Generator hard to start

Topic: Generator hard to start (Read 1175 times) previous topic - next topic

Generator hard to start

January 15, 2020, 08:49:03 pm

I took my coach to a generator specialist because it had been hard to start.
They said I need the injectors and injector pumps rebuilt.
They will take them out and send them somewhere to rebuild them.
Estimated total cost for labor $1800.
My question is there another way.

Re: Generator hard to start

Reply #1 – January 15, 2020, 09:39:45 pm

Need more info. Kubota or Isuzu motor. Either way I would look a bit further, pumps and injectors don't give much trouble. Might check things like the electric fuel, glow plugs, fuel lines. Is it long cranking time or doesn't want to stay running? How many hours on the generator?

Re: Generator hard to start

Reply #2 – January 15, 2020, 09:43:37 pm

With your statement it is hard to start I would look hard at the glow plugs and the circuit that controls them. Like Bruce the injectors and injector pump are low failure items.

Mike

Re: Generator hard to start

Reply #3 – January 15, 2020, 10:04:15 pm

Agree. Glow plug relay and glow plugs are where to start.

This assumes your symptoms are it cranks for a long time and when it does start, it is a little ragged for half minute or so.

Bad injectors/injector pump will run poorly even after warming up.

Re: Generator hard to start

Reply #4 – January 15, 2020, 10:20:20 pm

Quote from: 18360 – January 15, 2020, 08:49:03 pm

Estimated total cost for labor $1800.
My question is there another way.

Any chance of getting a second professional opinion at a different shop?

Are you trying to start in very cold conditions or are you located where it is warm?

Lots of things worth checking before you start replacing expensive parts.

Beside the excellent suggestions from our Forum members, you can also find trouble shooting ideas online, such as:

Troubleshooting Diesel Generators

Re: Generator hard to start

Reply #5 – January 15, 2020, 10:22:30 pm

If it comes down to the injectors and pump. These are not hard to do items. Removal and replacement is to dissemble the fuel lines from injectors and pump. Take pictures. Then unscrew injectors from head. Then unbolt pump from block.

Do a search for shops that will rebuild these items. Best bet ask tractor shops who they use. Injectors are usually exchanged or rebuilt. Buying brand new is usually not needed. Same with pump. Rebuilt injectors, pumps are common use items with all diesels.

Re: Generator hard to start

Reply #6 – January 15, 2020, 10:49:50 pm

As Chuck said are you starting the gen when it's cold. If it is cold out you my want to cycle the glow plugs. They only are on for a
set time and the colder it gets the longer the glow plugs need to be on. Onan generators have a temperature gauge and the colder
it gets the longer the glows plugs are on before it turns over. Glow plugs are easy to check. They can be checked with an ohm meter
and the can be checked by putting voltage threw them and they should get red hot.

Re: Generator hard to start

Reply #7 – January 15, 2020, 10:55:53 pm

Inline injection pumps are usually pretty trouble free. I would check the glow plugs as it only takes one bad one to make starting impossible in cold weather, hard in moderate temps. Check for air leak in the fuel supply line. Put a gallon of diesel in a container and run a clear line to the electric pump intake. Electric pump could also be failing or bad. Do all this stuff first before having a shop work on the pump and injectors. Once the engine is running off of a gallon container, you can use a strong dose of injector cleaner. A bad copper washer below the fitting the injector pipe screws onto could also be bad. I caught one of these on Ken's U300 generator back in '14 at Q. Had a Mercedes 190D with the same problem. Hard to start and lower power. Easy to fix with hand tools. I usually just flatten the washer on a flat surface with a sheet of 600 wet or dry changing position of the washer every few seconds. Return relief valve on the back of the main injection pump may also be leaking at lower pressure than designed for. Pressure gauge on the outlet of the secondary filter housing will tell the tale on fuel pressure. Look at my old posts with photos. Housing must be drilled and tapped to fit the gauge. A little harder than might be expected. Pressure should be about 5 psi.

