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HELP! 500i may get the parts cannon

Porečka Koza

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Fellas, I could use some help here.

A guy brought me this 500. It pops and dies within 5 seconds. No amount of throttle or priming improves it. Will not pop if throttled while starting.

I’ve been all through the saw. It had some light scoring on the intake side of piston so I replaced that. The decomp was leaking terribly, now plugged. No other leaks. Saw hasn’t seen much use. When I pump the primer more than 6 times fuel leaks from the line where it connects to the injector. Could be the injector is bad, could be the module, could be fuel sensor, could be stator, could be wiring related to any of the above. Replacing all that costs over half the saw.

I had a buddy at the Stihlership plug it in. It’s been started successfully about 800 times, over 3000 failed starts (probably a few hundred from me messing with it). My Stihl friend really didn’t have a good guess.

So where do I go with this? My guess is injector or module, but I don’t know these saws very well. Any insight would be helpful.
I've been researching the Stihl 500i. I know tree guys who swear by it BUT I've read a lot of people reporting that they've had issues with the saw flooding on cold starts and also people having hot start problems. I'll stick with my carbureted screw driver adjusting, hit rodded up Husqvarna 390xp.
 

Porečka Koza

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You know, that fuel injector depends on a minimum pressure to be able to squirt fuel when the electrons tell it to open. If it’s leaking, you might not be getting the pressure you need, and since it does leak you should change it. It’s a fire hazard otherwise. The early ones were recalled for a leaking fuel line. That could be the line they changed. IDK
Me thinks you could be overlooking the obvious.
Stihl actually recalled several Stihl 500i chainsaws citing a fuel leak issue and stating that it is indeed a fire hazard.
 

HumBurner

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Stihl actually recalled several Stihl 500i chainsaws citing a fuel leak issue and stating that it is indeed a fire hazard.
I never heard about the 500i, but the concrete saws that were the first to receive fuel-injection had some leaking issues
 

Ketchup

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I never heard about the 500i, but the concrete saws that were the first to receive fuel-injection had some leaking issues

Yeah. They have a different injector that’s somewhat rebuildable.

The 500i from this thread leaked like a sieve out the side of the injector. I have since fixed that but the saw doesn’t run for more than 5 minutes. I think the pressure sensor under the stator is also bad. A Stihl dealer I respect insists it needs a new cylinder kit. That doesn’t square with me. The bore is near new. The piston had a grey streak about the width of a pencil lead. I put in new rings and buffed the piston. Should run, but doesn’t so I’ll fire the cannon again…
 

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Yeah. They have a different injector that’s somewhat rebuildable.

The 500i from this thread leaked like a sieve out the side of the injector. I have since fixed that but the saw doesn’t run for more than 5 minutes. I think the pressure sensor under the stator is also bad. A Stihl dealer I respect insists it needs a new cylinder kit. That doesn’t square with me. The bore is near new. The piston had a grey streak about the width of a pencil lead. I put in new rings and buffed the piston. Should run, but doesn’t so I’ll fire the cannon again…
Has it been hooked up to the MDG?
 

dall

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I never heard about the 500i, but the concrete saws that were the first to receive fuel-injection had some leaking issues
He is probably some fuktard just trying to start some *s-word
You can tell because no link and he sucked his own dick when he mentioned his saw
Like others are supposed to be impressed
 

Ketchup

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What did the Stihl dealer do?

Plugged it in, told me it had thousands of start attempts, recalibrated it, ran it, watched it die. Told me it needed a new cylinder. I asked him to explain why. He said because that’s what worked with the last one.

But I’m being stubborn. I’m going to try the baro first. It’s cheaper and makes more sense to me. The saw seems to be shutting itself off. A false pressure reading could do that. Could be the main coil/processor too. I just can’t see why a clean bore with fresh rings would cause a fault.
 

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Plugged it in, told me it had thousands of start attempts, recalibrated it, ran it, watched it die. Told me it needed a new cylinder. I asked him to explain why. He said because that’s what worked with the last one.

But I’m being stubborn. I’m going to try the baro first. It’s cheaper and makes more sense to me. The saw seems to be shutting itself off. A false pressure reading could do that. Could be the main coil/processor too. I just can’t see why a clean bore with fresh rings would cause a fault.
One of my 500s died and refused to restart. Dealer couldn't find anything wrong. Stihl wanted it to diagnose. It went to Virginia Beach. They replaced the module, and returned it. Never was anything said about the fact that it was modded.
 

lehman live edge slab

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Plugged it in, told me it had thousands of start attempts, recalibrated it, ran it, watched it die. Told me it needed a new cylinder. I asked him to explain why. He said because that’s what worked with the last one.

But I’m being stubborn. I’m going to try the baro first. It’s cheaper and makes more sense to me. The saw seems to be shutting itself off. A false pressure reading could do that. Could be the main coil/processor too. I just can’t see why a clean bore with fresh rings would cause a fault.
Is the bore actually clean or does it have a spot that may be letting enough compression by that it’s messing with the pressure sensor in the case? And it’s just a thought they must be pretty sensitive since Stihl says they won’t show spark with the plug out resting on the cylinder, the muffler off or the throttle plate off. Though others have said they will but you need to pull real fast
 
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Ketchup

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Is the bore actually clean or does it have a spot that may be letting enough compression by that it’s messing with the pressure sensor in the case? And it’s just a thought they must be pretty sensitive since Stihl says they won’t show spark with the plug out resting on the cylinder, the muffler off or the throttle plate off. Though others have said they will but you need to pull real fast

That’s good info. It’s been a bit since I ringed it, but if I remember right the cylinder wall showed no marks, just the piston. I would think that if the case sensor was that sensitive you wouldn’t be able to port the saw. Lower intake and higher transfers should reduce case pressure…
 

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That’s good info. It’s been a bit since I ringed it, but if I remember right the cylinder wall showed no marks, just the piston. I would think that if the case sensor was that sensitive you wouldn’t be able to port the saw. Lower intake and higher transfers should reduce case pressure…
So, he piston was damaged but the cyl was unscathed? Even a small amount of transfer can ruin your whole day…
 
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