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Old 10-02-2010, 07:06 PM   #26
cyberpine
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Re: 87 TBI to Carb conversion

Sir - You have been incredibly generous with your time and expertise.

I've got a new android phone that lets me post right up to youtube and picasa (all 3 are google products so it's incredibly seamless)

I've read your last post 3 times now and have a printed copy in hand.

It's going to take me a few days to do this and will likely run into next weekend ... but am going to do it! a I almost can't wait to reach my limits .

I think setting the timing on the truck will be the most ambitious task I've ever performed on a car or truck. A few months back I changed the shocks and brakes on another truck and was impressed that I was able to do that.

Somewhat off topic (warning may want to skip) About my level: I'm not without some mechanical skills. I think I'm much better with construction stuff like plumbing and home electrical than I've ever been with engines. Don't need to state the obvious that home repair has nothing on the complexity of a combustion engine and all the crazy wiring, sensors, etc. But anyways (rambling on now) my background is not even in construction either - I'm a software developer building Web and Database backends and I can tell you that science is pretty crazy and deep too and I know that some of the crap I've had to reverse engineer and build rivals whatever mysterious flowchart stands between me and a success on this one. For me, personally, I don't think it's about the grasping how this might work - granted trying to grasp that from some manual is tough and usually what separates the men from the boys I'm sure. For me (like many I'm sure) it's probably more about patiences and organization. I'm a freakin mess with my tools. I probably own (no lie) 5 hammers and 10 messuring tapes. When I feel the rare urge to work on the truck, It burns to find the right tool (which I know I own 2 of) , so I end up stripping something or f*ing something up even worse. I will confess to having done some task that a novice should never do for the a 1/3 of the price, but 3 times at that price to finally get it right. And To me - that's a GIANT win.

Back on topic.. . Yeah a bit scary and certainly outside my comfort zone. Got nothing to lose. Thanks again man .. here's my next video


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Old 10-03-2010, 11:07 AM   #27
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Re: 87 TBI to Carb conversion

Quote:
Originally Posted by cyberpine View Post
Sir - You have been incredibly generous with your time and expertise.
You welcome

Quote:
Originally Posted by cyberpine View Post

I think setting the timing on the truck will be the most ambitious task I've ever performed on a car or truck. A few months back I changed the shocks and brakes on another truck and was impressed that I was able to do that.
JC
I do not want to sound cavalier, but in the end, looking back at it, it all will be straight forward. The key to success is a state of mind, preparation, organization, time to do it correctly the first time, and tools.

Quote:
Originally Posted by cyberpine View Post

Somewhat off topic (warning may want to skip) About my level: I'm not without some mechanical skills. I think I'm much better with construction stuff like plumbing and home electrical than I've ever been with engines. Don't need to state the obvious that home repair has nothing on the complexity of a combustion engine and all the crazy wiring, sensors, etc. But anyways (rambling on now) my background is not even in construction either - I'm a software developer building Web and Database backends and I can tell you that science is pretty crazy and deep too and I know that some of the crap I've had to reverse engineer and build rivals whatever mysterious flowchart stands between me and a success on this one. For me, personally, I don't think it's about the grasping how this might work - granted trying to grasp that from some manual is tough and usually what separates the men from the boys I'm sure. For me (like many I'm sure) it's probably more about patiences and organization. I'm a freakin mess with my tools. I probably own (no lie) 5 hammers and 10 messuring tapes. When I feel the rare urge to work on the truck, It burns to find the right tool (which I know I own 2 of) , so I end up stripping something or f*ing something up even worse. I will confess to having done some task that a novice should never do for the a 1/3 of the price, but 3 times at that price to finally get it right. And To me - that's a GIANT win.

Back on topic.. . Yeah a bit scary and certainly outside my comfort zone. Got nothing to lose. Thanks again man .. here's my next video

In my professional life I am EE, but it is common for me to work with corp attorneys down to assembly folks, and everyone in between on daily basis. You let me know what explanation level you need and we'll go from there.

//RF
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Old 10-05-2010, 09:12 AM   #28
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Re: 87 TBI to Carb conversion

had about 20 minutes this morning..

The two codes 15 and 34 are the only being reported.

