Anyone has a full load vacuum switch for sale?
Glad to see parts for an HE are for sale
I need ( DESPERATELY NEED) to find the fuel temp sensor / boss that screws into the fuel rail on the LH driver side …
It’s a 3/4 " threaded brass boss that screws into a blind hole on the fuel rail… temp is measured and sent back to ECU when the two faces come together … it’s quite short with wires connecting to male/ female plug ins on a nearby harness that also serves heat sensor on left air filter funnel tube
Not all HE’s have this kind of fuel temp sensor… some work by vacuum…
Here’s hoping w/ fingers crossed
Above pic is supposed to read fuel temp sensor … apologizes
Rudy,
First, I believe your engine will run pretty well without it. Just jump the harness connector that the sensor connects to. The effect on fueling will likely be less than 10%. Some rough running after hot starts may be experienced.
Second, the part is NLA and you will not likely find one. However, I managed to find the sensor element itself on eBay and paid a machine shop to adapted it to the base that screws into the rail. Sensor was cheap, machine work was, as I recall, about $100. I don’t know if you will be as lucky as I was in finding the sensor, but let me know if you’re interested and I’ll dig out some specifics.
BTW, the only reason I have such a sensor is I retrofitted an HE rail to my PreHE.
Ed Sowell
'76 XJ-S coupe, red
Hi Ed
I was reading your jag repair web page yesterday and found it pretty interesting … I called britalia motors maybe 2 yrs ago but they had just wrapped up and closed business… not many left in the South Bay now … there’s British European auto in San Pedro if you don’t want to risk getting stuck on the Vincent Thomas bridge
Anyway back to the sensor … the white XJS I’m talking about has never had one since I bought it in 2000 … I even wondered if it made any diff like you said… my other car is in good working order so I took this same sensor off and tried it on white but didn’t notice much …
I’m even wondering if the fuel heat sensor supply wire on white is still working or if its gone dead … tested it with a volt/ ammeter and there was no reading … that same supply feeds sensor in L air filter housing tube and that had no current either
But the sensor … didn’t think I’d have much luck no one seems to have heard of them … even worse some don’t know what they are
I’ve been taking my car to Import Service Centre in Brea since Britalia closed. It’s owned by Phil O’Brien who has decades of British car experience. He’s brought a young tech on board who’s pretty good.
Here’s a photo of a broken OF rail temperature switch alongside a generic switch.
With a little digging I might be able to find the generic part number so you can Google it. I had:
Odd Parts make a brass body to accept the generic part. Let me know if you would like me to pursue this.
Ed
"I’m even wondering if the fuel heat sensor supply wire on white is still working or if its gone dead … tested it with a volt/ ammeter and there was no reading … that same supply feeds sensor in L air filter housing tube and that had no current either "
The thing on the rail is really a switch. The thing on the air filter housing is an air temperature sensor, basically a thermistor that changes resistance with temperature. The switch is in series with the sensor. Testing of the sensor should be resistance vs. temperature, not current. ROM has the correct readings. Testing the switch is to see if it is closed at temperature less than some value (70C?), and opens when hotter. When the switch is open (or unplugged from the harness) the ECU sees infinite resistance and thinks it’s really cold outside so bumps up the fueling about 10%. If you instead jump the harness pins together where the switch plugs in you won’t get an increase in fueling when the rail is hot.
Ed
I need ( DESPERATELY NEED) to find the fuel temp sensor / boss that
screws into the fuel rail on the LH driver side …
Well, you can’t really desperately need that part because the car will run fine
without it. It’s only to avoid potential hot start issues.
– Kirbert
Anyone has a full load vacuum switch for sale?
IIRC, there’s a report that you can get a very similar switch from a
Harley-Davidson dealer.
– Kirbert
Thank you very much, I will look for it tomorrow.
Bets Regards
Antonio Segurado
I do have potential hot start issues … if it’s hot and you leave it for maybe an hour then fire back up it goes into an up and down gulping mode until fuel supply has gained equilibrium… then it idles not too bad … to overcome this I have to put my foot on gas and keep it around1200 … “forcing” it to calm down if you will … but I shouldn’t really have to do this
It’s not a vacuum leak that makes it gulp by the way
A generic part # would be a good idea since I do think my cars affected by heat soak
Let me know if you have trouble finding one. I probably have one on one of my parts cars.
Are you saying you might have a pigtail like in pic above that says “heat sensor?” If so I want one … ideally one that works then I don’t have to do too much modifying … XJS 1985 HE
As I have looked for the full load vacum switch, in Harley “VOES” (vacum operated electric switch) they have several vacum rates.
I have also read The following.
“For racing applications or supercharged, turbo-charged or bikes using Nitrous Oxide, we do not recommend using a VOES. This is due to the possibility of a sudden timing change causing a backfire which can be a bad thing under these conditions!”
Please tell me what is your opinion on the matter and if the 5,5 in HG vacum is the best choice if the switch is to be mounted.
In attach a photo of my jag.
Best Regards
Antonio Segurado
I believe I do. Contact me off list
I have one of those on a 1985 parts car in the driveway. I didn’t really know what it’s purpose was, but noted my 1983 has the screw in location but does not have the sensor, so was kind of thinking maybe my car needed one and the previous owner took it off of the car. Anyways, if my car doesn’t need it and you still need one let me know. The one I have looks to be in very good condition. The engine caught on fire and someone spent a small fortune replacing everything under the hood around 1999, then I think the engine blew around 2001, it was parked in a field for 14 years or so and I bought it. So I am going to assume that sensor doesn’t have a lot of hours on it.