I'm having trouble with my 1990 F250 7.3 N/A 5 speed.

It started in February sometime if I remember correct. When I got into the neighbors yard, I let it idle for a couple min, then shut it down. It sounded like the engine just spun down and died when I turned the key off, cause the DMF usually clunks to a stop, and the engine usually shakes a bit and dies quickly; the DMF was almost silent. I thought it was odd, but whatever.

Driving home I took my foot off the throttle cause I was coming to the intersection where I turn and the truck didn't start to coast as it has always done before. It held its speed kind of, as I was in fourth at low rpms. I turn the radio down to hear that the engine is running very rough.

I clutch, and the engine revs up a bit (tach don't work), and is shaking quite violently when I came to a stop. I hurry home to the garage, pull in the yard, and it all goes away.

I'm sitting there playing with the throttle, and sure enough it starts this again. It revs up maybe 500 rpm? not sure, and sounds like it is missing very badly. The passenger seat is shaking quite hard. I revved it up, maybe half throttle, and it seems to be barely noticeable when holding the throttle there; quite smooth actually, like everything is normal. Take your foot off, and its the same surge and shaking/missing like it had before.

Nothing I do seems to make it better, but blipping/playing with the throttle seems to start it. It will come and go without me touching the throttle also.

Now, this is what I have done in the last ten thousand kilometres (I'm Canadian if ya don't know lol)

Reman IP from my local parts store (second one actually, as the first one had the timing advance coming on randomly and a base idle of about 900 rpm. Leaked too. Have had no trouble with this second IP until this issue)

NEW Stanadyne D code injectors

All fuel line olives

Caps and o-rings were done when injectors were replaced (had local shop do injectors, return lines, and IP)

When IPs were changed, the fuel filter was changed each time

Rubber hose between steel supply line and lift pump

New Motorcraft lift pump

All return line hoses

Fuel heater (upgraded to new fuel heater with one o-ring)

Checkvalve in fuel filter head that goes to number one injector

And today I just finished putting in a new front tank, new pollack fsv, and all new rubber fuel lines from pickup tubes to steel supply line.

I had at minimum a half a tank of fuel when the truck did this. I was running on the back tank in the winter when it did this, and I redid the front tank today due to air intrusion happening last summer. The shower head wasn't broken in the front tank, but I started it today and it did the same thing all over again. I haven't gotten to the rear tank yet; I also havn't started it since it did this in February.

I always take clean diesel from the farm tank (has filter), and drain my fuel filter every so often. I grabbed a half tank of winter diesel from the local service station, as I was in a pinch. I have seen other diesel pickups fuel up there, so I don't think its one of those service stations.

Every fill-up or second fill-up gets a sip of Howes lube conditioner.

I havn't had the time, parts, or weather to work on this truck until now (I'm working outside)

The idle sounds just the slightest bit rough, barely noticeable at all when it isn't surging/shaking/missing

My apologies for the story, but I want you guys to have as much info as possible. I'm really feeling defeated, and a bit flustered as I need this truck this week. Maybe its something little that I'm overlooking, I'm just not sure

There is no visible smoke of any color when it surges/shakes/misses, only a bit of black smoke when I rev it up

Any ideas/suggestions are welcomed and appreciated

Thank you

 

I had a similar thing happen when my Coolant Temperature switch failed. I just unplugged the connector from the switch and my surging stopped. It's the two-pronged probe that goes into your cylinder head at the front passenger side of the engine.

 

Thank you for the quick reply genscripter. I have had that unplugged since the first IP surged on me. I thought that was what was causing my issue, turned out the first IP was bad. Accompanying this surge is some violent shaking and missing, whereas the cold timing advance surge was smoother and gave more power and a different "clatter" to the engine. If that makes any sense; its been a long day

 

Somehow, you are getting air into it.
Get a jerry can and connect that(with a new piece of hose) to the inlet of the lift pump.
That should eliminate any air issues - everything past the lift pump is on the pressure side(so fuel will leak out, not air in)

 

Thank you for your reply Macrobb. I just came in from removing the skid plates on the rear tank so I can get it out and the plastic lines with it. Hopefully I'll get it out tomorrow and do what you said with the jerry can to the lift pump. I just want the rear tank out of the way for now, as I planned to clean it, paint it, and check the showerhead before all this happened.