The mechanic mentioned he kept the original injectors and said he did not use a gasket between the tbi and intake, but rather some special red paste. Injectors appear to shooting well. here's some pics and a video.

Thanks.







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Old 10-05-2010, 11:36 AM   #29
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Re: 87 TBI to Carb conversion

Quote:
Originally Posted by cyberpine View Post
had about 20 minutes this morning..

The two codes 15 and 34 are the only being reported.

The mechanic mentioned he kept the original injectors and said he did not use a gasket between the tbi and intake, but rather some special red paste. Injectors appear to shooting well. here's some pics and a video.

Thanks.
JC

Your current TB (OE 17089063) was sourced from 89-90 F-Body (Camaro or Firebidrd) with manual transmission (MT). Make sure that you can connect your transmission TV cable to the TB throttle arm - I saw empty stud without a cable end pointing toward TB. If you have 700R4 trany (aka OD or 4 speed automatic) it must have TV cable connected - otherwise it will fail quickly. You can find explanation on 700R4 elsewhere, but please verify before driving!!

The red 'form a gasket' is Hill-Billy solution - there is a high probably of a vacuum leak and that is causing surging idle. You'll need source a TB gasket - 89-90 Camaro with 305/TBI. There are three bolts holding down TB to Intake manifold. The tricky part is lifting TB up high enough to clean the red poop off completely without any of falling into intake. Alternatively a full disconnect and removal of TB - fuel lines, vacuum lines, and electrical allow for a full access to the top of the intake manifold flange. Fuel lines disconnect require two (2) wrenches to prevent twisting of the fuel lines. Let me know your course of action.



Interestingly enough engine seems to be settling down - did try resetting codes and reconnecting sensors?

//RF
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Old 10-05-2010, 01:22 PM   #30
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Re: 87 TBI to Carb conversion

The last mechanic that worked on the truck told me I have 400 turbo and he based that on the distinctive pan shape. I don't have a good pic to confirm that , and really not sure otherwise how to confirm what transmission I have. I do wonder if my base factory 305 with came with that transmission. He says there was no port on that transmission to connect to the TB.

Will try to do these two tomorrow. I never noticed any moving parts int he in the IAC.

Should be interesting as I've never adjusted idle RPM on this truck either.

from your earlier post:
1) Lets clear all those DTC codes as they were artificially induced. This is easily done (engine off) by disconnecting negative Battery terminal for about 30 seconds. ECM will clear its fault memory from these codes until it sees subsequent fault conditions.

2) After clearing ECM fault memory we need to make sure that IAC (Idle air) is correctly reset and knows where it is. The procedure is very simple:

a) Place ECM into diagnostic mode by shorting pins A&B - this will force ECM to command IAC to continuously move into fully close position.
b) Without starting engine, ignition in run position you should be able to hear clicking noise from IAC being jammed into full close position. You can see IAC pentacle fully closing idle air passage in the TB (10 o'clock).
c) Remove the connector (It is 4 wire arranged in box) from the IAC and start engine while monitoring idle speed. Minimum idle speed for a stock engine should be around 450 rpm (can be adjusted).
d) Shut of engine, remove A+B jumper, re-connect IAC connector. Restart engine - idle should be around 600-650 RPM. Provided that base timing is correctly set and there are no vacuum leaks.
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Old 10-05-2010, 02:17 PM   #31
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Re: 87 TBI to Carb conversion

Quote:
Originally Posted by cyberpine View Post
The last mechanic that worked on the truck told me I have 400 turbo and he based that on the distinctive pan shape. I don't have a good pic to confirm that , and really not sure otherwise how to confirm what transmission I have. I do wonder if my base factory 305 with came with that transmission. He says there was no port on that transmission to connect to the TB.

Will try to do these two tomorrow. I never noticed any moving parts int he in the IAC.
JC
TH-400 trany pan looks like a state of Texas. 700R4 pan is a square shaped pan.

http://www.nastyz28.com/chevy-transm...tification.php


//RF
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Old 10-05-2010, 09:15 PM   #32
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Re: 87 TBI to Carb conversion

All I can add to this is the last "mechanic" truly proved himself a hack by using the red form a gasket. If you must use a mechanic in the future, this guy is not the one.
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Old 10-06-2010, 09:35 AM   #33
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Re: 87 TBI to Carb conversion

RF and 67 chevy team,

Cleared ecm. Error codes disappeared!

