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Jimmy9190
Dodge Dakota
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3/27/2008
19:06:58
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 Subject: Stiff spring on V8 TB
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I put a V8 TB off a 1998 318 motor on my 3.9 a couple of weeks ago. I had to loosen the screws on the TPS because it felt like it was binding up and the truck would not throttle down when slowing down. Mine is a manual 5speed. It would bog down like it was getting no gas whan I would let off the gas to slow down or make a turn, and it would chug real bad unless I pushed down on the throttle really hard, which ran the tach up to like 3000. I loosened the TPS screws and that helped it for a while but then it started having the same problem again.
I really liked the performance I got with the V8 tb but I can't drive around town with it like that. Cruising on the interstate is fine, but it is so sluggish to respond when slowing down and speeding up in normal speed driving I had to put the old V6 TB back on. That one is working fine, so I don't think the cable is the problem. The V8 TB requires a lot more foot pressure on the gas pedal to drive the truck. Is the spring stiffer in the V8 TB than the V6? I would really appreciate some help on this one. I got the TB at a junk yard and they won't give a refund.
Thanks
Jimmy
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daddio
Dodge Dakota
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3/27/2008
21:11:09
|  RE: Stiff spring on V8 TB
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they should be the same. unless someone removed the butterflies and shaft from the TB and reinstalled it with the spring too tight. it can be done. i know first hand.
bought a used v8 tb from someone and it was tight as you describe but i didn't have any driveability issues just didn't like the feel of the pedal. i took the butterflies and throttle shaft out and reinstalled with the spring a little looser and all is good.
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Jimmy9190
Dodge Dakota
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3/27/2008
21:19:42
| RE: Stiff spring on V8 TB
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The V8 TB is off a 1998 318 from a Dodge van. I don't think anybody would have done anything to it. It was very dirty and crudded up pretty bad when I got it. I took a good hour and half a big can of carb cleaner to clean it up. I put all the sensors off my old TB on it too, and they are all working fine.
Did you take the spring off your old TB and put it on your new one? If so how did the spring come off? How did you get the throttle shaft and butterflies out?
Thanks
Jimmy
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dakownr
Dodge Dakota
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3/30/2008
22:37:43
| RE: Stiff spring on V8 TB
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did you figure it out yet jimmy?
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Jimmy9190
Dodge Dakota
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3/30/2008
23:02:29
| RE: Stiff spring on V8 TB
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I took the v8 tb apart thinking something was wrong with the spring tension. 3 out of 4 of the butterfly plate screws broke so I had to drill them out and put in screws and nuts to hold the plates. Put it back together and I don't think it will ever work right for me. I studied the pictures of the tb in my service manual and there is a cam on the front of the linkage that is not present on my oem tb. The only thing I can figure is it has something to do with the throttle control for an automatic transmission. The cam is supposed to ride on the throttle cable. My truck is a manual and the cam was in the way. My cable could not get a straight shot at the ball stud for the cable connector with the cam in place. So I cut it off with a dremel. The cable pulled on the linkage straight and nothing was binding when I had the v8 tb on the engine. I have no idea why the tb didn't work other than it must be different for a v8 tb on a 5 speed.
Truck runs just fine with the oe tb. The junk yard of course won't take the v8 tb back because the linkage has been modified. This might just be a $65.00 lesson learned. Maybe it would work with a v8 tb cable for the 5 speed but I thought the manual and automatic cables were the same.
Jimmy
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ConcertBb
Dodge Dakota
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3/31/2008
09:10:44
| RE: Stiff spring on V8 TB
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Jimmy,
I have a V8TB I can sell you. It is on my 02 right now, but I am selling the truck and will be putting the stock TB back on. It works very well. I just feel it might scare some people away when they see a modification on the truck. Let me know if you are interested.
