# Proper way to route spark plug wires



## de-nagorg

Never cross them, always run them as close to parallel as possible.

That 30,000 + volts that they carry will cross-over to another and cause mis-fires.

On a dark night raise your hood while it is running and see a light show, where any wires are crossed and you will see what I am saying.

Do not cross them.


ED


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## papereater

Good tip, de. I will run straight and check at night!! Wish I knew that years ago......


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## ukrkoz

What nagorg is saying is that old leaking insulation wires will arc onto engine and itself. In a dark place or at night, one can see mini lightenings jumping from wires onto metal.
Or, one can mix soapy water into a spray can and spray over wires. If one here's crackling sound, wires are leaking.
At that age, there can be many reasons car runs poorly.
Best practice is to start with basic tune up - spark plugs, SPW, distributor cap and rotor at least. Air filter.


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## de-nagorg

ukrkoz said:


> What nagorg is saying is that old leaking insulation wires will arc onto engine and itself. In a dark place or at night, one can see mini lightenings jumping from wires onto metal.
> Or, one can mix soapy water into a spray can and spray over wires. If one here's crackling sound, wires are leaking.
> At that age, there can be many reasons car runs poorly.
> Best practice is to start with basic tune up - spark plugs, SPW, distributor cap and rotor at least. Air filter.


Depending on the age of the car and type of ignition system, do not forget the points and condenser.


ED


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## Bigplanz

Usually there is a routing clip to hold them in place. My Olds and Mercury had them. I would think a Sunbird of that era would have them too.


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## papereater

Bigplanz said:


> Usually there is a routing clip to hold them in place. My Olds and Mercury had them. I would think a Sunbird of that era would have them too.


Right- my wires do have one clip- left them attached to the set I turned in last night at AZ when they gave me a free new set (it was Lifetime). Now, I have to go back there and get it back!! They still have it- saving it for me. 

Anyway, yea, my car does not have condenser/points. Elec ignition, TBI. Got new rotor. Now need new dist. Anyway, big thanks, people, for the support!


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## ukrkoz

New distributor? Why? If dizzie works fine, all you need there is cap and rotor.


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## ddawg16

Wow......just WOW.....

Do not cross them? Wow....goes against every electrical principle....

Ok.....time for some facts.

Running them parallel increases the chance of induced voltage on adjacent wires.

Crossing the wires reduces the chance of induced voltage.

Why do you think Ethernet cable has wires twisted inside?

In regards to spark plug wires......they don't care. Look at how much insulation is on them. Grab one....no...you won't get shocked....and nor will enough voltage be induced on adjacent wires...or wires crossing them to fire a spark plug.


So...the proper way to route wires? Away from hot stuff....and the shorter the better....

To the OP....instead of using the internet for wrong answers....find a good mechanic to figure out why it's not running right.


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## Brainbucket

A good set of wire wont matter if they are crossed or not. The manufactures generally run them inline/ side by side in the wire insulators. Now I have seen 2 plug wires side by side and fire one wire and both fire but that was cheap wires. That's why they were crossing them to cancel out the magnetic fire in the other wire but this was years ago. Now the twisted wires are done that way to cancel out the magnetic field. That is done usually on crank/cam sensors and speed sensors as they generate around 1 volt so it has to be precise. The computer doesn't like voltage spikes in those circuits. I don't 'grab' spark plug wires to see if they are leaking but I do use a 12 volt test light connected to ground and slide the probe around the wire. If it is leaking, the test light will 'see' it. It will arc safely to ground and you have found the break. Now the modern vehicles have DIS (Distributorless ignition system) and they fire 2 plugs at the same time. In order to do that, there has to be a good amount of voltage and some amps. I takes 1/4 of an amp to kill you and these have anywhere 6 to 10 amps and 60,000 to 100,000 volts. It could be more but I'm not sure as I have forgotten. So don't 'grab' one of these wires as it could kill you. I use the test light. It works like a charm :vs_cool:


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## Windows on Wash

Most of the newer wires have twisted wire insulators around the wires as well.

Crossing them was never an issue with the newer ones, but wear through could be problematic in those cases if it wears off the jacket.


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## papereater

ukrkoz said:


> New distributor? Why? If dizzie works fine, all you need there is cap and rotor.


