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As a part of cleaning and inspecting, replacing some things under the intake (this car had sat for some years) I recently removed my intakes, TBody and the TPS sensor. Everything went smoothly. I wont get into all that for the needs of this post - but it was needed.
I read as much as I could (amazing site) before getting into all this as to the (re)setting of the TPS, listening for the click, which kicks in idle. I hear the click (did before putting everything back together and now with things together, engine off, key on) but I don't think it's a solid drop to idle position on peddle release. Sometimes the rpms will float around for a few seconds (more or less) just above 1000rpms and then settle to about 700-750. Also high for my liking. Looking for a steady 650 + or - ... I don't think it's a solid drop into idle. Or,,, is this normal?
Is there anything I can do to slightly adjust idle screw OR TPS, OR both with car running and WITHOUT major surgery? Can i do this thru the spaces in the intake...? I like to deal with idle problems when car is running, if I can.
I also have the inner most throttle arm link (the little ball/cup link) to change out. It is loose, flopping around, to the point I fear it will plop off someday... When that is done I think tightening that link (which is close to right now) will be right-er maybe helping the idle drop...?
Is it possible to back the idle screw off (thru the spaces on the intake) a bit to really land the TPS "click" in the idle function/position on the TPS as a way of lowering/stabilizing idle? I'm sure messing around with the TPS or the idle or the throttle arm link for that matter with the intake ON would is a bear.
How can I go about this?
As usual and always many many many thanks
Last edited by JayPoorJay; 06-21-2019 at 04:10 PM.
It is possible to remove the T and access the tps switch. Takes a lot of patience, backlighting under the T so you can see how the clamps are clocked and just right length screwdriver or socket. Ive done it, back in 2010 or so on my 85 platinum car. Posted a thread, but search isnt the strongest suit of the forum. Tight but doable, though I did gall the paint on the T and closest runner.
The only thing I did today was back off that inner most link (cup) and replace, then snapped it back onto the ball. I removed the air filter and MAF, peaking through the intake, with a looooong pair O pliers (the ones ICS suggested I get when I do the short shift switch out) and snapped it back on. It made a difference in my confidence it would not just drop off but NONE in the idle situation and really landing that drop down and click into idle mode...
Also removed the blower resistor and straightened that out. Pulled coils up and pushed the lead 8 strip down and bent the contact away from the point... That worked! Good!
I looked and looked - I really don't see how there is a good way to deal with the idle screw OR the TPS without taking lots apart. Then, ya take it apart, put it all together to test again, and if it ain't right,,, do it again,,,, !?!? Only removing the T makes total sense... Maybe I will give that a try tomorrow.
Still open to any and all suggestions at getting this throttle body right - or at least, right-er...
Still,,, new trans mounts on the way,,, soon an actual working fuel gauge thanks to Roger and them folks,,, new rear shocks somewhere down the line... Beast O Burden, lol...
The only thing I did today was back off that inner most link (cup) and replace, then snapped it back onto the ball. I removed the air filter and MAF, peaking through the intake, with a looooong pair O pliers (the ones ICS suggested I get when I do the short shift switch out) and snapped it back on. It made a difference in my confidence it would not just drop off but NONE in the idle situation and really landing that drop down and click into idle mode...
Also removed the blower resistor and straightened that out. Pulled coils up and pushed the lead 8 strip down and bent the contact away from the point... That worked! Good!
I looked and looked - I really don't see how there is a good way to deal with the idle screw OR the TPS without taking lots apart. Then, ya take it apart, put it all together to test again, and if it ain't right,,, do it again,,,, !?!? Only removing the T makes total sense... Maybe I will give that a try tomorrow.
Still open to any and all suggestions at getting this throttle body right - or at least, right-er...
Still,,, new trans mounts on the way,,, soon an actual working fuel gauge thanks to Roger and them folks,,, new rear shocks somewhere down the line... Beast O Burden, lol...
Cage rebuild on the XJS. Ain't life grand!?!?
I chased this annoying problem for a couple of years. One shop insisted it was the computer boards. Another shop said it was fixed but it wasn't.
Third time's a charm. Dave C. went through the proper procedure of setting up the MAF and idle adjustments. Turns out that all you have to do is back off the idle adjust screw (under the intake tubes). Problem solved.
