When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Fellas, I bought this 1996 XJR about 2 years ago. I posted on here about some issues back then. I had my mechanics due tons of work (8K) but had them leave the engine service to me as I wanted to learn/enjoy that process. I drove it on three 2 hour trips and barely made it home the last trip. As it was new to me, and I planned on keeping it, I took the advice from here with respect to a new purchase and replaced a bunch of things that I would have regardless if it was running poorly or not. I completed most of that work but Medical/life/etc got in the way of finishing this car and it's sat in my shop since then. With respect to the engine it has new cam cover/spark plug well gaskets, new champion RC9YCC plugs, new NGK U5045 ignition coils, new temp sensor, new fuel filter (that job made me wish I had the shop do it! Rusted *** POS), new NGK O2 sensors, fuel pressure regulator, drained gas and put in fresh. At least it runs now but idle sucks. I plan to list this car on Bring a Trailer this month and I want to have it right for the next owner. Well, it won't be perfect but it will be leaving me better off than when I got it. Hopefully the next owner can take it over the finish line to being perfect. I don't want to sell it but I just bought a Green 1996 XJ12 (I'll do a post about this too) and at the moment I just can't keep everything. I have an XK8 and XJS too.
I also found cracked exhaust manifolds. As I have a small manufacturing business with a basic machine shop, I researched how to best repair these and completed that task. I took tons of pictures and plan to make a separate post about that process. I made a few fixtures and I would be able to do this for forum members.
Now to the title of this thread. I wasn't planning on doing this but after finding a thread on here about doing it from the bottom of the car, I decided to tackle this last night while listening to the election results. Everything went reasonably smooth until I got to what I think is the last step. I can't get that thing to budge! In addition to the hose, plug, cable, I removed 4 long bolts. I read about opening the butterfly to access the throttle plate bolt/screw but I don't think that has to happen to remove just the throttle body right? If so that's bullshit! Ha. I've tapped on it using the handle end of one hammer while hitting the head with another. I tried gently camming it off of the aluminum bosses that mount the spring flipper, and last night I drenched it with penetrating fluid. I plan to try again later today and hit it with a heat gun (not flame) to maybe get it to expand enough to pop loose.
May be glued on by the guck that accumulates and hardens , soak for days the inside and outside mating flange with penetrating oil as I don't know of anything mechanical that would hold it on ?
Ok!! I finally got this damn thing out. Someone had put a little gasket maker on the mating surface. It's not as nasty as I was expecting but it is oiled, greased, carboned up. Looks like the iacv plunger and port has some carbon and oil/grease. I'll search on here to see if there is a way to test the iacv as I'd like to know it's working before putting all this stuff back.
Guys, Thanks for the replies. I'll look up Vee's post later today before getting back to it. There is a small screw to adjust the plate idle stop. I planned to not touch it. Should I put a dab of loctite on it? I had read about heating the iav screws and used a heat gun and a 1/4" ratchet and snuck up on it. I read about the spark plug change after ordering these!
Loctite on the present position on the idle stop screw wouldn't hurt , but you know of it's existence as my idle stop screw ( maybe visually missed ) was not there on the normally aspirated
This would seriously effect the idle / TPS null
Vee has one on his normally aspirated in his AJ16 ( same ) powered XJS model
The IAC bolts are an odd size of 5.5 or 6.5 , can't remember when I look mine off
There is a Loctite dissolver chemical
Gasket between the IAC valve body and the TB ? Sometimes missing from reading others , this would effect valve poppet seat gap / idle speed breathing to get it right
Tonight I got under the car and plugged in the iacv. I kept my hand on it with the plunger in my palm. I had my best girl operate the ignition switch. Seems to work going both in and out. I noticed it park itself after the key was turned off.
Tomorrow I'm hoping to get all this back together. Cleaning the rest of the gasket material off the throttle plate adapter was fun as it's still on the car.
Mine had a green cardboard type gasket. Everything is pristine clean now.
