6.9 Injection Fuel Pump Intermittent Problems

[mariner45]

Hi guys,

I am experiencing intermittent problems with the injection pump on my truck engine. It will cut out - governor I think, without warning and when this happens I get the loss of engine power - clouds of grey/blue smoke billowing out of the exhaust. Then the governor resets, the smoke clears up and I have power again.

It most often happens when climbing steep hills and the engine is working hard. I don't have a tach, so I don't know exactly why it does it. I suspect that going up a steep hill, I will move the throttle a little and this causes a momentary change in the engine load and allows the engine to tend to overspeed and trip the the governor.

But, I don't think the engine is overspeeding, but rather the governor is toooo sensitive to load changes. Maybe a worn spring or even the wrong spring was installed when the fuel pump was rebuilt about ten years ago. The pump did not trip when it was first installed and now that it does, it seems to be more frequent than before.

The engine runs great with no smoke at all when under steady load. Smokes a little at start up when cold. No blowby from oil filling neck on engine front.
Other than the intermittent cut outs and 50 - 55 mph maybe, the engine responds readily to the throttle.

I am 99% sure that it is not a transmission problem - slipping etc. My own suspicion is that the wrong governor spring was installed or the spring is tired and behaves erratically.

I do have a spare UHaul pump to put on, but I would like to know what is going on with the fuel pump on the engine.

Any help you guys could send this way would be greatly appreciated. Mel - are you around ?????

Thanks in advance

mariner.

 

[mariner45]

Ooops - I forgot to mention that I have the fuel pump adjusted so that I can't go above 12 psi boost on the turbocharger i.e. the engine won't put out any more power than that needed to give 12 psi boost.

Thanks

mariner

 

[Hyde]

No knocking or anything when this happens?

 

[mariner45]

No knocking or anything when this happens?

Absolutely nothing - just obvious loss of power and billowing smokey exhaust. Obviously when the fuel pump resets, there is a surge if you like, in the engine sound. But as far as knocking or any other noises, nothing at all.

Thx

mariner

 

['94IDITurbo7.3]

You said ten years since pump install.

How many miles on the pump?

Could be the pump is just plain tired and is dying

 

[mariner45]

You said ten years since pump install.

How many miles on the pump?

Could be the pump is just plain tired and is dying

About 60,000 miles (100,000 kms) since being fitted. This truck only gets driven through the winter and these days I probably only put about 140 miles (say 230 kms) a week on it - I have been retired for over six years, so it only gets used to go into town once a week for groceries etc.

In all other respects the pump works just fine. Gives good response to throttle and clear exhaust. The injectors are obviously in fair condition as well otherwise exhaust would be dark/blackish.

It is as if the governor is working either on or off after a certain speed and 55 - 60 mph isn't what I call fast. So something is changing with time. I am at a loss to know what is happening just now. I guess I will be better informed once the spare pump is on and the truck running with it in service. Hopefully, the sudden shut down of fuel will be a thing of the past.

There are other signs and symptoms that would indicate a failing pump - none of which I seem to have.

Thanks

mariner

 

[RLDSL]

When was the last time you changed the filter on that thing, and if it sits that much, to you keep a fuel biocide in it all the time?

 

[mariner45]

When was the last time you changed the filter on that thing, and if it sits that much, to you keep a fuel biocide in it all the time?

I have just done a service on the truck - lube oil and filter, fuel filter (Ford and additional Racor), air filter. Greased front end and driveline. Checked both diff. oil levels and the transfer case ATF. I also use fuel additive on a regular basis - both Power Service and KleenFlo. Racor fuel filter bowl was clean and no signs of water or sludge - 12,000km since last time changed.

Actually the fuel pump cut out on me while I went for local drive today - which prompted me to do the post. I might get lucky and find that someone will know the cause of the problem and a fix for same. The problem is intermittent which is why it is hard to pinpoint. I am sure the governor is working to give fuel as needed for the most part - it is the sudden shut downs and resetting of the pump,that stump me. No noises (knocks, bangs, shudders) or warnings of any sort. It might be several weeks or months before it goes again or it might happen tomorrow !!! Nothing regular about it - hence the concern. It is getting a little more frequent.

Thanks

mariner

 

[RLDSL]

I have just done a service on the truck - lube oil and filter, fuel filter (Ford and additional Racor), air filter. Greased front end and driveline. Checked both diff. oil levels and the transfer case ATF. I also use fuel additive on a regular basis - both Power Service and KleenFlo. Racor fuel filter bowl was clean and no signs of water or sludge - 12,000km since last time changed.

Actually the fuel pump cut out on me while I went for local drive today - which prompted me to do the post. I might get lucky and find that someone will know the cause of the problem and a fix for same. The problem is intermittent which is why it is hard to pinpoint. I am sure the governor is working to give fuel as needed for the most part - it is the sudden shut downs and resetting of the pump,that stump me. No noises (knocks, bangs, shudders) or warnings of any sort. It might be several weeks or months before it goes again or it might happen tomorrow !!! Nothing regular about it - hence the concern. It is getting a little more frequent.

