Engine/Transmission (1994 - 1998) P7100 & ULS fuel

[mechanic]

I would be interested to know if any one has had a 7100 pump fail because of the new ULS diesel. I have a customer who owns a 94 2500 auto with 177,000 miles which had a sudden shutdown, followed be a restart then repeated die and start. (I owned this truck until 156,000 and had no problems. ) The fuel shutdown solenoid is ok, transfer pump pressure was 3# to 30# on a come and go basis. So I replaced the transfer pump & filter (Fleet Guard), cleaned the heater screens, which were almost perfectly clean. And we now have 23# at idle up to 41# at higher RPM and it is stable. It started and ran fine until fully warmed up then the same problem returned. #3 cylinder starts missing and the corresponding pump cylinder starts to tick or tap, sounding much like a loose tappet on an old 235/6cyl chevy engine. Also the throttle will stick, not the linkage but the RPM will be very unstable and high idle then low idle then die, ect. If you are driving it will loose power, then it dies. After restart it will try to run then do the same sequence again. Let is cool off and it runs fine until warmed up again, but it will set and idle all day with no problem if you don't put a load on it. It has had power service lubrication additive in the fuel, but only on an every so often basis. At this time it has a heavy shot of "Howell's Lubricator" in the fuel, but no change.



My concern is that the ULS fuel combined with the "no-to-low" fuel pressure caused by the tired transfer pump has caused a problem with the upper end of the injector pump. I thought (hope) some of you pump guys may have seen this if it is a problem.

We do have a fuel sample on the way to the lab because of the possibility of vandalism where he works.



Also, we are looking at replacing the '94 pump with one from a '97 5 spd. Does anyone know if the '97 215 pump will work with the '94 160 injectors?



If you have seen this done I would like to hear from you, or if you have seen a problem like I described above.

 

[Extreme1]

It could be a bad pump plunger & barrel due to mileage, ULSD or vandalism. A 215 pump will work with the 160 injectors but a set of 215 injectors would really wake it up. The repair bill for replacing a plunger & barrel in a 180 pump I had turned up was ~$200, cheaper than a good used pump.



I was talking to the Bosch Rep at Sheid's show the last couple of years. In 2005 I asked if we should start using a fuel additive when the ULSD comes out, he said I should already be using one to lube the pump. Last summer I asked what additive works best, he said it really doesn't matter as long as it says something like "Formulated for use with ULSD".

 

[Timebomb]

I was talking to the Bosch Rep at Sheid's show the last couple of years. In 2005 I asked if we should start using a fuel additive when the ULSD comes out, he said I should already be using one to lube the pump. Last summer I asked what additive works best, he said it really doesn't matter as long as it says something like "Formulated for use with ULSD".

My pump guy said the same thing, But pointed out Standyne as an addative,he said it was the only addative Bosch will waranty.

 

[mechanic]

Thanks to EXTREME 1 & TIMEBOMB for the good information. I will post the results of the fuel analysis and what the final outcome is.

Extreme 1, you might check with the SHADY NOOK AUTO SALVAGE in the Oklahoma City area. Their phone is 405-769-3377. Tell them that Dave from Wooded Acres Auto Service referred you to them. Another place is JAY'S PICKUP & VAN SALVAGE, 405-424-6104. A couple of other good places here are RUPPERT'S truck salvage (Phone # I don't have here now), and B&B SALVAGE, 405-769-3341. If those don't pan out there are a couple of other ones I can check with if you contact me.

 

[ccsial]

Does anyone know if a P7100 is rebuilt are there new seals compatible with ULSD?

 

[mechanic]

Does anyone know if a P7100 is rebuilt are there new seals compatible with ULSD?

At this time the Bosch re-builders in the Oklahoma City area are telling me that the P7100 has not been a problem in the leaks area, but the VE pumps are leaking like a stuck pig, and no one knows if the new seals will hold or not, because they don't know if the leaking is because of an incompatibility with the new fuel or a chemical reaction between the new and old fuel and the seals. Which ever is the case, they have been hammered with VE leaks since the new ULS fuel has been imposed on us. If some one has later information let us know.

Our fuel sample got mishandled and the price quadrupled so my customer opted out of the test. Since I am scheduled to have another rotator cuff surgery in a few days, we sent the truck to a pump shop for the repair. I will try to find out what they find and let you all know.

 

[Joe G.]

We have been running ULSD in CA for quite some time. I have noticed no affects from it. Mileage is about the same. No fuel leaks. Performance is about the same. I don't use any additives. My P7100 has 244K miles on it. The switch from the old high sulpher fuel to LSD caused me to loose about 2 MPG. The switch from LSD to ULSD has had no affects as far as I can tell. Maybe a little less smoke.

