Does your oil pressure gage take a while to start moving?

[Kevin ACR]

I just paid attention today when I did a cold start and the pressure gage didn't move for seconds. Then when moving the car a couple hours later, still luke warm, the same thing.

My question, is it normal to see what I consider to be a long delay (~`2+ full seconds) before the gage starts moving up in its sweep? Is the car running with no oil pressure feeding teh bearings , etc? Thanks.

 

[Kevin ACR]

Well, thats not too encouraging. Anyone else?

 

[luc]

Kevin,
Do your oil pressure warning light go off as soon that you crank the engine?
You have 2 oil pressure sending units,1 for the oil pressure gauge and 1 for the warning light.
Luc.00GTS

 

[Kevin ACR]

Luc:

Just did a cold start, 40f with one week old 10w30M1 and the gage stayed all the way down for ~`2-3 seconds after the start and the oil pressure warning icon on the cluster stayed on too until the gage jumped.

I find it hard to believe its always been like this, since whenever I did an oil change I watched for pressure to come up and the only time I remember this being an issue is when I had a new filter that wasn't all the way full of oil.

Anyone with an ACR want to take a look on cold start and watch the gage and light I'd appreciate it. If there really is no pressure something must have changed, now just to figure out what it was. Don't like hearing the rumble with no pressure showing on the gage. With a restart pressure reading is immediate, what could cause this? Any ideas appreciated, if they are all like this then no issue?

 

[John ACR]

Kevin,
Will do later today I hope.
I'll post ASAP.

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Kevin ACR:
I just paid attention today when I did a cold start and the pressure gage didn't move for seconds. <HR></BLOCKQUOTE>

Normal.........does NOT mean ZERO pressure, however! LOW at start, but not stuck on zero.

When Team Viper engineers hooked up my GTS and we rented PIR for some early diagnostics, the PCM-interfaced readouts on the laptop would read almost intantaneous pressure changes....but the "capillary" nature of the guage sending unit causes it to be slow to react....hence the brief delay.
CONVERSELY:
Main factor for most is fast, high-G turns that FALSELY indicate high, good pressure, when you may in fact have almost NONE ! This is why MANY 1996.6 -1999 Vipers have starved oil, broken rods, and were UNAWARE that they were having periods of oil starvation til the motor let go.

Commercial message:

Please call me to UPGRADE YOUR 1996.6 - 1999 PAN / tray at a minimum. (WORST years) All years can benefit from trap-door baffles and improved windage / scraper / drain trays.
And Stage 3 ....an ACR Oil Filter Adapter.
Peace of mind, and NO rebuild: Priceless!

 

[Sean Roe]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JonB - PartsRack:
.......
When Team Viper engineers hooked up my GTS and we rented PIR for some early diagnostics, the PCM-interfaced readouts on the laptop would read almost intantaneous pressure changes....but the "capillary" nature of the guage sending unit causes it to be slow to react....hence the brief delay........<HR></BLOCKQUOTE>

So, um, Jon, are you saying that the PCM has the ability to monitor the engine oil pressure and display this information in the running datastream? Also can you explain the capillary nature of the electric sending unit and why it would cause a delay in the gauge reading, but not the PCM reading?

Thanks,

 

[Ron]

<FONT face="Comic Sans MS">Not to get in the middle of this, but the slow responding nature of the stock oil gauge is a pet peeve of mine.

While I too am excited to know that the PCM monitors oil pressure readings (anyone have any idea how one could monitor that?) I can say the the capillary quality Jon referrers to is actually a silicone dampening gel that in in the needle mechanism. Figure out a way to flush that crap out and I'd bet that you have a more responsive gauge.

Perhaps some ingenious individual could figure out how to change the mechanism while retaining the stock needle and gauge face... Hint, hint....</FONT f>

 

[JonB]

Sean.......

When T.V. came to town in 6/96, they tested COOLANT PRESSURE, VACUUM, OIL PRESSURES, temps, and more. That TEST resulted in 42 brand-new Vipers already in Reliable trucks going BACK TO CAAP, and 152 total getting new oilpans! Never before....never since.

However, Since I believe electricity is carried by tightly-condensed smoke particles......and the PROOF is that if you cross wires the smoke particles can be seen leaking out...

The simple answer is: the slow-reacting OE guage is NORMAL. Everyone here has it.

More background.....Back in 6/96, due to some unusual problems on the 1-st released GTS, Team Viper hooked up some sensors and leads to my GTS. What I was told by the Team Viper engineer who came to PIR 6/96 for the ride-along is that the Viper IP oil guage and water guages are analog and slow to react, due in part to the slowness of liquid moving to the sensors. [liquid-in-tube=capillary action. Yes? Maybe it was liquid in guage?! Or Would that be viscosity slowing the needle? ] ....

