Throttle Body Lifespan ?
#22
#23
This throttle body has a precision stepper motor to run the throttle butterfly, and there are two throttle position sensors that talk too each other and the requisite air passages .
It is also heated by the cooling system to prevent icing and help with fuel atomization. Although compared to a DCOE Weber or big Dellorto, the parts don't look too complex, but with the systems they are attached to together are very sopisticated, much more so than any carburetor.
It is also heated by the cooling system to prevent icing and help with fuel atomization. Although compared to a DCOE Weber or big Dellorto, the parts don't look too complex, but with the systems they are attached to together are very sopisticated, much more so than any carburetor.
What I was really getting at is that the hunk of metal itself when it comes to carburetors are a real precision device compared with the hunk of metal that is a throttle body. I recall constantly tweaking the jets and adjusting the floats on my Holley, and then suffering the consequences once daily heat cycling eventually caused warpage of the various flow paths. With a throttle body there is no such precision in the hunk of metal but, rather, with the various electronic sensors that attach to the throttle body. In the case of my old Corvette, there were basically 3 things that attached and were cheaply replaceable. The throttle position sensor, the IAC sensor, and the bottom casting where coolant flowed through to heat the throttle body (by the way many folks would bypass the coolant flow in warmer climates where it was not really needed).
My point is that all of the "precision" sensors that connected to the throttle body were relatively cheap and easily replaceable. It is a real shame (and sham) that this would not be the case with Jaguar.
Doug
#24
It seems that 198500 is the Denso base part number, and the variant is 3250.
denso 198500 - Google Search
If you know the variant, and can cross-reference the particular resistance characteristics as well as the shaft drive dimensions in the Denso catalogues then you are golden. BTW, the resistance characteristics and tolerances should be in the pinpoint tests found in JTIS for the TPS. Failing that, it may be in the electrical diagrams.
Even if the pins are reversed, not a problem ... solder the sucker or re-arrange the pins on the harness side. (with a permanent label noting the change so some future owner does not go crazy!)
Last edited by plums; 07-24-2012 at 12:44 PM.
#25
The TPS on my '05 XJ looks identical except the number is 198500 3300. I expect that the faded number 06019H is a Jag part number or the like. I have searched the web for a source, but haven't found one yet. I had limp mode problems starting last winter that culminated in repeated episodes on a trip this past week across the US. I found a new throttle body at an online parts house and had it shipped to a trusted mechanic in OK near where we were visiting. We made the 1100 mile trip home without any further problem. No ECU reflash was necessary. Still it's nutty to have to replace the whole throttle body for want of a simple potentiometer.
#26
Looking into other cars fitted with similar TPS sensors here...
https://www.jaguarforums.com/forum/x...e2/#post599781
Found a useful pdf for cross ref'ing TPS, figure 48 looks good.
http://www.tomco-inc.com/Catalog/tps%20sensors.pdf
https://www.jaguarforums.com/forum/x...e2/#post599781
Found a useful pdf for cross ref'ing TPS, figure 48 looks good.
http://www.tomco-inc.com/Catalog/tps%20sensors.pdf
#27
Since the original poster has a 99 I thought I'd post a link to my throttle body and position sensor surgery I did some 30k miles ago. My point is the old AJ-26 and (I think) AJ-27 engines had a position sensor that looks a lot different than the postings above. I couldn't find a replacement for it. I ended up finding a fresh TB on Ebay (for about 15% of the cost of a new one) that finally fixed the worn out APP (Accelerator Pedal Position) sensor.
So, for the guys with the old XK8s -- https://www.jaguarforums.com/forum/x...-repair-53905/
Mike
So, for the guys with the old XK8s -- https://www.jaguarforums.com/forum/x...-repair-53905/
Mike
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plums (10-13-2012)
#28
#29
#30
IMPORTANT NOTE TO ALL XK & XJ OWNERS - as soon as you purchase an XJ or XK make sure you also buy a spare TB and keep it in the boot (trunk). Make sure you get the right one - one uses cruise control by vacuum (early model), and the later one is fully electronic.
These pics are from my 2002 XJ8 SE - TPS died at 90K. Replacement TB is still going at 240K
These pics are from my 2002 XJ8 SE - TPS died at 90K. Replacement TB is still going at 240K
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