strangethursday Posted July 19, 2007 Share #1 Posted July 19, 2007 I have a 73 w/ L28 & tripple webers & have always had a lil problem with the fuel supply being unstable. The pump just went out, so I replaced it with a carter 4070. Come to find out the pump that was on there (I thought it was original) is a mitsubishi pump. Did mistubishi even have a performance carb'd car in the us? Anyway I put the carter on yesterday & the car had more power & didn't bog or stumble at all. This morning on the way to work it kept flooding to the point it would stall. I have a switch for the pump & had to turn the pump off for a min as soon as it started to bog (all the way to work). I'm sure it needs to be tuned now but, the second it stalls, fuel pours out through the air filter. Mainly from the 3rd carb. I've been meaning to change the banjo on that carb to make the system back to having a return line. Any help? Link to comment Share on other sites More sharing options...
240ZX Posted July 19, 2007 Share #2 Posted July 19, 2007 You may want to identify the new pump's pressure output. Is a regulator being used? Typically, carbs do not want to see more than 5 psi....otherwise you will overriding the needle and seat and have a flooding situation.Tom Link to comment Share on other sites More sharing options...
Chino 240Z Posted July 19, 2007 Share #3 Posted July 19, 2007 A Carter 4070 can push good volume of fuel at approx. 4psi, and this might be too much for your fuel bowl floats and gross jets to handle, you get fuel flooding out the carbs and this could be a fire hazard near the hot exhaust manifold. If you wish to use this or another after market electric fuel pump you may need to install a fuel pressure regulator after the pump and before your fuel line "T"s to both carbs. Holley and others make pressure regulators you can install inline and adjust to bring the pressure from the pump down to around to 2.5 to 3psi. This can be done by trial and error, keep cutting the fuel back until you stop flooding your carbs, or better yet purchase a fuel pressure gauge and install it off of the "T" of the pressure regulator so you can see the fuel pressure. Modified motors with larger cams, thirsty carbs, fuel line OD and running at high rpms may fuel starve a motor acting like it's cutting out, or Rev limiter is coming on... been there with that problem. My correction was with a 7 psi Carter pump and pressure regulator at 5- 5.25 psi. So you can see I was having just the opposite problem.Good Luck. Link to comment Share on other sites More sharing options...
strangethursday Posted July 19, 2007 Author Share #4 Posted July 19, 2007 No it's the 1 top end performance say "DOES NOT and SHOULD NOT" need a regulator.http://www.racetep.com/webfuelspark.html That's the reason I bought it Link to comment Share on other sites More sharing options...
Chino 240Z Posted July 19, 2007 Share #5 Posted July 19, 2007 The pump may not need a pressure regulator, but the carbs may need it to keep from getting too much pressure. Sorry I'm not a Weber guy, but it is this way with SU carbs. Link to comment Share on other sites More sharing options...
strangethursday Posted July 19, 2007 Author Share #6 Posted July 19, 2007 Top end was reffering to when used with webers. Check the link I posted Link to comment Share on other sites More sharing options...
Chino 240Z Posted July 19, 2007 Share #7 Posted July 19, 2007 Hmm, well I guess you proved them wrong. You may need to look at the Webers to see which one is not holding back what that Carter is putting out. I don't think Carter's statement of no regulator required will be worth much once the car burns to the ground after going up in flames from fuel all over the header... that would not be good. Link to comment Share on other sites More sharing options...
Chino 240Z Posted July 19, 2007 Share #8 Posted July 19, 2007 I think if you were making above 200HP or as they say 300HP you wouldn't need a regulator. Carbs feeding that build of a motor probably would use up the supply from the 4070 at start-up and idle too. Link to comment Share on other sites More sharing options...
strangethursday Posted July 19, 2007 Author Share #9 Posted July 19, 2007 You don't think that would be exciting? JkUr probably right. I'm gonna pull the gauge & regulator off my spitfire & see. There are other people runnin this pump but I don't kno about the other mods Link to comment Share on other sites More sharing options...
strangethursday Posted July 20, 2007 Author Share #10 Posted July 20, 2007 ok I got a fuel pressure gauge on. it's this lil spectre pos & while i never thought it was precise, it always seemed about where I thought it would be on my spitfire. anyway if it IS, that pump is puttin out about 8psi when its supposed to be about 4. defective pump? Link to comment Share on other sites More sharing options...
Zs-ondabrain Posted July 20, 2007 Share #11 Posted July 20, 2007 Same thoughts here. They (TEP) say the Carter 4070 cause it is supposed to be around 4 psi. "No regulator required"But it sounds like it's defective so if it's always gonna put out 8 pounds, go with a regulator just to be safe. I just bought a triple set of 40 DCOE's for $800 so I think I'l go with the Carter and a regulator (for the hell of it)Dave. Link to comment Share on other sites More sharing options...
strangethursday Posted July 20, 2007 Author Share #12 Posted July 20, 2007 Any recomendations on a regulator? I have 1 that looks like the same as in the VB catalogue layin around. Maybe a spectre brand 1? Link to comment Share on other sites More sharing options...
zKars
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