Right- I goofed. I meant dist cap....


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## papereater

Jeez, I worried for nothing. I made sure the wires did not cross anywhere. Oh well, I still appreciate the help here/ Now, DDawg, you say

"..instead of using the internet for wrong answers....find a good mechanic to figure out why it's not running right."

So, I guess I shouldnt come to this Auto forum for help, right? Cuz thats "internet", as you say. Interesting. The members here (including you) have helped me so far.

Also, to your point, I have had mechs look at my car for that rough running problem - about 5 of them, all around 12 years ago when that started. All of them promised they would fix it- NONE have, and Im out about $500-600 wasted on experienced mechs. Yeah. Ive been my own mech on that car ever since. yes, it runs a tad rough, so what, Im living with it. Just wish I could figure it out. Meanwhile, Im original owner, got 199,500 miles on it, original clutch, no ever engine/trans rebuild. I will keep coming here for advice........


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## de-nagorg

With the very little information given on this vehicle, it is impossible to diagnose a "rough running" issue. 

There are so many factors that all have to be just right for an engine to run that it is sometimes an educated guess on the diagnoses. 

With this many miles I would suspect a timing chain or gear wear, or maybe a burned valve or seat.

But I am not present to do any testing.

Do come back anytime, do not let some grumpy person keep you away, We all have bad days and it is too easy to pop off on an internet site and be in error.


ED


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## Brainbucket

87 Sunbird...wow I haven't thought of that engine for a very long time. I use to build those. Have you flushed the injectors? Use Motor-Vac if you can. You might have to do it more than once since it is old. Compression test? Smoke the vacuum system for vac leaks? Now I remember those injectors were notorious for leaking fuel. Man your taxing my memory.:vs_worry:Fuel pressure must be 9-13 lbs. I like 11-13 lbs. Is your timing belt on correctly? Let us know.:vs_cool:


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## SeniorSitizen

So it has been running rough for 12 years and 5 mechanics couldn't find the problem. I'm wondering if any of those 5 considered putting a vacuum gauge on it.


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## Windows on Wash

How about just some carb spray and watch the idle too?


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## de-nagorg

It should have an OBD port to plug in a testing meter, It may be worth the cost to do this.

Would help you pinpoint where to start looking for things that are worn, cracked, broken, or otherwise at fault.


ED


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## ddawg16

Cross fire is an extremely rare event with today's quality resistive plug wires. When it does happen, it's usually in the cap, not the plug wires.

If it was me.....

I'd pull the cap and inspect it for moisture and signs of cross fire. Corroded terminals can create issues.

Next, I'd check the resistance of each wire. They should all be pretty close...the longer the wire, the higher the resistance. 

Then check the coil to cap wire. My jeep had a bad one of these. Open resistance...but my jeep was still running...just had a stumble at low idle. 

Next...I'd be looking at plugs. The color of the plug will give you a clue as to what is going on...if anything. Also check the gap. 

87? Early TBI? If so...15 PSI fuel pressure. Make sure the pressure is correct. TBI might need cleaning.


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## papereater

Many good tips, guys. Thanks. I will report back maybe by tomorrow with some history/feedback. have a good night.


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## Brainbucket

87 Sunbird has a CCC system, Computer Command Control. OBD1 came out in 95. OBD2 came out in 96. You can take a paper clip and probe the diagnostic connector and get your codes. Google or Bing it. :vs_cool:


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## Brainbucket

ddawg16 said:


> 87? Early TBI? If so...15 PSI fuel pressure. Make sure the pressure is correct. TBI might need cleaning.


Not TBI (Throttle Body Injection). It does have individual injectors. 9-13lbs of fuel pressure. I like 11-13lbs. Now the throttle body may need cleaning but I highly doubt that is his problem. That causes a idle problem and what you call a 'tip in' hesitation meaning as soon as the throttle moves off idle, it hesitates then runs fine. Running bad for 12 years tells me it's not mechanical because it would have reared it's ugly head. I bet you a dime to a doughnut that it's the injector/s. They were really bad about leaking fuel in the cylinder and outside as well.:vs_cool:


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## ddawg16

Brainbucket said:


> 87 Sunbird has a CCC system, Computer Command Control. OBD1 came out in 95. OBD2 came out in 96. You can take a paper clip and probe the diagnostic connector and get your codes. Google or Bing it. :vs_cool:


Actually, the first BM OBD1 systems came out in 86. OBDII started around 95/96

The 5.7L TBI in my jeep is out of 93 Chev PU and it's OBD1


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## papereater

OK, follow up/clarification, people: It is a TBI. Also, yes, it ios OBD I. I do have a diagnostic connector tool which is a glorified paper clip with plastic body, and sell for way more than a paper clip (hey, auto industry has to make a living). THERE ARE NO CODES STORED. 