Once out, I will do your test and go from there. It might not be every day, but I will update when I have results/info

Thank you

 

I agree with Macrobb, but one more thing, MAKE SURE that the fuel line to the IP is not leaking at the connection fitting on the back of the IP. The line that connects in the Center. I think that air could be pulled into the pump from there. It's difficult to see or detect a leak there because it would go straight down and you need a good bright light to see back there. I think I used a piece of a paper towel held under and against the fitting and it picked up some fuel so I knew it was leaking. Fuel on the valley pan(?) below too. I just needed to tighten it slightly to stop it. I didn't have any symptoms like you described, just typical symptoms of leaking return lines which were all redone.

The hose from the metal fuel line to the lift pump (which you replaced) is also suspect. There is supposed to be a loop in that piece of rubber fuel line, not to run straight from the line to the lift pump without the loop. I guess that loop is to accommodate vibrations and movement of the engine under torque. A fuel or air leak could develop there and be difficult to detect.

 

This is a very good suggestions. Those seals are notorious for leaking, and since they are hidden way in there, it can be hard to find. I upgraded to the R&D compression fitting, and I highly recommend you do that too. Link: DB2 injection pump inlet fittings

 

Thank you for the reply Fixnstuff, you reminded me that I had bought that o-ring for the IP inlet fitting from Ford when this problem started. The one off of the inlet fitting (original I'm assuming) was quite large. I figured it had stretched by now.

The one I got (E3TZ-9N693-B) was much smaller and refused to stretch; refused so much I broke the darn thing trying to get it on. I grabbed a similar size from my kit, rolled it on, put some light motor oil on it and installed it. I also re-lubed both olives on the steel line from filter to IP.

Started truck, and it did the same raise-rpm-up-shake-and-miss as before, then died. It took more cranking than I thought to get it to run. I let it idle for a few min then shut it down. Upon startup, it shook and missed like before for about 3 seconds then idled normally (still a slight bit rough, hard to tell).

I shut it off again, started it, and it revved up and shook and missed like before. After about 10 or 15 seconds, I shut it off cause I was getting a headache from shaking in the seat. I spun the fuel filter off after getting my ratchet and gloves (ratchet to find lefty-loosey and gloves because it was tight) to find that the filter was only about half-full of fuel. Is this normal?

 

Thank you for the link genscripter, I wasn't aware of such a thing. I will look into that and if I can get it shipped to Alberta for a reasonable price I will do so later on

 

I did some searching online, and this is my thinking:

1. half-full filter is not normal after shutdown

2. I have a drain-back issue from the lift pump forward, towards IP

3. Somewhere a large amount of air is able to get in, maybe constantly?

Am I somewhat on the right track?

I haven't hooked up a jerry can to the lift pump yet, but today I did get my rear tank out so I can focus fully on testing now

 

Thanks for that! What's the nicest fuel line you can put on there? It think IDIoit mentioned using a stainless braided hose. Not sure what to do at the other end (see comment below photo)

I've seen this "replace the steel line with a flexible one" many times and I've been very reluctant to accept that and wanted to keep the rigid steel line- since when everything is hooked up it won't move and also because my line from the lift pump to the filter is a solid steel line WITH a fuel heater on it, (1987 and back I think).
I am never going to cut that that very nice line to splice rubber into it.

I've changed my thinking on replacing the first line, (as you suggest) with a flexible line and I'll show you why:

When/if you change the thermostat, there is going to be stress placed on that rigid line that could (probably will) move it enough at the IP connection to possibly cause a leak, especially with an old 'olive seal'. Possibly even bend or crack the line if the lift pump to filter hose is rubber or if not careful. I used a 2x4 wood block under the fuel filter to prevent it from pulling down on that line, as shown in this photo. The 2x4 was a little bit too thick (at 1-5/8 in.) slightly less would be better (anything to hold it in place) while changing the thermostat.

I'd still have to block it anyway due to the steel line to the lift pump. Notice the clamp on the mounting bracket (acting like a hinge) where the bracket has been moved to the left like an opening door. It's clamped to the in-line fuel heater.
See my comment below the photo:

.


Notice the brass compression fitting on the steel line that goes to the IP, at the back end of the first bolt. I over- tightened that fitting after replacing the 'olive seal' - it had been leaking before and I wasn't thinking right when I over-tightened it. I heard a "crack" sound so I'm quite sure it cracked.
These fittings don't take much tightening at all. BE CAREFUL NOT TO OVER-TIGHTEN

So, the only practical way to replace it is to cut the fuel line to put another one on and splice the line with a rubber hose piece (which would be UGLY) unless I carefully set it up in a jig and welded it.

