Oil pressure intermittent - Competition Diesel.Com

madmikeismad · 05-07-2016, 03:42 PM

I know the stock sending units are junk and are pretty much just telling you that you have oil pressure. Starting today, my oil pressure drops to ZERO at idle, but if I bump the throttle and give it another 50rpm, the oil pressure jumps back up to the middle like it usually sits at.

So, does the sending unit just stop giving a reading once oil pressure drops below a certain point, or does the oil pump actually not pump enough below a certain rpm? It's idling at 800-850 by the way.

Mark Nixon · 05-07-2016, 03:49 PM

Funny you mention this, my 2002 has the gauge stuck at ~35 psi with the key on, not running.
The best way to know is to verify it with a mechanical gauge.

Mark.

madmikeismad · 05-07-2016, 03:54 PM

Quote:

Originally Posted by Mark Nixon

Funny you mention this, my 2002 has the gauge stuck at ~35 psi with the key on, not running.
The best way to know is to verify it with a mechanical gauge.

Mark.

Thats the plan, I'm just asking this here because I'm paranoid, and like to be sure. Plus I like to understand how things work.

stubz616 · 05-07-2016, 04:45 PM

My truck did that too and it was a bad sender. Verified with a mechanical gauge.

Sent from my iPhone using Tapatalk

stubz616 · 05-07-2016, 04:45 PM

Another time it would drop to 0 if you went over 2k rpm. Also was a bad sender.

Sent from my iPhone using Tapatalk

Blueboy · 05-07-2016, 05:27 PM

My truck did the same thing, 0 at idle, step on pedal it would come up.
Dealer said sending unit was bad, told me to drive it until new one came in.
A week later when I took in for replacement, I received a call telling me
They had to replace my motor. Bad oil pump.

madmikeismad · 05-07-2016, 06:18 PM

Quote:

Originally Posted by Blueboy

My truck did the same thing, 0 at idle, step on pedal it would come up.
Dealer said sending unit was bad, told me to drive it until new one came in.
A week later when I took in for replacement, I received a call telling me
They had to replace my motor. Bad oil pump.

Well ****

jasonc · 05-07-2016, 06:34 PM

I've had two work trucks that would read zero at idle sometimes and wrote it off as the sender. Both made it 400k no problems.

Ram12vcummins · 05-07-2016, 06:57 PM

Automatic? Maybe raise idle? I've read the stock shows zero below 15 psi or something. Mine dives now and again if I lug motor down just putting round in yard or something.

DDually · 05-07-2016, 08:19 PM

Quote:

Originally Posted by Ram12vcummins

Automatic? Maybe raise idle? I've read the stock shows zero below 15 psi or something. Mine dives now and again if I lug motor down just putting round in yard or something.

I tried bumping the idle on a customers 98 12v that eats oil pressure sending units and at the point that it helps it read oil pressure correctly the idle is set obnoxiously high. It works... but its annoying. Trying to find a short in the system somewhere. The customer also found a new gauge cluster to swap in just to see if that solves anything. Hope it isnt the oil pump because its been doing this for 100k+ miles haha

biggy238 · 05-07-2016, 11:27 PM

Pretty sure the OE stuff has a massive amount of hysteresis built in to keep people away for the dealer with complaints. Mine reads a needle below 40 no matter what, which is completely illogical.

I think doctoring the factory setup into a scientific level of accuracy will be fruitless in the long run

Sent from my XT1053 using Tapatalk

madmikeismad · 05-08-2016, 12:50 AM

What thread/fitting is it where the sender goes into the block? I'm going to T it off and run a sender just so I can keep the idiot light function in the cluster, and a mechanical gauge that will end up in the cab permanently so I can keep from chitting myself when the light does come on..

blackedout12V · 05-08-2016, 06:18 AM

i have a 98 12v that does essentially the same thing. sometimes at idle the oil pressure light comes on and dings, barely touch the throttle it goes away. when i take off and the rpm dips down(5spd) same thing will happen. been this way for over 6yrs. when i first got the truck it bothered me also, a guy told me that it was a problem in the ecm if i remember correctly and that he seen it on a bunch of 9812v trucks, just what i was told, and my experience with my 9812v.

Blueboy · 05-08-2016, 08:37 AM

Quote:

Originally Posted by madmikeismad

Well ****

They replaced motor with 18,000 on it.
Chrysler sent complete new motor, plug and play.
Marina Dodge here in Webster NY was the dealer that
said sending unit was bad.

Drasko · 05-08-2016, 12:37 PM

Quote:

Originally Posted by Blueboy

They replaced motor with 18,000 on it.
Chrysler sent complete new motor, plug and play.
Marina Dodge here in Webster NY was the dealer that
said sending unit was bad.

Was it on their dime or yours?

Blueboy · 05-08-2016, 04:22 PM

I paid nothing and they gave me a rental car to use for a week.
Before they changed it, Chrysler sent a rep to see if I did done
anything to it. Modifications!

