for your reply. You realy know what you are talking about and I shall try this .