Originally, I removed the sensing valve and plugged the hole in the "block".

I Then removed the rear brake lines from the block, plugged the holes, and used an adjustable prop valve from Jeg's.

Booster went bad a few weeks ago so while it was out, I decided to eliminate the block altogether and use fittings in it's place.

Interesting thing. the orifices in the block for the front brakes measured .040" versus .100" in standard brake lines. Brakes have never felt better. I had been prone to locking rears no matter how I adjusted the valve for the rears.....

 

Is there a reason for that? Never understood why would 1 would be bigger than the other....engineers I guess...
This was the first time I tackled a brake booster upgrade and changing fittings around...I'm glad it worked!

 

Sometime I'll look inside an XJ prop valve.

 

While the water bottle is out, clean up this ground.


According to Cruiser54, this ground is shared by front windshield washers, rear windshield washers, AC clutch relay, fan control relay, fog lamps, fan motor, headlamps, front turn signals, front side markers, and park lamps.
http://cruiser54.com/?p=211




Clean it up, put it back together with OxGard.




I found a 1/8" bit the correct size for the new holes.




Some consequences of using a bigger booster: Wiper fluid bottle must move forward. This really squeezes the airbox and getting the lid on is a challenge.




I don't know why I didn't notice this when I swapped the radiator in, but the new fill neck keeps this clip from engaging.




I cleaned all the vacuum lines as best I could, then RTV'd the big one together, as it comes apart with very little effort.

 

While putting the old TPS sensor back on my bored throttle body, I broke the connectors.



Still haven't refined my back-probing technique. Broke the plug.






Solder in a new connector.




This is the ECU pigtail and TPS part numbers from O'reilly. Decided not to swap the TCU pigtail. The handwritten PN is the TCU harness.




Put heat shrink on, solder connections, then move the heat shrink up and shrink it.




Hard to see, but install the new vacuum line from the TB to the MAP sensor.




Reconnect the washer fluid motor electrical connectors.

 

Any idea where this hose plugs in? I found it flopping around by the oil dipstick. The other end connects to a hard line that disappears down behind the engine....


No idea where this plugs.




Connects to this hard line below and just to the right of the MAP sensor.

 

I THINK the evap cannister.

A side note: If you use the 99 to 04 booster, you don't have to move the washer rezzy, but you have to notch the firewall seam.

.

 

That makes sense - into that "Purge" location in the background of the above picture? I'll take a look when I get home.

I prefer to drill 2 small holes rather than notch the firewall, at this point. That may change in the future if this presents problems.

I'm letting the RTV dry and will start the heep up this evening for the first time in awhile! Then bleed the brakes and I'm back on the road

 

You won't have any problems.

I've done the swap both ways.

Wait til you feel those brakes!!!!

 

But I've gotten used to planning my stops 1/2 a mile beforehand!

 

Fasten your seatbelt....

 

Ha! I know this feeling until I did the swap! As mentioned below and might need a neck brace lol...huge difference!
Who needs seat belts? Lol jk

 

So I spent a week or two chasing a high idle. One I got everything bolted back together, when I started up, the Idle would sit at around 1700 rpm and I could never get it down. Ran in circles chasing this one - emptied a can of TB cleaner hosing off all my vacuum lines and gaskets looking for a vacuum leak. Went through 2 more TPS's, an IAC, and ended up replacing the IAC harness side connector as well. No go, still high. If anything, it was starting to creep higher.

The only thing I could think of was that when I bored my throttle body, the new butterfly plate wasn't seating tight enough against the bore and the excess air was causing my high idle.

So ripped the TB off and spent 5 hours walking a new butterfly valve in by hand....very tedious but I'm proud of the results; It's tighter than the stock one.

A little bit of a gap, but maybe it's enough for my high idle...




Cut it in by hand....get the axis to the correct diameter, then walk the butterfly down by slowly filing away the high spots....






looking good! toit like a toiger.




Cut a new gasket...bolt her down

And this is where the bug got planted. Hard to see, but look at that IAC in the last pic...notice anything? It should be closed. By design, when you kill the motor, there's a little relay that engages and powers the IAC to bottom it's pintle out and close off the air bypass. The computer assumes that the IAC is "home" when it starts the motor and uses that as it's reference position and only opens from there.

Needless to say, when I bolted the TB back on, the idle was still high! Then my brain finally caught up with my eyes and realized that the IAC never closed on shutdown. First thing is to check the relay that closes the IAC on power down....

The red one. These 4 sit right behind your battery on the passenger side.

I pulled it, cleaned all the blades and the mating connector and plugged it back in.

I started the engine and then killed it - this will cause the IAC to "home" and close the pintle. When I started it back up, perfect idle...700rpm.

 

Wow!! A crappy connection on a 29 year old vehicle can cause issues? LOL. Great job!!!!

Had you done Tip 3?

 

Weird how that works, eh?

I should also say that Cruiser was a very helpful sounding board for chasing this down - thank you! Many a private message was exchanged.

Tip 3 - Not completely - I've done the plug behind the drivers headlight, the 2 tranny connectors and various others as I've come in contact with them. Need to dedicate some time to systematically working through the engine bay.