Community Forums

Epp · 06-12-2021, 11:09 PM

On our 2001 DSDP, Spartan chassis, The dash oil pressure reads “absolute” pressure ( roughly 15 psi higher than gauge) instead of “gauge” pressure. The air pressure gauges on the dash are also picked out at 150 psi and I suspect they are reading absolute also. My scabdisk shows proper “gauge” oil pressure, And shows this offset through the entire oil pressure range. Our coach still has the old style oil pressure center it reads real oil pressure not just 55 psi constant.

Are 99DSDP on the Spartan Chassis had the binary oil pressure send or so I didn’t notice it there but if I remember right the air pressure gauges front and rear would always show about 135 psi.
Our coach has the Stewart Warner gauges.

Has anyone else run across this issue?
Is there a way to re-calibrate?

Thanks
Epp

John_Penzi · 06-13-2021, 06:29 AM

A lot of the 8.3's were refitted/retrofitted (by/through Cummins) with an oil pressure switch instead of a sending unit. Either on or off. Either you have oil pressure or you don't. I think my gauge will read 55-60 psi when the engine is running regardless of temp or RPM. Don't remember the reason why but if you do a forum search there is a lot of information on here about it. I asked my diesel guy about it and I think his thought was customers were being a real pain complaining that they though oil pressure was too low under certain conditions so Cummins just dumbed down the gauge. Not sure if that is true but that's what I remember.

My air pressure gauges read normally and fluctuate with actual pressure.

I also have a 2001 DSDP with the cummins/spartan combo.

Epp · 06-13-2021, 10:53 AM

Correct, I still have the original style oil sender in my rig. Oil pressure will fluctuate depending on oil temperature RPM etc. etc. But it is reading consistently 15 psi higher than what is shown on the scandisc. For example, the scandisc display reads 75 psi oil, but the gauge will show 90 psi. Front and rear air pressure read 150 psi, when I think I remember air pressure is normally around 135 psi.

Quote
“ My air pressure gauges read normally and fluctuate with actual pressure.”
End quote
What pressure are you seeing on your air gauges?

Thanks
Epp

John_Penzi · 06-14-2021, 07:27 AM

Quote:

Originally Posted by Epp

Front and rear air pressure read 150 psi, when I think I remember air pressure is normally around 135 psi.

Quote
“ My air pressure gauges read normally and fluctuate with actual pressure.”
End quote
What pressure are you seeing on your air gauges?

Thanks
Epp

Not front and rear air pressure, primary and secondary tanks. I think mine are usually around 120 psi when the suspension is all aired up and the engine is running. Maybe a little higher- I just do a quick scan of the gauges and just make sure everything is about where it needs to be rather than exact numbers when going down the road.

Not knowing much about what you are using for readings I would just focus on fluctuations rather than what the gauges are reading vs what the scanner is.

Epp · 06-14-2021, 11:52 PM

That is one of the problems. My air pressure readings are reading around 150, and the factory gauge tops out at 150. My oil pressure gauge reads 15 psi without the engine running, which is absolute pressure (psia) at sea level, instead of 0 (psig).

By the way, which tank is primary (Front or rear) and which is secondary. I just assumed that one tank was for the rear and one was for the front with the way the gauges were labeled.

Thanks
Epp

John_Penzi · 06-17-2021, 04:27 PM

Quote:

Originally Posted by Epp

That is one of the problems. My air pressure readings are reading around 150, and the factory gauge tops out at 150. My oil pressure gauge reads 15 psi without the engine running, which is absolute pressure (psia) at sea level, instead of 0 (psig).

By the way, which tank is primary (Front or rear) and which is secondary. I just assumed that one tank was for the rear and one was for the front with the way the gauges were labeled.

Thanks
Epp

Out in the coach today- air pressure (gauge) is 120-130 PSI. The gauges on mine are also marked front and rear which I never noticed before (I've had my CDL for over 20 yrs and have never seen that before). That can't be the way they are set up. I'm going to have to look into how these things are configured/plumbed.

Epp · 06-17-2021, 05:54 PM

Thanks for checking. With my gauge reading front and rear and not knowing any better that’s just it I assumed what they were.

Epp · 06-20-2021, 10:44 AM

One of the reasons I was asking this question is if your gauge is reading 20 psi (absolute-psia) at idle then that means you only really have 5 psi of oil pressure (gauge - psig).

Skip426 · 06-20-2021, 12:17 PM

Quote:

Originally Posted by Epp

Are 99DSDP on the Spartan Chassis had the binary oil pressure send or so I didn’t notice it there but if I remember right the air pressure gauges front and rear would always show about 135 psi.
Our coach has the Stewart Warner gauges.
Epp

Epp, I have a Spartan air system diagram ( dated June 99 ) that indicates the gauges on the 99 chassis were manual . So electronic gauges must have come with the wiring changes , as detailed in the 2000/2003 pdf.
I wonder if Spartan Motor Home Support would have any info on air system or gauge calibration .
Have your serial number handy .1-800-543-4277

Epp · 06-20-2021, 02:23 PM

I know for sure that my 99 DSDP had electronica air gauges with the electronica sensor, I had to replace one before I sold it LOL.
I agree, I think Spartan will have to be my next stop for some of this information. I noticed that the gauges go through a Stewart warner control box before they go out to the gauges themselves.

Thanks for the reminder for the spartan Chassis number. I will have to get that before I give them a call.