Engine/Transmission (1994 - 1998) Stupid oil pressure gauge

[WPeschel]

Lightman is right on the money! It is only the 1998 12 valvers with this trouble. I have this trouble and am so tired of dings and zero pressure if I let my truck drop to normal idle, I'm gonna go for the TSB to fix. Mine is worst with AC on sitting at a light in hot weather. If your truck isn't a '98 don't assume it's a programmers fix. IT could cost some bucks. I heard their is a way to add a resister in parrallel to the sender to fool the "brain" and prevent this ding zero pressure crap. Any ideas about this? My local Dodge ******* repair shop didn't know of this TSB. Scary!:{:{

I have the TSB printed out for when i finally get the time to take it to the dealer to have it done... . Here it is for the ones that need it... TSB 08-22-99 ... .

As stated above it only for the 98 twelve valves...

 

[TLarsen]

Yep, since the hot weather has returned and I'm running the AC the same dinging and zero oil pressure on the gauge as returned for me as well. It seems that I have to readjust my idle about every two years, it slowly creeps lower over time. And now that it's hot, my truck will idle down to about 650-700 rpm in gear with the AC on.

BTW, I have also switched from the 5W40 synthetic to 15W40 Valvoline and it's made no difference.

 

[HerbW]

Well I just upped the idle today and I haven't had any dings yet. The first time it's been upped since new. The zero reading and dinging is un-nerving, especially when you're out in the boonies trying to burn some diesel and have fun! I'll probably still consider the TSB upgrade for '98 trucks to once and for all stop the problem. The TSB should of really been a recall. Dumb to have to pay for their problem.

 

[Signal73]

when the idle is too low the oil pump does not spin fast enough to maintain the oil pressure the computer likes to see. The eariler ones do it too, my 95 will with the ac on at a stoplight, especially with the 93% converter thats in my trans, it drags the idle down.

Up your idle to 800 in gear with the AC on and 90% of your guys problems will most likely go away.

 

[WPeschel]

Well I did the TSB a week ago... I havent had a ding or 0 reading guage since... It was 44 bucks though, but worth it...

 

[fest3er]

See these two threads:

• https://www.turbodieselregister.com...ission-1994-1998/185760-low-oil-pressure.html
• https://www.turbodieselregister.com...ransmission-1994-1998/203588-need-advice.html
  

for more info on this problem.



The short answers:

• the sensor gets weak over time and the PCM stupidly interprets this slightly weak signal as 'dangerously low' oil pressure
• parts stores want hundreds for the sensor; Cummins Atlantic here wanted a whopping $33 plus $15 for overnight shipping.

 

[WPeschel]

See these two threads:

• https://www.turbodieselregister.com...ission-1994-1998/185760-low-oil-pressure.html
• https://www.turbodieselregister.com...ransmission-1994-1998/203588-need-advice.html
  

for more info on this problem.



The short answers:

• the sensor gets weak over time and the PCM stupidly interprets this slightly weak signal as 'dangerously low' oil pressure
• parts stores want hundreds for the sensor; Cummins Atlantic here wanted a whopping $33 plus $15 for overnight shipping.

I replaced my sending unit with one from orielly a few months ago... It only took care of the problem for a month or two. . Replacing the sending unit is only a temporary fix. . The real fix to this is the TSB TSB 08-22-99

 

[fest3er]

Perhaps the aftermarket sensors are not as reliable? I replaced mine in '01 I think, and again in '07 with the OEM part from Cummins. My experience is that the OEM sensor lasts 4-6 years. But, as always, YMMV.

 

[WPeschel]

Perhaps the aftermarket sensors are not as reliable? I replaced mine in '01 I think, and again in '07 with the OEM part from Cummins. My experience is that the OEM sensor lasts 4-6 years. But, as always, YMMV.

The TSB explains it all... Fix it right the first time... Unless you like snaking your arms up under there to change it out every few months/years... To each his own...

 

[TLarsen]

Wow, so I started this thread about 1. 5 years ago. I believe I have this solved finally.



When this started, it only happened in the hot summer months, it slow has gotten more common and started happening even on cold winter days.



4 months ago I decided to change the oil pressure sending unit. I was at the dealership picking up a new thermostat because the old one taking forever to warm up, and picked up an oil pressure sending unit while I was there. I swapped out the thermostat, then couldn't remove the sending unit because my deep sockets aren't deep enough. I set the sending unit aside and told myself I'd put it on later.



I haven't done anything else, and I haven't had anymore issues, none!



I've noticed that with the new thermostat the truck runs about 10-15 degrees cooler than the old one, so either the cooler engine has fixed it, or unplugging the sensor and plugging it back in fixed it.



All winter long the oil pressure light was a daily occurrence, and it hasn't happened since. I can't explain it, but I'm happy.