I had a fuel plate and pyrometer installed on my 94 yesturday. Ran great, they had to turn it down a pinch. Today its not running as well. I called the shop he suggested it was because I started running my veggie oil agian today and probably have plungers sticking in the fuel pump from the veggie. Is that a possibilty? . For the last week or so I have run on reg diesel with amsoil cleaner and was running great especially after fuel plate. Today began running veg again. Today another difference is I was climbing hills with a trailer (8K). Should it matter? The thing acts like it will not rev up, then once I get it up to speed it takes off again. Sometime fuel plate sometime not - I really need consistancy. This is used for work. Is it the veggie or something else. Maybe just needs fine tuned? And if it is the plate how do I do it.

Sounds more like the fueling arm is hanging up then getting unhung, especially since it just started happening when they messed with it. I really doubt it's the veggie oil. As long as it's filtered good and the fuel filter isn't clogging up it will burn it fine. You would have to take the AFC housing off, push the fuel shutoff solenoid up then manually pull the throttle back and the fueling arm will come out and hit the plate, you need to make sure it is hitting it and riding up it smoothly. There is a way to adjust it.You might double check all your filters to make sure nothing is clogging.

ISX got it covered...

  ISX said:

Sounds more like the fueling arm is hanging up then getting unhung, especially since it just started happening when they messed with it. I really doubt it's the veggie oil. As long as it's filtered good and the fuel filter isn't clogging up it will burn it fine. You would have to take the AFC housing off, push the fuel shutoff solenoid up then manually pull the throttle back and the fueling arm will come out and hit the plate, you need to make sure it is hitting it and riding up it smoothly. There is a way to adjust it.

You might double check all your filters to make sure nothing is clogging.

I am interested in what you said about the fueling arm hanging up. I just posted the below paragraph on another forum but I thought it might help you see what is going on. Do you have pics or a diagram for the adjustment above you are suggesting that I do?

I noticed that the truck will sometimes wrap up to 2200 rpm and max out with a temp of about 600F and stay there. Other times it will take right off with no limit on the tac seemingly and the temp skyrockets. Is this how the truck should be running? Or am I missing something?

  busymountain said:

I am interested in what you said about the fueling arm hanging up. I just posted the below paragraph on another forum but I thought it might help you see what is going on. Do you have pics or a diagram for the adjustment above you are suggesting that I do?

I noticed that the truck will sometimes wrap up to 2200 rpm and max out with a temp of about 600F and stay there. Other times it will take right off with no limit on the tac seemingly and the temp skyrockets. Is this how the truck should be running? Or am I missing something?

I saw what you posted on the other forum and you were a little more detailed there. The info they are telling you over there is more spot on than what I said here because you made it sound a little different here. But yeah, probably AFC issue..

I am still having intermitent problems with the truck. I just posted the info below on another forum and thought you guys may be able to help. The more eyes the better.

I took my road trip pulling trailer today. Started off great good excelleration and power. Around the 40-60 mile range it started to poop out again. No power, pedal to the floor to get 65 out of it barley up to any heat on the exhaust. Later after it cooled down and began home still ran poorly. Then stopped for about 1/2 hour it took off like a truck. Ran great almost all the way home - on diesel only just to make sure. About 3 miles from home just after I got off the interstate it lost its power again. Cant really tell why.

I spoke with the shop who did the plate and he really likes the sticky plunger in the pump idea. Is there any merit to that one? Its pretty expensive. I asked him about possible problems with the AFC, he did not seem to think to likely. He suggested if we have problems after it heats up then starts to fail that may suggest a pump prob. (sticky plunger) Said he used to see alot of issues with that but that was years ago.

I have got an idea: The electric 3 way valves that control fuel type are set up for my truck - the "stock" version. Am I just demanding more fuel than those valves can produce. Sometimes maybe it just works because I have good pressure from the raptor we installed so it goes good for a while but then when it looses momentum it dies out? On the other hand it runs good up and down hills even when I let up on the excellerator to get off the temp for the exhaust.

Are those AFC units prone to problems? Intermitent?

--- Update to the previous post...

