I have a 1990 Chevy 454 and while have found the way to check the timing, I have not found the spec.. This is Winnebago Chieftan RQ 33. The reason I'm asking is because when I shut the engine off it keeps on running. Thank you so much in advance for your help. Any other suggestions would be greatly appreciated.
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!
Being a 1990 the timing may be computer controlled and non-adjustable. The way I check is to pop off the distributor cap and see if the rotor will move without the engine moving. If it will move a couple of degrees you don't have computer controlled timing.
I can't help with the factory spec but with this being a 21 year old engine the factory spec may not be the best to go by. I hook up a vacuum gauge and time it to where I get the best steady vacuum. If I hear pinging on the test drive I back it down a degree or two.
Is it fuel injected or carbureted? Dieseling (run on) could be any number of things but my understanding of the root cause is that you've got enough heat somewhere in the engine/heads/exhaust/plugs to ignite the fuel in the absence of spark. With a carburetor that doesn't have a fuel shutoff solenoid it will deliver fuel as long as the engine is spinning.
I would also suspect it may be a too-lean mixture which could be caused by a number of things. An engine that runs too lean will have high cylinder and exhaust temps.
If it is carburated check the throttle shaft for wear. This is the shaft that runs thru the front venturies. Mine was worn and the throttle would hang to far open and would diesel when the key was turned off. New bushings were installed in the carb when I had it rebuilt.
Before my carb was fixed I would shut the key off before putting the transmission in Park. This eleminated the dieseling most of the time.