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I was driving along on the highway. Everything going better than perfect. Will explain later...
I don't know if my problem is connected to this but it seemed to coincide. I turned the temp setting on the dash front hot to cold... That's it.
Whats happening. Driving along I started to notice that she wouldn't slow down when I took my foot off the gas. I came off the highway and she was fighting forward. I pulled over, popped it in neutral. RPMs shot up to 2k + and stayed. I opened the hood, throttle seemed stuck and wheel on capstan was stuck open, enough for 2k... I reached and disconnected the arms, the capstan snapped shut. Arms are now off. RPMs staying at 2k +. Capstan at usual position for idle,,, linkage at usual idle position BUT idle is still dangerously high 2k+ and will not respond to linkage being at idle or to capstan wheel being at idle. I'm a little lost. A out of the blue vac leak somewhere??? Must be it, right?
If you are out there,,, I need help now. This ain't good.. I'm all ears.
You removed the 2 crossrods, and the capstan snapped shut, tick. Its something AFTER the capstan.
What happened to the 2 crossrods, did they also move to the idle position, I doubt it. I reckon something has jammed one, or both throttle discs/arms/rods.
If its not that, look at the 90deg elbow on top of the AAV, if its split, common, plugging the AAV will do zero.
The trans vac line would have almost zero affect on idle speed.
Hi Grant... Can't tell ya how nice it is to hear from you, lol
****! So yes. Cap is at zero full idle. Arms were disconnected at the time. Butterflies alllllllllll the way closed. .002...
There is a TON of air getting in somewhere. The elbow at the the top of the AAV is new-ish. When I out my thumb in the hole at the breather,,, holds a steady pull. The two elbows at the cross pipe are BRAND new. Inspected, they are fine. Turned the idle screw ALLLLLLLLLLL the way in. Took it down a tad,,, but not much.
I am confused as all hell.
Idle is at 14k now. Don't know why is as low, don't know what I did. But,,, I am going to drive it to where I was going. Let her cool down to cold,,, look tomorrow.
I'm very very nervous about my next 4 miles. This is bad.
~~~ Throttle body shaft seals/bushings???? Where the shaft that holds the butterfly goes into the throttle body??? There are 2 sealed bushings on either side...Might explain the temporarily stuck throttle of one failed? I was so panicked and rushing I didn't take time to notice which side of the linkage was holding everything open at 2400 RPMs. I wish I had...
Might also explain where all that additional air is coming from (if where the bushing failed left a big gap) even tho everything in the throttle assembly and linkage APPEARS to be fully in the idle position.
Tomorrow morning I'll walk over to the auto zone and grab a bottle of brake/carb cleaner so I can spray it around some places in the engine to check out the bushings in the throttle body butterfly shafts - and a bunch O other places...
Have a look at your throttles, see if some carbon has them jammed.
Make sure air cleaner box bolts are tight.
Narrow it down to one side or the other... Block off your balance tube and aav... then the side that is less responsive to throttle changes has the leak.
once the side is identified you can have a closer look.
JJJ
If you block the air filter box trumpets what happens?
Check that all the vac tubes each end of the intake manifolds are in place and not leaking, especially the blanking plugs.
Check that the fuel pressure regulator vac tubes are attached.
VERY CAREFULLY go round the two throttle bodies as both have various vac take offs on them, particularly the A bank underneath has a large diameter takeoff that powers the cruise control.
Check that the vac takeoff to the ECU in the centre of the crosspipe is connected and not leaking somewhere between the pipe and the ECU' you can do this by sucking or blowing, but put a piece of string on the pipe first! If you drop it that is a disaster...
Then if nothing found remove the airbox covers and the filters and with a large solid balled up cloth, cover the throttle bodies so nothing can get through, cover any other inlet holes, start the car and listen for the hiss.
Remove the air filters, and LISTEN, you will possibly hear a CLICK as the throttle returns to idle stop position.
I reckon something has/is jamming one or both throttles open. I doubt those shaft bushes have enough ***** to overcome the return spring, but a throttle disc stuck on the air filter, coz you just had to go WOT, is possible. Mine did that way back, and the fun side of WOT disappeared in a flash.
To get that sort of revs from a vac leak would need a HUGE pipe to be off its spigot.
The capstan "sprang back" as you said, the rod/s did not, there is your gremlin.
I just woke and going to have to go and figure this out, and on my way out soon. I am about 20miles from home.
