Rebuild time some Questions Part I

[Tim]

I spent some time this evening filming and removing the air/cleaner vacuum hose and the like and plan on pulling the towers off tomorrow and taking them a part. I parcticed on a old set I got on Ebay, but I still have some questions.

1. What is the best solution to use for cleaning them? I had planned on just using break cleaner....any problem with that?

2. I got the kit for rebuilding both front and rear but I could only get the Rear injector not the front. How much difference is there? Don't suppose there's a local place to get the Front? (reality is I had them backward in my head when I was ordering the parts - front vs. rear - it's really the front that is giving the odd spray pattern)

3. Shouldn't be any "adjustments" necessary after the rebuild?

4. I read that using a K&N filter might cause one to have to remap to avoid lumpy idle and poor tip-in....any suggestions? True? How the hell do you remap?

5. Since I'm only taking the injector tower off do I need to worry about fuel pressure? Should I still remove the fuel pump fuse and crank the car a few times?

I follow up with some pics.

[Tim]

videos

camera sucks --LOL just realized I could have talked while i filmed...next set will be better.

[Tim]

Here are some stills.

The Rochesters are numbers....24 and 21.

Below connected

Below Unconnected

Below Additional plugged vaccum...not used on this car...what would they have been used for?

[Desertdawg]

1. I would say your best bet would be brake cleaner of carb cleaner, either one will work.

2. The front and rear injectors are the same (I think) or at least there's not enough difference to make a difference.

3. Just working on the injectors you shouldn't need to re-balance them, but it never hurts to check, also check the IAC voltage (I think its called IAC).

4. The K&N won't mess with anything unless you have it over oiled, and it will flow better then stock. remap - would be just letting it idle for a minute or two without turning anything on or off, or touching the throttle.... the puter will remap the air/fuel itself.

5. You might get a little fuel spillage, but nothing that you couldn't catch with a rag!

The vacuum port you see in the last picture is used for balancing...

[Buccaneer]

Tim the injectors and the springs on the bypass and regulator side are diiferent on the front and back TBs, just don't mix them up or you'll have issues. If you pull the TBs actually off the manifold, you will have to balance them again. The IACs can be removed and cleaned, but torque them back in, if you go too tight, they will crack. If you remove the injectors from the pods there are three gaskets, one small one at the bottom of the injector pod (oil it before installing a new one) one large one at the top (oil it also) and a metal ring at the top. Ensure you install them the correct way or you WILL have leaking injectors. Hope this helps.

[Desertdawg]

Thanks Tom, I'm glad your here to keep my from posting something stupid!!!

It's sad, my CFI knowledge is already fading from my brain.

[Tim]

As always, thank you gentlemen!!!

I'm not removing the TB. I'll going to wait for the intake and have them done at the same time (If Tom and Jim will do them).

The kit I bought was the for rebuilding everthing including the TB, but I'm only going to do what I call the towers, they call the Fuel Meter Body. Only thing I can't do is replace the Front injector...because I don't have it. It appears to be easy to do when I find one, with just a sinlge gasket replacement along with the injector

Has good instructions that include a torque table for all the screws.

I still don't get the remapping? Why would that come up if it was handled by just driving the car with the new filter?

[Tim]

Thanks Tom, I'm glad your here to keep my from posting something stupid!!!

It's sad, my CFI knowledge is already fading from my brain.

Well come on down then....I'll be in the garage all day...you can refresh that knowledge....

[Tim]

Got the rear off...quick break....I'll post more video and stills this evening.

[Tim]

rear is done and reinstalled.

Found some interesting differences...will show those later.

Going to go pull the front off and give that a cleaning and new gaskets and regulator parts. And see if she'll start.

[Tim]

Ok..she's back together. (for the 3rd time)

Ok....here ya go.

Rear got done just fine. Put in back on the TB hooked up both gaslines (there's two for each)....I think the gaslines were really the biggest pain. In the video I'll post a bit later you'll see the some of the process.

Took the front off and while I was cleaning it, I looked over at the kit and there were two small gaskets instead of just one....F%%%%$#$#$#$ I put the rear back together with out the small gasket for the side channel (can't recall the techincal name).

Great so I finished the front tower and then bolted that in to place.

Took the rear off again and then replaced the gasket. Hooked up all the gaslines and replaced the Fuel Pump fuse and turned the ignition on....got out and looked her over and there was gas leaking from the front tower.....great...turn off the ignition and then checked the torque on the screws on the top and on the TB. Turned the ignition on and watched as a gas spurt...ran across the engine. So pulled the fuse and disconnect the gas lines to remove the Front tower.

As I was doing so...two of the torque screws on the holding the tower to the TB stripped...just the heads.

Great..so I sop (is that a word) up the gas and get out the dremel and cut a couple slots in the screw heads....while reaching from the leftside of the engine to cut the slot in that screw on that side...I slipped and snapped off one side of the vacuum tree that pops out of the value cover.....F%$%$%$%$%$%$.

Ok..screws are out...can't use them again..grabed those and the broken plastic vacuum tube and run off to Checkers and Ace hardware. Checkers doesn't have part (didn't expect them too) so I pick up some different size tubing and connectors to make a temp patch. They didn't have the screws either...got those at ACE.

Got the Front apart and looked at the gasket..it was the small one for the side channel. Tossed it and cut one from a piece of gasket material I had in my took box. That did the trick....but it all back together and she fired right up.

Still have to out this evening and put the air cleaner and hoses back on.

I'll add a couple more replies with some video...(not great video) and some stills..That was fun....good thing I got a day job!!!!

[Ted Y]

Glad to hear you got it back together and running!

[Eddie44]

Good job! Now ACE has another expert

[Tim]

Good job! Now ACE has another expert

LOL..won't be adversting my skills any time soon.....

thanks. It was fun.

[Eddie44]

Good job! Now ACE has another expert

LOL..won't be adversting my skills any time soon.....

thanks. It was fun.

You're one up on those of us that have never done it. That makes you the expert.

[Buccaneer]

Thanks Tom, I'm glad your here to keep my from posting something stupid!!!

It's sad, my CFI knowledge is already fading from my brain.

LOL, just making sure people know what to expect before they start rippin' things apart and then freak out when it all goes to hell on the reinstall. You know about all the querks the CF as to offer no matter how long you've been away from it. Its good that you still chime in though...thanks.

Glad you got it all back together and running. I didn't see it posted, but might have missed it...if you removed the IACs to clean them thats where your high idle came from until the ECM has a chance to relearn and things will settle back down or you had a vacuum leak.

Tim, one thing I did notice was that on your FPR the tab was low in the slot which means you have low FP. Have you ever checked the FP? If not, set the FP to 14-15psi measured inbetween the TBs and you'll be suprised how much better the motor will run especially on high end. Typically, with the lower FP on a CF motor the motor will run out of power at around 4,000 to 4,200 rpm because its running rather lean. I'm willing to bet that you only have 10-11psi and thats not enough for a CF motor. GM says 9-13 is ok...NOT!! Put your FP at 9psi and see what happens at WOT and then bump it up to 14 and retest. 13 would be absolutely the lowest, but that extra one or two psi makes a big difference. Hopefully your pump will be able to support the increased pressure to make it run properly. If not, just replace it with the 85-87 corvette Delco pump which is a direct replacement and it will be able to support the motor and any other mods down the road you may want to do until you reach the stoker motor class and then go to an LT1 pump for the higher pressures needed. We've done a lot of testing on this subject and found this works the best. Good luck.

[ChadC]

...nice