Triple Crown Today with the 97!
#21
10-05-2010, 02:21 PM
I suggest doing a thorogh investigation of the harness to the TB. There can be corrosion in the contacts to the throttle position sensor that can cause this problem. Others have found broken studs on the plugs that let them fit too loosely. You might just need a harness. There is a TSB on these thhat explains that some harnesses had tin connector coatings whne they should be gold. Thsi problem can also be sporadic so th econector and wires have to be wiggled while testing. The fact that two TB's have caused the same problem tells me that you might not have replaced the right thing.
#22
10-05-2010, 02:34 PM
#23
10-05-2010, 02:35 PM
#24
10-06-2010, 10:03 AM
I do not know much about the specifics of the throttle body problems on the older models but there are 2 things I wonder about: (1) to my knowledge, a throttle body is basically a hunk of metal with a bore and a butterfly--much much less complicated than a carburetor so what could possibly go wrong (2) given the simplicity of these things (hunk of metal, etc.) why should they cost more than a couple of hundred dollars to replace? I seem to recall that carburetors, which are much more complicated were not all that much to replace.
Doug
Doug
#25
10-06-2010, 10:13 AM
Veteran Member
Acutally, the throttle body is fairly complex, it includes a throttle position sensor and a stepper motor assembly that operates the throttle butterfly based on input from the pedal to the Trac module. The ABS system is tied to it as well as the traction control module. The traction control takes over the throttle in attitude situations and actually operates the throttle plate in certain circumstances. One of the problems with the throttle body is that the Denso TPS on the throttle body is what is failing prematurely and the part is not available separately, requiring a new TB. I think commercial rebuilders can get it, just not shade tree guys. If the problem is not the TPS, it's usually a bad harness connector. If I had a bad throttle body, I would send it to BBA Reman, get it rebuilt for a couple hundred and reinstall it.
So the real problem is not the "hunk of metal" but the various electronic components that are attached to it. Given how cheap computers and electronic devices are these days, it seems like it should honestly cost about 25 bucks for the parts that make up the throttle position sensor and stepper motor. The real problem seems to be not being able to get these electronic components separately from the throttle body and/or ridiculously high prices for the components. I believe the TPS for the throttle body on my Corvette was available separately for a pretty reasonable price so why is this not the case for the Jag?
Doug
#26
10-06-2010, 10:37 AM
Most likely (just guessing), the TPS is not available separately because it has to be adjusted with the Jag dealer computer when installed. The TPS on the car has its mounting bolts painted over which tells me that they are adjustable. It would seem to us that one could just use trial and error to adjust it but we have to remember that Federal emissions control requirements mean the thing has to be set accurately according to the manufacturer.
#27
10-06-2010, 04:13 PM
Veteran Member
The TPS on the pre-1995 Corvettes were adjustable but the one on mine (and later) were not adjustable. For the older ones, the adjustment could be simply performed by anyone with a volt meter and was not rocket science. For the later (nonadjustable) one, the computer would sense the closed position and adjust the baseline voltage to the TPS based on that (I believe that you could check for correct operation by using a volt meter to chekc the voltage at close position, which I believe was about 0.5 volts and then again at WOT which was a different value--or I may have that backwards). In any case, there was NO need to make any manual adjustment since this was taken care of by the onboard computer. Hence, the screws to mount the TPS were just that, mounting screws and NOT adjusting screws.
Doug
Doug
#28
10-07-2010, 10:25 AM
Well the orig tb was attempted to be rebuilt but failed the companies bench test. So they just got another used one and that is the latest to fail. If this next being installed today acts up i am getting my $$$ back and she will sit for the winter and be addressed next spring. I have too many other irons in the fire to keep throwing $$ at the car right now. Basement resto, another car repair needed, holidays coming up.
#31
10-07-2010, 08:01 PM
#32
10-11-2010, 06:33 PM
The device/machine they use is one that has a JAG program to look at this car as well as other jags. He says all codes that have been thrown are TB related. Nothing else on the car is throwing codes. So the next TB should be installed tomorrow. He says the TB messing up is what has thrown the traction control, engine fault, and gearbox faults when it started acting up. WHen the car is runnign fine, which it does after sitting, they put it on the tester and there are no codes. OBDII as I have said is throwing no codes.
Its hard to beleibe the throttle positioner sensor, trac controll sensors are all in that damn TB and once the start acting up, you get my issue. Sucks that when they go the whole TB is toast, cant replace just the one part.
Its hard to beleibe the throttle positioner sensor, trac controll sensors are all in that damn TB and once the start acting up, you get my issue. Sucks that when they go the whole TB is toast, cant replace just the one part.
#33
10-13-2010, 04:24 PM
#37
10-14-2010, 11:52 AM
#38
10-14-2010, 12:47 PM
Veteran Member
I am trying to get a fix on your problem and I am not sure what it is so I will try to provide you a little information on the TB recall. This information should help a little http://www.xclusively-jaguar.co.uk/xj04_fandi.html#5 I have this link http://www.jaytanindustriesinc.com/ on my page for rebuilt TB and they may be in a position to help you understand what you have going on with it. The question is what you are having a problem with. Now as for the TB plugs the TSB is 303-58, now you may ask if this is the problem? We had several plug problems without this P0121 code. Cleaning first will only help. http://www.gusglikas.com/AutoRepTB.htm
I would like to help but your problem is diluted in all the posts. Do you have or did you have codes and what are they and what is it doing now?
I would like to help but your problem is diluted in all the posts. Do you have or did you have codes and what are they and what is it doing now?
Last edited by Gus; 10-14-2010 at 01:39 PM.
#40
10-15-2010, 05:03 PM
They got codes that said it was the TB which I don't know what they are at this point. They checked the battery, it was fine, showed good output. If it were the battery would that not make the car act odd in other ways also? I have seen threads here about how it can do other things that my car has not presented. Does not mean the battery has a short or dead cell thay acts up.
At this point it is back home. Maybe I will throw a battery in it soon and see if it fixes it. I tend to agree that the issue is something diff since two other TB's did not work, did the same thing.
I think when I get a chance I will start it and stat fiddling with the harness and see if it makes it go bonkers. I just hate to start throwing harneses, batteries, TB's, and lord knows what else to fix it.
At this point it is back home. Maybe I will throw a battery in it soon and see if it fixes it. I tend to agree that the issue is something diff since two other TB's did not work, did the same thing.
I think when I get a chance I will start it and stat fiddling with the harness and see if it makes it go bonkers. I just hate to start throwing harneses, batteries, TB's, and lord knows what else to fix it.