Tonight I got the throttle body back on the car. Note this is the XJR6 so not an easy task. I decided to use a micro thin layer of sealant, just like I found it. I only hooked up the TPS and passenger side coolant line as you almost have to do that stuff before bolting it on. Note I did this from under the car. One thing I'd like to add is that I didn't disconnect the EGR hose when taking it out. However putting it back in with that thing in the way was a problem. My EGR hose connection down there was rusted and rather difficult to get to. So after spraying it down with penetrating lube I thought about it a minute and decided to disconnect the other end of the EGR hose by the EGR valve. I had just reconnected all that stuff with the installation of my repaired exhaust manifolds so I knew it would be easy! I could then pull enough slack to push the hose under the starter and slide the throttle body up in there. I connected the coolant line and tps before applying the sealant on the throttle plate side. I was afraid the sealant would start to dry before I could get this done. Plus there was a chance of bumping into it and messing up the sealant. It's difficult but you can look through the hole on the control arm to see what you are doing. That being said it's impossible to get a perfect bead. I used my finger to smooth it out super thin and clean up any excess. I then did my best to keep the throttle body from touching and inserted the bolts to catch a few threads. That way I could mate the two pieces perfectly in one go. At that point I had enough. It can cure for a day and I'll put everything back Monday.
Update! So it's been 9 months since my last post. I've been working on this car on and off. It still hasn't left my warehouse. After getting everything together from my last post, I tested the car and had a high idle. I've been reading posts and doing little tests here and there. Some of them requiring buying things. I tried UV smoker oil yet still found no vacuum leaks. I bought the elm27? and the torque app. This is awesome but i'm still learning. I did learn my intake temp sensor is working and my TPS seems to be working fine. I didn't know the temp sensor was on the bottom of the inter-cooler or I would have replaced it when I had the throttle body out! Having read other posts on the issue I grabbed the throttle tension spring NBD3030AA and voila the RPM's settled down. Then I did something I haven't read about but seemed like a good idea. I detached that spring and the throttle cable to take them out of the equation. I started the car and the RPM's were actually a little low, bouncing around between 650-700. If I recall the TPS was then reading a little low at 10.59%. I had my best girl press the accelerator to pull the throttle cable in so I could then pull it back out to feel for drag. It seemed fine but then again I've never felt one before. I do think I did kink it slightly when removing the throttle body using the from the bottom technique. I turned my attention to the throttle tension spring. It was rusty but seemed ok. However it seemed like an extra 0.5 lbs of pressure was all it took to lower the idle from 1200 to 700-800. I could see the TPS live numbers decrease as I was pulling on the spring.
I've measured my spring and it takes about 0.5 lbs to begin to open it using a trigger pull gauge. At 1 inch extension it's about 1.25 lbs maxing out at about 2 lbs around 3 inches. Of course I don't know what a new factory one measures and they are NLA. I've ordered 5 different springs from McMaster Carr that have around the same specs biased to slightly higher numbers. If I find one that seems to work better I will post the part number.
On a good note I will now be keeping this car. At least for the rest of this year. I've been doing a paint correction and have it about 95%. I'm on the last super fine step now. I'm going to ceramic coat it using Gyeon Mohs.
As I separate post I wanted to ask about these two wires. Having followed the throttle cables to this device I noticed two wires at the bottom with bare wires touching. By chance are they both grounds or do I need to repair this. Is this item part of the abs/traction control?
The bare 2 wires on the traction control actuator seems to be common
If you don't use the traction control feature in your driving habits might consider just pulling the system fuse ( s ) to rid of warning lights on dash , but not ABS
Ok fellas, I figured out the first high idle mentioned above. Turns out it was NOT the return spring. When re-installing the throttle cable I thought it went in way too easy. But it was secure and worked. Turns out the barrel had just lodged itself in there at a 90 degree angle and was not secure. This is rather difficult to see when re-installing and it had been so long since I had it in my hands I didn't recall what it looked like. However if you contort yourself just right you can see up in there and with the help of my new best tool, a magnetic base led light, I was able to see the problem. I didn't get a photo with the barrel in the wrong place but I did get one with it installed correctly. On that note I spent two hours trying to get that thing installed only to realize the only way is to remove the throttle cable from the bracket so you have plenty of slack. You then need to open the throttle by hand, push the extra slack to create a loop around the throttle pulley so you can slide the barrel into the hole, then rotate the barrel and cable back around the pulley to secure it.
If I had this to do over I would add a few steps. First if I had a good idle to start with, I would have used the ELM and got a baseline on my TPS readings. Then when the job was done I could compare and I would have caught this mistake right away. I think I would also have checked for vacuum leaks both before and after doing the work.
I finally finished the paint correction and ceramic coating. I also removed and re-painted the grill as the rock chips were too bad to just fill in with touch-up paint. Here is the result. I got it out of my shop thursday and drove it home today. I'm feel I'm very close with getting the engine running correctly. I think I've figured out how to log some data so I can post here and get your feedback.
XJR6 Throttle body removal and cleaning