Had nothing to do with the MAF or TPS.
There are some true experts out there. DaveC is the guy in the Northeast, along with Pete who has hands full with Long Island and other New Yorkers True experts.
I chased this annoying problem for a couple of years. One shop insisted it was the computer boards. Another shop said it was fixed but it wasn't.
Third time's a charm. Dave C. went through the proper procedure of setting up the MAF and idle adjustments. Turns out that all you have to do is back off the idle adjust screw (under the intake tubes). Problem solved.
Had nothing to do with the MAF or TPS.
Hey! Thanks DeMille...
How do I get to and make the adjustments while the car is running? I've been thinking I was going to mod some kind of box end wrench, cut it, bend it, make an extension & whatever I have to do, to get to that bloody nut/bolt set up while the car is running. If I got it right while the car was running I would then happily go in and retightening (if I couldn't do it with the intake on) after it was right.
I was also thinking of some kind of a contraption to make it so the adjustment screw is accessible >>> somehow. The large intake and the way it blocks one from all that's going on underneath,,, is an interesting and limiting design...
Should be easy to access the adjust screw. It's at the front of the throttle body. You can see it thru the gap between the first and second row of intake runners.
Should be easy to access the adjust screw. It's at the front of the throttle body. You can see it thru the gap between the first and second row of intake runners.
Heyyyy,,, good morning Snark. Thank ya!
Yes... I can see it. What has been your approach at getting a wrench or some kind if tool on the adjuster? Long handled wrench? Can that be done with precision? And tightening?
Shouldn't need a wrench. I just put a socket on a long extension and use it like a screwdriver. A wrench will give you wayyy too much torque. It should turn easily. If it doesn't, it's probably at the stop. Think of it like a dial instead of a screw. You might want to keep track of how far you have turned it in case you need to put it back where it was.
Hmm. Maybe I'm looking a the wrong thing all together, then!?
What I thought would be the idle turn (it's hard to explain) but a threaded section screw/bolt without a head (a nut on the bottom side, facing down, as the lock nit), secured to an arm (a stop) on the drivers side front of the throttle body just to the front of the whole spring loaded throttle apparatus...? No?
I was on line looking for a good picture from the 85 86 TBody but couldn't find one...
It seem that one would have to unlock the lock nut then that headless threaded section of bolt,,, in or out --- up or down... CRAZY ANGLES... Maybe I'm just a punk ***, lol
EDIT >>> Is the idle screw the bronze set up JUST above the 2 red vac blocks? Pardon my ignorance,,, but I'm learning here. The bronze/brass just above the 2 vac blocks???
Last edited by JayPoorJay; 06-24-2019 at 12:27 PM.
Lol,,, crazy! I just edited my last post, same photo, asking if the idle adjustment was that bronze/brass fitting just above the 2 red capped vac inlets...?
I was looking at the wrong "screw"... So, question,,, turning that brass/bronze fitting will create a change in the position throttle shaft which will affect the the butterfly valve and the TPS? Allowing me to adjust the "click" in the TPS?
I thought idle adjustment "screw" was this one or looked more like this.
That other nut is the factory adjustment, hence the yellow paint. You'll probably want to leave that one alone, unless a previous owner mistakenly adjusted it.
The idle screw won't change the "click". But I'm not sure that's what you need. I'll have to leave that one for somebody more expert. But I believe you would have to adjust the throttle cable for that.
Nah... My throttle cable sits nicely and I wouldn't want to start fiddling with that. What I want is for my TPS to fall back slightly more and to completely to settle in idle with the audible click. Sometimes I think (for a few seconds) it falls just short. It was perfect before I "fixed" it.
I messed around with the position of the TPS when I took down the top end,,, it was a leafy and greasy mess under there due to years of neglect, sitting and mice. In order to clean it as well as I did (needs more) I had to take off the electronics --- TPS... It was a must. Had some hoses and vac lines that needed attention too.
I guess I'll just have to take some things apart again. Still, there MUST be a way to make adjustments with the car running and at temp... THAT is my real question...
06-21-2019, 03:42 PM
1986 Throttle Links, TPS and Idle Screw Adjust
