Engine/Transmission (1994 - 1998) What happened - need counsel #2

[CKHeller]

I went to the dealer to pick up my truck. The service manager said it would be hard to start and blow out gobs of blue/black smoke. It started right up with no more smoke than usual and ran fine about half way home, thats about 7 miles. Then it started to stumble and blow out clouds of white smoke as I stomped the gas and kept it in gear. This is the same thing that happened to my wife the other day when she had it towed to the Dodge dealer, see yesterday's post of the same title. After a few seconds it would catch, accelerate for a while then start to stumble and I went through that same cycle with increasing frequency as I drove. It also had more difficulty getting itself running again each cycle until I was about a half mile from home and it stopped completely and would not start. I hope after a cooling off period it will start again and get it home.

It doesn't seem to me that the dealer replacing the FSS changed anything. That diagnosis by the dealer didn't make sense to me any way: Correct me if I'm wrong but it seems to me; the FSS would not cut off the fuel if the ignition switch was in the on position and make the truck stumble while running. It may be starved for fuel but not for that reason. Water in the line doesn't make a lot of sense either because it runs fine for a period of time, maybe until it reaches a certain temperature. Water in the line was suggested by a couple of guys last night. I think water an unlikely cause because I had no problem with the first 3/4 of that tank and I get fuel at a very active diesel truck stop and again the tank is now just below 1/4 tank and with the first 3/4 it ran fine. The problem started before we had the freezing weather overnight that should rule out condensation.

Oops! I thought I'd sent this and went out with my old Power Wagon to pull it back if necessary but was able with great difficulty to get it started and with billowing clouds of white smoke and 4 complete stalls in just under a mile to get it up my long driveway next to my garage.

Vaughn - I wasn't able to get a bottle under the fuel filter/separator to check for foaming. My filter does not have one of those long tubes the diagram you included yesterday and there is no room without removing something I'm not sure what is or does to get anything under there. I couldn't find any leakage around the fuel heater anywhere.

I used the ignition to run the codes to see if that told me anything. I'd never done that except once months ago and that time it gave me double 5's. This time it was difficult to read I think because I'm unfamiliar with what is a pause. At first I thought I got 35 but there is no 35 in the Haynes. Once I thought I got a 12 and a 23. The 12 makes sense because the batteries are new. The 23 also says the check engine light will light when the engine is running so I tired to start it just for sport and to my total surprise it started and ran fine for several minutes. Does this truck have a ghost? Anyway the check engine light didn't come on while it ran.

Does this make sense to anybody? It's too late now and I've used all the energy I have for today getting this much done but maybe for tomorrow someone can give me some clues about what to check next.



Kru Heller

Powhatan, Va.

94, 2500, 5 sp, 4 WD, reg cab, long bed

 

[bodacious]

Does it have a cat in the exhaust? If it does it could be plugged.

 

[CKHeller]

Does it have a cat in the exhaust? If it does it could be plugged.

No cat, one long fat pipe from the turbo to the tail.



Kru Heller

Powhatan, Va.

 

[DAbsher]

Here's a thought, this happened to me last year. The truck started stalling once the fuel level started getting low and I found out, when I went to replace the fuel pick-up and sender unit in the tank, that it had fell apart. The unit is two piece and the bottom piece came loose, with the only thing holding them together was fuel pick-up line. The bottom part is made to float up and down with the fuel leveland my guess is when it seperated it started floating upside down and when the level would get to low it would start sucking air, making it stall or run rough. If it died it would start back up with a little work and run fine for a bit, then do it again. I think one thing to try would be to fill the truck up with fuel and see from there. Good luck, Darl Absher III

 

[KAlder]

I think I would try to borrow a fuel pressure gauge from someone or buy one at most. hook it up and run it up through the hood and tape it to the windshield. see if you can duplicate the problem, and see if the fuel pressure drops off during.

 

[McLaughlin]

My first guess is you have an air leak of some kind. One of the problems with the scenario you described is that it could be a problem almost any where in the fuel system. The manual for my 97 list most of the fuel related system as a possible cause. From what I've read been told and experienced, start by looking for air leaks (fuel lines - you man not be able to tell if they are actually leaking air, lift pump/fuel heater, and overflow valve), verify that you have fuel from the lift pump and engine timing. If all those are good then your injectors could be hung or you could have an injection pump problem. The injection pump is one of the less likely causes and most expensive to evaluate so it is really something to check as a last resort (but they do sometimes go bad).



A bad FSS may cause unexpected engine shutdowns and failure to start but shouldn't cause much of a smoke problem unless the truck cranks a lot before starting (a little unlikely because if the FSS isn't working correctly when you first try to start, it problably would allow the vehicle to start later).

