New Member, Needs Help!

[DonTX]

I need some fresh ideas from people who have had the old 5. 9 cummins. I recently bought this motorhome with one in it, the previous owner had gotten a gut full of it too. When it is running, it performs nicely, smooth idle, good acceleration, plenty of power. The motor did on two occasions die when coming to a stop light, and starting is a matter of cranking and cranking, and cranking. Onec in a great while, it will fire up like it should. Not often though.

I am an aircraft mechanic and a certified auto mechanic as well, so I have a little basic knowledge, but at 68 years old, am not up on the newer stuff.

The previous owner had become convinced it was electrical. A Cummins tech told him the batteries went down so low the shut off solenoid was shutting it down, and keeping it from starting. He had replaced the alternator, all 6 batteries, all fuel filters of course, and the converter when I came to own it. In the 200 miles home, it died no less than 5 times! In each case starting aids, waiting, or whatever finally got it going again. It appeared to even possible be heat related, the last 100 miles were uneventful, sun had gone down.

I got all the manuals together, and started off. First thing I did was put new batteries in again, larger amp capacity. In checking, I found the lift pump (diaphram type) was totally inoperative, plunger rod had end off it. I put on a new one, bled the air all the way to injectors, and finally started. Let it run a while, shut it off, and repeatedly started it again and again, maybe 10-12 times. So happy with it now, I went home. Today I tried to start it, same old routine, crank for ever and ever.

This evening reading the book, it says one place to keep your foot off the accelerator when cranking, in another place it says to give it full throttle when cranking at less than 60 degrees because it RICHENS the mixture! I had not tried that one yet. It does not appear to smoke either when cranking or when it starts. If you give it a shot of starting fluid, it lights right up and idles and performs quite well.

I see plenty about the newer ones wrecking the injector pump when the lift pump goes out, will that happen on the old VE44 Bosch as well? Could that be my problem? The fuel shut off has to be working well, pumps plenty out the loosened injector connections when cranking.

Come on, I am tired of this, can someone give me some fresh ideas? I might add that this is in an 88 motorhome with only 40,000 miles on it, so it has sat a bit in its life.

 

[Paychk]

Welcome to the TDR



I would look at a couple areas



Electrical



Check the wire & connection at the fuel solenoid on the injector pump. Also the quickest way to eliminate the electrics is to remove the plunger from the fuel solenoid, then replace the solenoid to the pump. You can shut down the engine by using the manual shut off lever on the side of the pump. See if it acts properly without the plunger. If it does then the problem is in the solenoid or electric circuit connected to it. If it still dies, then it has to be the fuel supply system; pump, lines, & tank.



Fuel supply



Drain, drop & clean the tank. Also clean and blow out the supply lines to & from the engine. You may get by hitting the tank with a strong dose of biocide, this will kill any algae in the tank. It won't help if the fuel is rancid, but draining the tank would take care of that. After cleaning the supply system replace the fuel filter with a new quality filter; Wix, Baldwin, or Fleetguard.

 

[tugboatphil]

Welcome Aboard, Don! I don't have anything to add to what Alan said. However, we have another RV Cummins owner, Michigan Don. Haven't heard from him in a while.



Anyway, I hope you get her starting right. I've never had one that didn't fire with just a slight key turn. There are many here that are much more knowledgable than I am, so keep asking and you'll get the right answer.

 

[LMcCary]

The previous post is onto the problem. On 70's and 80's vehicles, there is a lot of rubber fuel line failure. Remember a small pin hole leak will air lock the fuel pump. Also check the tank and fuel lines for silicone seal (RTV). Some mechanics still use this stuff around fuel systems and it will not work. Silicone will continue to grow and stop up everthing when exposed to fuel. Also there must be 10 to 20 psi pressure from the pusher pump.

 

[WyattEarp]

I would for sure make sure the fuel supply set. . tank, lines, fuel, filter are all in good shape, it could be a case of bad fuel or algae in the system... But you for sure come to the right place Don, and welcome aboard.

I myself am not familiar with the RV setups so sorry on that note.

 

[DonTX]

Thanks guys, I appreciate that, I need all the support I can get at this stage. :-{} . I am putting on a DAVCO fuel processor, eliminates the three fuel filters and allows you to see if there are bubbles etc, would have had it on this ofternoon, but dropped a bolt and had to go get a magnet. This unit will allow me to insure the fuel is getting to the injector pump and is free from air (or not). In the re plumbing of the fuel line, I am adding a fuel pressure gauge and a switch to put on a dash light if it falls below 2 lbs. The RV setup is nearly identical to a pickup, just backwards of course. Since the fuel is spurting out well when I crack an injector connector, I assumed that the fuel shut off had to be working, but in trying to eliminate everything, I think I will pull the steel plunger rod anyhow. The new lift pump does a fine job by hand cranking as well, puts out a good stream of fuel at the filter bleeder screw.

