Running issues/sometimes no start

Talk and Tech about turbocharged 924/944/968 cars
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BennSport
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Just run a bottle or two of seafoam and you should be all good :lol:
‘83 Platinum N/A 944

#11

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johnb
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I knew I shouldn't have deleted the cat...

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Tom
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johnb wrote: Wed Oct 08, 2025 5:23 pm I knew I shouldn't have deleted the cat...
I was thinking he must have gone in through the air intake snorkel and made his way to the filter, which is soft and might seem like a nice place to make a nest. The debris probably just got sucked into the front of the turbo after he chewed it up.

If he went in through the tailpipe, I can't think of any realistic path that takes him to the filter -- he'd have to make his way through the turbine blades, into the cross-over, up the headers, down an open exhaust valve, out an intake valve (and I don't think there's ever enough overlap for that), then through the intake, etc.

I'd get out the shop vac and suck all that out -- maybe some compressed air blowing from the outlet side too. It's paper, so I'm thinking there's a decent chance it didn't damage anything (knock on wood).

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johnb
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Tom wrote: Wed Oct 08, 2025 5:38 pm
johnb wrote: Wed Oct 08, 2025 5:23 pm I knew I shouldn't have deleted the cat...
I was thinking he must have gone in through the air intake snorkel and made his way to the filter, which is soft and might seem like a nice place to make a nest. The debris probably just got sucked into the front of the turbo after he chewed it up.

If he went in through the tailpipe, I can't think of any realistic path that takes him to the filter -- he'd have to make his way through the turbine blades, into the cross-over, up the headers, down an open exhaust valve, out an intake valve (and I don't think there's ever enough overlap for that), then through the intake, etc.

I'd get out the shop vac and suck all that out -- maybe some compressed air blowing from the outlet side too. It's paper, so I'm thinking there's a decent chance it didn't damage anything (knock on wood).

I pulled the j-boot and started picking the paper out carefully with a pliers. I noticed the turbo could still spin easily so I don't think paper got wedged between the ends of the blades and the tube (I can easily imagine that causing damage).

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It was packed in there densely and getting pretty hot by the looks of it.

That second last pic is the rubber turbo->intercooler pipe. It looks like the paper was turned into lint. I had forgotten about the intercooler until I started tearing it apart. Then I realized anything that gets into the engine would have to be small enough to pass through the intercooler, so it might have sacrificed itself to save the cylinders. I'm not sure how to tell.

All in all the impeller blades look fine. I vacuumed it at the end to get the last few bits out and it spins freely. I think I am going to just button it all up with a new filter and drive, and see what's up. Any real damage must have been done already.

What say you?

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Tom
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Pump a leaf blower or compressed air into the intercooler from the throttle body side to see if you can blow anything out... If anything is in there, my guess is it's packed up in the inlet side tank. But the amount of material missing from the filter plus what you got out of the turbo makes me think there isn't a ton of filter material floating around still... I'd check the throttle body side i/c pipe, blow if out from that direction, and unless you see signs of it getting up toward the TB, I'd fire it up myself...

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johnb
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Tom wrote: Wed Oct 08, 2025 6:24 pm Pump a leaf blower or compressed air into the intercooler from the throttle body side to see if you can blow anything out... If anything is in there, my guess is it's packed up in the inlet side tank. But the amount of material missing from the filter plus what you got out of the turbo makes me think there isn't a ton of filter material floating around still... I'd check the throttle body side i/c pipe, blow if out from that direction, and unless you see signs of it getting up toward the TB, I'd fire it up myself...
Sounds like a good plan. I don't have a leaf blower but I might be able to connect my air compressor with some coolant pressure tester adapters I have.

BTW the cat thing was a pun I didn't really think he got in through the exhaust

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Tom
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johnb wrote: Wed Oct 08, 2025 6:56 pm
Tom wrote: Wed Oct 08, 2025 6:24 pm Pump a leaf blower or compressed air into the intercooler from the throttle body side to see if you can blow anything out... If anything is in there, my guess is it's packed up in the inlet side tank. But the amount of material missing from the filter plus what you got out of the turbo makes me think there isn't a ton of filter material floating around still... I'd check the throttle body side i/c pipe, blow if out from that direction, and unless you see signs of it getting up toward the TB, I'd fire it up myself...
Sounds like a good plan. I don't have a leaf blower but I might be able to connect my air compressor with some coolant pressure tester adapters I have.

BTW the cat thing was a pun I didn't really think he got in through the exhaust
You can probably just cup your hand over the end with the air hose to get some pressure blowing through. And I totally missed the cat joke -- it's actually pretty funny now that you point it out. :lol: I get a bit of tunnel vision with interesting car issues.

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johnb
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Tom wrote: Wed Oct 08, 2025 7:06 pm
johnb wrote: Wed Oct 08, 2025 6:56 pm
Tom wrote: Wed Oct 08, 2025 6:24 pm Pump a leaf blower or compressed air into the intercooler from the throttle body side to see if you can blow anything out... If anything is in there, my guess is it's packed up in the inlet side tank. But the amount of material missing from the filter plus what you got out of the turbo makes me think there isn't a ton of filter material floating around still... I'd check the throttle body side i/c pipe, blow if out from that direction, and unless you see signs of it getting up toward the TB, I'd fire it up myself...
Sounds like a good plan. I don't have a leaf blower but I might be able to connect my air compressor with some coolant pressure tester adapters I have.

BTW the cat thing was a pun I didn't really think he got in through the exhaust
You can probably just cup your hand over the end with the air hose to get some pressure blowing through. And I totally missed the cat joke -- it's actually pretty funny now that you point it out. :lol: I get a bit of tunnel vision with interesting car issues.
Your advice was gold as usual @Tom! I got a decent amount of paper out of the intercooler by blowing air back from the outlet. All back together now and the problem is definitely fixed. There doesn't seem to have been any real damage, it still boosts ok as far as I can tell from a quick drive.

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Tom
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johnb wrote: Fri Oct 10, 2025 6:30 pm
Tom wrote: Wed Oct 08, 2025 7:06 pm
johnb wrote: Wed Oct 08, 2025 6:56 pm

Sounds like a good plan. I don't have a leaf blower but I might be able to connect my air compressor with some coolant pressure tester adapters I have.

BTW the cat thing was a pun I didn't really think he got in through the exhaust
You can probably just cup your hand over the end with the air hose to get some pressure blowing through. And I totally missed the cat joke -- it's actually pretty funny now that you point it out. :lol: I get a bit of tunnel vision with interesting car issues.
Your advice was gold as usual @Tom! I got a decent amount of paper out of the intercooler by blowing air back from the outlet. All back together now and the problem is definitely fixed. There doesn't seem to have been any real damage, it still boosts ok as far as I can tell from a quick drive.

Great news. Happy to hear there was no major damage. :) Mice have good memories. You might put a wire mesh over the end of the intake snorkel or otherwise mouse-proof the car's environment... :shifty:

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Latitude48
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This episode with mice is similar to what happened to my 2023 VW Golf R. During the installation of my APR intercooler at 4,317 miles, the shop found the airbox full of some type of grain. Since my car came through the port of Houston, I can only guess there was grain storage nearby and some critter used my car for storage. No harm, no foul as it never made it past the air filter and it ran fine. Weird.
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Tom Pultz
- 1989 944 Turbo - Guards Red/Linen
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