 

[CKHeller]

Here's a thought, this happened to me last year. The truck started stalling once the fuel level started getting low and I found out, when I went to replace the fuel pick-up and sender unit in the tank, that it had fell apart. The unit is two piece and the bottom piece came loose, with the only thing holding them together was fuel pick-up line. The bottom part is made to float up and down with the fuel leveland my guess is when it seperated it started floating upside down and when the level would get to low it would start sucking air, making it stall or run rough. If it died it would start back up with a little work and run fine for a bit, then do it again. I think one thing to try would be to fill the truck up with fuel and see from there. Good luck, Darl Absher III

Thanks Darl,

The fuel level sending unit is new since Aug. I just had it replaced so I suppose this is possible but my guess would be unlikely. When I bought the truck the fuel gauge didn't work because the sending unit was absent and I had it replaced.



Kru Heller

Powhatan, Va.

 

[CKHeller]

I think I would try to borrow a fuel pressure gauge from someone or buy one at most. hook it up and run it up through the hood and tape it to the windshield. see if you can duplicate the problem, and see if the fuel pressure drops off during.

Thanks for this. I was hoping this fall to have 3 gauge's installed a exhaust temp, fuel pressure and Boost but unexpected expenditures prevented that and now this will also keep that from happening. I need a running truck first and gauges next. If it takes any kind of special equipment to diagnose this truck it will have to go into the shop. It may be that installation of a gauge or two will help with diagnosis and maybe I can justify it to the family that way. I'm going to have to hold on this route for today. The only person that has a gauge to borrow that I know also owns a repair shop and he will want to work on the truck rather than lend out his tools. Although he did let me rent a lift for a few days to do a timing belt change on my Nissan. Thanks though, maybe you just helped me get the gauges I wanted.



Kru Heller

Powhatan, Va.

 

[cojhl2]

Then it started to stumble and blow out clouds of white smoke

If it's just for some reason running low on fuel,, why the white smoke?



Running low on fuel, (air in the sytem or whatever) explains the stumble but I don't think that it explains white smoke does it??

 

[CKHeller]

My first guess is you have an air leak of some kind. One of the problems with the scenario you described is that it could be a problem almost any where in the fuel system. The manual for my 97 list most of the fuel related system as a possible cause. From what I've read been told and experienced, start by looking for air leaks (fuel lines - you man not be able to tell if they are actually leaking air, lift pump/fuel heater, and overflow valve), verify that you have fuel from the lift pump and engine timing. If all those are good then your injectors could be hung or you could have an injection pump problem. The injection pump is one of the less likely causes and most expensive to evaluate so it is really something to check as a last resort (but they do sometimes go bad).



A bad FSS may cause unexpected engine shutdowns and failure to start but shouldn't cause much of a smoke problem unless the truck cranks a lot before starting (a little unlikely because if the FSS isn't working correctly when you first try to start, it problably would allow the vehicle to start later).

Thanks for this response. I will read through my manual with what you have written and see if I can do any of what you recommend. You are a bit over my head. I appreciate your concurrence that the FSS was likely not the cause.



Kru Heller

Powhatan, Va.

 

[CKHeller]

Then it started to stumble and blow out clouds of white smoke

If it's just for some reason running low on fuel,, why the white smoke?



Running low on fuel, (air in the sytem or whatever) explains the stumble but I don't think that it explains white smoke does it??

Thank you sir, for asking a question I don't have the experience or knowledge to ask. I hope someone has an answer for both of us. This started suddenly and letting the truck sit apparently it goes away but comes back when it is thoroughly warmed up.



Kru Heller

Powhatan, Va.

 

[McLaughlin]

You might want to do a search for "white smoke" on the forum. You will get a lot of responses as this discussion comes up a lot. The following is an extract of some information from my shop manual. Since I've got a 97 it probably won't be identical to yours but a lot of the info should be applicable. I included the stuff about the FSS just because it was mentioned in your post. In particular take a look at the two notes. The first one pretty much duplicates what I mentioned earlier and the second brings up something I didn't mention which is the fuel filter and pre-filter.



PRELIMINARY INSPECTION & ADJUSTMENTS

VISUAL INSPECTION



1) Check for water in fuel filter/water separator by placing drain pan below drain tube at fuel filter/water separator.

2) If no water exists and a clean flow of diesel fuel exists, close drain valve. Go to next step. If water exists, allow water to drain until clean flow of diesel fuel exists. Close drain valve.

3) Verify fuel filter/water separator has been serviced according to proper service schedule. Ensure pre-filter was cleaned when fuel filter/water separator was serviced. Pre-filter is located at bottom of fuel heater on driver’s side of engine.