Pierce

Re: Generator hard to start

Reply #8 – January 15, 2020, 11:23:18 pm

While you are at it, check valve clearance (easy) and check injection timing (harder if you have not done it before) as the injection pump has to be loosened and the pump moved a tiny bit if the timing is off.

Pierce

Re: Generator hard to start

Reply #9 – January 15, 2020, 11:26:48 pm

My izuzu had the valves and injectors set and replaced the glow plugs. Starts and runs great. The intake plastic pipe was melted from the exhaust heat. Nothing to do with starting just a wear point

Re: Generator hard to start

Reply #10 – January 16, 2020, 04:49:40 am

This is a Power Tech generator.
So I had some work done at WWWilliams.
I asked them to check out the generator.
See attachments.
They the glow plugs are getting enough power.
They loosened the injector line and it fired right up.
They tried to start it again and it had extended crank time.
Conclusion:. Possible issue with high pressure fuel system. Would need further diagnosis.
So that's when I took it to Generator Specialists, a local company.
They called Power Tech and they said the injectors and pumps need replaced or rebuilt.
It's in the 20's to 50's as far as the temp.
But it was even hard to start in the summer.
Once in 90 degree weather it started on the third try, ran for about a half hour are stopped and indicated it overheated.
Thanks for your input.

Re: Generator hard to start

Reply #11 – January 16, 2020, 05:33:24 am

If it were me, I would not spend $1800 on rebuilding the pump and injectors based on that information.

Voltage to the glow plugs does not mean that they are working properly, need to take a ohm or amperage measurement.
Also .... what color was the smoke? that can tell you a lot, grey? black? If it runs good for a little while and shuts down, even if hard to start, its doubtful and unlikely there is a need to rebuild the high pressure injector pump.

More testing needed............ or another shops' opinion.

Most shops think that if you own a motorhome that you own a bunch of "money trees"

Re: Generator hard to start

Reply #12 – January 16, 2020, 06:33:41 am

18360,

With this added info this is better for troubleshooting
Now what engine does your generator have on it? Power tech used several different power units in your year coach, most likely either a Kubota or a Isuzu. Knowing this info will help us proper lead you to a fix as different engines have parts located in different places.

With the cracking of the fuel line that was done (to blead out the air) this leads me to think that you have a supply fuel line that is leaking air into the system which will need fixing/replacing. This could be anywhere in the line clean back to the tank. If your engine has the small electric fuel supply pump, is it running and suppling pressure? If this is not running it could be either a bad pump or a bad relay that runs this pump.

The over heat is most likely the remote radiator is low on water and needs to have the air bled out from the vents and the system filled. If the air is behind the thermostat this will cause the thermostat not to function properly as it don't understand the concept of air. It might also be a bad sensor that sends info to the ES52 module needs to be looked at. It could be that the fan on the radiator isn't running and this can cause an over heat issue. If the generator is running and producing power the fan should be running. If it isn't report back as you could have a loose wire, bad capacitor, bad motor.

Mike

Re: Generator hard to start

Reply #13 – January 16, 2020, 08:12:00 am

Attached is a picture of the generator.

Re: Generator hard to start

Reply #14 – January 16, 2020, 08:22:04 am

I echo much what others have already said.

From your picture, looks like the cooling fan breaker in on, so confirm the fan is actually is running. If not, confirm power is getting to the fan. There is probably a junction box mounted just above the fan.

Temporarily replace the short section of fuel line between the supply pump and the fuel filter with clear hose. Mine is 5/16" ID. This will let you monitor for air bubbles. If air is getting in the line, ensure all the hose clamps on the supply hose are tight and check for deterioration of the line.

