Help! throttle valve/body/gasket question

alicheat · Post by **alicheat** » Sat Jun 15, 2002 10:25 am

Help!

In replacing hoses and gaskets in a search for a vacuum leak, I must have installed the throttle components wrong, because now I get no acceleration at all and the idle remains really low and cuts out within 30 seconds.

I have an automatic 412 with l-jet fuel injection. In the Haynes manual there is mention of the vacuum unit attached to the throttle body, and adjustment of the spring-loaded rod thing (idle speed limiter?). It says to unscrew the lock nut and turn the rod until the gap between rod and throttle part is .02-.04 inches while idling. I don't get any kind of gap, whatever I do, the throttle part is always resting on the rod.

Before all of this the car obviously had a vacuum leak, but I could drive it, and the acceleration was fine.

I guess my question would be if someone could help me out with instructions on the proper set up of the throttle body, vacuum thing, etc. So after that's set up, I know it's correct, and can go on with finding the original vacuum leak, which by the way is very illusive. I have a feeling my intake manifold has a leak in that center seam, possible? common?

Thanks in advance for any help. I'm posting this again in Fuel Injection.

Alicia

ray greenwood · Post by **ray greenwood** » Mon Jun 17, 2002 11:14 pm

A couple of things. If the rod does not move at all when you rev the car...either it still has a vacume leak from the source that supplies the throttle positioner, or the diaphram in the throttle positioner is bad. Have you hooked up the vacume to it properly? Check all of your vacume lines. There is also a high probability ...knowing how hard it is to reach the screws on the throttle body....that the seal between the pleum nd TB is leaking still. Did you use a sparing amount of sealer on it? If the plenum was still in the car when you put it on, there is a chance that the seal slipped crooked. There is also the chance that the idle and throttle positioner were both adjusted when the car had a serious vacume leak. Their settings would be eay off. The 7mm lock screw on the rod of the actuator is what you want to loosen. With the car off, turn the the accuator rod all the way in so the rod is at its shortest. Get it as far away from the throttle lever as possible. Now start the car. Check your timing, as your vacume adavance will have been altered if you fixed the leak. Now check your idle adjusting screw. Get the car to idle first. Go through a normal vacume leak procedure. Check all gaskets, hoses and boots. When thats done, and the engine is idleing healthy, Then adjust the throttle positioner. The vacume source should be holding it closed. When you open the throttle its should extend. If it tends to move in and out slightly on idle...it either has a leak in the diaphram..or the hose assembly and vacume point are leaking. A last note...if you have a 411/412 fastback with the built in oil funnel...take the oil breather assembly loose, pry off the "D" shaped platic cap underneath, and check the PCV valve for leaks. Most of them leak. This valve is a flawed design. It works much better to knock the little disc out of it so that it is a constant flow. The restrict the flow of the hose coming from it to the manifold with a plastic marble or plug with a 4mm hole drilled in it. That is for D-jet. You probably have the mushroom shaped air bleed type PCV if the car is L-jet. Ray

ray greenwood · Post by **ray greenwood** » Mon Jun 17, 2002 11:19 pm

Oh..forgot. It would be quite rare to have the center seam leaking...But, the fitting on the right hand side of the plenum, that goes to the "T" fitting that supplies the transmission modulator could be leaking. Also the auxiliary air regulator is one of the most common leak areas. It could be not working at all. The boots, injector seals and manifold gaskets are also leak areas. Its really best to just replace all of them at once. Also all of your PCV lines must be in good shape. I would replace intake to head gaskets, runner boots, throttle body gaskets and the injector seals all at once. Since one or more of each will have to be disturbed to reach the others, it will be better just to replace them all. Its about 2 hours of work and about 30-40 bucks in parts. Let me know how this goes. Ray

alicheat · Post by **alicheat** » Mon Jun 24, 2002 12:45 pm

Thanks, Ray.

I did replace all mentioned gaskets and hoses. The vacuum leak seems to be gone now, and I have determined that I have this to fix:

1. AAR was not working. So I dismantled it, cleaned the rust out, tested the function by hooking it up straight to an extra battery, and it works. Now, I'm having trouble figuring exactly how the coil/connection rod fits back into the valve body. I heat up the thing, outside of the body for 15 minutes, then, because the valve is closed, I can fit the heated coil thing back in and test it again. It's working now, but does not open all the way when cool - just about 1/2 way. It closes fine when heated. Is there an exact angle at which the rod should be inserted? and what keeps it from rotating once in there? should I use some sealer?

ray greenwood · Post by **ray greenwood** » Tue Jun 25, 2002 10:11 am

Hello, slip the cylinder/rod assembly (I am assuming you are talking about the tubular type 411/412 AAR...and not the later funnel shaped disc type?) in while cold. You will motice that the slot in therod contacts the spring and leaves the tube/orifice in the open position. There should be, on the tube/valve, a narrow slot...feeding onto a wider slot. Most of the narrow slot and part of thewider slot being open to the port is enough. Some models had a lock screw on the spring that allowed you to let the spring turn just a bit to open up or close down theorifice for best idle when cold. For max opening position, put theAAR assembly into thefreezer for max cold weather opening position. It should be a little farther into the wide slot position. No matter the cold asjustment, the heater coil by itsel...away from the heat of the engine, must have enough heat to fully close the valve in about 5-7 minutes. If it does not fully close when hot...use the lock screw on the spring to turn the spring so it fully closes. To re-assemble, mark the open position on the end of the shaft with a sharpy marker so you do not get disoriented. Look at how that lines up with the spring tang. I think its about 1/4 turn off. Now remove the screw holding the spring. Insert the valve and line up the mark so you know it is in the open position. Now re-install the spring in the shaft slot...give it the proper 1/4 turn twist/load on the spring and put the screw back in. OH...mark the spring position relative to the littel scale on the side of the spring mount with a sharpie before removing the spring. Tighten it all down and re-set according to the above directions. Check it with the freezer method...and then theheater coil. How far it is actaually open is less of a worry than if it closes all the way when warm. Yep... use a little sealer. There is a small chance that if the body is not sealed...it will leak a little vacume. That small boot with the spigot that attaches the AAR to the plenum is very important and a good source of leaks. They are still available at the dealer. They are $11. Get two....you never know when they will disapear. Use both screw to hold down the AAR...or the vibration will cause the little boot to leak. Secure the boot with zip ties or it will leak. Ray