Engine/Transmission (1994 - 1998) Air in Fuel?

[jtowery1]

First off, thank God that there is a place like this where I can ask for advice, and actually get usable information. I shold have my head examined for ever letting my subscription here slip. Anyway, here's my dilemma. I have a 1995 4x4 club cab 12 valve, 5 spd. trnasmission with 3. 54 gears and slight mods. Nothing big, just a TST #5 plate (smoke screw turned a little), BHAF, South Bend clutch, straight pipe exhaust, pyro and boost gauges. Otherwise, to my knowledge its stock. The truck has 199,000 miles, and I've had it for about 4 years (since it had 183,000 miles). This should tell you how often I drive it. I'm pretty religious about maintenance. Rotella synthetic every 10,000 miles and Fleetguard oil filters every 5,000. Fuel filters every 15,000. I use the truck when I need to haul a tractor, wood, heavy things. You get the picture. Despite it's relatively low mileage, and apparent infrequent usage, it's one of the more valuable tools I have in terms of doing what it's supposed to do. In that regard, I've been completely satisfied, and I've had basically no problems with it. One morning last week I went to crank the old beast, and during cranking, it acted like it wanted to start, but didn't. Almost as if there was enough fuel in the pump to kick it off a little, but not enough to keep it running. Thinking maybe it was some bad fuel (i had just filled up), I drained the fuel filter to let out any water that may have been in the bottom (something I must confess, I have not done as often as I should). By the way, I've never had the water in fuel senson idiot light go on, though I do know that it is operable. This seemed to do the trick, and it fired right up as normal, with a little coaxing of the accelerator. Being a little proactive, I thought it would be a good idea to change the fuel filter, as it was close to being due anyway. Bought a new one, took the old one off (while cursing myself for not investing in the filter relocation kit), filled the new one with fuel, and installed it. Reconnected the sensor, opened the banjo bolt a little and pressed the primer button several times. Tightened the bolt, and went to start it. Though it had been a while since I changed it (with the help of a diesel mechanic friend of mine) I remembered that it was a little hesitant to start the first time after installing the new filter. After a few tries, it started right up. I'm here now because it doesn't seem to be any different . After sitting for a day or so, I have to go through the same process of turning the keyswitch to "on", waiting for the glow plugs, and starting. It seems to take about 6 tries and the accelerator at least halfway down to make it start. Once it's running, everything seems normal. All I can figure is that there is some air trapped somewhere in the system, but I'm not completely clear on how to properly bleed it, and the procedure for doing so. Any help would be much appreciated, as I'm limping along at best currently, and I don't want to get stuck on the side of the road. Sorry for writing a novel here, but I figured the more information you guys have, the more likely I'll get it fixed right the first, well second, time. Thanks in advance. John

 

[bmoeller]

Grid heaters, not glow plugs.



How long does the truck sit before having the starting problems? I know on some of our farm equipment, we have to prime them before starting, if they sit for about a month or better. Need to operate the primer til you hear fuel go through the return line, then pump a few more times, then try to start it.



If the truck does it even after sitting a few days, to a week, you may need to replace the rubber fuel lines. They can crack and leak air, but not necessarially any fuel. I've had to replace mine.

 

[Joe G.]

John,



The most likely cause of the problem is bad fuel hoses. The next most likely problem is the fuel heater. There are other things that can cause this problem. If a little pedal helps start it you may have the idle too low. This sort of question is pretty common so I wrote up an article about the fuel supply system, how it works and how to fix it. If you would like a copy e-mail me at -- email address removed -- .



BTW. There are NO glow plugs in a Cummins.

 

[bdcraig]

Sorry to highjack the thread but I have a question about fuel heaters. What trucks had them and where are they located? Neither of my 95's have one and none of the other trucks I been under the hood of (94,98) had one either.



Thanks,

Brian

 

[Joe G.]

The fuel heater is part of the pre-filter assembly that is mounted to the engine block with the same two screws as the lift pump. There is a black plastic thing with a wire connection to it that looks kind of like a hockey puck. That's the fuel heater.



Here is what it looks like:



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This is what the assembly looks like with out the worthless fuel heater:



#ad

 

[CToney]

I had hard start troubles too this is all what I fixed. New overflow valve, new lift pump, new rubber fuel lines from engine to frame, new gaskets on all fuel system fittigs, eliminated fuel heater, new injectors, and new grid heater relays. Also the timing had slipped and the head gasket was leaking which probably didn't help. Change the cheaper easy stuff first and go from there. Good Luck.

 

[RottenRon]

I just had this exact problem. It turned out being 3 things that were leaking fuel out/letting air in.



1) Fuel heater was leaking at the burned out electrical connection - removed the heater and electrical harness going to it.