Re: Generator hard to start

Reply #15 – January 16, 2020, 09:48:31 am

Quote from: Pamela & Mike – January 16, 2020, 06:33:41 am

With the cracking of the fuel line that was done (to blead out the air) this leads me to think that you have a supply fuel line that is leaking air into the system which will need fixing/replacing. This could be anywhere in the line clean back to the tank. If your engine has the small electric fuel supply pump, is it running and suppling pressure? If this is not running it could be either a bad pump or a bad relay that runs this pump.

Mike raises an excellent point on a 1998 coach. If this coach has not had fuel lines (all of them) replaced (and done so properly), then it is a strong possibility the fuel lines are a concern.

Re: Generator hard to start

Reply #16 – January 16, 2020, 10:07:29 am

I have to agree with the other comments above. Before you spend $1,800 on parts and labor that may not fix your problem further diagnosis is needed. you can pay that shop $120 an hour or whatever it is you're charging to do that, or you can do it yourself. If the fuel lines haven't been changed on a 21 year old coach you will have fuel line issues. You may not even be able to see cracks but they'll be there and they could let air into your fuel line. So either put in a piece of clear plastic hose which won't cost you anything, or put some clean fuel in a bucket and put new hose from the bucket into the fuel pump and see if that helps your issue. If it fixes your problem then you know it's your fuel lines. Which can either be an expensive thing to fix if you have a shop to it or not sort of expensive if you do it yourself. Many of us have done it it's not impossible to do. And you may just need to do it from the generator to the fuel tank for now and then later do it from the fuel tank to the engine and aqua hot. Or you can do it all at once. If however after trying that's it's still doesn't run properly then look at the glow plugs. I'm not anywhere near an expert on diesel engines but there are people here that are and they can tell you how to check your glow plugs to make sure that they are working the way they are supposed to. Might want to check out what a rebuilt injector pump for three cylinder Kubota engine is. You might be able to save some money by just doing it yourself. But the generator is an important piece of equipment on these coaches and I'm not sure that I personally would replace that part without having professional assistance. But that's just me I'm sure there's some YouTube videos on it that would enlighten you on that how hard or how difficult it would be.
Good luck Hope you get it fixed and please let us know how it all turns out.

Re: Generator hard to start

Reply #17 – January 16, 2020, 11:26:57 am

Don't know how many thousands have been spent on injection pumps that nothing is wrong with. Concentrate on the fuel supply system after checking the glow plugs. Few shops know what they are doing. It's replace items until it works...all at your expense. If you need to replace the fuel supply line, you don't need to pull the generator out. Much better to leave it in place. And yes, if you have a pair of strong glasses or a magnifying glass and bend the supply line back on itself, you may see millions of tiny cracks. Any dampness on the line is a sure indication also. Buy a 25 foot roll of hose. PM for how to do the installation the easiest way.

Diesels were my business for many years and have seen almost every problem. I have never seen an inline injection pump fail. CUPS pumps yes and a very few rotary pumps like VW Rabbits, Perkins, Ford 6.9/7.3, etc.

Pierce

Re: Generator hard to start

Reply #18 – January 16, 2020, 12:16:42 pm

18360,

After seeing you pics. you have the Isuzu engine. With out seeing the tag to be for sure but that looks to be the 3LD1 to be sure check the exact engine tag before ordering glow plugs and things like the water pump because there is some slight changes in the bolt on parts.

With that engine I have only seen 2 coaches that had to have the injectors and pumps freshened up. So before you through good money at this you need to do some more troubleshooting.

After taking a close look at your pics. there appears to be a fuel leak on your supply hose. If that is dampness on the protective cover that I see you need to pull the cover off and check to see if that area is wet. On those engines the likely other place that you will have the fuel line fail is where it leaves the insulated box and loops down and back up before it goes to the cable tray. This loop is for slack to be able to pull the generator out on the slide. This loop I am talking about is famous for cracking and causing your hard start problems. I know of at least 8 coaches (that is of this age) that have had the fuel hose leak in this loop.

