High Alititude Diesel Generator Problems

[actionjackson]

HDKA 7500 Watt Diesel Genny won't start above 6000'. Is there anything a DIY can do? We spend a lot of time above the tree line and this being our first Diesel Generator I'm concerned that I won't have electricity when I need it most. Any help would be appreciated.

[wolfe10]

What are the symptoms?

Do the glow plug work (higher elevation usually means cooler temperatures, so glow plugs are much more important)?

Does the generator turn over at normal speed?

Starts and stalls? Smoke/no smoke

The more details the better

[dickandlois]

Got more questions then answers for now.

What year is the generator ?

Will it start easy at a lower altitude?

When its running and you drive to a higher altitude does it run OK? Other then the reduced output that altitude causes.

How many hrs on the generator?

Have the fuel and air filters been serviced?

Hard stating when cold even at lower altitude ?

Rich.

[actionjackson]

The air filter was changed prior to our trip, so air interruption was not an issue. The unit is 2002, 7.5 HDKAJ with approx. 1250 hours showing. The service records show regular oil and filter over the life of the genny. My air filter, was the FIRST one installed on this unit. And it was plugged. We had a previous non start issue, that was wholly the result of the plugged filter.

The unit starts easily at lower altitudes and does not emit any black smoke. There are no other issues that I'm aware of.

This incident occurred during last winter in Mexico, so my recollection may be a bit tainted. As I recall we were at about 6500' and were boondocking for the night. The temperature was about 60F. I attempted to start the genny depressing the start switch. It caught briefly then stalled. That was it. I believe the fault codes were 3-6 which is generic for lack of oxygen. Well ya! I haven't had the opportunity to drive from a lower altitude to a higher elevation with the generator operating, so don't know if it will quit.

Thanks **** and Wolfe. Hope this helps.

[dickandlois]

This is how to recheck the last code the generator set. you mentioned a code 36.

Did you check the oil level?

Restoring Fault Code Blinking: The fault code

stops blinking after five minutes. Press Stop three

times within five seconds to restore blinking. Note

that the last fault logged will blink, even after the

condition that caused the shutdown has been corrected.

ENGINE CRANKS BUT DOES NOT START

(Fuel delivery, glow plugs or engine are marginal)

Corrective Action:

1. Check fuel level. (Note: The genset fuel pickup is probably higher than the vehicle engine pickup.)

2. Prime the engine fuel system by holding the control switch down in its Stop position for at least 1 minute.

3. Check the engine air filter and remove any blockage (Page 16).

4. Replace Fuse F3 (glow plugs) if blown (Page 6).

Brett and I mentioned or ask questions that relate to Glow plug issue, so check fuse 3.

Do you have the manual so you can locate the fuse mentioned ? There is another fuse, that if blown will prevent the unit from turning over.

You mentioned that the air filter was changed and that it starts at low altitude OK. There might be an issue with the air intake system beyond the air filter, if the old filter allowed dirt into the intake pathway.

Rich.

[actionjackson]

Guys, sorry to be contrary, but the only issue here is high altitude starting, or lack of. The generator is starting and running like a clock. All the other issue regarding oil levels etc. are non applicable. Is there something mechanical that I can change. Like less fuel and more oxygen.

I notice Onan does does not have a help line and I don't feel like driving into an RV and paying somebody big bucks for nothing.

[wolfe10]

Indeed, some of the issues would make it difficult to start at any elevation/temperature.

But, glow plugs are MUCH more critical at cooler temperatures.

I will repeat my first post:

What are the symptoms?

Do the glow plug work (higher elevation usually means cooler temperatures, so glow plugs are much more important)?

Does the generator turn over at normal speed?

Starts and stalls? Smoke/no smoke?

[dickandlois]

Over all these are kind of dumb engines for lack of a better term.

You have fuel,air and cranking speed requirements. and a hot glow plug to get fuel to fire and at altitude it is very critical because of the low air pressure, to get the cylinder compression cycle high enough to fire. Cranking speed is also very important. This has a direct relation to the compression needed to start the engine.

Could you run a code test to see what the last code set was for sure?

There are only 3 that are relevant at the time. Codes 23, 32 and 36 the other 23 plus mean nothing, because the unit will not start.

With out any information, check the fuel line for possible leak allowing air into the supply line.

Clean the battery contacts and the contacts at the generator so you get the maximum cranking speed.

Could have a restriction in the fuel filter. The fuel pump could be an issue. If you have not started the unit sense it failed to start the last time it was a 6500 ft.