 

[LMcCary]

I forgot to mention another common problem on 80's motorhomes, that is the wiring at best is poor. Connect a volt meter or test light to the shut off solenoid wiring , turn on ign. switch, and start wiggling the wires under the dash and engine compartment,(we call this the wiggle test) and watch your voltmetter or test light for any fluctation. I have repaired several electrical burned motor homes, and almost every time the wires are scotch lock together, causing a poor, high resistance connections. When ever you find these type of connections, repair them with quality crimp and heat shrink connectors or solder and heat shrink. Then tie the wiring up out of harms way.

This may not be your problem, but I wanted to give you a heads up on the electrical.

 

[DonTX]

That is on my list too. A side problem is that this is an Executive Industries Prestige motorhome They only made top of the line quality stuff for a couple years and went out of business, there are very few around. I have been trying without success to find a wiring diagram or manual, so tracing the wiring for the stop solenoid is not really easy either. I have considered a jumper from the starter terminal or alternator direct to the solenoid just to eliminate that possibility, the engine is 36 feet from the ignition switch!

 

[MMiller]

It runs fine, dies, then is hard to restart? Does it go it more with full tank, 1/2 tank or less? Those wonderful foil wrappers that they put under the cap of fuel conditioner are wonderful things to find in fuel tanks. They float around, and when the level is low enough, then it can suck up against the fuel pickup, and then fall off after the engine dies and the suction goes away. Get a jug of fuel, and some fuel line. When it dies the next time, rig up a short hose to the lift pump from your jug and then start and run.



On a note about the start up. My knowledge of injection pumps in simple principle is this: When the pump is at rest(ie not running) the governor is set at full fuel. Upon startup until the governor balances, it is at full fuel. Sometimes if the idle is set too low, pushing on the accelerator just a little will net a better start, but mashing it to the floor will do nothing IMO.



Other then these two, sounds like you are on the right track, when you pull the shut off solenoid, look for metal flakes in the pump, lots o VE's run with low fuel pressure, but it can't be good for them, and I suppose they will fail if ran with poor fuel circulation.



Welcome to the group, when you get it running right, then we'll have to help you get it running REAL well.



Michael

 

[MicroOutlawRacer]

"If you give it a shot of starting fluid" If you are cold starting it with starter fluid and it is colder the 60 deg. outside then I would also take a look at the grid heaters. This will not cause the stalling problem but it could cause hard starting when cold.

 

[DonTX]

Yep, that is sure what it acts like. Problem is, in 1988 there WERE NO heaters. Nope, no glow plugs, no grid heater, just diesel fuel and compression. .

 

[Scot]

I recently had about the same problem on my repower. Turned out that the screen on the inlet of the lift pump was becoming plugged with particles out of the tank. When it died, they would drop away from the inlet.

 

[cojhl2]

This certainly sounds like fuel,, but guys he said he cracked an injecter line while cranking and fuel was present!!



Now what,, I have no clue but I think we msut move from the shutoff/fuel/delivery pump/line/etc issues.



Why does it not fire when there is fuel at the injectors. . Maybe the injection pump not providing enough pressure to break the bias in the injector??



Worked on a diesel one time that had extremely hard and unpredicable starting,, would give er a snort of gasoline thru a rag at the air intake, whe would start right up. What we found was the injectors set too tight.



I dunno the particulars of how that was fixed,, but that was the issue anyway.

 

[cojhl2]

BTW Don,, its too bad you replaced the batts already. That solnoid doesnt take enough kick that if the bat will turn the engine over there is enough to hold that solnoid. (How the heck doya spell solnoid anyway?)

 

[DonTX]

I like your thoughts there cojhl2, thanks for the help. I have sat back there and read the book and studied, and sure enough it seems like the injectors are not getting enough pressure to snap! Why could that be I ask myself. I put on the new DAVCO fuel processor, a lot of that was to make sure I was not getting air in the line from the tank to the pump. Went to start it and batteries were too dead, there are five of them new suckers, and the garage I have it stored in has no elec power. Took them all out, home and on the charger, will see tomorrow what happens. I have had low battery problems on diesels before, gotta spin those suckers if you want them to start. . Would it not make sense that if I am getting air someplace, it would just compress and not fire the injectors? With 40k on the setup, I have trouble believing that the pump or injectors are bad, but with 20 years of age on the long fuel hose, it sure could have a crack. If no air shows up at the DAVCO, is it possible to get air from inside the injector pump somehow, like from dryed out seals from sitting or something? Book says it takes 8. 2 volts to open the fuel solenoid, have not measured that yet, but as you say, it seems to be a moot point.