It has not leaked and it probably won't but I want to replace it anyway and I will when the opportunity arises. I just have to find a correct fitting to go into the filter header because that is not a barbed fitting for flexible hose. Probably at a hardware chain store??

 

That seal is thick and the cross section is not round like an O-ring. it's square, flat on the top, bottom and each side. Someone posted in the 'water-methanol injection' topic (which I have to get back to in another hour or two) that you can get these with an injection pump installation kit for about $7.00 at Rock Auto Parts. (you'll have a couple of extra aircraft bolts to use for something).
The larger of the 3 olive seals would probably go at the return line fitting on top-front of the injection pump because that steel line is larger than the steel fuel lines.

The other olive on the other end (filter end) of the steel line to the pump is the same as the olive seals that come with good fuel return line kits. THEREFORE, assuming that the pump fitting uses the same seal, that's another source for those olives and if I'm not mistaken someone posted a source maybe a couple of years ago or longer where we can buy those olives of the right size.

 

1 kit from rock auto will do the two on the filter to ip line and the one big one for the ip return, if you need to change the one on the fuel filter inlet line coming from the fuel pump I just buy another kit and use the larger return one over there.

You can order fuel line olives on eBay in a various size kit which will have all you need, a lot of older tractors used these things but it's the same price just about and your taking a chance you might have to trim to fit ect http://www.ebay.com/itm/191600799281

It would be nice if we could find these things in bulk that are the perfect size!

Fun fact, the injection pump mounting bolts that come in the kit from rockauto fit the crankshaft on those Honda gx160 air compressors that everyone uses. A buddy of mines had the bolt back off and snap, we replaced it with one of my spare grade 12 bolts and it fit perfectly!

 

I've got rubber hoses on both sides of my filters in all my trucks.
The great thing is that I can just loosen the filter head assembly and move it out of the way, for valve cover clearance or thermostat, or injectors... all without losing any prime.

 

These fuel line 'olive' seals are called
Compression Tube Sleeves.

At the following url you can see a Viton rubber compression tube sleeve for a 5/16 in. OD line.
$1.66 for one or $10.40 for a pack of ten. (plus shipping etc) The Red tint in the image is actually the Red Stripe which apparently indicates the temperature service range (shown in the information below the image) = -15*F. to +450*F.

We might want a different colored stripe. Read all of this post before ordering any.

https://www.freshwatersystems.com/p-...od-tubing.aspx

Here is the url for their specifications page. Upper left box and the one below it (apparently a different formulation of Viton) both boxes showing exact dimensions of the sleeves. The Right hand column shows fittings and respective drawings = the black area is the sleeve and where it is fit onto the line- the first few drawings showing exactly what our fuel lines look like with the sleeve on them. I didn't bother to look at the rest:

https://www.freshwatersystems.com/sp...og-60VLV-4.pdf

We need to know what the exact dimensions are for the seals we've been using, if anyone wants to check or confirm that but I think they should be the same since these sorts of fittings are standard as far as I know.

These are available from other places, by other manufacturers. Suppliers of return line kits and the pump mounting kit mentioned earlier, surely buy these in bulk OR they can buy a roll and cut them off of the roll themselves.

Now to add some confusion: (NO CONFUSION see bold type below) I think it may have been the Parker Website (the actual manufacturer of these sleeves) I opened a PDF on rubber specifications, I think it was 128 pages, I don't remember, but it was more than I ever want to know about rubber formulations at this stage in my life. I noticed a number of different Viton formulations for special chemical or environmental resistance applications but I didn't read those I only looked at the first few pages, maybe there are not many differences. I have been under the impression that Viton is fuel and oil resistant regardless of which formulation. ---->CONFIRMED! Verified at two different websites, one being an extension of DuPont... who created and patented Viton. See NEXT post for data.

The seals above are good for dynamic service (moving vehicles, machinery,vibrations etc) down to -15*F. up to +450*F. (Red Stripe) The standard formulations go down to -25*F. to +400*F. (would be a different colored stripe) Special formulations go down to -40*F (-40*C) which would have again a different colored stripe. I'll look for the new one I have and confirm the color of the stripe. I think it is white and I don't know if that is -25*F or -40*F. for low end of the temperature service range.

>Paragraph deleted<

As I recall, the seals that I got in my return fuel line kit had a double WHITE stripe- ( apparently indicating service temperate range- possibly something else like the formulation- which might be close to the same thing.

>Paragraph Deleted<

I didn't notice the color of stripes at several ebay listings.

At least, knowing now what they are called, it will be easier to find sources for them.