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Forseti
Dodge Dakota
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3/31/2008
13:06:32
| RE: Stiff spring on V8 TB
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This is a shot in the dark but ..... on the older 3.9L engines .. the intake ports on the intake manifold are a little smaller than the butterflies on a 5.9/5.2L throttle body .. maybe the butterflies are hitting the manifold and sticking ....
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ConcertBb
Dodge Dakota
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3/31/2008
14:02:39
| RE: Stiff spring on V8 TB
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The intake opening is slightly smaller, but the heaight of the TB is the same, so that would not be the case.
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dakownr
Dodge Dakota
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4/02/2008
18:02:07
| RE: Stiff spring on V8 TB
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Jimmy; as I have mentioned before, I have a couple of V8 throttle bodies that I am not currently using. They are both from auto trans vehicles of different years. I also have a '92 dak with a V6 and manual trans. If you want, I can try to swap a V8 tb onto it and see if I can find a solution for you so that you don't end up having wasted the money on your throttle body. Even though the vehicles are of different years, the procedures should be the same.
Also, don't feel bad about breaking the screws, they are a b1tch to get out and in. If you can, try to get somebody that can tap the holes so that you don't end up getting the nuts and bolts in your engine...Trust me, this will ruin your day, week, and month really quick. If you can't get the holes tapped, either use lock nuts (they have nylon in them to hold them in place) or perhaps I can send you the necessarry parts. In any case, please reply to this post so that I know you are actually still reading this and are here to actually benefit from the help.
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Jimmy9190
Dodge Dakota
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4/02/2008
18:18:17
| RE: Stiff spring on V8 TB
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Thanks for the offer Dakownr. I am still here and I appreciate everyone's help but I think I will leave well enough alone for now. I am even considering disputing the charges with my credit card because the TB did not work, and it was the junk yard employees who told me to modify the linkage. I normally would not try to dispute it and just take it as a lesson learned but the bottom line is the part did not work. The credit card is sending me some forms to get the dispute process started. If I get the charges reversed, I may start over on the TB mod. I just wonder if anybody else with a manual trans and v8 TB has had this sort of drivability problem. The performance at speeds above about 30 mph was great with it but my Dakota just did not drive or idle down right in normal driving and when downshifting it really caused problems.
Thanks,
Jimmy
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ConcertBb
Dodge Dakota
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4/03/2008
07:00:24
| RE: Stiff spring on V8 TB
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Jimmy,
I'll take a pic of my TB on the truck and send it to you. I have an 02 5sp w/cruise and have had no issues with the V8TB. I modified the cable for about $5. When you get around to doing yours you can use it as a reference.
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daddio
Dodge Dakota
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4/03/2008
07:34:01
| RE: Stiff spring on V8 TB
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Jimmy, i installed a V8 TB on my '00 3.9 - 5spd w/ no problems. i didn't even have to modify the linkage. i do not know what the TB came off of as i bought it second hand from someone about 4 yers ago.
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Mike98
Dodge Dakota
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4/03/2008
10:09:51
| RE: Stiff spring on V8 TB
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Jimmy,
Sorry to hear about your trouble... It was your original post that convinced me to buy a v8 tb myself! (now just waiting for ball stud assortment--on back order... we'll see how it goes)
I had a few ideas for you. It seems that the TPS might be at fault, since adjusting it seemed to initially fix the problem. Maybe your V8 TB isn't properly actuating the TPS sensor... I mean, perhaps it's off center, so the sensor's sticking at "throttle open" position when you let off the gas too quickly. Try greasing it up, or grabbing a different TPS sensor from a V8 TB. Maybe also bore out the mounting holes so you can position it properly?
It might also be the idle valve actuator, not the valve itself, but maybe the hole it goes into is malformed? That would definitely be a faulty throttle body, then, and essentially be like a vacuum leak.
As for the spring tension, that might just be a mechanical advantage issue. My v8 TB has the cam, just like yours; I'm going to try to leave it in place though. That gives it a longer effective lever arm at low throttle openings, and then as the throttle opens further, the spring becomes effectively stiffer once the cam swings out of the way. Kinda like opening the secondaries on a quadrajet (except without the kick in the pants!)