2) Rubber return fuel line that goes from the metal overflow valve return line to the metal line by the transmission was all cracked and deteriorating - replaced the line with marine grade 5/16 rubber hose I got from the local marine supply store.

3) Washer between the overflow valve/return banjo bolt and the fuel pump was leaking - Replaced it (Cummins part number 3918192 washer, sealing $5. 19 canadian).

3. 5) After I replaced the washer there was still a leak at the banjo bolt so I took it apart again and had a better look. Turns out there was a nick in the fuel pump and sealing washer couldn't seal properly. I just polished out the fuel pump sealing surface with 300, 400 and finally 800 sandpaper, put on a new sealing washer and there was then no leak.



That's what worked for me, and I just based it on first researching TDR website and past magazines, looking at my truck and doing it. Didn't cost much and the truck now starts better than it has for the 4 years I've owned it. I suspect there have been minor leaks at these three locations for quite some time. Good Luck! All these topics have been covered before, do a search.



Ron

 

[TWhiting]

What Size Of Hose Is Used Between Heater Bowl And Pump In Picture Above, And How Long Of Hose Do Need For The Over Flow.

 

[RottenRon]

I don't know about the hose from the pre-filter/heater to the lift pump.



The return fuel line from the metal line return line to the metal line at the transmission is exactly 17 inches on a 1995 Automatic truck. I think it's longer on later trucks. I'm not sure if the Manual transmission trucks are the same. My recommendation would be to get three feet of it, it's not very expensive. Then just cut to the same lenght as the one that comes off. I used marine grade 5/16 ID hose. It should say A1 SAE J1527 right on the hose no matter what brand hose it is. Don't just use normal fuel injector hose or fuel hose because you'll be doing the job again. The marine hose is quite a bit thicker than normal fuel line and is US Coast Guard approved for use with diesel fuel. Get a couple of good hose clamps while you're at it; the kind that have a smooth surface inside so as to not damage the hose. The hose is easiest to change if you first disconnect the metal line beside the transmission at the quick disconnect. If you have a flexible shaft hose clamp nut driver, it makes the job easier... the connection at the overflow valve pipe is at the back and to the inside of the fuel pump and it's no fun to get to.

 

[jtowery1]

Thanks (and one more question)

I can't thank you guys enough for all your help. I guess I'm going to order some parts (new overflow valve, fuel pressure gauge) and get some rubber hose to start. I plan to remove the fuel heater also, as it seems to be worthless. Maybe once I've done all that, the problem will be solved, at least for now. I'm sure there's a thread for it somewhere, but I can't seem to find it... Procedure for bleeding the fuel system? I hope to get started on this stuff this Saturday. I'll let you guys know how it's going when I've had a chance to turn a few wrenches. Thanks again.

John

 

[Howard Durand]

I recently replaced the rubber fuel lines on my 94 with a set from Larry B's Foster Truck. He sent me a set of hoses, one is 5/16" ID and the other is 3/8" ID which is standard for these trucks. The wall of the hoses is thicker than the original ones and is a real pain to get over the humps in the steel lines. One hose went on easier than the other so I got out the calipers and find that both of the steel lines for my truck are 5/16" I left it that way but am having a problem with loss of prime and suspect the 3/8 line is not fitting right. If it ever warms up here again, I'll have to check it out.

 

[CogginsP]

Procedure for bleeding the fuel system?

The best way to bleed the fuel system is to crack the high-pressure lines on the injector pump at cylinder 1 and 3 and crank until you see fuel coming out of them. I have never tried this myself but was told this works well.

 

[Joe G.]

You really don't need to bleed the high pressure part of the fuel system on a 12 valve. It will take care of it without any help.

 

[jtowery1]

Issue Resolved... Sort of

Thanks again to all you guys who have helped. Even though the problem turned out to be something simpler, I learned of a few things I need to correct. (Fuel heater, hoses, etc. ) Turns out my problem was the famous fuel shut off solenoid. Boot was history, and the remnants were getting tied up in the spring. This explains why starting was eventual, but sporadic. After doing what so many others have (trying to find one for less than a million dollars), I decided to go with Bruce Adams' PTO cable fix. (Issue 48 p. 20) Seems to make more sense to me anyway, and I don't mind the small amount of extra "work" to shut it down. By the way, the price of the cable has increased a whole dollar to $18. 99. Though it stands to reason that if I did buy another FSS, it would likely last about another 200,000 miles (which is admirable by the way), it would still be something to replace at some point in the future. In the process of all this, I did manage to get the return fuel hoses replaced with USCG approved hoses, which were needed anyway. So next weekend I'll be trying my hand at the PTO fix. Maybe I'll even improvise a little, as I have my Ultima brake controller pretty close to the proposed location already. Guess that engineering degree will come in handy after all... (I can hear the boos and hisses from here, lol. ) Anyway, thanks again for all your help.