why am I seeing 90% inj duty with 2 pumps?
Senior Member
Joined: Feb 2006
Posts: 436
Likes: 1
From: Oklahoma city, Oklahoma
How do you have your fuel pump lines intersecting? WIth a Y fitting? Just curious.
Have you checked the socks on the fuel pumps? if they were to collect a lot of debris somehow it can restrict flow.
Have you checked the socks on the fuel pumps? if they were to collect a lot of debris somehow it can restrict flow.
Full Member
Joined: May 2005
Posts: 54
Likes: 0
From: trinidad
yeah guys at 20-21 pounds of boost on my buddys s6 engine full bridge we were seeing around 90% duty cycle too with 2 850 inj and 2 1600 inj so we went ahead and changed out to the two 850inj and went with 1600inj all round and were fine know. but u need to get all the gauges and stuff pluss some bigger fuel lines yeah..
interesting thread. I was thinking about running the same setup as I've already got an rx7.com fuel pump and a walbro is so cheap that adding one wouldn't cost too much more but would supply that much extra fuel. So when we are talking about this y splitter are we talking about splitting it before it goes into the fuel rails? Also I guess that if you used a microtech to instruct the second pump when to come on it would still have the same 90% duty cycle outcome? What would be the absolute correct way to run a dual intake fuel pump setup? Also does anyone have a wiring diagrm for hooking these two pumps up (electrically).
this kenne bell boost a pump is really starting to sound good, lol.
this kenne bell boost a pump is really starting to sound good, lol.
So far I do not think I have found anything wrong. I have check both pumps and they are working. I did notice the fuel inj. hose I ran from bulk heads to pumps was ver soft and seemed to expand. I would think under pressure it would swell even more. So I replaced with aluminum hose. I am also testing and trying to see if y'ing them together in engine bay then going to primary rail, then to sec. rail into reg. will help. Before I was running each pump to a differant rail.
'Tuna'
Joined: Feb 2001
Posts: 4,637
Likes: 3
From: Miami,Fl,USA
yeah guys at 20-21 pounds of boost on my buddys s6 engine full bridge we were seeing around 90% duty cycle too with 2 850 inj and 2 1600 inj so we went ahead and changed out to the two 850inj and went with 1600inj all round and were fine know. but u need to get all the gauges and stuff pluss some bigger fuel lines yeah..
'Tuna'
Joined: Feb 2001
Posts: 4,637
Likes: 3
From: Miami,Fl,USA
So far I do not think I have found anything wrong. I have check both pumps and they are working. I did notice the fuel inj. hose I ran from bulk heads to pumps was ver soft and seemed to expand. I would think under pressure it would swell even more. So I replaced with aluminum hose. I am also testing and trying to see if y'ing them together in engine bay then going to primary rail, then to sec. rail into reg. will help. Before I was running each pump to a differant rail.
7 Rx-7s since 1980
Joined: Mar 2004
Posts: 438
Likes: 1
From: oHIo
No flow sheets. I believe they are Bosch. I bought them from JAson rx7store.net. They are the greenish color if anyone can varify. No dyno numbers yet but I do expect to break 500 but not at 21psi. This is the 4094 turbo not the standard 42r. Its a 42r in a 40r size. Uses the 42r comp wheel and 40r turbine. So I expect it to take a little more boost to see over 500. I am not using meth yet. I am looking into either water or a 50/50 mix. I have a kit just not sure its the one I want to use. I will post results from fuel system if i find anything this weekend after I work on it.
Did you use resistors? 25w / 3Ohm? Check the wiring on the secondaries and insure the connections are solid. Showing abnormally high duty cycles can be an indication of a wiring issue with the injectors. I know this by experience.
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