4) Check color of Filter Minder. Filter Minder is located on top cover on air filter housing, just above air filter. DO NOT remove air filter from air filter housing for inspection. If Yellow disc in Filter Minder has reached Red zone, remove and inspect air filter.

5) Ensure intercooler inlet and outlet duct clamps are tight and front of intercooler is not restricted with dirt.

6) Check all fuel supply and returns lines for damage, kinking or leakage.



FUEL SYSTEM

FUEL SHUTDOWN SOLENOID OPERATION

NOTE: Ensure fuel shutdown solenoid operates correctly. If fuel shutdown solenoid fails to operate correctly, engine may fail to start or may shut off during operation.



Fuel Shutdown Solenoid (Preliminary Inspection)

1) Ensure ignition switch is in OFF position. Check that lever pin on fuel shutdown solenoid is extended downward and pump lever is in SHUTDOWN position.

2) Turn ignition switch to START position while noting if lever pin and pump lever moves upward to the RUN position.

Release ignition switch from START position to the ON position. Ensure lever pin and pump lever remain in the RUN position.



AIR IN FUEL SYSTEM



NOTE: Air in the fuel system may cause hard starting, excessive smoke, poor engine performance, engine misfire, poor fuel economy and fuel knock. Air may enter fuel system whenever fuel supply lines, fuel filter/water separator, fuel injection pump, fuel injectors or high-pressure fuel lines are removed or disconnected.

1) Inspect all low-pressure fuel lines to fuel heater, fuel transfer pump and fuel filter/water separator for signs of leakage.

2)Inspect all high-pressure fuel lines for signs of leakage.

3) After repairing fuel leak, bleed air from fuel system.



NOTE: A blocked or restricted fuel filter/water separator may cause starting problems and prevent engine from accelerating. Low power and Blue or White fog like exhaust may also result. If an excessive amount of water collects in filter/separator in a short period of time, it may be necessary to drain and clean fuel tank.



FUEL TRANSFER PUMP

NOTE: A defective fuel transfer pump may cause low power and/or hard starting. Check fuel transfer pump output pressure and then fuel transfer pump output volume. Low fuel transfer pump output pressure may also be caused by worn eccentric on engine camshaft.



Fuel Transfer Pump Preliminary Inspection



1) Check for restricted or leaking fuel supply line to fuel transfer pump, located on driver’s side of engine.



2) Check for fuel leaking from weep hole on housing of fuel transfer pump. Replace fuel transfer pump if fuel is leaking from weep hole. Check fuel transfer pump output pressure.



Fuel Transfer Pump Output Pressure



3) Start engine and warm engine to normal operating temperature. Record output pressure with engine idling and then at 2500 RPM with no load. Output pressure should be 17-22 psi (117-152 kg/cm)

 

[Vaughn MacKenzie]

Then it started to stumble and blow out clouds of white smoke

Running low on fuel, (air in the sytem or whatever) explains the stumble but I don't think that it explains white smoke does it??

Yes tons of white/blue smoke can be the result of air in the system. That's because injection happens at very high pressure (10-17,000 psi) in order to finely atomize the fuel. But if there's air in the injection lines it compresses and greatly reduces injection pressure, making poor atomization and fuel combustion. Hence the blue & white smoke.



Kru, the FSS went bad on a friend's '97. The symptom was very low power, but it ran perfectly smooth and smoke free.



Here's another thing you might try. . . if there's a leak inside your fuel tank, some fitting along the line, etc. you might try pressurizing your fuel tank to about 5psi with an air hose if you have a compressor. I did mine by stuffing a rag around the hose. Do that, then inspect the fuel lines for fuel leaking especially back by the tank pickup.



I have read of a case recently where someone's plastic line from the tank to the metal fuel line had rubbed a hole through. And someone else had algae or some crud block up the fuel pickup in the tank.



Another thing to try is take a 17mm socket and drop the prefilter and see if the screen is crudded up.



Just in case, too, might just replace the fuel filter to rule that out. When you replace it you could add a new piece of tubing to your water-in-fuel sensor/drain valve piece that screws in the bottom of the filter then try the thing I mentioned in your other thread.



Vaughn

 

[Joe G.]

Kru,



Carefully check the intercooler boots. If you have a torn one or a loose one it can cause the smoke. You really need a fuel pressure gauge. You can get a simple mechanical one pretty cheap. It will have to be installed with a needle valve to dampen the pressure spikes. The best place to install it is the input fitting to the injection pump. See the picture below. A little tip to get room to work on your '94. Remove the two nuts that fasten the master cylinder to the brake booster. That will allow you to lean the master cylinder toward the fender. E-mail me at -- email address removed -- for a write up on the fuel supply system and how to fix it.