IN ANY CASE: the doo-hicky-thing-a-ma-bob sensors that they hooked up both underhood and underdash for the hot laps test reacted faster, ie real-time and digitally, not analog..... Does that make better sense? If I mis-stated the sensor/electrical relationship, I regret it. Smoke-particle mentality due to Lucas Electrics training!

But my answer to Kevin and JM stands: NORMAL. Don't panic! I hope you agree.....NORMAL

 

[Sean Roe]

Yes Jon, I agree that when the oil pressure is slow to come up on the Viper at startup, it is "normal" for a Viper, unfortunate for many reasons, but normal.

The rest of your answer, well, I guess I'm going to have to let the pain killers wear off before I think much more about it.

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Sean Roe:
Yes Jon, I agree that when the oil pressure is slow to come up on the Viper at startup, it is "normal" for a Viper...The rest of your answer, well, I guess I'm going to have to let the pain killers wear off before I think much more about it.
<HR></BLOCKQUOTE>

Sean, I did not know you were injured. Get well fast!

I was indeed puzzled as well when they measured COOLANT PRESSURES (!) in 3 internal locations with the sensors they installed, as well as other unusual "Step-4" data.....

To paraphrase an old physics class cartoon mocking scientific method:

Step 1) Guages acting weird - reasons unknown.
Step 2) Car acting weird - reasons unknown.
Step 3) Engineers get involved - sample the data.
Step 4) A MIRACLE HAPPENS "Step 4"
Step 5) Engineers have answers.
Step 6) The probelm is solved, but I don't know how!

 

[Sean Roe]

Thanks Jon, just some fractured ribs and soreness from an unusually bumpy ride at work. Just don't make me laugh

 

[Rich Carlson]

When I went to doo-hicky-thing-a ma-bob sensor school, they talked about NTC and PTC's. A coolant sensor is an NTC which means that when the temperature of the engine goes up, the sending unit resistance goes down. The temp gauge in the dash changes the temp reading based on the resistance to ground from the sending unit.

The oil pressure sending unit is a PTC which means when the oil pressure goes up, the resistance goes up. The oil pressure gauge in the dash changes the reading based on the resistance to ground from the sending unit.

No smoke or mirrors, just really really fast electrons on wires.

Put a external oil pressure gauge on the engine if you suspect a problem.

 

[luc]

Sorry JonB,but on this "capillary " thing,you got it wrong.

You have 2 types of pressure gauges.
Mechanical and electrical.

Electricals work as Rich explained with Ohms and Mechanicals are based on a 1849 French Patent by Eugene Bourdon,and work with a Bourdon Tube.

In a Bourdon Tube ,you have a small tube that contain a gas that expend with heat.
The gas in expending,put pressure on a mechanism that move the needle.

Capillary come from the Latin word "Capillaris" and mean "hairlike".
A mechanical gauge with a Bourdon Tube is also know as a "capillary gauge" due to the size/nature of the small tube used in it.

Capillary action or attraction is the name for the force that causes a liquid to be raised against a vertical surface,as water in a clean glass tube.

Capillary action and capillary wall resistance are the basis for a US Patent (5,158,359) that I got for a "Multi-color Chemical Lighting Device"
A very complicated name for the multi-color "Glow-in-the-dark" necklaces that you see at fairs or fireworks.

Luc.00GTS

(I hope that my spelling is more to your liking this time!!!!!!!)

 

[John ACR]

Kevin,
Sorry for the delay, but I will post my results this afternoon.

 

[Steve-Indy]

Stopwatch said 3.8 sec. from time 2001 GTS engine fired til oil pressure gauge moved...has NOT been started in two weeks...temp in garage a steady 60 degrees.

 

[Sonny 00 GTS ACR]

I respect all of the opinions given even if they do conflict somewhat. But low oil pressure at any time makes me nervous. So call me paranoid, but I bought the windage tray/trapdoor setup and an accumulator sump to fix the problem, and I feel much better now.

Sean, I hope you have a quick recovery!

 

[Ron]

<FONT face="Comic Sans MS">2:32 seconds for a non-ACR GTS. Last start 5 days ago, also 60 degrees. M1 10W-30.

While not exactly scientific, can one assume that the 64% delay is caused by the need to refill the ACR oil cooler?

Note that the idiot light extingished (meaning &gt;8 PSI of oil pressure) by the time I released the key.</FONT f>

 

[John ACR]

Kevin,
Same on my ACR.
Started at zero and after a few seconds delay went up.
Enjoy the ride. I just did.