Looking at the fuel line from the filter to the fuel rail I see that it is OEM so with that being never replace I am thinking your hard start problem is bad fuel lines somewhere.

Mike

Re: Generator hard to start

Reply #19 – January 16, 2020, 02:37:36 pm

Quote from: Pamela & Mike – January 16, 2020, 12:16:42 pm

Looking at the fuel line from the filter to the fuel rail I see that it is OEM so with that being never replace I am thinking your hard start problem is bad fuel lines somewhere.

Especially since it would then only be a matter of time before the fuel starvation issue hits the big engine in the back

Re: Generator hard to start

Reply #20 – January 31, 2020, 10:21:48 am

Here is the last shop I ook it to.
I'm not sure what they all did.
Any comments.
I appreciate all your help.

Re: Generator hard to start

Reply #21 – January 31, 2020, 11:31:39 am

What is this low fuel flow at the injectors? The injection pump only sends a very small amount of fuel to the injectors. It would be almost impossible to judge the condition of the main injection pump by watching the amount of diesel it flows through the high pressure lines. The attachment is poorly written. They didn't test glow plugs, just parroted what info they got from Powertech.

Check glow plugs for operation
Check fuel volume at the discharge of the secondary fuel filter or supply line at main injection pump. Check pressure/volume at electric fuel lift pump.
Test generator operation with alternate fuel supply as in gallon container.
If still hard to start, check bypass/return valve mounted on main injection pump. Replace if necessary. Inexpensive and fairly easy to get at.
Just under 800 hours on the injection pump is very low hours. A failure is very unlikely.
Possible bad sealing copper gasket under one injector fitting on injection pump.
Possible injector with bad/poor spray pattern. Remove and test injectors. About one hour of work. See link to tester.
Diesel Injector Nozzle Tester Pop Pressure Tester Dual Scale 600-8000 PSI...
Injectors should open at about 3000 psi and make a buzzing sound. Pattern should be a spray not a solid stream.
Remove and replace the copper ring/gasket under injection pump high pressure fitting to injector pipes and torque properly.
If the injectors are removed, it's a good idea to replace the seals under the injector. One each. Most all indirect injection diesels have one of these. This is just an example: Amazon.com: Mercedes (95-99 DIESEL) Fuel Injector Seal set (x6) OEM Bosch:...

Pierce

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Re: Generator hard to start

Reply #22 – January 31, 2020, 11:50:43 am

Rick , mirroring what others say, sounds like fuel line issues. I just did a temporary repair on mine for the same reason. If you are able do the troubleshooting your self with some help from the forum, it will save you a bunch of $$. I have been working on Diesels for many years, asPierce said very few of the pumps and injectors ever fail.

Re: Generator hard to start

Reply #23 – January 31, 2020, 11:58:32 am

Well if you were hard fast going to replace the fuel injector pump and injectors I would want to protect your investment with replacing the filter and soft lines to prevent contamination and air leaks. If the pump is actually bad with no air leaks it has run contaminated fuel. I would do the filters and lines first to see if in fact you actually resolve your original fault caused by a air leak somewhere. IMO. Age of your coach also reflects fuel/air leak issues. Before I replaced the fuel system ohm out the glow plugs and verify voltage and power draw on each glow plug. After everything else I would finish with the pump and injectors. Air in the fuel will present like a poor performing injection system. IMO. And yes it still may have something causing it to overheat and shut down after running 20+ minutes. That's a different chapter to the problem
Scott

Re: Generator hard to start

Reply #24 – January 31, 2020, 12:11:28 pm

Rick,

Here are a couple of items that make troubleshooting the generator easier. The "T" handle valve can be opened to bleed the generator fuel system but should be closed in normal operation. Temp gauge is good for checking but sending unit to dash would be better. Pressure gauge installation is a little tricky so best to have decent DIYer looking over shoulder. Pressure gauge installed photo is with generator in operation.

Pierce

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