05-07-2016, 03:42 PM	#1
madmikeismad Name: madmikeismad Title: So mad Status: Not Here Join Date: Dec 2009 Location: Newalla, OK Member`s Gallery Posts: 14,347	Oil pressure intermittent I know the stock sending units are junk and are pretty much just telling you that you have oil pressure. Starting today, my oil pressure drops to ZERO at idle, but if I bump the throttle and give it another 50rpm, the oil pressure jumps back up to the middle like it usually sits at. So, does the sending unit just stop giving a reading once oil pressure drops below a certain point, or does the oil pump actually not pump enough below a certain rpm? It's idling at 800-850 by the way. __________________ Mike Hill

05-07-2016, 03:49 PM	#2
Mark Nixon Name: Mark Nixon Title: No Savior among the flesh Status: Not Here Join Date: Feb 2009 Location: Brownville, Nebraska Member`s Gallery Posts: 8,676	Funny you mention this, my 2002 has the gauge stuck at ~35 psi with the key on, not running. The best way to know is to verify it with a mechanical gauge. Mark. __________________ If you or I did business like the PEOPLE in government do business, we'd be put in jail. Government is coercive. Anarchy: The state of existence where there are no masters & no slaves. Therefore, Anarchy means the ABSENCE OF SLAVERY, or, in other words, FREEDOM.

05-07-2016, 04:45 PM	#4
stubz616 Name: stubz616 Title: Too Much Time Status: Not Here Join Date: Oct 2008 Location: Brewster, MA Member`s Gallery Posts: 1,327	My truck did that too and it was a bad sender. Verified with a mechanical gauge. Sent from my iPhone using Tapatalk __________________ 95 RCLB Farrell Diesel Stage 5 13mm pump,Hamilton Springs,Retainers,Pushrods,Fluidampr,Steed Speed,S467.7/soon to be S488 atmo,Full Billet Trans,DPC 4 disk TC,BD Pressure Loc,Haley Speed 5x.022s,Diesel Pros Custom Cam,O-Ringed,.010 over HG,A1000,Hellman sump,625 Studs, 30*

05-07-2016, 04:45 PM	#5
stubz616 Name: stubz616 Title: Too Much Time Status: Not Here Join Date: Oct 2008 Location: Brewster, MA Member`s Gallery Posts: 1,327	Another time it would drop to 0 if you went over 2k rpm. Also was a bad sender. Sent from my iPhone using Tapatalk __________________ 95 RCLB Farrell Diesel Stage 5 13mm pump,Hamilton Springs,Retainers,Pushrods,Fluidampr,Steed Speed,S467.7/soon to be S488 atmo,Full Billet Trans,DPC 4 disk TC,BD Pressure Loc,Haley Speed 5x.022s,Diesel Pros Custom Cam,O-Ringed,.010 over HG,A1000,Hellman sump,625 Studs, 30*

05-07-2016, 11:27 PM	#11
biggy238 Name: biggy238 Title: Too Much Time Status: Here Join Date: Aug 2008 Location: Just North of Wrong Member`s Gallery Posts: 10,859	Pretty sure the OE stuff has a massive amount of hysteresis built in to keep people away for the dealer with complaints. Mine reads a needle below 40 no matter what, which is completely illogical. I think doctoring the factory setup into a scientific level of accuracy will be fruitless in the long run Sent from my XT1053 using Tapatalk __________________ Check out @bdmaximusworx 05.5 Campanella White TDi Jetta 5spd 45.5MPG -Little Sexy '10 Silver F250 CCLB 4X4 6.4L cummins Swapped Insta @trash.panda250

05-07-2016, 05:27 PM	#6
Blueboy Name: Blueboy Title: Too Much Time Status: Not Here Join Date: Aug 2006 Member`s Gallery Posts: 993	My truck did the same thing, 0 at idle, step on pedal it would come up. Dealer said sending unit was bad, told me to drive it until new one came in. A week later when I took in for replacement, I received a call telling me They had to replace my motor. Bad oil pump.

05-07-2016, 06:34 PM	#8
jasonc Name: jasonc Title: Too Much Time Status: Here Join Date: Nov 2009 Member`s Gallery Posts: 4,412	I've had two work trucks that would read zero at idle sometimes and wrote it off as the sender. Both made it 400k no problems.

05-07-2016, 06:57 PM	#9
Ram12vcummins Name: Ram12vcummins Title: Too Much Time Status: Not Here Join Date: Mar 2015 Member`s Gallery Posts: 1,659	Automatic? Maybe raise idle? I've read the stock shows zero below 15 psi or something. Mine dives now and again if I lug motor down just putting round in yard or something.

05-08-2016, 12:50 AM	#12
madmikeismad Name: madmikeismad Title: So mad Status: Not Here Join Date: Dec 2009 Location: Newalla, OK Member`s Gallery Posts: 14,347	What thread/fitting is it where the sender goes into the block? I'm going to T it off and run a sender just so I can keep the idiot light function in the cluster, and a mechanical gauge that will end up in the cab permanently so I can keep from chitting myself when the light does come on.. __________________ Mike Hill Last edited by madmikeismad; 05-08-2016 at 12:51 AM.

05-08-2016, 06:18 AM	#13
blackedout12V Name: blackedout12V Title: Green Behind the Ears Status: Not Here Join Date: Mar 2010 Member`s Gallery Posts: 70	i have a 98 12v that does essentially the same thing. sometimes at idle the oil pressure light comes on and dings, barely touch the throttle it goes away. when i take off and the rpm dips down(5spd) same thing will happen. been this way for over 6yrs. when i first got the truck it bothered me also, a guy told me that it was a problem in the ecm if i remember correctly and that he seen it on a bunch of 9812v trucks, just what i was told, and my experience with my 9812v.

05-08-2016, 04:22 PM	#16
Blueboy Name: Blueboy Title: Too Much Time Status: Not Here Join Date: Aug 2006 Member`s Gallery Posts: 993	I paid nothing and they gave me a rental car to use for a week. Before they changed it, Chrysler sent a rep to see if I did done anything to it. Modifications! Last edited by Blueboy; 05-08-2016 at 04:30 PM.