PlatinumV8

After wrapping a black poly glove over the shaft, I was able to get enough force on it with small vise grips to back off the nut. Here is the throttle cable adjusted so that the first touch of the cable does nothing, put a little pressure and the butterfly valve mechanism starts to move.

It is hard to show in the picture, but you can see the cable is now arrow straight and shows where I headed next to solve the hesitation issue. The air mix port with the two Phillips head screws and brass in color right in front of the throttle body.

PlatinumV8

The next part kind of shocked me, based on my machining background.

Our largest machine my partner and I owned was 14 X 56.

Measurements in feet, not inches.

So I'm pretty familiar with steel and aluminum interfaces.

Lexus used some sort of phenolic gasket, a stiff material to seal the mild steel cover to the aluminum intake. Trouble is, the intake port has a rough milled finish. It is not polished. It has grooves that extend from the port to the exterior. Then they used just two screws that cannot be stretched to give adequate compression of the gasket, even if the port was polished flat.

When I detached the port cover, the two screws were just hand tight and the cover slid off with no semblance of a seat, like you feel with fiber gaskets.

It lead me to believe it has been leaking vacuum and contributing to our issues.

Also, if you look closely you can see carbon traces along the hard gasket. They should not be there with a good perimeter seal.

If you have a 98-2000, I'd do what I show next, along with check for a loose throttle cable, make a new gasket by hand from a roll of stock any auto parts store will have for custom car needs.

Lots of supercharger and turbo/nitrous piping is hand made, so there is no gasket off the shelf that fits.

Curved surgical scissors and a hole punch for construction paper will also make your life much easier.

To keep the testing accurate. I DID NOT DO THE SOLVENT CLEAN OUT. This is for you guys that did the cleaning and had little results or results that did not last.

Hesitation off the line is gone now. There is smoother shifting and much better response.

Idle is still lower than Yamae-san would prefer, but maybe these are complimentary fixes and not a one or none issue.

Here are the pics! PM me with any questions or comments.

Debbie

PlatinumV8

More coming, tablet almost dead! Damn it Scotty I need more power!

sha4000

iTrader: (1)

Nice work, I'm watching you closely.

PlatinumV8

So my sewing and scrap booking scissors in the pic were useless, that was when I turned to my surgical scissors from my combat first aid kit. I even have the clotting powder, Quick Clot. I hear it is painful to use, but I want it on hand just in case. Too many gas powered tools in my garage!

Notice the thread locker too, it is a red container, but is the blue liquid. Those little Phillips screws are terrible IMO, at least the locker will let me know what is happening with them.

PlatinumV8

Thanks Sha400! I want to drive it a few days, maybe the whole week and then do the clean out like Yamae-san recommends. As you will see the two large ports and the small ones are open, but covered in carbon.

PlatinumV8

Here we, my sister and me, are buttoning things back up. When you build the gasket, always do the bolt holes first, it would be a shame to make a perfect port opening and then punch the holes too wide or narrow.

The last thing you want is a gasket that bunches up when you cinch it down.

I set my drill in a light clutch and ramped it up back and forth between each screw until it did a nice quarter turn extra and stopped on a nice compressed custom gasket. Work kind of quick, you don't want the locker to set while you are still tightening.

PlatinumV8

Oops! Here is the one with the CURVED surgical scissors. Amazon is great for stuff like that.

Again, I let the car warm up, drove it a few miles and played around in a parking lot that was empty, doing the slow speed stuff like stuck in traffic. No problems now. The only time it lurched was when I buried the throttle and it seemed to try and kick down two gears.

It is a totally different car now. Lets see how tomorrow's commute goes.

Doing a repair is a placebo effect, so I'm trying to remain objective.

Take off that cover guys and see if it looks like it is leaking past the gasket.

That and check to see if your throttle cable has any play. Don't make it too tight! It needs a small dead spot so engine vibration at idle does not open the butterfly valve.

Debbie

Yamae

What a great write up!
You are more than who succeeded to fix a TV changing capacitors. She must have encouraged many boys.

To me, the capacitors change job was easier than the throttle body job since I am quite comfortable to do a soldering job.

I now have two questions.
1, Is your shifting problem totally gone?
2, What is the current idle rpm status? The ECU relearns the new conditions and you need to drive some more may be 15 miles or more in a city though.

PlatinumV8

Deep bow, Yamae-san. You honor me.

I will persevere for all of us with this problem.

Edit: My idle RPM is slightly higher. I'd say 750-800 rpm when warmed up, in park.

In drive it is about the same 300-350 RPM, with foot on brake. I'm doing all these tests at night so the daytime running lamps are on. Is there a way to shut them off?

Looking forward to tomorrow!

Go Speed Racer! Go Speed Racer, Go! Love running this engine with the slap shift!

Debbie

PlatinumV8

If this gasket turns out to be the problem, I'll get my machining buddies to punch out some if there is enough of a demand. Let me know if there is already a fiber OEM replacement out there, hate to duplicate an existing retrofit.

What would be a fair price for a limited run item like this? I'd have to have a die made after doing a cad of the hard gasket profile. $20? 10$?

alien1974

Hi i noticed mine didnt have a gasket either on the air pass cover, i cleaned mine it made a difference for about 5 mins then back to the norm, what did you make the gasket out of? i might buy some instant gasket, i am surprised there isnt a gasket on there from factory. Buy the way i have noticed the low speed shunt is less apparent when the AC is on as the idle is slightly higher.

PlatinumV8

Alien,

If you want to make a gasket like mine, just go to your local auto parts place and ask for a roll like you see in my pics, it is the stuff with the white lettering repeated across it. That roll is ten years old at least, as it does not go bad. It's solved problems from lawn mowers to my marine motors in my boat.

As far as using a liquid gasket maker, I was thinking of using the red permatex I use for water pump replacement and timing belt work. The only worry I have is if any of it were ever to get in those small holes and get lodged between there and the injectors. Shudder to think how you could get it out.

Tonight I am going to take off the cover again and run the red permatex in a skim layer on the outer edge of the gasket on both sides, using a flat wooden coffee stirrer.

The car is running much smoother now, but I really think the twin screws are completely inadequate, especially at high vacuum. Going to take the battery offline too, so the ECU relearn again so I can compare apples to apples.

Then this weekend I'll do the solvent clean out and we can have all the data on a low mileage example like my car, with just 91K. 1K of which was driving it back from Florida recently after purchasing it.

Also I think the five minutes was the time it took for the fluid seal of the pooled solvent on the mating surface of the cover to evaporate. Just a guess, but makes sense, because everyone talks about it getting doused. That or the gasket swells when soaked in solvent and shrinks back up after heating. Who knows.

alien1974

Platinum V8

Incidentally what mileage do you get? i get around 13 city and 22 highway i converted it to us for you its done 98k by the way.

PlatinumV8

Before doing this gasket work I was getting 15 in the city with many hard launches on the street on the way home or doing errands. Tires chirping in first and second!

Need to wring her out (named her Sophia after the Modern Family actress) so I can see what is what, with her state of repair. All my vehicles have names. Trucks and SUVs get boys names and cars get girls names.

As soon as I saw her big headlights and look at me paint job, I knew what her name would be!

I have not done any highway driving lately. IFIRC, I only filled it up three times from Orlando to Michigan and had lots left over once I got here.

After my drive home tonight I'll have a better idea where the MPG is with the new gasket.

Debbie