1999 xj8 early AJ27 engine.

This is a very simple question, but I don't know the answer too.

Im attempting to clean the throttle body, cleaned the top half above the butterfly valve, but CANT open the butterfly vale to clean inside it?
The throttle cable is attached on the side , I can turn it to introduce slack to the throttle cable, yet while holding it with said slack the butterfly valve (towards the windscreen) does not go down. It feels like the butterflyvalve has a stop to it almost immediatelty as if its hitting something.
battery is disconnected, car runs fine.
Help.

best regards
Peter

 

If you connect the battery, ignition on and press (or have someone in the car) the throttle pedal it will open fully. Or you can use a 40-50 cm stick to keep the pedal pressed , with the other end on the seat base.Worked on mine.

 

I always just push mine open by hand. The spring is strong, though.

 

Yours must be very dirty; like Rob noted, above, I can push in on the low side of the throttle with my fingers and open it. Do not use a hard tool, it is coated; but it needs cleaning.

Might need to clean the spring as well. Again, gently.

 

Rob:
Do you realize your car has a different throttle control than an AJ27 engine, which is a stepper motor instead of direct?

 

I am not really sure. I have an XJ8 and an XJR. I was referring to the 8. I clean it every three months or so because if I don't, the car will quit on the highway. I am hoping that the new car will not do that.

 

Same here: I can push it open, and clean the bore and plate with throttle cleaner spray. I have a 2001 NA XJ8. Peter's is different? Don't think so.

 

I always pushed it open and stuck the plastic handle of a screwdriver in to hold it open.

 

Ok, guys- There is a major difference in the AJ 26 and AJ 27 throttle body. Jim, your car came with an AJ27 engine. I did not say your car was different.

Rob, both of your cars came with AJ26 engines. The XJ8 had AJ26 in MY 98, but it changed to AJ27 in MY 99. The XJR had AJ26 in MY 98 and MY 99. Ergo, both of your cars are AJ26, at least according to your signature line.

The TB in an AJ26 is direct driven by the input throttle cable with a spring return. The TB in an AJ 27 is driven by a stepper motor commanded by a double pot connected to the cable cam.

I did not speak to the method (or the recommendation) of opening the throttle plate. Only that they are completely different in design and operation. I assume you can push the throttle plate open on either without much concern. I would be very careful to not flush anything evil from the throttle bore into the potentiometers, though. That would trigger purchase of a new or rebuilt TB.

 

Gentlemen thankyou
I did have a pdf of a chap here who did just that, open throttle pedal with a stick, but he didn't mention in the pdf that ignition was on.I thought his setup mayhave been diferent on an XK8 as opposed to my car. It was my suspicion that "iginition on" was a requirement but wanted to make sure.
Hope I didn't damage it in anyway on my last attempt by trying to open it. Will clean with some electrical contact cleaner on a rag or something.
best regards
Peter

 

OK thanks Ross. Peter, ignore everything I said. Even with all the info available here, you still have to be careful!

 

I would caution against having the ECM powered during throttle cleaning.
I don't know if the throttle motor is powerful enough to sever fingers but I would hate to have my hand trapped if it closed and nobody was around to help free me.

A wooden dowel can push it open and hold it when the KEY IS OFF!!!!!!!!!!!!!

I use a small hammer handle.

bob gauff

 

ok
jut cleaned it, not much gunk at bottom just on ends of butterfly.
started car seems good.
many thanks to peoples advice. Its always good to have a bucket of opinions.
best regards
Peter

 

Now, I think I have the terminology right...but just in case I will describe what I am referring to... I removed the air intake hose to clean the intake. I used air intake cleaner and a rag to remove as much of the residue as possible. I used my fingers to prop open the valve and clean as much as possible. I shone a flashlight up the opening and the inside seems pretty darn black and filthy. I assume there is a way to get into this area to clean it. I am just wondering what the proper/easiest way to access it is? Is there a technique for removing/opening this for cleaning....is it even necessary to clean it?

 

Prop the throttle plate with a soft wood or plastic stick; spray the throttle clean along the bore and plate, wipe clean with a clean rag or paper towel. Pretty simple. Then be sure to connect the tube and parts correctly to preclude leakage. While you are at it, clean the MAF sensor and replace the air filter if dirty.

 

As the butterfly has been known to be sticky I myself have pushed her completely open it using a 12” screwdriver wrapped in a clean cloth, sprayed carb cleaner in the joints, use an old toothbrush to agitate it , wipe clean with mechanics blue HD tissue, avoid any deposit falling into body. Give one last shot spray then reassemble. She ran a bit better afterwards.
cheers