Hello! I’m somewhat new to aviation, but have been living with a 1972 piper arrow ii for the past year. She’s been pretty good to me until as of late. After installing a JPI 900 the io-360 has been catching debris in the fuel injectors. In the install process a new hose was added to accommodate the fuel flow sensor, other than that the fuel system has remained fairly untouched. It all came to a point when out of nowhere I lost a cylinder in the air after we had already thought that the issue was resolved. Went in and cleaned the injectors, as well as putting 8 gallons of fuel through the new fuel hose, and afterwards a prolonged on ground run up. A tank and a half later, I noticed that cylinder 3’s egt was running 300 degrees hotter than the rest. Landed, checked the injector, but it seemed fairly clean. Took apart the fuel splitter (spider) and there was no debris there either. Both my mechanic and I are stumped.
Debris Caught In Injectors- Piper Arrow
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Clip4
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You are buying contaminated fuel, the sensor itself is contaminated, or the hose is bad.
I’ve used fuel from two different sources, both of which have had no issues when I’ve run them in the past/ no other planes or pilots have had issues. The debris seems dark, and rubbery, making me think that it’s the fuel line rather than the sensor.
interesting problem. It could be a coincidence with the JPI timing installation too. How old are the other fuel lines? does the arrow have bladders or wet wings? Either way, there could be something in the tank that doesn’t turn up when you sump the tank. if you get another sample, maybe send it to a lab?
3393RP
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I suspect that when removing the original hose which was replaced during the JPI install, it was pulled and twisted from the fittings in a manner that released debris into the system. Unless there's a logbook entry that states the OEM hoses were replaced in year XXXX, all of the fuel system hoses in your airplane could be 51 years old.
The fuel lines are only 3-4 years old. The arrow has wet wings. The lab sounds great! But I have my commercial checkride in a week and a half with 7 hours of flying left to do… are there any labs that would be able to work that fast?
My prime culprit would be the fuel line that comes up between the
cylinders and goes to the Flow Divider. A Type C hose is rated for 250
degrees. Type D is 450 degrees. That is a very hot area and I’ve seen
crumbly leaking hoses there.
I would also disconnect all the injector lines and purge into clean jars.
Clean the Injectors also.
cylinders and goes to the Flow Divider. A Type C hose is rated for 250
degrees. Type D is 450 degrees. That is a very hot area and I’ve seen
crumbly leaking hoses there.
I would also disconnect all the injector lines and purge into clean jars.
Clean the Injectors also.
Already have run a lot of fuel through the empty injector lines. I don’t think it’s them. They appear to be all metal and they were not touched as a part of the installation process. All the injectors have been cleaned multiple times now.
Stewartb
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I’d disconnect the fuel line at the servo, add a fuel filter, and run lots of fuel through it to see what shows up. Then work the problem until I was satisfied it was resolved.
How old is your mechanical fuel pump? That’ll be hard to test unless you place a filter in front of the servo and run the engine.
Given the timing of the JPI install? I’d probably change the new hose. If the inner liner wasn’t captured properly when pressing on the fittings? You’ll fight it forever. Since it’s the last thing changed? It’s the first thing to suspect as the cause.
How old is your mechanical fuel pump? That’ll be hard to test unless you place a filter in front of the servo and run the engine.
Given the timing of the JPI install? I’d probably change the new hose. If the inner liner wasn’t captured properly when pressing on the fittings? You’ll fight it forever. Since it’s the last thing changed? It’s the first thing to suspect as the cause.
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The problem has been found! While dissecting the spider (with a&p supervision) I found that the new fitting for the hose was screwed in such that several of the threads had been destroyed. We both believe that it was the debris that was making it into the injectors!
Great! Glad you found it.
I once encountered a new Maule with a somewhat similar problem.
It turned out to be the Aux Tank Fuel Cap fitting.
From Aux to Main through Strainers and finally Injectors.
Unbelievable!
I once encountered a new Maule with a somewhat similar problem.
It turned out to be the Aux Tank Fuel Cap fitting.
From Aux to Main through Strainers and finally Injectors.
Unbelievable!
Dan Thomas
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That spider is supposed to have a fine-mesh last-chance screen in it. We had a Seneca that kept fouling injectors on the left engine. It turned out to be paint flakes from when the airplane was painted with the engines off, and paint got into the uncovered fuel bulkhead fittings in the firewall. That last-chance screen was loose in the spider, allowing the paint flakes to slip past it.
tyndall
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No screen on a lycoming.
Dan Thomas
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It was a Seneca II with Continental TSIO-360s in it.