Furthermore, the angle formed by the throttle cable clip (assuming you drilled thru the factory location and put the ball stud there) and the throttle cable, at zero throttle, is about 30 degrees, which is a lot harder to pull through. The v6 TB has the ball stud lower, so it's more like a 70 degree angle, and it's further from the pivot point for more mechanical advantage. If you haven't yet, try locating the ball stud straight below the shaft pivot point, near the cruise control clip if it's there, basically as low as possible. This gives the best mechanical advantage. My v6 TB has the ball stud in the exact same position as the cruise control clip, just on opposite sides.
In conclusion, I hope you don't give up! Maybe a little grease will fix it?
But then again, I haven't done any of this myself... Like I said, I'm waiting for parts, so I might just be full of it for now. We'll see...
Well, good luck!
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Jimmy9190
Dodge Dakota
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4/03/2008
12:05:58
| RE: Stiff spring on V8 TB
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Thanks for all the help here. I appreciate it. Yes Concert if you could email pics to JamesN710@aol.com that will help. I think the nuts and bolts I had to put in the tb the other night really messed up its operation. Even by hand it doesn't open and close right. It might have been bad to start with, I don't know. I found another v8 tb at a local junk yard and it is from a 2001 RT 5.9 motor, same year as my 3.9. I am going to go check it out on Saturday and if it's in good shape I might get that one and try it out. Everybody who has done the v8 tb has had good results from it, so this has to be some error on my part. I even called the Dodge dealer here who has a really good Parts Dept. and confirmed the throttle cable is the same for an automatic and manual trans. So, there has to be a way to make this work but not with the TB I modified and tried to put back together.
Thanks Mike for the info on the cable angles. I'll take a look at that too. Thanks everyone for the help.
Jimmy
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Mike98
Dodge Dakota
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4/04/2008
01:34:35
| RE: Stiff spring on V8 TB
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Hey Jimmy, I'm drilling the hole for the ball stud right now. I don't have a proper bit, we'll see if I can finish it tonight anyway.
When I finish it, and IF it works, I'll try to post a picture or at least send you one.
One more thought I had for you -- even though I doubt you made this mistake... Anyway, the TPS sensor can't just be blindly bolted onto the throttle body. The rotating shaft has to catch the teeth inside the TPS. At least in my case, this means I had to bring the TPS into contact with the TB at a slightly clockwise rotation, then rotate counterclockwise to align the screw holes, then bolt down.
If I had first inserted the screws through the TPS, then brought the assembly into contact with the TB and tightened, I'm pretty sure that would mash the teeth inside the TPS into the blade on the throttle shaft. Maybe that would cause erratic TPS behavior that was fixed by loosening the screws? You said it "clicked" when you loosened the screws, that's what made me think of that.
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Jimmy9190
Dodge Dakota
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4/04/2008
10:22:44
| RE: Stiff spring on V8 TB
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Thanks Mike I appreciate any pics you have. When I put on the TPS I did have to turn it to engage the tps to the tb shaft then turn it counter clockwise to put the screws in. I think the TB I bought just wasn't any good and was not compatible with my truck. The one I am looking at tomorrow is supposed to be from a 2001 SXT with a 360 motor. Will take a real good look at the linkage before I buy this one, the junk yard wants a lot more money for it.
Thanks for all the help here. I appreciate it a lot.
Jimmy
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Mike98
Dodge Dakota
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4/04/2008
23:50:55
| RE: Stiff spring on V8 TB
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First, the good news -- everything worked. V8 TB installed, and it runs smooth as ever, didn't even stumble on the first start. I'll figure out how to post some pictures here when I get a chance.
Now the bad news. My truck doesn't seem a single bit faster. If anything, it's slower in regular driving, because now I don't press the gas pedal as far to get going, so my auto tranny shifts sooner. I'll fix that though, adjust the TV cable somehow...
