problems after throttle body bore

[Fred85]

i took the drill and the sanding drum to my throttle body today and bored it out to 60mm

aside from the whistle, which i'll fix later, my engine is idling at really close to 1000rpms now when warm (as opposed to the 500-600 rpms prior to the boring)....what happened

also, when i'm going like 45-50 mph and up, when in OD, and i just let off the gas, the tach will jump between 1200 and 1500 rpm's until i start braking.......what's going on here?

i was really careful with my sensors while removing, cleaning, and reassembling.......

with the butterfly completely closed, should you be able to see light between the TB and the butterfly when you hold it up to a light source? i ask because i can see light all the way around mine now.....

 

[2001XJeep]

You said it in the last sentence of your question. You have created a huge air leak all around the throttle blade. To the engine it's like you've got the throttle cracked open all the time, even though the TPS isn't registering any movement. I'm surprised you don't have a code yet, wouldn't surprise me if you have one pending that will show up in the next few days. You must get a properly sized throttle blade in there asap. Either replace the throttle body, or the blade to the proper size, just whatever you have to do to get it solved. I personally wouldn't drive it like that anymore than absolutely necessary until you get it fixed.

 

[Kuasimodem]

You now need to get a 60mm throttle plate as you now have about a 1mm gap all the way around the throttle plate.

When I bored mine I only removed the restriction below the throttle plate and didn't touch anything higher than that.

You could also try looking in the junkyard for another stock TB and try boring that one.

 

[Fred85]

damn, i knew that had something to do with it

i've got a check engine light too

the local u-pull-it only has older model xj's on the lot, some are renix and some are HO but they're all definately pre-97........would one of those HO throttle bodies work with the sensors on my '01?

 

[Fred85]

nevermind, just realized that the newer model TB's are different with an extra sensor

 

[Littlewhitexj]

a 96 TB should work, they were OBD2 with the map on the TB

 

[Fred85]

that was a $65 mistake

luckily the last local salvage yard i call today actually has a TB in stock

 

[ricot83]

dude your old tb isnt bad, all u need is to make a new plate for it that is all. shit i would take it for the price of shipping. I can make a new tb plate and use it for myself.

 

[fitbmxseries1]

i would send it to aplace and have a plate made and also bore out the tb to 62mm. after i did mine i found out that i could do this for under 100$ im still considering this option though! i also see on ebay a few guys do this, you just hit buy it now and send your TB to them and it will be back in a few days, but then you have to go with out a vehiclee for a while.

also since the hole in the intake manifold is 62 mm youd probably see a huge differance!

heres one auction on ebay that ended
http://cgi.ebay.com/ebaymotors/Jeep-96-04-4-0-62mm-throttle-body-cherokee-wrangler_W0QQcmdZViewItemQQcategoryZ33558QQihZ018QQitemZ280043822828QQrdZ1

 

[xj92]

If you decide to do this yourself, what exactly do you buy to use with your drill to get it out to exactly 62mm? Probably a dumb question, but oh well. Somebody please give me the obvious answer. And if you were to make the larger throttle plate yourself, buy some thin aluminum sheet and use a holesaw to get it 62mm around, and then clean it up? Doesn't sound like it would be a perfect fit.

 

[mud-dog27]

i have the same question bout a new throttle plate

 

[balloo93]

Just FYI, I had the high idle after I bored my TB to 60mm. I tried to manually move the throttle arm to the closed postion and it wouldn't budge.

I removed the TB and looked underneath and there is a small hex set screw under the throttle arm that acts as a stop. If you back it out a hair, the idle will drop. I was able to tune mine with only two removals and adjustments.