Diagnosing Air Throttle?

freds · February 04, 2022, 08:19:04 AM

Quote from: oltrunt on February 04, 2022, 07:57:33 AM
It might be fun to bipass the bus air system and hook up a small compressor to the gas pedal. Would that get you down the road? Jack

Interesting idea would a small tire inflator pump do it? Or hey take the front tire off the ebike LOL!!!

richard5933 · February 04, 2022, 08:20:25 AM

Quote from: freds on February 04, 2022, 08:19:04 AM
Interesting idea would a small tire inflator pump do it?

You'd need one with a built-in pressure cut off switch. Some tire inflators don't automatically stop pumping. Probably would also need at least a small tank so that it doesn't have to cycle every time you pressed the throttle pedal. That pedal is exhausting air every time it moves up.

freds · February 04, 2022, 09:31:25 AM

Hi Everyone

Thank you for your help. In looking at why the windshield wipers are not working I found a line to a pressure regulator off of a manifold port that in the parts manual is supposed to have a plug.

Then working upstream I found an air solenoid valve that wasn't receiving power. A quick jumper wire to the front junction box wiring stud 80 and hey now I have throttle!!!

Now I have an electrical problem to diagnose but that's more in my skill set...

buswarrior · February 04, 2022, 09:57:00 AM

Good find!

An electric solenoid involved in obstructing the filling of a system tank is unorthodox.

Some previous owner had some idea or other... you really want to figure out what he had in mind, and consider re-working to a more traditional pnuematic valve solution, that does not rely on electrcity for coach air system function?

Happy coaching!
Buswarrior

richard5933 · February 04, 2022, 10:06:03 AM

You're talking about a Skinner valve? As in, an electrically operated pneumatic valve?

freds · February 04, 2022, 03:12:18 PM

The value is between the accessory tank and the distribution manifold. That's what threw me off I knew that the tank had pressure...

Not sure of the type, give it juice and it opens.

richard5933 · February 04, 2022, 04:09:35 PM

Check the contacts on the valve... A little corrosion can make things act really wonky. Also check out the grounded side of the valve for corrosion where it gets its ground.

dtcerrato · February 04, 2022, 07:23:10 PM

In our 42+ years of same bus ownership we've used a 3000psi scuba tank a few times prior to installing the electric aux. air compressor. One time in the early 80s when our compressor drive failed entering NB NJ turnpike on the south end for Hartford CT @ 3pm on memorial day w/e we quickly bungeed up a scuba tank on one of the engine cradle vertical tubes with the engine door propped open just to get ahead of the rush hour traffic. It was a blast listening to the truckers on the CB radio wondering WTF is that on the back of your bus. LOL We had the fitting we needed to tap the bus air and dropped the tank pressure to 100psi using the 1st stage of the scuba regulator - that would give you enough air for an air throttle for 1000s of miles FWIW...

Tedsoldbus · February 05, 2022, 02:29:13 PM

Been down with Covid for 4 days and just saw this thread. Did you get going? I think I have an air map of mine including air throttle if you think it would help. Can scan it and PM it to you.
Great to be back with the living. Rita and I mask everywhere (but seem to be the only ones), We are doubly stuck and boosted, She had a "cold" for 5 days. Gave it to me on day 5. Just got our home test and I am positive. She is not, but doctor says she had it and gave it to me. Neighbors are calling me Typhoid Teddy. Real nice.....
Hope you are up and running Fred. Let me know if I have any documents you might need.

freds · February 06, 2022, 10:46:46 AM

Hi Everyone

Thanks for the help and problem has been totally solved!!!

The root cause of the failure was more and likely changes that the PO to the last PO made to replace the dash and then never finished the project.

In looking at the wires to the air value they are not factory wiring and looks like they were added as part of the dash project. That and the fact that they are wired to stud 80 which is not used by Prevost. Their recommendation was to wire the valve to stud 20 which is the bus running voltage line.

I am lucky that it decided to stop working while I was parked camping and not rolling down the road.

So in final analysis nothing wrong with the air system and it was an electrical problem.

luvrbus · February 06, 2022, 10:59:31 AM

Quote from: buswarrior on February 04, 2022, 09:57:00 AM
Good find!

An electric solenoid involved in obstructing the filling of a system tank is unorthodox.

Some previous owner had some idea or other... you really want to figure out what he had in mind, and consider re-working to a more traditional pnuematic valve solution, that does not rely on electrcity for coach air system function?

Happy coaching!
Buswarrior
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Prevost loves the Norgren and Humphery valves they are everywhere