There are no adjustments you can make with out removing covers and have some special tools. Diesel engines do not have carburetors to adjust.

Rich.

[actionjackson]

Thanks ****. I'll see if I can recover the last codes. As I mentioned in my last posting, the unit is running fine under "normal" circumstances. Brett mentioned in his post, that there is nothing mechanical I can do to enhance high level starting. This is the information that I was looking for.

Stay tuned.

[hermanmullins]

Action, just thought I would wade in here and ask a question. Have you ever had your Gen. running while traveling at low altitudes and begin to climb to higher elivations? If so did the Gen. continue to run? If so it may be a glow plug problem as Brett aluded to.

Herman

[dickandlois]

One more thought regarding your starting problem. Do you see a heavy carbon build up in the exhaust pipe ?

The air flow through the engine is critical and restricting that flow can cause a starting problem. You already have one strike against you with the lower air pressure, restricting the the air flow on the exhaust side could cause a starting problem.

Have you ever removed the plug from the exhaust system ? This plug needs to be removed at times to clear the build up of carbon from system, check in your operators manual for the location an method to perform this operation. Remember you are opening the system before the spark suppressor and muffler, so be very careful where you do this. Hot gases and sparks can be discharged directly down starting a fire if any combustible material is under or around area.

I mention this fact because you mentioned in one of your posts the the air cleaner was very dirty and changed.

That could cause the engine to run rich increasing the carbon build up in the engine and exhaust system. Running the engine at altitude with a dirty air filter increases the chance of a faster build up of carbon.

Rich.

[actionjackson]

I just did a fault recall. Fault 33. It doesn't really address the problem of high altitude. Any other suggestions **** or Brett?

[actionjackson]

Thanks for the info Rich. I'll check it out and get back to you. This sounds a bit more promising.

[actionjackson]

Thanks Herman. The anwer is no. The situation has never arisen, yet.

To answer Rich's question regarding the fault code. I erred. The correct fault code was 3-6, as I originally suspected. I've been outside working on replacing the oil filter with a generic filter and so far am sticking with either the Onan and/or WIX.

We're heading west to California this winter and will try running the genny over the Rockies and see what happens.

I'm surprised that someone hasn't weighed in on this subject. I can't be the first soul to run afoul of high altitude starting. Somebody must have booned in Butte.

[RVerOnTheMove]

During your talks with HDKA, what do they seem to think the problem might be?

[actionjackson]

Hi Rich.

Just finished removing the plug from the exhaust system and ran the generator hard, as per manual instructions. Not sure how much carbon soot came out, but not as much as I thought. Maybe a couple of tablespoons. Hard to tell with the wind. Closed it up.

Also replaced the fuel filter. It had approx. 700 hours, so it was probably time as well. I'm stil not sure I understand the glow plugs and how to access them. Thanks to you and Bett for all your help. Quite a learning curve.

actionjackson

[dickandlois]

action, said: "I'm still not sure I understand the glow plugs and how to access them."

The glow plugs can only be removed by removing the generator covers. Not a normal DIY job.

You can check the Glow plug fuse. Fuse number 3 is located under the access plate. There are 3 fuses under this panel. Location on page 6 of the manual.

From the time stamp on your post, it looks like you started the generator in midday temperatures. Try to start it in the early AM (cooler the better )and see if it starts harder. Should that be the case an you have checked the Glow Plug fuse. There could be some issues that need to be addressed by a service center. The up side is you have replaced the filters and other service checks, that they would not need to redo.

The amount of carbon you got out of the clean out does not seem like much, but in the wrong place it can cause problems.

Your can now add a better understanding to your learning curve though !!!

Rich.

[wolfe10]

Yup, check the fuse to the glow plugs AND the relay.

[actionjackson]

I just started the generator. No problems. It's about 45F here right now. This may not be cold enough, but it didn't sound uncomfortable.

I'm thinking that there's not much more that I can do until we cross the Rockies In December. I'll be sure to run it through the mountains and see if a) it works at altitude or it will start.

Thanks to Brett and Rich for all your input. It helped me a lot.

ActionJackson

[dickandlois]

Actionjackson, I just thought of one more item. It may not be an issue, but if you have a problem starting the generator at altitude. Depress the start / stop switch on your unit to the stop position and hold it for a good minute, you will hear the fuel pump start. This is the prime operation for the fuel supply.

Then depress the start side of the switch. Generally you will get a 36 code for a fuel supply issue. I'm going outside the box on this one.

Keep us informed on the next trip.

Rich.