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[JFaughn]

In the last yr. I had some of your symptems , and it required several repairs , the only symptem I did not have was the smoke .
1st some times it just wouldn't start , turned the ing. to the on pos. and went under hood and lifted the linkage to the FSS , and it stayed up , turned the key the rest of the way to start and it started and ran normal , had some one turn key to start pos. and did not see the linkage lift , so I took out the FSS relay and removed the plastic cover and found burned points , filed them and no problum for 1 1/2 yr.
Next much like yours , when the fuel got to about 1/4 it would be very hard to start , did a fuel pressure test , after making fitting like above , pressure would not go over 18-20 lbs at any RPM , also when I pumped the prime button and did not get the overflow valve buzing noise so took the lift pump out & apart , found bad check valves , now the truck would start fine , but the pressure was still low , so I pulled the OFV out and measured the spring less than a 1/2" [ should be about 9/16 ] , put in a new one and pressure is up to about 36 lbs full throdle under load .
Then to check the fuel lines & hose from tank to LP I made a new fitting with old gas cap & shrader valve and put 2-3 lbs in fuel tank to look for leaks between tank & LP [ this is where you would normanly have a vacume , so no leaks visible ]

 

[Vaughn MacKenzie]

JFaughn that's a good idea I hadn't seen mentioned yet- could possibly be the overflow valve, or maybe some piece of crud got stuck in there. Kru the OF valve is a piece where the fuel line comes out of the injection pump at the very front between the pump and engine.



Joe G is right you should check your fuel pressure. As far as the intercooler boots go it would be a good idea to check them out and tighten up the clamps (snug but not hard), but bad/leaking intercooler boots isn't what's causing your problem. If they leaked your engine would still run smooth and make black smoke only under power.

 

[cojhl2]

Yes tons of white/blue smoke can be the result of air in the system. That's because injection happens at very high pressure (10-17,000 psi) in order to finely atomize the fuel. But if there's air in the injection lines it compresses and greatly reduces injection pressure, making poor atomization and fuel combustion. Hence the blue & white smoke.



Vaughn

Very good explanation!! I had not thought about that. .



Thank you Vaughn

 

[CKHeller]

Thank you all that wrote in offering suggestions for what to do to get my truck on the road. I'm not a mechanic by any stretch of the imagination but on gasoline engines considered myself a fairly adept parts changer. Tell me what part to change and I'll get it done. I was hoping that because this came on so suddenly after running so well I would get a reply something like "Oh that's your cranzit box - Just pull it out and put in another, you can get one at NAPA or Advance Auto. " It looks like this is going to be a much more complicated process but with your patience I'm going to do what energy/time and finances allow.



Mr. McLaughlin - Thank you for dumbing down your instructions to my level, I understand them much better but some of it may still be beyond the scope of what I am able to do at present. I am almost 60 and recovering from cancer surgery with very limited energy - that should get better. I also have limited mechanical experience but a keen desire to learn how to do what I can with this truck. Some other limitations I have are no garage space, no lift and a gravel driveway to crawl around on in the cold weather. The pre filter was not cleaned when I changed the fuel filter. When I bought the truck it was leaking fuel at a dramatic rate from multiple sources. The only one I was able to fix myself was the fuel filter/separator and when I did none of my advisors at the time suggested that I clean out the pre filter first. I just now used what energy/time I had for today doing that and now it is clean. I asked my wife to pick up a new fuel filter/separator on her way home from church but the local parts place didn't have any in stock. Maybe I can find one tomorrow and she can pick it up on her way home from work. I started and ran the truck after cleaning the pre-filter and that alone did not solve the problem but there was plenty of crud in there.



Vaughn - Thank you for all of your notes because of the above it is going to take some time to get to each of the suggestions and I am going to be hampered by the weather. Time today is a problem as there were family obligations planned in advance. I can't just skip out and work on the truck even if I had the energy.



Joe G. - This episode is going to provide the excuse to get the gauges I wanted to install this fall but finances wouldn't allow. But that may push the whole repair process into past Christmas. This truck is my secondary vehicle. My primary is an old Nissan 300ZX and I put it in the shop for a state inspection last week and the suspension failed inspection. I hope to get it back this week. That affords me the opportunity to learn on it. I just hope this turns out to be something I can do.



John and cojhl2 - thanks to for your counsel. I'm saving this whole thread to guide me through the process. Your comments will be considered in time and are appreciated now.



Thank you all. I'll be in touch as I go along but please don't expect me to go as quickly as some of you might. I hope this old truck is worth everything I'm putting into it.



Kru Heller

Powhatan, VA.