Recent content by System1459

That sound very plausible. I appreciate your help. I think this is as close to knowing for sure as I will get. Thanks again.

The trucks won't start semi randomly. Basically when the truck is off air leaks cause the tanks to lose pressure. My concern is why they fill at different speeds. Starter and main tanks. The only thing separating them is about 5ft of air line and a check valve that protects the starter tank...

Yes they have them per DOT. Set to 150 I believe as most trucks are.

I'm not sure what a decompressor is. As far as I know the trucks do not have them. Yes the trucks all have Bendix AD9 air dryers and of course purge valves. This is fed from the compressor, then splits off to the main and starter tanks. I haven't noticed a specific issue with not starting...

Yes the starter only requires 90psi. Possibly less. All the trucks are 95-98 models. All with the same quirk.

Depending on the pressure of the main tank. There is either no change in pressure if the main tank gauge reads 120. Which makes sense. If the main tank reads less than 120 it will raise until it reaches 120 but the vehicle still will not start. I'm going to try disconnecting the aux line as...

The aux line is connected to the main air system/tanks. Which then continues on to the starter tank as usual. The aux input was designed to allow supplemental air for braking while towing the vehicle

I agree. But bosses don't see it as necessary. "Just plug an airline into it." :-/ Thank you all for your thoughts.

I realize what you are saying and agree. I also realize their is information that I didn't provide. The system is maxed out at 140psi. I.e. The safety valves prevent it. Normal operating pressure is 120psi for the maintanks. If the main gauges show their is 120psi but the engine won't turn over...

The pressure in the starter tank is significantly lower than the main tank, more than a few pounds. I was hoping for a better explanation from some unknown to mortal men physics lesson. Haha The main tanks drop lower than the starter tank due to the check valve. The design theory is that your...

So I am a heavy vehicle mechanic. One of my vehicles has an air starter with a separate air tank dedicated to the starter. This tank is fed from the main air tanks on the truck with a check valve to only allow air into the starter tank. The gauge on the dash only displays the pressure in the...