 

[CBeeman]

we had a 95 do almost the exact same thing except it was cyl's 3 and 5 the place where we send our pumps said it is actually common those pumps. This is the explaination I got from our pump shop. It is not fuel related. When the oil goes into the pump it hits the plungers on 3 and 5 before any other and if any debris is in the oil it can eventually score the plunger or barrel and would cause them to stick at times.

The one we had would miss at 1100-1300rpm and would almost clear up above or below that. And this truck only ever off road fuel in it.

I have been running ULSD for about 10,000 miles and have had no problems.

Hope this helps

 

[CEdwards]

mechanic, if you figure out the problem I would like to know what it is. My '94 did the exact same thing you're describing, I did everything I could come up with from this site and never did get it to run right. I finally gave up after a year and a half and sold it and bought another '94. It usually always happens after truck is warm and running a while especially if under load. It willstart making that tapping sound and act like it's running out of fuel even though it isn't.

 

[R.ebel]

A buddy of mine lost the #5 barrel, no output. Mileage 225,000. According to him PDR is saying they are see more failures on higher mileage pumps.

 

[mechanic]

mechanic, if you figure out the problem I would like to know what it is. My '94 did the exact same thing you're describing, I did everything I could come up with from this site and never did get it to run right. I finally gave up after a year and a half and sold it and bought another '94. It usually always happens after truck is warm and running a while especially if under load. It willstart making that tapping sound and act like it's running out of fuel even though it isn't.

I talked to the man at the pump shop today about the truck. (We sent the truck to them so they could see what is is doing) He told me that the ULS fuel hit the market here in Oct. 06, and that the first thing that they saw was the VE pumps started to leak, and that the o-rings were hard when they tore them down. He said now however that they are seeing several P7100 and other in-line Bosch pumps doing what ours is doing. They are finding the plungers and barrels damaged, and that in turn causes the rack to stick and loss of governor control. They say to run additive to prevent this problem. I tend to think that it is a combination of problems causing these failures. I suspect the the ULS fuel combined with production tolerances in the pumps along with some kind of damage from fuel or oil contamination is the combined cause. If the fuel were not involved, we would have seen the same number of problems all along, but with the introduction of the ULS, the problems are increasing. So it makes sense that the fuel is contributing to the failures. But not all pumps are failing so there would have to be other contributors.

I will keep you posted on the results of the tare down. It will be several days yet as they are long on pump problems and 2 men short on labor.

 

[Skydiver]

Please keep us posted Mechanic.

The only thing I am noticing different.

While on my trip to work 29 miles at 65 mph the truck has much less smoke when I do have to floor it. Normally I drive 65 mph on the interstate and when I have to floor it smoked real bad. I don't mind it not smoking but I want to know why it no longer smokes. Kitty also ran off 8 years ago.
From what I read MMO is the best lube for the pump ??? I do add power/service when the temps drop below freezing.

Thanks for any advice.

 

[Forrest Nearing]

My pump guy said the same thing, But pointed out Standyne as an addative,he said it was the only addative Bosch will waranty.

I'm gonna go out on a limb and call buffalo chips... how can they tell?



I think the fuel we get down here (Alvin, TX) has got to have something added to it because even the ULSD stuff smells like Power Service... I realize that lubricity is important, and I run PS Cetane boost whenever I'm out of town, and I use ashless 2stroke oil at every fill up, but I don't use a lot of either.

 

[mechanic]

For all the who replied, and like me were wondering what is going on, here is the sad end of the saga.
I talked to the pump shop (Thompson Diesel, in Oklahoma City) and the man there told me that the problem was that a plunger and it's barrel were damaged, and that the only plausible explanation is the ULS fuel. He also said that it is getting more common now, to see the 7100 and other in-line pumps with plunger and barrel damage.
It almost seems that these environmentalist wackos are trying to kill any vehicle that they don't like or can't afford. They have fought SUVs tooth claw and toenail and now they are after our diesel trucks. If they can't get us to stop driving them with pseudo-science, they will try it by making the fuel so sorry and expensive that it slows sales of diesel trucks. They will not succeed but they have cost several sales of diesel units. That little educational venture cost my customer around $2200. 00 by the time he got it all said and done. A lot of money!! Thanks for all the input, that is what makes a forum work, a little here and a little there and you get the information you need to plot a strategy.

 

[w-cummins]

_IF_ it was the fuel that caused the problems why did it only effect one plunger and barrel?? I would expect to see all 6 messed up not just ONE if the fuel was the cause.....

