Onan 7.5kw won’t crank

[Terry W]

Went out to exercise the generator and no dice. It primes just fine but when it comes time for it to start nada. The switch stays lit, but it won’t turn over. There is no starter click like a low batt just nothing.

Due to a couple of issues it has been sitting, plugged in, for a few months, batt voltage is good, all connections are clean, coolant level and oil level is correct. From what I can decipher I have a 33 code, high coolant temp!

There are hardly any hours on new coolant, cap, oil and filter and fuel filter as well as a relatively new belt.

Before I tear into this thing I am looking for suggestions of what to tackle first. I’d obviously like to start with the easiest possible solutions and go from there. Any sensors, oil, coolant level or temp etc. I will use Cummins as a last resort.

Thanks, Terry

[whalepirot]

Originally Posted by Terry W

Went out to exercise the generator and no dice. It primes just fine but when it comes time for it to start nada. Thanks, Terry

Does this mean you hear the fuel pump running? In my case the 'time to start' is extended if the coach sits for months. Continuing to hold the interior start switch, much longer than I am accustomed to, starts it.

Code 33; does that refer to a control panel display about AutoStart or manual start? It rings a distant bell(!) and was not a malfunction as I recall ('07 FDDS).

[Kid Gloves]

Please verify the code.

[Terry W]

Soooo, trying again, I ran the primer a couple of times up to 90 seconds, just kept running like usual. Following each prime I held the start button. First time for two minutes second time for three minutes and nothing. No cranking or attempt to crank or any sign of the starter wanting to engage.

I am rethinking a fault code, I misread the lights. Pushing the start button produces a rapid flash for about 20 seconds and then flashes 3 times slowly with a pause as it always had before it started.

In retrospect there is no reason for a fault code. The last time I ran it I shut it down like always, with no load and at a normal idle. It has never not started and never failed to run normally.

At times it has been slow responding but it always started.

Terry

[Schuby]

Might be worth a try to hold down the battery boost while trying to start the generator?

[whalepirot]

Originally Posted by Terry W

Went out to exercise the generator and no dice.

Do you have the repair manual for it? It's 50+ pages, contains a troubleshooting section, including retrieval of trouble codes.

There's 3 fuses under an access plate on the Genset, protecting the control circuits.

Selected pages attached; hope this helps.

[Terry W]

Shabby, Batt boost makes no difference.

Whalepirot, No I don’ have the manual you mentioned. I have a couple of owner/installation pamphlets, about 30 pages each. They are fairly useless for troubleshooting, mostly they say, “see authorized dealer”.

I did find a parts manual on line and scoured it for any kind of sensor or switch that might inhibit cranking due to low fuel pump pressure or low oil or coolant level. I didn’t find anything except a low oil pressure switch which lead me to believe it would inhibit starting rather than cranking, which to me would make sense.

I’ve wondered about the starting process and how it works. I know when I push the start button the fuel pump runs for a few seconds, stops and then a couple of seconds later the starter engages and it cranks. This is as far as I know normal operation based on other MH generators I’ve used. The starter engaging step is absent in the process.

I can’t find any info on how the process plays out.

Terry

[Jim Durley]

If there is a persistent code that has not cleared, it will not try to start. Turn off the chassis battery disconnect in the battery compartment for 20 seconds and it will clear the code. Try again.



Jim Durley
2004 Alpine MDTS

[Terry W]

Jim, I’ll give it a try tomorrow, thanks

[Terry W]

Update,

I took the side cover off this morning, checked connections all looks good.
All voltages are good to the fuses and also to the starter.

Still no go using the switches even opening up the harness taking the dash switch out of the picture.

We ended up jumping across the starter solenoid and the starter engages and it starts like it would normally start. We did hold the start switch while we jumped the starter solenoid so it was primed and in the start mode. We let it run for a little while and shut it off using the switch and it wouldn’t restart with switch. Wishful thinking! Jumped the solenoid again and it fired up again.

Does this give anybody any ideas for a cause and a remedy??

Hoping to dry camp second week of Nov.

Terry

[Kid Gloves]

I’ll put bad solenoid, or solenoid isn’t getting the 12V signal to close, in the idea hat.

[Jeep401]

Originally Posted by Kid Gloves

I’ll put bad solenoid, or solenoid isn’t getting the 12V signal to close, in the idea hat.

One of the two!

[Terry W]

I’ll pull the starter off in the next couple days and get it checked out and replace it if bad. If it’s not bad then I’ll start looking elsewhere.

Obviously hoping for the easiest solution.

Thanks, Terry

[tiffy2000]

put a test light on the starter solenoid small wire terminal and hit the start button , if it lights up but doesn't start I'd suspect the solenoid , same procedure but big terminal of starter, if it lights up then solenoid is probably good and starter is bad.