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Discussion Starter · #1 ·
(1) one-owner early 1994 powerstroke, 5-speed manual, 170,000 miles in light personal service (no hauling), smooth-running, 22 mpg from 1994 until today, use only Texaco, Exxon, Shell, or Chevron fuel, have not kept fuel receipts

(2) two or three months ago, engine started becoming a little rough at idle, with smell of Diesel oil under the hood

(3) a few days ago I added 10 gallons fuel and pint can of two-cycle oil

(4) 3 or 4 hours of driving later, engine suddenly (within 15 minutes) began running extremely rough with missing and loss of power

(5) mechanic found low fuel pressure and replaced fuel pump

(6) engine now runs a little better, but not much; still very rough, severe missing, and little power

(7) mechanic says first-generation computer makes diagnosis difficult, and that too much labour is required to replace injectors one by one; so he recommends that I replace all injectors at once, or else sell truck

(8) I am poor as a church mouse; what should I do?
 

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wow my stepdad is going threw the same thing right now. were gonna rebuild the injectors ith a diy kit. you might want to look into that witch is about 300 to 400 bucks after you get the pistons machined. its alot cheaper than buying new ones.
 

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Discussion Starter · #3 ·
what would cause damage the injectors?

My question is,what could have damaged the injectors so rapidly? Within the space of less than two or three hours of operation, the engine went from very smooth running with plenty of power to being almost unserviceable.

If the injectors indeed have been damaged, I am unwilling to install new injectors until I understand what damaged the existing injectors.
 

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how long have you drivin it after the mechanic replaced the pump? air can mess up injectors quickly, maybe you still have a little air in the heads. the injector system is a dead head system, meaning once air passes the fuel filter it goes into the head galleries, and it has no where to go but out the injector. you might have to drive it some more, but then again after the pump was replaced the pump is sucking in air. the fuel fittings to the pump are a bad design and are known to suck air.
 

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Discussion Starter · #5 ·
should I drop and drain the tanks?

I drove it about a hundred miles after the pump was replaced. I did not perceive a change in performance during that time.

Immediately after I picked up the truck, I drove about five miles to the Texaco station and put five or ten gallons of fuel in the front tank, and have been driving on that.

Neither I nor the mechanic drained the tanks. But the mechanic did replace the fuel/water separator (filter) with a Wix filter. Should I have purchased a genuine Ford Motorcraft filter?
 

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Discussion Starter · #6 ·
How does low fuel pressure damage injectors? Do I have a "steel" tank?

I spent the past couple of hours going through the "911" posts; I should have started this thread there, because I'm having to borrow a car while my truck is out of service.

Anyway, from the "911" posts, it appears that low fuel pressure (from a failing fuel pump) can damage injectors. Can someone here please tell me how the damage takes place, and how quickly the damage occurs?

Also, I presumed that my fuel tanks (1994) are galvanized steel. Is this the sort of "steel" tank which the postings claim that "biodiesel" (diesel plus alcohol) damages? Do I need to drop and clean out my tanks?

Finally, can the 14-year-old computer possibly be at fault?
 

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i have been having this kind of problem myself after alot of sensor testing and replacing everything seems to point to the pressure regulator on side of cup on my 1996 powerstroke direct injection turbo deisel
 

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some friends suggested that i replace the filter with motorcraft because it does make a difference i had trouble with my aftermarket one fuel filter light would come on under load and stop pumping fuel
 

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Discussion Starter · #9 ·
does the 1994 powerstroke have a fuel pressure sensor?

Does the 1994 powerstroke have a fuel pressure sensor? If so, where is it located? What does it look like?

This engine was the first generation of the powerstroke.

My mechanic replaced the fuel pump, which sits in the vee, underneath the fuel/water separator. The pump was leaking and was not providing but about ten pounds of pressure. But it is a conventional diaphragm-type pump, which is operated by the camshaft. It is not a high-pressure pump.
 

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the reason the lift pump can take out injectors is that the piston that creates the fuel pressure for atomization is lubricated by the fuel it is a class fit part. running it with low fuel pressure or an air bubble is the same as running an engine with low oil pressure.
 

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Discussion Starter · #11 ·
Thanks, dieselman.

I went back to my mechanic, and he told me that it is common practice to replace the fuel pump about every 100,000 miles.

I found a web site (PureFlow Technologies) advertising a fuel de-aerator for diesel pickups, which removes entrained air and thus eliminates the possibility of cavitation. If I were purchasing a new diesel truck, I think I would install a de-aerator right away.

The engine now runs rough, and there is significant power loss -- I am driving about one gear lower, and I am able to use 5th only on the highway without acceleration. But the mechanic drove it again and says that all cylinders are firing.

Within the past year I have replaced the brake calipers and rear cylinders, the water pump, the starter, the batteries, and the air-conditioning evaporator. The truck has many miles left, having been in light passenger service only (no hauling, no trailering). The only major component over which I have any concern is the clutch. But I cannot afford new injectors in the near future.

At this point, I plan to sell the truck -- hopefully getting enough to purchase a Honda Civic or a Toyota Corolla. But I shall miss the Diesel.

Twenty years ago a friend gave me an old 4-cylinder Peugeot 504 Diesel, which I enjoyed and drove until I no longer could find parts to keep it running. Four cylinders are plenty for my needs.
 

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Discussion Starter · #12 ·
I need an engine computer - where can I find a used one?

After driving the truck daily for the past month and thinking over the matter, I think I understand the sequence of events.

