oil pressure gauge
Thread Starter
|
Senior Member
Joined: Sep 2016
Posts: 916
Likes: 389
From: VA
oil pressure gauge
The quest to get the '86 back on the road. Getting closer.
My oil pressure gauge does not register any pressure.
Car is filled with new oil and filter to spec's.
I have removed the existing (original) sending unit behind the throttle tower. The well had oil in it as did the sending unit.
I am guessing the part mounted to the side at an angle (I don't know what it is called) with a single blade electrical connection is for the 'Idiot" light.
When I removed that part there was no oil up in it.
Q: Is that part supposed to have oil up in it?
Is it the 'sensor' for the idiot light?
What is it called? I can't find it in my parts catalogs.
Before I try out the new sending unit I have a stand alone gauge screwed into the port with a hose out to the gauge. I am 99.9% sure the car actually has oil pressure. It has been driven sparingly around the neighborhood and to the transmission shop with no issues.
If these parts test out good then I think the last option is to service the gauge in the instrument panel. Not desired.
My oil pressure gauge does not register any pressure.
Car is filled with new oil and filter to spec's.
I have removed the existing (original) sending unit behind the throttle tower. The well had oil in it as did the sending unit.
I am guessing the part mounted to the side at an angle (I don't know what it is called) with a single blade electrical connection is for the 'Idiot" light.
When I removed that part there was no oil up in it.
Q: Is that part supposed to have oil up in it?
Is it the 'sensor' for the idiot light?
What is it called? I can't find it in my parts catalogs.
Before I try out the new sending unit I have a stand alone gauge screwed into the port with a hose out to the gauge. I am 99.9% sure the car actually has oil pressure. It has been driven sparingly around the neighborhood and to the transmission shop with no issues.
If these parts test out good then I think the last option is to service the gauge in the instrument panel. Not desired.
Senior Member
Joined: Dec 2011
Posts: 780
Likes: 459
From: Central California
Joined: Feb 2010
Posts: 28,791
Likes: 11,269
From: Adelaide Stralia
The one on the side IS the Idiot light sender. NOTHING special, as mine run whatever we had at work with 1/8BSP thread and spade terminal, the car will never know.
HOWEVER
That larger:"thing" in the vertical position, is for the gauge, and Smiths brand. It is a known problem child.
Reverse Ohms innards, so a generic is not easy to locate, and Smiths/Jaguar units are fickle at best. It ONLy ever provided a "guide" and NOT accurate pressure.
A mechanical gauge in the idiot light port is the ONLY way to verify pressure.
The o/rings on the SUCTION and SUPPLY tubes inside the sump are known to shrink and not seal as designed. It usually gives SLOW pressure rise, and I have never seen NO oil pressure caused by them, purely due to the enormous volume of oil the pump povudes.
Have fun.
HOWEVER
That larger:"thing" in the vertical position, is for the gauge, and Smiths brand. It is a known problem child.
Reverse Ohms innards, so a generic is not easy to locate, and Smiths/Jaguar units are fickle at best. It ONLy ever provided a "guide" and NOT accurate pressure.
A mechanical gauge in the idiot light port is the ONLY way to verify pressure.
The o/rings on the SUCTION and SUPPLY tubes inside the sump are known to shrink and not seal as designed. It usually gives SLOW pressure rise, and I have never seen NO oil pressure caused by them, purely due to the enormous volume of oil the pump povudes.
Have fun.
Thread Starter
|
Senior Member
Joined: Sep 2016
Posts: 916
Likes: 389
From: VA
Thanks. It all makes sense ......now 
I have replacement sending units for both from donor cars so we'll see what happens later this weekend.
PS ... I re-checked the idiot light sending unit and it did have oil up in the center so that port is not clogged as I first thought.
I have replacement sending units for both from donor cars so we'll see what happens later this weekend.
PS ... I re-checked the idiot light sending unit and it did have oil up in the center so that port is not clogged as I first thought.