Thanks

mariner

aside from a loose connection on the fuel shutoff solenoid that might be acting up once in a while, , if thats not the case, sounds like the pump is ready for retirement . Hmm it likes to shut down and go to sleep without warning every once in a while... sounds old and tired , just like me

 

[OLDBULL8]

Don't quite understand whats going on, but I've never heard of a governor completely shutting off the fuel, as far as I know it just regulates the fuel so you can't exceed the RPM that the spring is set for. The fly weights in the pump act against the spring preventing more throttle (fuel) for higher RPM. Does your speed actually decline when this happens ? You should be able to max out RPM wise to 3200 RPM. Rental companies usually max the RPM at 2800 to keep the top speed down around 80-85 MPH depending on the rear end gearing.

 

[RLDSL]

. Rental companies usually max the RPM at 2800 to keep the top speed down around 80-85 MPH depending on the rear end gearing.

It's not just rental companies, all the IH spec pumps for engines that went into anything other than the ford pickups, got the pumps that are governed out at 27-2800 and have a different torque curve ( even the ones that went into Ford F700 F800 etc got those pumps)

 

[mariner45]

Thanks for comment so far.

I have just got back from looking at the electrical connections on the injection pump. The ones on the pump housing over the governor case were not too bad - didn't appear loose at all. Took the wires off and found a lot of verdigree/oxide on the spade terminal. Brushed with a small brass brush and got them clean and covered the terminals with "electric tune up grease" which I take to be conductive. Checked the connections to the casing and they seemed good and tight - didn't take the cover off to check inside. Connected the wires back and ran the truck - everything seems fine.

So, I really don't know what is going on - maybe there is a broken/loose conncetion in the wire loom ? The wires that connect to the fuel pump looked fine and no signs of rubbing or fraying.

This fuel pump has done it from when it was installed - the first time not a problem and I thought this was normal at higher highway speeds (I have 3.55 rear end). Then perhaps a few years later it happened again, but this time it was on a steep hill (8% or so - we have lots of them in BC ). I now live on top of a steep hill (8%) and the fuel pump is starting to do it more regularly - though usually months apart .

I don't think the transmission is slipping - even if it did, it shouldn't cause the fuel pump to shut the fuel off and then reset itself a few seconds later - with grey/blue smoke billowing out of the exhaust. Once the pump resets the smoke clears straight away. It sure seems like something is either out of spec or starting to fail. I would hate to put the spare pump on the truck without knowing the cause of the problems.

Thanks

mariner

 

[Black dawg]

do you have a way to verify fuel pressure to the injection pump?

 

[RLDSL]

Thanks for comment so far.

I have just got back from looking at the electrical connections on the injection pump. The ones on the pump housing over the governor case were not too bad - didn't appear loose at all. Took the wires off and found a lot of verdigree/oxide on the spade terminal. Brushed with a small brass brush and got them clean and covered the terminals with "electric tune up grease" which I take to be conductive. Checked the connections to the casing and they seemed good and tight - didn't take the cover off to check inside. Connected the wires back and ran the truck - everything seems fine.

So, I really don't know what is going on - maybe there is a broken/loose conncetion in the wire loom ? The wires that connect to the fuel pump looked fine and no signs of rubbing or fraying.

This fuel pump has done it from when it was installed - the first time not a problem and I thought this was normal at higher highway speeds (I have 3.55 rear end). Then perhaps a few years later it happened again, but this time it was on a steep hill (8% or so - we have lots of them in BC ). I now live on top of a steep hill (8%) and the fuel pump is starting to do it more regularly - though usually months apart .

I don't think the transmission is slipping - even if it did, it shouldn't cause the fuel pump to shut the fuel off and then reset itself a few seconds later - with grey/blue smoke billowing out of the exhaust. Once the pump resets the smoke clears straight away. It sure seems like something is either out of spec or starting to fail. I would hate to put the spare pump on the truck without knowing the cause of the problems.

Thanks

mariner

Tune up grease is not conductive, that is dielectric grease which is non conductive, it is for use on spark plug boots on high voltage circuits to prevent arcing ONLY! Never use the stuff on low current connectors or you are likely to loose your connection . Use of that stuff on cars with computer circuits is the largest cause of cascading electronic failures there is. It causes a buildup of resistance in the circuit that it is on and burns out whatever is attempting to operate.

 

[oregon96psd]

kinda sounds like you are either loosing fuel pressure to the pump, sucking air or the pump is just worn out like everyone else has said. if it were a governor problem there would be no smoke associated with it. on a truck with a good pump hits the governor there is no smoke just stops speeding up. try putting some atf in the filter run it ten seconds and let it sit for a few hours, might loosen a sticking advance but the pump is probably done. make sure everything is tight no fuel leaks and nowhere for air to get in.