  ISX said:

Sounds more like the fueling arm is hanging up then getting unhung, especially since it just started happening when they messed with it. I really doubt it's the veggie oil. As long as it's filtered good and the fuel filter isn't clogging up it will burn it fine. You would have to take the AFC housing off, push the fuel shutoff solenoid up then manually pull the throttle back and the fueling arm will come out and hit the plate, you need to make sure it is hitting it and riding up it smoothly. There is a way to adjust it.

You might double check all your filters to make sure nothing is clogging.

I really like your thought about the fueling arm hanging up. I am not sure how to do it. Your directions are straight forward but my knowledge about the AFC is not there. If you still like this fix after the problems I have been showing let me know - I will tear into the AFC and get it figured out.

--- Update to the previous post...

I thought it might be my electric valves that switch my fuels. They have 1/8 opening as set up for stock truck. I ordered new valves with larger openings and by-passed my existing ones. I thought it might be getting restricted fuel - nope! Good fuel supply, good return. As the truck gets warmer it seems to loose more power.

We did install a raptor pump at the same time we had this plate put in. Has anyone seen them fail or give problems. It is acting like it is starving for fuel.

If you have got ideas for me I would like to hear them. Thanks

--- Update to the previous post...

This is what I have done to make this work.

[*]retightened with new hose clamps pressure hose from turbo to AFC

[*]confirmed its not a fuel problem - happens on diesel and veggie

[*]confirmed its not restricted by electric fuel valves - by-passed - same problem

[*]moved AFC housing and adjusted starwheel

This is how the truck is acting:

Runs great, obvious fuel plate addition. Truck warms up and then power slowly dies out of it. Sometimes the power comes back after it has been running weak. I wonder if there is a hairline crack somewhere that expands when it heats up and it looses boost.

When the truck loses power it raps out to around 2000rpm and it drops the heat on the exhaust. If I let it set for awhile and come back it runs great for awhile.

Suggestions from others - if you can rule out any of these ideas or add to them I'd apprecaite knowing about it.

[*]Local shop suggest it is a sticky plunger in the main fuel pump - rebuild fuel pump!

[*]Put on new AFC housing and see if it solves problem

[*]pressure test AFC housing

[*]check pressure from newly installed raptor - pump/plate installed same time just as problems started

[*]leave fuel cap off tank and see if it was getting a vaccum in tank

Really sounds like the foot on the governor arm is hanging on the bottom of the fuel plate once in a while.Run through that adjustment procedure first. If you're not comfortable doing so, slide the plate all the way back and the arm shouldn't be able to miss it unless it's WAY out of adjustment. Your truck will be a dog, but if that was the issue it'll be a consistent dog instead of intermittantly loosing fuel.Did you get a working fuel pressure gauge yet? I expect your pressures are good and it's just restricting fueling as opposed to starving for fuel.We are talking about a P7100 12v right?

  mr.mindless said:

Really sounds like the foot on the governor arm is hanging on the bottom of the fuel plate once in a while. Run through that adjustment procedure first. If you're not comfortable doing so, slide the plate all the way back and the arm shouldn't be able to miss it unless it's WAY out of adjustment. Your truck will be a dog, but if that was the issue it'll be a consistent dog instead of intermittantly loosing fuel. Did you get a working fuel pressure gauge yet? I expect your pressures are good and it's just restricting fueling as opposed to starving for fuel. We are talking about a P7100 12v right?

No I have not got a gage yet but it sounds like it may be the way to go especially when I pull a trailer. Yes we are talking about the big P7100 12 valve. The block and head are from a 93 but the rest is 94. You mentioned the adjustment procedure for adjusting so the foot on the governor arm will not hang up on the fuel plate. Do you have a direction for me on that? I will snoop around on the forum but if you have directions and maybe pics that would be great.

  busymountain said:

You mentioned the adjustment procedure for adjusting so the foot on the governor arm will not hang up on the fuel plate. Do you have a direction for me on that? I will snoop around on the forum but if you have directions and maybe pics that would be great.

I know I've read a good one as a part of an AFC tuning writeup, but Google isn't being kind to me on that. I didn't find any exceptional writeups on arm adjustment either. If your truck is a 5sp you could just pull the plate out too. There are urban legends that it can hurt the pump but experience of many says otherwise. I ran without a plate for a while. I wouldn't do it on an automatic or without boost and pryo gauges either. Your foot controls EGTs once you hit 20-25psi and the AFC is at full travel.