Note ~~~ I changed all plugs yesterday. Had the dizzy off the car. Checked inside of dizzy and rotor. Reset all and drove the first 14miles of my trip and she was running better than she EVER has. I was and still am excited to posting what I found in swapping plugs. But it's nothing that should be causing this. I don't think.
After the problem showed up....
I removed every vac line, car running, and plugged holes with finger on the intake side of things. All the intake spigots one by one. No change. Used my mouth the check vac on the hose side. All held vac... I need to double check this when calmer.
I had breathers open and with my hand checked the position of the butterflies, they are seated in there usual place. Used a rag to clean orafices... Checked the gap yesterday morning when all was normal at .002. The little locking screws are against the little adjustment arms and things seem "normal" there.
I have tried carefully rocking both the entire manifolds to see if that might have a change or have an effect on idle,,, like a blown and sucked in manifold gasket (or something) no change. Inspected the best I could the gaskets between the TBodies and the intake. Seems normal.
All 8 bolts for TB, 4 per side, are tight and in place. Checked them with a 13mm socket I borrowed from a side of the road tire shop in Brooklyn.
Removed the line going to the ECU on the balance pipe. Plugged hole created on balance pipe, no change. There was a change to running there BUT I think that was associated with the signal vac to the ECU being disrupted...
When this started, I got out of the car on the highway, the capstan was definitely stuck open. 1/2 to 3/4 of an inch off the stopper... Revs were HIGH... over 2k and loud. I tried to turn it back by hand at first and, nope. Flicked off the long arms and, I DONT KNOW WHICH ONE things were happening fast, it clicked back to place... Idle STILL stayed well over 1000. Mind you I had idle set and really well at 600-650...
After cap back to "normal", the peddle feels normal and it drives "normal" although idling at 1200 and fighting forward. The throttle springs seem ok (I will have a better look today) but using throttle peddle and by hand the cap and arms will spring back once released. At least one spring is working. Springs (after long search) are new-ish OEM parts.
Could this be some catastrophic,,, valves or valve seals in the head gave way? A dropped valve seat? Please say it ain't so.
I, for the life of me, cannot figure out where all this air could be coming from.
Imma have some coffee. Try to find a parking spot where I am, borrow and buy some tools, and 2 cans of some kind of spray to start spraying around the engine bay.
I will remove and close off the balance pipe. Great suggestions. And close off the breathers openings one by one. And try to pin down which side and report back.
I have also turned the small AAV idle control all the way in. Had an effect but very very little. Idle is high with long arms off or on. Linkage on throttle shaft appears to be in the same place as it was when things were good.
I'm babbling here... I really need to figure this out. I WONT pay for a toe.
OK, it appears that linkage WAS at play, and now its back to normal, but idle still too high.Odd at best.
You are familiar with the over run valves I know. remove the short hoses, plug the alloy spigots, and see if that changes anything.
CALM DOWN.
Leave the balance pipe intact, just ensure the hoses are good, and by that I mean check them for loose fit etc etc. Forget they are new/newish, just systematically look for things that dont look right. That 90deg top AAV hose is also in need of checking, particularly the underside.
That Vac port UNDER the A Bank throttle body, mentioned by Greg, would be a good starting point.
You are looking for about a 1/2" open spigot/hose to give the rev rise you have.
If its definately NOT mechanical, as in linkages etc, it must gbe an open vac port, and a large one.
FORGET valves and seats and other rubbish, waste of time, it is not that.
The A bank butterfly adjustment screw,,, I guess I left it loose. And, somehow, over what was only a 30-40 minute NYC 15miles had walked its way down holding the A bank butterfly open - what I could only guess - was something like .015 .020 OVER the usual .002/.003... craZy 😂
I SWEAR I checked that. Swear I must have... I have ZERO idea of how I didn't... Feel kinda dumb. Yikes
Still doesn't explain the stuck open capstan wheel,,, or does it? The cap was 1/2 to 3/4 of an inch offt the stop! And, fighting being righted when found...!
Coolant leak... I just gummed up the SPOT that appeared on the VERY SAME DRIVE with,,, wait for it,,, JB Weld epoxy... It's drying in the sun as we "speak"... I CANNOT afford a Jaguar expansion tank right now... Hell no!!! Heaven Help Me
03-14-2020 | 04:42 PM
Broken down