So far I've done a dynomax muffler, 1.7 rollers, v8 TB, and K&N drop-in. I don't think it's any faster than the day I bought it, and the mileage is down. I guess I'm just a bad mechanic :)
Anyway Jimmy I'm certain you'll have better luck with your next TB attempt, if I could do it anybody can. I guess you just got unlucky with a broken body or TPS sensor.
PS - if you wait patiently on ebay you might get a better deal than your local yard. I got my TB for $65 shipped, new old stock, with new TPS and IAC motor. But I'd been watching ebay for several months, they're not that plentiful. Also junkyards here in socal will part with them for $50, at least the ones in Bakersfield or San Bernadino, so that's another option (check car-part.com)
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Jimmy9190
Dodge Dakota
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4/05/2008
00:10:49
| RE: Stiff spring on V8 TB
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Mike thanks for the info. I have read that it takes putting some miles on the truck for the pcm to adjust and to feel any better performance. Some say anywhere from 50 to 200 miles and the truck will learn the new TB. Mine seemed to do that but in less time. Yours may do the same and do better after adjusting the tv cable. Mine's a manual so I don't have the tv to worry with. I'm going to the junk yard tomorrow and if the linkage is not the same as mine I am not buying their TB. I think you were right and I got the location of the ball stud wrong on that other one. I drilled it out in the same spot as the original stud and that might have been what caused all the problems. Of course now that I tried to fix that TB it's useless. I think I am done monkeying around with new ball studs. The guy at the junk yard said the one they have is from a 2001 R/T so maybe it has the right linkage. This junk yard has always treated me right, so hopefully this one will work. The junk yard can't really afford to not treat people right. I live in a really small town in rural Florida, and a bad reputation spreads around pretty fast. I'll post what happens. I bet your TB will wake up soon. There's a lot of posts here about that.
Jimmy
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Mike98
Dodge Dakota
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4/05/2008
02:01:40
| RE: Stiff spring on V8 TB
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OK here are some pictures of my TB project. I couldn't figure out how to post the html tags, you'll have to cut and paste the links to see the pictures.
Here's a diagram of my original V6 TB:
http://s298.photobucket.com/albums/mm267/IdiotMike/?action=view¤t=V6_TB_diag.jpg
The throttle cable ball stud is located on the same shaft as the cruise control stud.
Here's the new V8 TB (Sorry for out of focus, I forgot to turn on macro mode):
http://s298.photobucket.com/albums/mm267/IdiotMike/?action=view¤t=V8_TB_diag.jpg
The throttle stud is a disc-type, and located behind and above the cruise control stud.
Here's the ball stud I chose to add to the V8 TB:
http://s298.photobucket.com/albums/mm267/IdiotMike/?action=view¤t=ball_stud.jpg
Dimensions match the v6 ball stud exactly. The part came from a kit of 4 ball studs (Holley 20-2). Two of them are the wrong size, but I have one remaining ball stud, 0.2495", with 1/4-20(?) shaft, which I think would fit the dakota V6 cable. If anybody wants it email my gmail address idiotmike, first person who asks I'll drop it in the mail for you.
Here's the drilled V8 TB:
http://s298.photobucket.com/albums/mm267/IdiotMike/?action=view¤t=Mod_TB_diag.jpg
This isn't the optimal location for the stud but it was the only place I could drill a simple hole and get the ball stud to fit (the nut had to fit on the back side too.) I was careful about the measurements and then I center punched the spot. But this had to be one of the most difficult hole I've drilled in my entire life, I literally tried dozens of my "good" bits (and bought two more) before I found one that would cut into the galvanized steel. I was using a hand drill and it took my entire body weight on it to get the bit to bite. Unbelievable. I guess that's why I not a machinist.
