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Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
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What are early 3.0L injector flow rates?
This is Cstreit posting at Souk's house trying to figure out the low power issue. Can anyone tell us the fuel injector flow rates with the air plate fully depressed?
Can't find it in the manual. |
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08-26-2003, 06:45 PM
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Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
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Interesting side note. The fuel from the injectors and the pumps is "translucent". No sediment, but definitely not see-through. We are replacing the fuel filter now.
The injectors flowed about 3-4 ounces in 30 seconds at full air-plate deflection, about 100cc or so... Seems awfully low! Fuel pump flow rates pre-filter were good. |
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08-26-2003, 07:37 PM
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Super Moderator
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Back home. After changing the filter, fuel started flowing clear in most of the injectors. I wonder if the track day stirred up some sediment from the tank and messed with the fuel delivery.
Still need a scientific-like way to test injector rates at home. Anyone?
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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08-26-2003, 08:48 PM
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Registered
Join Date: Nov 2002
Location: Arlington, VA
Posts: 1,045
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Chris,
Check the 4th post on this page. I had a similar question a little while back: CIS Gurus - Help me Safely Inject my Hot Rod 3.0
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Charlie Stylianos 1982 SC Targa www.Dorkiphus.com - (The Land of the NoVA/DC/MD Porschephiles) |
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08-26-2003, 08:49 PM
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Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
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The new filter seems to have helped, but I'm still not satified,and it seems that the transition from normal power development has moved up in the rpm range. So Chris' theory about sediment development as a result of the track time and possibly bad gas may be the only explanation at this point.
I'm going to drain the tank and flush the fuel system and see if the problem goes away completely. Charlie that flow rates seems pretty dang high...and current rate seems low  Thanks guys..Thanks Chris! --------------------------------------------------------------------- Edit (after reading...READING!): "I did a little flow testing by sticking all 6 injectors in a bottle and lifting the sensor plate to it's max height for 60 seconds. I did it twice and got 41 oz of fuel in 1 minute both times. That works out to 19.2 gallons per hour at the max flow rate. This is with the low compression non-lambda style fuel distributor (USA '78-'79 and euro '78-'80.) System pressure was 74psi. " (from other post) That's 6.8 ounces per minute. Since Chris and I did 30 second tests, the volume/inj we got doesn't seem that bad given the filtration and other potential problems. SO! A little flushing is the wya to go!!!! THANKS ALL..AND CHRIS!!! Lesson: Never out rule the easy stuff. I think I learned that lesson several times before..or did I learn! Last edited by MotoSook; 08-26-2003 at 09:32 PM.. |
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08-26-2003, 09:03 PM
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Super Moderator
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Anyone? Early 3.0L fuel injector rates?
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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08-27-2003, 09:28 AM
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Registered
Join Date: Jan 2002
Posts: 634
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Did you read the link that "kstylianos" posted referring to my test? I got 41oz with all six injectors in 1 minute. That works out to about 3.4oz per injector in 30 seconds. You stated your injector put out 3 - 4oz in 30 seconds. Sounds correct to me.
-Rob 1980sc |
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08-27-2003, 09:51 AM
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Registered
Join Date: Dec 1999
Location: TX USA
Posts: 9,804
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Chris,
To clean the injectors, I would suggest an overnight soak in a bath of B-12 Chemtool in an ultrasonic cleaner. If the ultrasonic machine is home model with plastic tank, be sure to put the injectors a 'boat' of heavy-duty aluminum foil to contain the B-12 ... it might dissolve some plastics! An adjustable-heat [120°F is recommended] ultrasonic cleaner would be preferable, but many folks have gotten good results on their injectors with a home model for jewelry, too!
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Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' |
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08-27-2003, 09:56 AM
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Good idea Warren.
The spray pattern is pretty good from what we can tell... But couldn't hurt. In fact Souk mentioned that a can of techron had helped things a bit. I'm betting bad gas and/or sediment crud'd things up good...
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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08-27-2003, 10:50 AM
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Schleprock
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,639
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I don't have the flow rates for the injectors. But I do have the ultrasonic cleaner. Unfortunately, it's a non-heated one. It works well nonetheless.
The B-12 stuff can be had at Pep Boys. I can vouch for this stuff and say that it rocks. One can of that stuff in my fuel tank cleaned up all the crud & carbon buildup inside my exhaust ports. This stuff does work. Mark also used it to manually clean his Motronic injectors (in the ultrasonic cleaner) and he said it worked great. Quote:
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Kevin L '86 Carrera "Larry" |
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08-27-2003, 11:24 AM
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Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
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The more I think about it, the more I am inclined to believe that my problem is debris/crud related. I just find it hard to believe that so much crud could make it pass the filter. Perhaps, I need to do a filter study, “Bosch Fuel Filter Inadequacy!”
My WUR regulator was plugged, and that should have made the light come on. However, I was busy chasing what I thought was an ignition problem and wrote the 20+ yr old WUR off as having exceeded its useful life. After seeing the gas that came out of the injectors last night, I bet that the crud plugged the WUR, which resulted in my high control pressure (70 psig !!!!). Any other crud that made it pass the filter is likely upstream of my injector nozzles and in my fuel distributor. All of which created the ghost I’ve been chasing. Even with the crud in the injectors, I was able to get a good spray pattern out of my injectors. So perhaps a little home cleaning will suffice. As for the fuel flow rate per injector, I think I was close enough. 6.8-7.2 oz/min! Some others have posted the 3.2 injector flow rate is about 7.2 oz/min. And there is not that much more HP on the 3.2 than the 3.0, so a 3.0 injector rate should be below 7.2 oz., but not by much. I ran some calculations based on the rule of thumb of 0.5 lbs per HP every hour. Using 180HP for the 3.0 motor: 180X0.5=90 lbs/hr=1.5lbs/min Gasoline is approx 6 lbs/gallon: 1.5/6=0.25 gal/min Since we have 6 injectors, 0.25/6=0.0417gal/min per injector. 0.0417 gal is equal to 5.34 fluid ounces (Damn English measurement units!) or about 160 cc/min. So 5.34 oz/min is probably the lower end for my engine, but I think we got more than that last night. |
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08-27-2003, 11:45 AM
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Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
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Kevin, Chris can crack me on the head, but it won't help...
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08-27-2003, 11:48 AM
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Super Moderator
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I could swear the 215cc measurement was per 30 seconds, not per minute, but I have been wrong before, a lot.
...and Souk, who said anything about that helping?
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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08-27-2003, 12:16 PM
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Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
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Yeah..it probably won't help in this case, but it might make my twitch go away and un-cross my eyes.
Varying the fuel rate slightly you can see the values that have been reported are not far off. 
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08-27-2003, 12:27 PM
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1970 Porsche 911 S 