But, I have a hunch it IS mechanical, as I have done everything to diagnose this. Started in 2002 after the head gasket, and chased it for oh, 3-4 years. I gave up. That was at 102,000 miles. Sincve then I now have, like I posted above, 199,000++. 

I tried a vac guage- very subjective, no luck finding anything. I tried all the methods to find a vac leak- best method I found was putting a 3/16 plastic tube in your ear, and other end use as a Doctor's stethescope. Found a leak in the intake manifold, fixed it, car still idles sloppy.

Oh- Important- car idles rough (not runs rough) but when you accelerate aggressively, or floor it around 4000-5000 rpm, car runs excellently, and has decent "pull" for a puny engine. Rough idle only, but not when running speed/acceleration. In the past, some people said this was a clear sign of a vac leak. I agree, but I cant find one anywhere. Sheesh.


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## papereater

Over the years I have replaced the TPS, the AIC valve, fuel injector, and checked a few elec sensors for proper resistivity with ohmmeter. All passed. What the heck do I do. 

I suspect, as one member posted above, it has to be a bad valve/spring. The valves appeard good when I did the head gasket, but in 2002 I didnt know what I know now. Im waiting for the head gasket to leak/fail again, and then I'll look at the innards more closely. Why do it now(?). WHAT ELSE CAN IT BE!!!??


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## ddawg16

Have you done a compression test?


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## papereater

ddawg16 said:


> Have you done a compression test?


Oh, right- I forgot to mention that- I did. Cylinders were 3 even, one was a tad off, within limits, I forgot the limit, was it 10-15% off from the others(?). I dont remember. But it was close. Car does not burn a drop of oil. Never.


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## papereater

It's not the dist cap, not rotor, nor plugs, nor wires. Timing belt new.


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## de-nagorg

Automatic transmission?

Check your vacuum modulator , causes a hidden vacuum leak. 


Never mind, I just remembered that you said it has a new clutch. DUH.

Went back and read original clutch.

hate this CRS that I go 

ED


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## papereater

Im afraid that sticking valve may be the only possibility left. Cant wait for the head gasket to leak. Oh- I am starting to "consume" radiator coolant. Pour 1/2 quart into reservoir and its gone in 2-3 days. No white exhaust yet though. No leaks visible, so gotta be introduced into cylinders and blowing out ever so slightly with no white smoke.


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## de-nagorg

That could be a head gasket, cracked head, cracked block, pinhole in the radiator, hose cracked, pinhole in the heater core, a poor hose clamp.

And many more.

Takes a very good inspection, or wait until the problem magnifies on a road trip.

ED


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## 47_47

Check oil and coolant level first get engine to operating temp. Trans in park, hold engine rpm steady at about 2,500 RPM for one minute and release throttle. Holding rpm steady is important for the minute. 

What does the engine do when returned to idle?


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## papereater

oK, I will try that tomorrow, upon arriving at work, with engine hot, right before I shut car off and go inside to clock in. I'll let you know after.
ALSO, MAYBE i SHOULD RENT FOR FREE A RAD PRESSURE TESTING DEVICE AT AND SEE WHERE LEAK IS FROM. tIRED OF ADDING EXPENSIVE COOLANT AND WASTING IT.......

hEY- MY CAR IS OFFICIALLY 30 YEars old. Not bad, eh??


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## SeniorSitizen

Idles rough but runs out ok at high speed. I still say there is a vacuum leak. You may need to load an eye dropper with gasoline and be very persnickety with the specific areas a leak would be possible when testing for rpm increase. 

Another method of narrowing down a broader area is exhaust temperature. Allow it to idle a few minutes then shoot the exhaust connections with an infrared temperature gun. The non firing cylinder will be cooler of course.