Today I was in the shop all day with the truck - first we tried the fuel plate foot which was actually too hi not to low. I am not sure why someone would adjust it that way. We adjusted it back down drove it, ran great then back to its old ways with low power. Then we tried a suggestion of tying up the arm on the fuel shut off. It did not seem to work either.

I even removed the K&N filter figuring maybe it was not enough air to make good burn. Not the case.

We also installed a boost gage today. Its is making only around 10psi when not running good and closer to 15-20 when the fuel plate decides to kick in. The truck runs well but its not wanting to rap out over about 2200rpm, low egts. Then it get a mind to open up and I have no limit on rpm and power, egts are up.

I am looking for an explaination of what the waste gate actuator on the turbo does and what are the symptom if not working properly? That was the next thing the shop wanted to check but we did not have time. The fuel injection shop that did the initial fuel plate install still likes the bad plunger in the pump idea.

  busymountain said:

Today I was in the shop all day with the truck - first we tried the fuel plate foot which was actually too hi not to low. I am not sure why someone would adjust it that way. We adjusted it back down drove it, ran great then back to its old ways with low power. Then we tried a suggestion of tying up the arm on the fuel shut off. It did not seem to work either.

I even removed the K&N filter figuring maybe it was not enough air to make good burn. Not the case.

We also installed a boost gage today. Its is making only around 10psi when not running good and closer to 15-20 when the fuel plate decides to kick in. The truck runs well but its not wanting to rap out over about 2200rpm, low egts. Then it get a mind to open up and I have no limit on rpm and power, egts are up.

I am looking for an explaination of what the waste gate actuator on the turbo does and what are the symptom if not working properly? That was the next thing the shop wanted to check but we did not have time. The fuel injection shop that did the initial fuel plate install still likes the bad plunger in the pump idea.

The wastegate is just a port that allows some of the exhaust gas to bypass the turbine so that the turbo does not overspool. If it doesn't work, the turbo will act fine but it will not be able to regulate boost so you might end up well above 20psi, sounds like you barely make it there. If it is stuck open however, the turbo will have trouble making boost. The actuator is just a diaphragm thing with a spring in it that is overcome at around 20psi, when that happens, it pushes the wastegate open.

http-~~-//www.youtube.com/watch?v=4JXCO49H0Vk

So if the wastegate is stuck open it will have trouble making boost. Does that mean the engine will have trouble burning fuel, not getting the egts hot? The truck acts like it has a low power problem could this be because the wastegate is open? Can the wastegate get stuck open intermitently?

We also installed a raptor pump at the time we first had problems with the new fuel plate. Do my symptoms coincide with low supply fuel? - I am wondering if the pump is working intermitently or if there is some debris in the inlet port screen.

  busymountain said:

So if the wastegate is stuck open it will have trouble making boost. Does that mean the engine will have trouble burning fuel, not getting the egts hot? The truck acts like it has a low power problem could this be because the wastegate is open? Can the wastegate get stuck open intermitently?

We also installed a raptor pump at the time we first had problems with the new fuel plate. Do my symptoms coincide with low supply fuel? - I am wondering if the pump is working intermitently or if there is some debris in the inlet port screen.

I would definitely attack that raptor! A fuel plate really doesn't have much that can go wrong and intermittent issues really shouldn't apply there, but something electrical like the raptor...that is a definite thing to check into. If anything, put a fuel pressure gauge on it and see if it drops. I take it you got rid of the stock lift pump? They won't work too good in series.

  ISX said:

I would definitely attack that raptor! A fuel plate really doesn't have much that can go wrong and intermittent issues really shouldn't apply there, but something electrical like the raptor...that is a definite thing to check into. If anything, put a fuel pressure gauge on it and see if it drops. I take it you got rid of the stock lift pump? They won't work too good in series.

Yes the stock pump is disconnected - have not taken it off until I get a plate to cover the hole. I will go into the raptor right away. It just seems like a good place to go since it seems like a low fuel issue that coincides with a pump installation. Thanks

I take it you dont like the turbo stuff as a problem?

If you want you can get an air hose and stick it in the rubber line that crosses over the engine (the 8" of it that are rubber anyways) and shoot at least 30psi into it and watch the actuator, it should extend when pressure is on it and retract when pressure is dropped under 20psi.