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Topic: Detroit 6V92 , Alison 4 speed  (Read 821 times) previous topic - next topic

Detroit 6V92 , Alison 4 speed

Just developed a condition I have not encountered before. Coach had been running fine, got down to half a tank and filled up. From that point on coach would not gain speed and did not want to shift up. Seems like will not exceed 2000 rpm's and that is keeping it from shifting as it should. Opinions requested, plugged fuel filters? Or something more serious?

Re: Detroit 6V92 , Alison 4 speed

Reply #1 –
Key here is that you filled up. Check the bottom of your Racor sight plastic on the primary. Betting you picked up algae at the fill up.

Do you need filter numbers? Is your frame mounted hand primer working?

Pierce

Re: Detroit 6V92 , Alison 4 speed

Reply #2 –
No Racor filter, replaced both primary and secondary fuel filters. Primary had a black sludge build up restricting the flow. Runs like a champ 💪. All kinds of problems going through my head, happy camper now.  ^.^d  Thanks for the reply.
Yes I have a frame mounted primer pump, never had to use it always prefilled the filters.

Re: Detroit 6V92 , Alison 4 speed

Reply #3 –
Quote from: Gerry Vicha –
No Racor filter, replaced both primary and secondary fuel filters. Primary had a black sludge build up restricting the flow. Runs like a champ 💪. All kinds of problems going through my head, happy camper now.  ^.^d  Thanks for the reply.
Yes I have a frame mounted primer pump, never had to use it always prefilled the filters.
Outstanding! Glad you are back on the road. Once you get to a location where you will be for a while, drop the tank side down with the HWH and take a look with a mirror and LED light at the bottom of the tank. Best done with a low tank level. You can use a hand pump or electric pump to get rid of any water/algae at the bottom of the tank. Might look at the sides also to see if any algae is stuck there. Warm weather and water make for great algae growing conditions. I take it that you have a anti-fungicide in your tank now?

The chassis mounted prime pump is great but after a few years, the little O rings go south. NAPA or most hardware stores with have O rings to fit. When I replaced ours, they cost $0.10/each. I had an air leak problem due to a crack from overtightening on the silver relief valve in the photo. The gold one is the replacement. You have to watch where you purchase it as many stores will charge about $70 for it. I went to the local truck/logging shop and they got it for me for about $35.

Prefilling filters works but there is a small possibility of introducing foreign material into the system. A cloth at the bottom of a funnel would probably do the trick.

Pierce
 

Re: Detroit 6V92 , Alison 4 speed

Reply #4 –
Quote from: Gerry Vicha –
Seems like will not exceed 2000 rpm's and that is keeping it from shifting as it should. Opinions requested, plugged fuel filters? Or something more serious?

Congratulations on your new fuel filter!

If you had grown up in New England, you would have experienced the same thing for a similar reason.

When it becomes cold enough the paraffin wax solidifies into flakes and plugs the fuel filter. There is an additive to prevent this from happening, or you can install an in-line fuel heater.