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## papereater

SeniorSitizen said:


> Idles rough but runs out ok at high speed. I still say there is a vacuum leak. You may need to load an eye dropper with gasoline and be very persnickety with the specific areas a leak would be possible when testing for rpm increase.
> 
> Another method of narrowing down a broader area is exhaust temperature. Allow it to idle a few minutes then shoot the exhaust connections with an infrared temperature gun. The non firing cylinder will be cooler of course.


doesnt carb cleaner accomplish the same thing as it is also flammable "fuel"? If so, I tried that and no change in rpm. Where/how would you drop drops from an eye dropper? 

What causes a non firing cylinder?


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## SeniorSitizen

papereater said:


> doesnt carb cleaner accomplish the same thing as it is also flammable "fuel"? If so, I tried that and no change in rpm. Where/how would you drop drops from an eye dropper?
> 
> What causes a non firing cylinder?


Sure, combustible carb cleaner will do the same thing if you can control where it's squirted and how much. We're looking for an about right air fuel ratio, about 14:1, to make that cylinder/cylinders fire and what I'm saying is the eye dropper is more controllable than a high pressure squirt can.

I once had a 300 cid V8 that a cracked vacuum hose knocked out 1 cylinder on each bank at idle. It was on a 70 mod. and easy to locate where the hose made a sharp bend. It was located with my fingers. I'll call it the finger suck method as no combustibles were needed.

Another experience was a 300 cid 6 banger that was made without a intake gasket. It was fine until I overhauled it, then cyl. #3 was down at idle. An experienced old man taught me the gasoline dribble method and said there is a intake gasket set for those now. That solved the problem.


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## Brainbucket

ddawg16 said:


> Actually, the first BM OBD1 systems came out in 86. OBDII started around 95/96
> 
> The 5.7L TBI in my jeep is out of 93 Chev PU and it's OBD1


Universal OBD1 (16 pin connector) came out 95 and universal OBD2 (16 pin connector) came out in 96. That's what they taught me in a boat load of update classes. 93 had a 12 pin connector non universal. Universal means that you only need 1 cable to connect to all vehicles. Non-universal means you need a special cable for each manufacture to connect to the vehicle. Now non-universal On Board Diagnostics came out when there was a diagnostic connector for the computer. Around 75 is when the first diagnostic connector was appearing I believe Chrysler's lean burn system and GM's came out 80 1/2. 81 had the 12 pin connector but I can't remember 80 1/2...6-8 pin? I was trained on the first computers, yes I'm old. But the universal OBD1-2 is the 16 pin connector from the tech's view even though they say that OBD1 started in the 70's.:vs_cool:


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## papereater

Dang, I WISH if it was a vac leak I could locate it. Good to know about your misfire cylinder experience. 

Anyway, I tried your rpm test, senior, and witjhout knowing what to look for all I can say is once I let off the pedal, rpm dropped as I expected, gradual, slowly, hesitated a tad at around 1900, the dropped to normal 1200-1400rpm. Mean anything?


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## SeniorSitizen

Those rpm don't mean anything to me except 1900 would be about 70 mph on my vehicles and 1200-1400 would be maybe 50 mph. It's been awhile since I paid any attention to Lo idle rpm but IIR it is nearer to 600 rpm.


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## de-nagorg

I'm thinking ( oh too much work), that the timing advance mechanism in the distributor is sticky.

You have 2 different timing advance mechanisms in distributors, a vacuum activated one and a centrifical one, if either is sticky, the acceleration response is sluggish. 


ED


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## 47_47

papereater said:


> Dang, I WISH if it was a vac leak I could locate it. Good to know about your misfire cylinder experience.
> 
> Anyway, I tried your rpm test, senior, and witjhout knowing what to look for all I can say is once I let off the pedal, rpm dropped as I expected, gradual, slowly, hesitated a tad at around 1900, the dropped to normal 1200-1400rpm. Mean anything?


Rpm should have returned to idle very quickly. I'd recheck for vacuum leak or sticking iac. The steady 2500 rpm test was checking for sticking valves. You forced them to rapidly open and close. If a valve is sticking it should have happened when you released the throttle and the engine would run very rough.