Tranny appears to be a 400 turbo so nothing to connect to right?



regarding:

You can see IAC pentacle fully closing idle air passage in the TB (10 o'clock).

I'm not sure where that is exactly or how to tell if closed.




I don't have an RPM gauge or Tachometer. I almost got a light gun with a tachometer on ebay for $10 yesterday - shipping included.

Here's my daily video. Was idleling really nice with the iac out. plugged it back in and tried to drive it, but it seems to running way too rich - stalls and lots of smoke and smell of gas. Is it just me or are the injectors pushing gas like crazy. I also wonder as the guy that was helping me had the truck for a few weeks and only worked on it a few hours and eat up $10 in gas.


While waiting for video to upload from phone.. I'd like to place unsolicited review here on Sprint's 4g Android phones (Evo and Epic). OMFG! guys if you are due a phone upgrade and you do anything online - do yourself a huge favor and check out those phones/plans. It's changed the way I work and I even use the device as a very fast internet modem from my laptop. At 4g speeds it's as fast as DSL. I've moved everything I need to my google account - contacts, calendars, pictures, videos, bookmarks, etc.

Thanks again.

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Old 10-06-2010, 10:22 AM   #34
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Re: 87 TBI to Carb conversion

IAC Air inlet location.
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Old 10-07-2010, 08:46 AM   #35
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Re: 87 TBI to Carb conversion

I don't see any difference in that chamber or the hole deep inside in any combination - off, on, running, unpluged. But I do hear a zipping sound when I turn the key to start position.

Always looks like this.

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Old 10-07-2010, 03:25 PM   #36
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Re: 87 TBI to Carb conversion

Quote:
Originally Posted by cyberpine View Post
I don't see any difference in that chamber or the hole deep inside in any combination - off, on, running, unpluged. But I do hear a zipping sound when I turn the key to start position.

Always looks like this.
It looks like it is fully retracted - this will result in very high idle!.

To verify, install A+B jumper, turn ignition key into run position but do not start. You should be able to hear a continuous clicking noise from IAC. Disconnect IAC connector, turn off ignition. Take a look - you should be able to see a pentacle head protruding into the chamber. If not - you may have bad IAC, carbon build-up or a bad connection between IAC and harness connector.

//RF
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Old 10-09-2010, 09:20 PM   #37
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Re: 87 TBI to Carb conversion

I lost a great video of me sticking my finger in there and it whistling like crazy. The hissing sound that I've been hearing is definitley coming from that spot. Also, as suggested I plugged a&b of the ECM and placed in start position and you can hear it trying to extend the IAC constantly.. it sounded like a stuck dc motor.

I have the valve out - from the tip to the base the cylinder is out maybe like 3/4 of an inch. But it's does not manually move. Any way to test it? fix it?

Question, does the head penetrate fully inside that chamber? Is that the open or closed position when it does? Right now(as you see it) now the head appears to be hidden inside the hole - how is that also open? It's unclear what's it's closing.

Factory oem is about $60 + shipping.




Would you recommend this replacement part. $16 with shipping included!

http://www.thepartsbin.com/catalog/?...358+4294963240




Thanks.
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Old 10-10-2010, 12:08 AM   #38
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Re: 87 TBI to Carb conversion

Quote:
Originally Posted by cyberpine View Post
I lost a great video of me sticking my finger in there and it whistling like crazy. The hissing sound that I've been hearing is definitley coming from that spot. Also, as suggested I plugged a&b of the ECM and placed in start position and you can hear it trying to extend the IAC constantly.. it sounded like a stuck dc motor.

I have the valve out - from the tip to the base the cylinder is out maybe like 3/4 of an inch. But it's does not manually move. Any way to test it? fix it?

Question, does the head penetrate fully inside that chamber? Is that the open or closed position when it does? Right now(as you see it) now the head appears to be hidden inside the hole - how is that also open? It's unclear what's it's closing.



Would you recommend this replacement part. $16 with shipping included!



