Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > RV SYSTEMS AND TECHNOLOGIES FORUMS > RV Systems & Appliances
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 12-02-2024, 02:48 PM   #1
Junior Member
 
Join Date: Dec 2024
Posts: 3
Onan preheat not working

I have an Onan Quiet Deisel 8000 that won't start. It's in a 2005 Mandalay. After trouble shooting, I realized when I hit the start button, it turns over immediately with no delay for the glow plugs to preheat. Ambient temp is about 40F. I checked the 25 amp fuse for the plugs and it's ok. I know there is supposed to be a delay to preheat before the starter motor begins especially when cold. I do remember there was always a slight delay, but now, no delay. Any idea what's causing this? Thanks
Flight Time is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 12-03-2024, 10:32 AM   #2
Senior Member
 
Twomed's Avatar
 
Monaco Owners Club
Join Date: Oct 2009
Location: On the road
Posts: 2,195
When it is really cold...hold the start switch down to the OFF position for about 30 seconds to preheat, then start. That should help.
__________________
Happy Trails,
06 Dynasty Countess III ISL//3060
07 Hummer H3
Twomed is offline   Reply With Quote
Old 12-04-2024, 06:57 AM   #3
Junior Member
 
Join Date: Dec 2024
Posts: 3
Thanks for your reply. According to the Operators Manual, the stop button will run the fuel pump for priming. When the Start button is pushed, it goes into pre-heat mode (turns on glow plugs) first. Then after a few seconds, the starter motor will engage. The time of the delay is based on ambient temperature. On warm days, it may take 1 to 3 seconds. On really cold days, 15 or more seconds. I tested mine the other day at about 40F and there was no delay. I'm thinking the timer function has gone bad in the circuit board. I am considering making a bypass. Pull the 25 amp fuse that feeds the glow plugs and run a wire with momentary push button switch from battery to the glow plug side of the fuse holder. That way I determine the delay time.

I have a Kubota tractor that operates in a similar way. Turn the ignition switch until a yellow light comes on indicating the glow plugs are on. Then, wait 2 to 15 seconds depending on temperature, then turn to start. I would be doing similar to that if I make the bypass. Anyone on the forum ever done this?
Flight Time is offline   Reply With Quote
Reply

Tags
heat, onan



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Onan DKC/DKD genset preheat tolazy2 iRV2.com General Discussion 5 07-10-2017 01:09 PM
06 Sig will not start without preheat on asheville Monaco Owner's Forum 139 03-24-2016 06:27 PM
How not to preheat your engine... two2go RV'ing Humor & Crazy but True Stories 8 04-02-2011 09:24 PM
Convection Oven Preheat Chief RV Gourmet 9 02-08-2009 05:21 AM
HydroHot - Does yours also provide engine preheat? RVDude Newmar Owner's Forum 3 05-15-2007 07:55 AM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 01:49 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2025, vBulletin Solutions, Inc.