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## papereater

47_47 said:


> Rpm should have returned to idle very quickly. I'd recheck for vacuum leak or sticking iac. The steady 2500 rpm test was checking for sticking valves. You forced them to rapidly open and close. If a valve is sticking it should have happened when you released the throttle and the engine would run very rough.


Thanks, 47. I forgot that it was you and not senior who asked me to perform this, sorry -I addressed the results to senior, and think I confused him a tad....LOL.

So, yes, rpms went down sluggishly, as always. And, without my ac running, rpms seem to stay a bit on the high side. So, sluggish means stick? Just what is "sticky" Seems also per De- that timing advance is also "sticky". Geez, too much sticky! Does sticky mean too much organic gummy sludge/carbonized varnish from oil vapors? bad valve springs? 

Tomorrow I have time. Will be scraping old window film from rear window (decided to continue it myself ), and may check for vac leak again, with gas.......


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## de-nagorg

Sticky is a term loosely used to describe a function that is slow to respond and not functioning as it was intended to. 

It could be caused by crud build-up on a place , or rust, or wear, or anything blocking the item from moving as it should.

If there is a vacuum leak in the vacuum advance module, you won't find it with gas or any other fuel.

You will need to visually see if the parts move when a vacuum is applied to the part.

Anyway with nearly 200,000 miles a lot of things are near their death.

Be prepared to spend some $ on the old thing. 


ED


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## papereater

de-nagorg said:


> Sticky is a term loosely used to describe a function that is slow to respond and not functioning as it was intended to.
> 
> It could be caused by crud build-up on a place , or rust, or wear, or anything blocking the item from moving as it should.
> 
> If there is a vacuum leak in the vacuum advance module, you won't find it with gas or any other fuel.
> 
> You will need to visually see if the parts move when a vacuum is applied to the part.
> 
> Anyway with nearly 200,000 miles a lot of things are near their death.
> 
> Be prepared to spend some $ on the old thing.
> 
> 
> ED


Thanks Ed, but I have to say, I have never seen any mention of such a vac advance module as a device which could be tha cause of rough running engine in my Official Pontiac Shop/Service manual, and that is a very extensive , huge, manual. No such mention to be found(did I miss it somewhere?). 

Ive been through that manual over the years so many times. Also, nothing in the Haynes (comic book ) manual for my car. Why would they leave this out if theres such a thing which could cause engine management?


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## de-nagorg

Maybe I misnamed it, I was speaking of the part of the distributor where a vacuum hose attaches to the distributor base, there is a diaphragm inside that when it develops a leak, it quits functioning, and since it is inside the housing, you will not get any fuel into it to cause an acceleration of the engine. 

I will look into my manuals to see if this even has a vacuum advance mechanism, I suspect that with Electronic controls that I might be an antique. 

ED


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## de-nagorg

I checked my manuals, You should have a GM HEI distributor, They do have the part that I was speaking of, GM calls it a vacuum advance UNIT, 

and as I suggested if the diaphragm inside it has failed you will not get any fuel to get inside in the eyedropper test suggested.

I noticed that you are not impressed with todays Chilton's manuals.

I too agree that the current Chilton's are nearly useless, I am old enough that I remember them as the PRIMO go-to book, but that was 40+ years ago when the original man that started the thing was still printing them.

He had an attitude to only produce the best, but his heirs sold out to someone more interested in making a buck, than quality goods. 

ED


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## de-nagorg

Dang: you said Haynes manual, The same philosophy applies to it though, Both companies are now PROFIT, PROFIT companies, not quality.

ED


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## papereater

Right, but I just checked both manuals and extensive notes, and there is no such thing as a vacuum tube at the base of my HEI distributor. Ed, I think youre talking about some ooooold system. But I appreciate your persistent support. Not easy to chase what Im after- hasnt been for 12-14 years.


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## de-nagorg

Then if it does not have a vacuum advance unit, it must have an electronic one, and it might be faltering due to age, and causing the hesitation .

GM might have upgraded the HEI to a fully electronic unit somewhere between my mid 80's memory, and your later 80's model.

Still might be worth looking at to see if the timing advance unit is working.

I am fairly sure that there has to be one, because they allow the engine to smoothly switch from low to higher RPM.


ED


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