(1) The fuel pump diaphragm began leaking, and the engine began running rough occasionally because at times it was starving for fuel.

(2) The fuel pump finally failed, so that the engine would hardly run.

(3) The first mechanic was a clown who did not discover the fuel pump failure -- he failed even to smell the leaking fuel and to see the leaking fuel in the vee of the block. But he plugged his tester into the factory port of the computer, rather than into the diagnostic port, and in doing so he damaged the computer.

(4) The second mechanic immediately discovered and replaced the failed fuel pump. But he did not know whether the rough running was due to damaged injectors or to the computer, and he did not have a spare computer on hand to swap and test.

Now, if the engine is cool and I drive late at night and the air is cool, the engine runs fairly smoothly and is able to accelerate, even in fifth gear. There is some power loss, but I can live with it.

But if the engine is hot and I drive in the heat of the day, the engine runs very roughly and has very little power, and the situation is intolerable.

So it appears to me that I need to replace the computer. But the dealer has a $300 price tag on a new computer. Are there any working computers in the wrecking yards?
 

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Try car-parts.com for the junkyards - I picked one up a lot cheaper than that. At least you'll know what to bring your local yard down to. Tough call on whether they all work or not.

Ben
 

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fix obs

well i dont think its the pcm.why,well if your pcm was bad your truck would not start at all.
I think it would be your fuel lines is clogged.pick up tube in tank or tank switch,the one under the truck in frame by front tank,
it could be your injectors.is there smoke?if you had bad Ps & Bs in your injectors you would know it.alot of white smoke.the old AA code injectors can go along long way.300 miles or more,if you take care of them,change oil every 3000 or 4000miles.if your hpop is full,i would say fuel.if its low,i would say bad O-rings.and they dont cost to much.to get air out of lines.on the right side of fuel bowl,there is a valve stem.just like on a tire,start truck and press it :watch your eyes:and fuel will spray out and you will see air come out too.and you will also find out if you got good fuel pressure too.
I hope you get that old work truck running good.
 

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Discussion Starter · #15 ·
problem solved by a good mechanic

After the fuel pump was replaced, the engine would run in one of three states: (1) smooth, but with some power loss, (2) rough, with significant power loss, (3) extremely rough, with much power loss. The engine would change state unpredictably while driving, both on the freeway at 50 to 60 mph and in stop-and-go city traffic.

My mechanic was convinced that only one injector was at fault, but the 1994 Powerstroke computer does not provide detailed diagnostics as do the later engine control computers. And about the time the mechanic had his test rig in place, the engine would start running smoothly again.

My mechanic finally isolated problem to the number five injector. It turns out that the tiny machine screw holding the injector electro-magnet C-core to the top of the injector plunger had come loose, so that the core did not pull the injector plunger as far out as it needs to be pulled. The mechanic has had success with reinstalling the screw with thread locking compound -- so he did that for me, to save me the cost of a new injector. He has had very poor success with rebuilt injectors, so he says that if the screw comes loose again, the only good solution is to install a new injector.

The mechanic has been unable to find a supplier for the special wrench needed to torque the machine screw. So he used a hammer and a punch to tighten the screw. After looking at the head of the tiny screw, I think that a precision machine shop could make a suitable wrench by drilling six holes in a small circular pattern, and then driving hardened steel pins into the holes. But Navistar should have used two or three screws instead of just one.

Now the engine again runs smoothly and has the power it had before the fuel pump failure, so there appears to have been no injector damage due to cavitation.
 

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A DIY injector rebuild kit is only about $250 and comes with new o-rings, new spring, and new armiture screw (what you described). There is a specific torque value for that screw. You will get much more life out of those injectors and better performance if you rebuild them.

If you can turn a wrench and follow directions, you should be able to do it yourself.
 

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Discussion Starter · #17 ·
Three questions, please:

(1) Does the kit provide the wrench (or socket) needed to remove the original screw?

(2) Is the replacement screw identical to the original screw, or does it have another type of head (torx, socket-head, philips, slotted, etc.)?

(3) Is there a supplier from whom I may purchase a wrench (or socket) which fits the original screw?

Thanks for the information.

RLH
 

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1) Yes, a bit is provided to remove the armiture screw. I attached mine to a socket and used a ratchet to loosen the screw until I could turn it by finger

2) I believe the replacement screw is different, but I can't remember for sure. It is an Alliant Power part though. You'll need to contact Jim at DIYInjectors.com to find out for sure.

3) Alliant Power (Alliance Power?) makes tools and parts for reconditioning injectors and other ford parts.

Additionally, there is a specific clearance that needs to be checked using a feeler gauge to ensure that the poppet is working correctly. If it is out of spec, the DIY kit comes with instructions for fixing it.

I have no affilliation with DIYInjectors.com, I simply have used their product with great success and wonderful support.
 

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Discussion Starter · #19 ·
Many thanks, cfunderb. That's what I needed to know.

I'll pass this information on to my mechanic, and file a copy for my own reference.

The engine is running so smoothly now that I see no need to go back and check the poppet clearance at this time. I'll know that all is well if I'm still getting 22 miles per gallon. I topped off the tanks yesterday, and it's going to be two or three weeks until I fill up again.

Regards.
 

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im also having no power on my 1994 powerstroke every time my truck is under load it has feels like it has a miss fire just replaced the pump and it got worse also idles extreamly rough only happend when the engine is warm.
 
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