Mikey Posted October 16, 2009 Share Posted October 16, 2009 so i finally got my Z to run well. off idle stumbles a little bit due to the cam and lack of vac but part throttle and cruise are great. off idle to 2000 rpm feels great, part throttle and wot. 2000-4000 part throttle and wot are good as well. but 4000+ part throttle is good but WOT feels heavy and is very sluggish. its hits a wall at 4500 and just stops reving. i have to back off the throttle to get better acceleration. so would that be a case of too rich or too lean? and since its a higher RPM range i need to change my air correction jets right? and for info, i have a l28/mn47 stage 3 msa cam, weber dgv's Thanks for the help Quote Link to comment Share on other sites More sharing options...
Zmanco Posted October 16, 2009 Share Posted October 16, 2009 IIRC the DGVs have 2 venturies, but one of them is only opened when "floored" - in other words, like a secondary on a holley 4 barrel. It sounds like you are fine until the second venturi opens and then it falls flat. I don't think we can tell for sure if you're lean/rich from what you've said, but you might want to start by making sure that basics are all ok, such as that you have proper fuel levels in BOTH sides of the carbs, that the floats move properly, etc. Also check to be sure that the jets for the secondaries are installed and match. When I bought my DGVs used a long time ago they were in horrible condition and none of the jets were in the correct locations. They're pretty easy to rebuild and there's lots of documentation on the web about reassembling them (including diagrams) so it's not a hard project. This is only a guess, but I suspect you will find that there's something wrong with one or both of the secondaries. Quote Link to comment Share on other sites More sharing options...
Mikey Posted October 17, 2009 Author Share Posted October 17, 2009 IIRC the DGVs have 2 venturies, but one of them is only opened when "floored" - in other words, like a secondary on a holley 4 barrel. It sounds like you are fine until the second venturi opens and then it falls flat. I don't think we can tell for sure if you're lean/rich from what you've said, but you might want to start by making sure that basics are all ok, such as that you have proper fuel levels in BOTH sides of the carbs, that the floats move properly, etc. Also check to be sure that the jets for the secondaries are installed and match. When I bought my DGVs used a long time ago they were in horrible condition and none of the jets were in the correct locations. They're pretty easy to rebuild and there's lots of documentation on the web about reassembling them (including diagrams) so it's not a hard project. This is only a guess, but I suspect you will find that there's something wrong with one or both of the secondaries. well at WOT it runs hard and just fine up till 4000ish rpm. and i checked the float height and travel on both carbs and its right where the manual says they need to be. Ive checked the jetting and they are what is recommended for a 240z. not for a 280z. Ill take a video later today, maybe it will help diagnosing this thing. Quote Link to comment Share on other sites More sharing options...
JOSHIE88 Posted December 17, 2009 Share Posted December 17, 2009 im no expert but that seems to me where you might have a problem your motors an 2.8 so it would need more fuel then a 2.4 right? idk just my oppion lol good luck =] Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted December 18, 2009 Share Posted December 18, 2009 If the jetting is for a L24 and not L28, then it sounds like you're running out of fuel at the top. Quote Link to comment Share on other sites More sharing options...
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