William.....

 

[NHays]

I have to chime in here. I have not done a viscosity test but I have heard and felt that the new fuel seems more slick to me. It might be our fuel here in OKLAHOMA, but thats just what my thoughts are. I am going to get some old fuel and new fuel tested in my lab at OSU (Oklahoma state university) and see what happens.

 

[mechanic]

_IF_ it was the fuel that caused the problems why did it only effect one plunger and barrel?? I would expect to see all 6 messed up not just ONE if the fuel was the cause.....

William.....

I don't have a proven answer for that question, but there and production tolerance variations that could account for it, ie, one plunger tighter then the others by a few hundred thousandths of an inch, with the ULS fuel, it is enough to cause a metal to metal contact and then Gaul the surface and stick the plunger. Also, there could be other temperature and /or lubrication issues as some pointed out.
I have been a professional mechanic for 35 years and a mechanic for 54 years total. I have seen many engines that have been run out of oil or water or both, and only damage some of the bearings or pistons, or crack only one head, or spin only one or two rod bearings. In these cases we do not say that because it did not destroy all the parts possible that it was something beside the fact that it was out of oil or water caused the problem. When any assembly runs low on lubrication whether from poor quality lubricant or not enough volume of lubricant, it always has some components destroyed and some that are repairable, but some that are not damaged at all.
A better way to look at it is, "if the ULS fuel is not the catalyst that is causing these problems, why did they not show up before?" The pump shops and the folks that have owned and or operated these type pumps for years have not seen any significant problems with these pumps until extremely high mileage, until the introduction of the ULS fuel. So to my pump shops (two of them) until a different cause is found the culprit is the the ULS fuel.
Of course not all pumps are going to fail even without additive, but I will not take that chance. I have seen several folks that had very good service out of a Chevrolet Vega aluminum engine, both before and after the introduction of the sleeved blocks in the production of these engines, but I saw a lot more that did not do well, I did not have to buy one to convince me that they were not up to the same standard as the other engines at that time.
I have even seen a very few folks that had good service from a Ugo. Everyone can do as they see fit for their own vehicles, I am only taking time to post this to return the courtesy of all those who responded with their experience and knowledge, and hopefully to add mine to theirs and by so doing, to increase the knowledge base of the TDR. And if after a period of time we learn that this was a false alarm, we can stop using the additive with no bad effects except for the cost of the stuff. But if it is a valid alarm, those who started and continued to use the additive will several hundred dollars ahead.
Hope I don't sound condescending in this post, that is certainly not my intent, I just wanted to encourage others to apply this logic and possibly avoid a problem.

 

[george]

I wonder if running B-20 would help

 

[mechanic]

I wonder if running B-20 would help

Sorry, but I am not familiar with B-20. I am going to start using Stanadyne Performance additive. (After I use all of the Howell's that I have now. ) It is the one I have used in the past. When the first LS fuel came out several years ago, I was driving a VW Jetta diesel which used the VE type pump. Having had several of them apart I was concerned about the lower lubricity of the first LS fuel so I ran the Stanadyne additive and it was rather remarkable how much better and quieter they (the VW) ran with that additive in the fuel. So based on my own and others experience, I will start using it again. Bio-diesel also seems to be a good alternative when it is truly diesel and not just vege oil that is filtered and heated or mixed with diesel. But I am not sure about the compatibility issues with the different fuel systems either.

 

[mechanic]

I have to chime in here. I have not done a viscosity test but I have heard and felt that the new fuel seems more slick to me. It might be our fuel here in OKLAHOMA, but thats just what my thoughts are. I am going to get some old fuel and new fuel tested in my lab at OSU (Oklahoma state university) and see what happens.

I would be interested in the results of your test. Are you sure that the fuel you said feels more slick is the ULS fuel? We still have some of the old fuel being sold in some places, at least they still have the warning label on some of the pumps. I ask because I find the new fuel to be a lot drier then the one it replaces. It evaporates much faster then the old fuel did. Other mechanics have voiced the same idea. Also could your supplier be adding a lubrication additive as a courtesy?
At any rate, please keep us posted on the results of your test. I would like to see the test on fuels from more then one supplier in different locations. (I am not too far away from you, as I am in the Harrah, Ok area.

I surely do not intend to promote the use of additives if not needed. I am rather opposed to the use of additives in any system of an automobile or truck in general, all be it with several notable exceptions where a given additive has shown to be of significant benefit, or a system has shown a need for some sort of additional benefit that an additive can provide.