Thanks.
JC

IAC is a dual coil bipolar stepper motor. You can look up about stepper motors here

Dealers used to have special test fixture that allowed to test them. Under no circumstances try to operate IAC unbolted from TB. The stepper will eject pentacle - you can not re-insert. If it makes continuous noise when A&B are shorted ECM is commanding IAC to close IA passage. There should be NO air going through. Over time carbon, oil deposits may build up and prevent IAC from closing off this passage. Carb cleaner and good brushing job will remove stubborn deposits. The head should completely close IA passage - amount of protrusion depends on head design.

When you shut off ignition ECM commands IAC to fully open position - wide open IA passage. When A&B are shorted ECM forces IAC to full close. You can disconnect IAC connector - and measure the extension of the pentacle. Re-install, re-connect - and allow ECM to move IAC into full open and repeat measurement. It is a poor mans functional check for IAC motor without resorting to parts swapping.

$16 it is a cheap verification of IAC functionality (parts swapping). In my case I resort to a large collection of used units from my JY trips.

//RF
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Old 10-14-2010, 07:59 AM   #39
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Re: 87 TBI to Carb conversion

So I just changed the IAC value. No real difference and I still don't see the pinnacle coming through. Truck stalls and heavy smoke and gas smell. I also hear that IAC motor trying to do something with a constant slgiht buzz with the key on start and and ECM A&B shorted.

I have not checked my timing or my RPMs at idle.

Here's the thing thing though, as before, when I disconnect the MAP sensor and that temp sensor it idles a little high, but it runs incredibly strong. I would say there is no way it could run like that if my timing was terribly off.

You may have answered this (need to go back), what's the worse that could happen from running the truck this way (with those sensors disconnected).. high fuel consumption? overheating at idle?

Remembering something the first mechanic told me.. he said he tried to get the timing on the truck but could not explaining the constant fluctuation I'm seeing with the sensors on.

Thanks.
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Old 10-14-2010, 11:00 AM   #40
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Re: 87 TBI to Carb conversion

Quote:
Originally Posted by cyberpine View Post
So I just changed the IAC value. No real difference and I still don't see the pinnacle coming through. Truck stalls and heavy smoke and gas smell. I also hear that IAC motor trying to do something with a constant slgiht buzz with the key on start and and ECM A&B shorted.

I have not checked my timing or my RPMs at idle.

Here's the thing thing though, as before, when I disconnect the MAP sensor and that temp sensor it idles a little high, but it runs incredibly strong. I would say there is no way it could run like that if my timing was terribly off.

You may have answered this (need to go back), what's the worse that could happen from running the truck this way (with those sensors disconnected).. high fuel consumption? overheating at idle?

Remembering something the first mechanic told me.. he said he tried to get the timing on the truck but could not explaining the constant fluctuation I'm seeing with the sensors on.

Thanks.
JC

TBI system was designed to use all sensors (TPS, CTS, MAP, VSS, KS, EST) and actuators (IAC, EGRCV, Injectors) for normal operation. Disconnecting them puts ECM in soft fail mode where it reverts to fixed value for a disconnected sensor - enough to get you pull over and limp over to a service bay. Disconnecting and otherwise rendering sensors inoperative will not get this problem resolved. Drivability and performance are compromised.

IAC appears to be functioning. I went to my local parts store and pulled a new TBI replacement IAC and compared to OE GM. OE unit tends to have longer - conical head. This would explain why I can see it from the top. I'll have to assume that it is functioning based on you report - it is clicking and that's what it suppose to do in diagnostic ALDL mode (A+B).

Timing - You must check and set correct timing. It is a very common mistake to incorrectly set timing on TBI systems with end results similar to yours.


How's bidding on Evil Bay?
//RF
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Old 10-16-2010, 07:12 PM   #41
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Re: 87 TBI to Carb conversion

Quote:
Originally Posted by rfmaster View Post
How's bidding on Evil Bay?
//RF
I should have all the tools to continue by next weekend.
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Old 10-16-2010, 07:29 PM   #42
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Re: 87 TBI to Carb conversion

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Old 10-16-2010, 08:30 PM   #43
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Talking Re: 87 TBI to Carb conversion

Quote:
Originally Posted by cyberpine View Post
So I just changed the IAC value. No real difference and I still don't see the pinnacle coming through. Truck stalls and heavy smoke and gas smell. I also hear that IAC motor trying to do something with a constant slgiht buzz with the key on start and and ECM A&B shorted.