Oddly enough when I started assembling it I found that the screw holes for the MAP sensor were drilled but not tapped. So I had to go borrow a 10-32 bottoming tap, too.
http://s298.photobucket.com/albums/mm267/IdiotMike/?action=view¤t=MAP_holes.jpg
Finally, here it is installed :
http://s298.photobucket.com/albums/mm267/IdiotMike/?action=view¤t=installed.jpg
I used new gaskets (Felpro 609581 and 60038). Fired it up and it ran fine, not even a stumble. Honestly I can't tell a difference, it has quicker throttle response but nothing new in the high end.
Well I hope this helps anybody trying to do this nominally low-budget upgrade. Even after buying a ball stud assortment and two drill bits, it still cost much less than buying a new throttle cable at the dealership.
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Jimmy9190
Dodge Dakota
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4/05/2008
08:39:46
| RE: Stiff spring on V8 TB
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Sorry but I can't see the pics on Photobucket. The increased throttle response is what I am after, my truck is pretty slow on take-off from a stop. It is already plenty fast enough for me on the top end, I never drive over about 75. WHen I had that v8 TB on it ran up to 85 like it was nothing, but like I said before in regular city driving I had problems. And I know it doesn't do you much good now but when I drilled the other TB I had to use a cobalt drill bit.
Well I am off to the junk yard. I hope I find the right TB this time.
Jimmy
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Jimmy9190
Dodge Dakota
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4/05/2008
22:19:23
| RE: Stiff spring on V8 TB
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Thanks for the pictures guys. The junk yard didn't have the TB from the R/T. I went to another yard, the you-pull-it type and found a V8 TB off a 99 Ram 1500. It had the wrong stud on the linkage to match my existing cable. So I left and went home but got to wondering if the junk yard had the TB cable on that truck. I went back and it was there and I got that cable and one off a V8 Durango and compared them, the one from the Durango was a little shorter so I used the TB from the Ram and the cable from the Durango. The junk yard owner was very cool about everything and sold me the cable, TB plus about a dozen lug nuts I found in the Durango all for $90.00. Seems every time either I remove a wheel or the tire store does it when balancing my wheels I lose a couple of the outer covers from the lug nuts. The parts stores don't sell the right lug nuts for the Dakota and one lug nut at the dealer is about $7.00.
Anyway I cleaned the v8 TB for a good hour and lubricated it with spray silicone. I transferred my sensors to it and installed it and the v8 cable and went for a test drive. It works great, it is as smooth or smoother than my old v6 tb when accelerating. Driving in town is the same as it was with the v6 tb, except that it's much more quick and noticably faster when taking off from a stop and a lot more responsive when gunning it at cruising speed like when I pass another car. With the v8 tb & cable, if I give it gas it goes. And I have absolutely none of the stumbling throttle problems like before. It gears down like it always has and shifts just as smooth as it always did with the v6 tb. I took it out on the interstate and it still cruises at about 75 mph but it takes a lot less time to get there, and I move thru the gears a lot quicker. MPG seems to have improved too.
The junk yard owner asked me to let him know how it turned out because he drives a Dakota SLT with a V6 and said he'd do it to his truck too if it worked out for me. I think he'll be glad to know it worked so well for me. I didn't think to measure it but the original v6 throttle cable from my truck is shorter than the v8 cable I put in today. The v8 cable went in just fine, fit the linkage on the pedal and snapped in the hole in the firewall perfectly. I have an aftermarket cruise and it is working fine with this new tb also. I think the difference in length and my incorrect placement of the Holley ball stud probably caused the problems I had, but I have no idea how it happened. Plus this new one has the mystery cam that rides on the cable in front of the linkage, it was easy to set it up and that must somehow have something to do with it too.
Overall I am very pleased with the new v8 TB and am glad I finally got it to work. I know that using the ball studs from Holley is one way to do it but it just worked better for me to get the v8 cable. Plus I had a great time at the junk yard. Now if it doesn't rain tomorrow I'm doing the rear brakes on my truck.
Thanks for all the help here. I do appreciate it.
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