 

[LMcCary]

Your post stated that there was 40,000 miles on this setup, but you didn't say how long it has been setting up. Moisture and old fuel can deteriorate the pump and injectors. Cranking RPM is important, but I have seen injectors gum up or rust up to the point of not opening until reaching 3500 psi. or more. Of course that is way to much for a VE pump to crack while starting. I can't remember that exact cracking pressure, but it is close to 2150 psi.

On the fuel system, be sure to bleed the injector lines at the injectors, watching for clear (no air bubbles) fuel while the engine is being turned over. As soon as the air bubbles clear or if the engine fires up, tighten the lines.

Five batteries dying so soon, must have an electrical drain, unless you have been cranking over the engine alot. Good luck. Hope you have found your problem.

 

[LMcCary]

In reading your first post, I found that you had the fuel filters change when you picked it up. Did you check them again? I have found that a partially clogged filter can cause you misery. One night we had over 100 trucks down due to bad (black algae) contaminated fuel. Some of the trucks woud run fine for a few miles, then shut down or loose power. When the drivvers called in, we had them to change the filter, which would get them going until the filter stopped up again. This would occur at varying distances, from 20 to 100 miles. It was a long and miserable night. Recently I have had this to happen in Houston, the truck ran fine for a couple of miles, loose power, or die, then sometimes restart untill finally it would not restart. Every time it would die, I would check for fuel at the injectors while cranking and there seemed to be plenty. A new fuel filter fixed the problem. You see pumps can move fluid in small quanities thru a partially clogged filter, but as the quanity demand increased the fuel would pull into (vapor lock) and stop the flow.

Just a little Info for all.

 

[BushWakr - RIP]

I have never personally had problem with bloom or algea in fuel. I understand it is most common in marine applications although our trucks can suffer from this if we get enough bad fuel and/or water contamination.

The first thing I'd suggest is to dump in an entire bottle of fuel conditioner... . one that has lubricity/cetane/detergent properties. This won't harm the engine/pump but it will help with ruling out fuel quality issues.

The VE pump has it's own supply pump. It is located in the front of the pump right were the fuel enters..... if you can get fuel to that point you should get a good start once you've bled off any air in the injector lines.



One of the other guys mentioned how long the truck has/was sitting. The injectors/delivery valves can, over time, become sticky due to fuel breakdown so don't be afraid of really "layin in the additive" for this ok.....

If you have had bad or contaminated fuel in it then there's no choice but to drain it all off, including the entire fuel system right up to the lift pump... . sorry that kinda sucks... The fuel will eventually form a varnish that is very hard to overcome without pulling hard parts off and flushing them.

You can speed up the priming process of priming by inserting an air nozzle into the fuel filler spout and pressurizing the system with air while someone cranks the old girl over for you... . don't release the air pressure right away, also don't go wild with pressure because you'll quickly find a weak spot in your fuel line if you do... .



Keep us up to date on this one..... we're ALL interested to see how you make out...



pb... .



edit: my apoligies to all the guys in here, including yourself, for my absence lately... . holidays/health and family have been at the doorstep lately...

 

[LMcCary]

BushWakr is right about cleaning the whole system. I know that this a lot of work but you will be pleased with the results. If you can't get it started without aids, then take the injectors out and have them pop tested. Some shops will do this and clean them too. Ther is no use of trying to get by with injectors that are out of range. The VE and VP pump is too weak for border line high pop pressure to work properly while cranking. Please do not use ether as this can cause an intake explosion and\or also make your engine ether dependent. Wish I could be of more help, but not knowing the over all pitcure or condition of the various systems, it is hard to diagnose your exact problem. Keep us posted.

 

[DonTX]

Status Report, New Years Eve: I installed the 5 fully charged batteries, and it cranked up, maybe more slowly than I would have liked, but was running swell. I sat a while at the new DAVCO unit and there are NO bubbles soming in, making the fuel line from the tank no longer suspect. Now I am getting non aerated fuel at proper pressure to the injector pump for sure.

I still am not happy with the amount of cranking to restart, when warmed up. It sounds like it is making about four revolutions (12 rrrr rrr you know) at regular speed, then about four more revolutions at a higher speed, almost like it is weakly firing, then starts. Don't these with the Bosch VE pump start like most other diesels, like about the instant the starter engages? Maybe I am expecting too much from it.