I have not checked my timing or my RPMs at idle.

Here's the thing thing though, as before, when I disconnect the MAP sensor and that temp sensor it idles a little high, but it runs incredibly strong. I would say there is no way it could run like that if my timing was terribly off.

You may have answered this (need to go back), what's the worse that could happen from running the truck this way (with those sensors disconnected).. high fuel consumption? overheating at idle?

Remembering something the first mechanic told me.. he said he tried to get the timing on the truck but could not explaining the constant fluctuation I'm seeing with the sensors on.

Thanks.


Time to trade it in for a 70,s model with a carb .........lol. Learning new things can be frustrating but were always better to go thru it. Theres some good repair manuals on computer codes and sensors from chilton or haynes, I would study it and enjoy the adventure if i were you.

Props to rf for his time, im sure alot of people have learned some info.
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Old 10-16-2010, 10:25 PM   #44
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Re: 87 TBI to Carb conversion

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Time to trade it in for a 70,s model with a carb .........lol. Learning new things can be frustrating but were always better to go thru it. Theres some good repair manuals on computer codes and sensors from chilton or haynes, I would study it and enjoy the adventure if i were you.

Props to rf for his time, im sure alot of people have learned some info.
That's how I started with my 75 - trying to get overall performance from a carb. But I got sick and tired of waiting for stupid thing to warm up early in the morning roaring at 2k RPM for about 5 min! With Delta 40 out in the back I was not making friends with my neighbors. Truck never performed up to my expectations until I switched to EFI - fuel consumption when down and it is now a joy to drive.

Both Chiltons and Hanes do not go into fine system details. Only factory service manuals (FSM) have detailed troubleshooting trees. These are very detailed, but do not (always) list sensor parameters which can be found else where.
For extensive details TBI component information, TBI swaps, into early trucks please see:

http://67-72chevytrucks.com/vboard/s...d.php?t=317519


//RF
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TBI retrofit completed (2007-07-29)
New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)
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Old 10-26-2010, 05:27 PM   #45
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Re: 87 TBI to Carb conversion

I'm back..

got a cheap timing gun and cordless 9v tachnometer.

Sorry, Don't have the distributor wrench yet.

Not to sound stupid, but my battery was dead and I charged it all last night.. this afternoon when I stared up and warmed up for a while it idled better than it ever has with everything connected. Not sure why. I was even able to drive it with everything connected.

Anyways, the reading on my timing looks like this.. The very left tooth and the brown arrow almost align the the arrow is just to the left of the very left tooth. took a video but can't see the brown lines in it.




Also, in a video I saw it said to disconnect the time cable (brown and black) before adjusing the distributor.. I see no such cable.
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Old 10-26-2010, 06:05 PM   #46
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Re: 87 TBI to Carb conversion

Update. Just cranked it up again and it idled nicely. But my Tachometer reads 7206 RPMs at idle?? Its not realy idling that fast. Its a cheap 9 volt cordless with lazer. I pointed it a the fan and any of the belts and get the same reading. Maybe there is a decimal there but I did not see it.

oNE more thing when I was connecting everything back up I got confused with the MAP and another sensor and end up pulling and pushing cables around.. maybe I jarred something lose and fixed the issue.

Right now it feels like I just need gas.. oh I have another issue where I'm low and try to drive it choke on air in the tank..
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Old 10-26-2010, 06:09 PM   #47
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Re: 87 TBI to Carb conversion

You may have a failing alternator. My dad was having all kinds of electrical problems with his 78 Caddy. No brake lights, turn signal, stereo etc... Turn headlights on and the car would barely run.

Turns out the alternator was barely putting out any amps so it couldn't keep the battery charged. When the battery was fully charged everything worked properly then the longer it ran the worse it got. After a couple hours of drive time the battery would run down and the car would run poorly and eventually it would not run at all.

You could be having a similar problem. HEI's need as much voltage as they can get to run well. A fully charged battery could make it run without a good alternator but as the charge wears down it will run worse.

It would be a good place to start by having the alternator tested to make sure it is fully functional.
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69 C10 shortbed stepside 400 small block - built like what a super sport truck could have been
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