Thread Starter
|
Senior Member
Joined: Sep 2016
Posts: 916
Likes: 389
From: VA
Losing my mind.
Mechanical gauge test indicated 54 Lbs of oil pressure.
Installed a different (but not new) Smiths brand sending unit. Re-assembled the throttle tower.
Set the butterfly valves again, .002 on each. Set throttle rods.
A point of concern is that the capstan is 1/2" (12-13mm) from the Stop. That is significantly farther than other cars.
Turned car on.
Starts easily
No oil pressure showing on the instrument panel gauge.
Idol is waaay TOO high. about , 1800 rpm.
Turned AAV in to almost closed. Lowered rpm's marginally.
Clearly things are not correct.
Thoughts???
Mechanical gauge test indicated 54 Lbs of oil pressure.
Installed a different (but not new) Smiths brand sending unit. Re-assembled the throttle tower.
Set the butterfly valves again, .002 on each. Set throttle rods.
A point of concern is that the capstan is 1/2" (12-13mm) from the Stop. That is significantly farther than other cars.
Turned car on.
Starts easily
No oil pressure showing on the instrument panel gauge.
Idol is waaay TOO high. about , 1800 rpm.
Turned AAV in to almost closed. Lowered rpm's marginally.
Clearly things are not correct.
Thoughts???
Member
Joined: Feb 2025
Posts: 42
Likes: 26
I have tried 5 oil pressure senders from various sources, have never gotten the dash to read properly.. (and that's with a fully functional gauge cluster!) I think proper ones are simply NLA
You can test the gauge without pulling the dash apart, just hook up a basic potentiometer (like $3 online, RIP radioshack) between the signal wire and engine ground, >300ohm should show 0 on the gauge, <20ohm should be maxed out
Frankly I'd recommend just using a standalone gauge, could mount it on the bottom of the dash somewhere so it doesn't look too trashy
You can test the gauge without pulling the dash apart, just hook up a basic potentiometer (like $3 online, RIP radioshack) between the signal wire and engine ground, >300ohm should show 0 on the gauge, <20ohm should be maxed out
Frankly I'd recommend just using a standalone gauge, could mount it on the bottom of the dash somewhere so it doesn't look too trashy
Veteran Member
Joined: Jan 2012
Posts: 14,567
Likes: 10,756
From: France
- unhook the throttle rods from the capstan and the lever mechanisms
- Unhook the throttle cable from the capstan
- start the car
Trending Topics
Joined: Feb 2010
Posts: 28,791
Likes: 11,269
From: Adelaide Stralia
Following on from Gregs suggestions.
That capstan ear MUST be against the stop and near enough will not cut it. TPS adjustment cannot be done unless it is.
Binding throttle cable, COMMON.
None OE throttle return springs at the throttle bodies, oops, can cause a linkage jam at full throttle, not funny, and NOTHING to do with the idle issue I know, just saying.
The internal spring of the capstan "wheel" and the base plate is binding.
That same shaft and base plate have never been lubed since Coventry made the car.
CAUTION, DO NOT remove that top plate to lube the shaft with the TPS attached, $$ will leave your bank in a heart beat.
That capstan ear MUST be against the stop and near enough will not cut it. TPS adjustment cannot be done unless it is.
Binding throttle cable, COMMON.
None OE throttle return springs at the throttle bodies, oops, can cause a linkage jam at full throttle, not funny, and NOTHING to do with the idle issue I know, just saying.
The internal spring of the capstan "wheel" and the base plate is binding.
That same shaft and base plate have never been lubed since Coventry made the car.
CAUTION, DO NOT remove that top plate to lube the shaft with the TPS attached, $$ will leave your bank in a heart beat.
Thread
Thread Starter
Forum
Replies
Last Post
amcdonal86
XJ6 & XJ12 Series I, II & III
15
Mar 1, 2012 10:26 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)