Quagmire Posted August 3, 2009 Share Posted August 3, 2009 OK, So i was going to go full Megasquirt and lose the SU's once and for all- but chickened out at the last minute. My 90 is my daily driver and i cannot afford to have it running poo whilst i sort ignition maps AND fuelling, and the idea of wiring and soldering so much spaghetti did make my knees quiver slightly. (well quite a lot actually) Plus, its more money right now as i havent even got the EFi kit all working yet, and as the mech advance on my dizzy is shot i needed to do something sooner rather than later. Enough excuses already! Anyways, as my Dad kindly offered to buy the MJ unit from me when i went to MS later my mind was made up. I ordered a MJ unit from autosportlabs and am currently awaiting its delivery. So i have got thinking about getting everything ready for the MJ installation. I have all the EDIS components- just need to get myself some leads now. I have the trigger wheel and mount. But where is best to take the MAP takeoff from on the inlet manifold? The MJ site states that you should really take a feed from each branch of the manifold- but that is going to be horrendous- 8 feeds?! I have heard that the standard SU vac advance take off is too close to the throttle butterfly and gives turbulent/unstable readings. So where should i take a MAP reading from? will one branch do? I imagine that would give a crazy pulsating effect- even with a small reservoir to smooth things.... Thanks Quote Link to comment Share on other sites More sharing options...
Quagmire Posted August 3, 2009 Author Share Posted August 3, 2009 Well i found this eventually: http://forums.lr4x4.com/index.php?showtopic=22090 so it looks like i'll taking a T-piece from the brake servo... Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 3, 2009 Share Posted August 3, 2009 Why didnt you just fit proper megasquirt, and only use the spark side? Would have saved you buying two ECU's Quote Link to comment Share on other sites More sharing options...
Quagmire Posted August 4, 2009 Author Share Posted August 4, 2009 Two things: the idea of wiring and soldering so much spaghetti did make my knees quiver slightly.my Dad kindly offered to buy the MJ unit from me when i went to MS later (He wants to MJ his 101) So i thought i'd see how i get on with constructing the $80 MegaJolt rather than fooing up a $180 MS, and then if that all goes well i can get things running and take the MegaSquirt plunge later Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 4, 2009 Share Posted August 4, 2009 Fair enough. I'll probably do exactly what you have done with my 'squirt to begin with too. Spark is generally the trickier bit to get right, so at least if i keep the carbs i can be sure of reasonably accurateish fuelling while i work on getting any quirks etc ironed out on the spark side, then i can swap the inlet and fit the EFI components once i'm happy. Quote Link to comment Share on other sites More sharing options...
RangeyRover Posted August 4, 2009 Share Posted August 4, 2009 In the image you can see where I have teed into the vacuum pick up on the left hand side of the plenum. This is the line that goes to the black sphere in the battery box, which is the vacuum reservoir for the heater control I think. This spot sees the pressure AFTER the throttle butterfly which is what you need for the MJ. RR Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 4, 2009 Share Posted August 4, 2009 hmm i think that same takeoff for the round sphere exists on the SU manifold too, its at the back i'm sure. Quote Link to comment Share on other sites More sharing options...
m&mv80 Posted September 9, 2009 Share Posted September 9, 2009 ive been looking at where to take the vacuum from for my mj install, having read this and various other threads i was going to T into the brake servo vacuum hose but whilst i was looking i noticed that on the servo housing there is a blanking plug, its on the opposite side of the servo to the hose inlet fitting but still on the front (hope that makes sence) does anyone know if this is still has the same vacuum and would be ok to use, it would be much easier to fit a hose tail here than a t piece in the hose, i know i could undo it and check but i wont be able to until at least the weekend and i was hoping someone here might know and maybe even done the same as i want to do. cant wait to get it all working thanks martin Quote Link to comment Share on other sites More sharing options...
m&mv80 Posted September 14, 2009 Share Posted September 14, 2009 ok well that doesnt work , the vacuum changes when you brake, quagmire; what did you end up doing in the end? did you t into the servo hose or find somewhere else? and did it give a good reading? ive got it all up and running now but need to sort this so i can start playing, cheers martin Quote Link to comment Share on other sites More sharing options...
RangeyRover Posted September 15, 2009 Share Posted September 15, 2009 ok well that doesnt work , the vacuum changes when you brake, quagmire; what did you end up doing in the end? did you t into the servo hose or find somewhere else? and did it give a good reading? ive got it all up and running now but need to sort this so i can start playing, cheers martin Find the line for the vacuuum reservoir for the heater control and tap into that. I'm sure that 3.5 rangies had the vacuum pickup for the black sphere, I don't know if it is in the same place as per my pic for the 3.9 above. No fluctuations, no oddities at closed throttle. Quote Link to comment Share on other sites More sharing options...
m&mv80 Posted September 15, 2009 Share Posted September 15, 2009 thanks for the reply rangeyrover, trouble is mine doesnt have that as its in a 90, after a bit of research ive found that there is a non return valve in the fitting for the servo hose, therefore putting a t piece in the servo hose isnt going to work, im going to have to remove this non return valve from the manifold and then get an adaptor/t piece to fit before it, there is also a plug at the back of the manifold that looks like it might be vacuum ill have to remove and check, either way im going to need to remove to find out the thread size, unless anyone here knows, im still interested to find out what others have done when running carbs? it seems to be easier on the efi's thanks again martin Quote Link to comment Share on other sites More sharing options...
Boothy Posted September 15, 2009 Share Posted September 15, 2009 Rangey Rover you dirty boy, have you not got a power washer or are you on a water meter you tight git???? Don't ever come on here saying " it's running hot" after you've encased it mud. TTFN Quote Link to comment Share on other sites More sharing options...
RangeyRover Posted September 16, 2009 Share Posted September 16, 2009 Rangey Rover you dirty boy, have you not got a power washer or are you on a water meter you tight git???? Don't ever come on here saying " it's running hot" after you've encased it mud. TTFN power washer...tick water meter.... tick The shots were taken during an event to point out to a heathen diesel burning friend that it was no longer allergic to oggin..... its normally a little cleaner... Can no one help this guy with a vacuum point for a 3.5? early carb rangies have the black sphere we just need to know where it was sodding connected! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 16, 2009 Share Posted September 16, 2009 As has been said, anywhere after the throttle plate will do. I'm sure there must be some drilling or blanked off hole in the SU manifold that could be pushed into service, they may be different on 90 to Range Rover but the casting will be the same thing. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted September 16, 2009 Author Share Posted September 16, 2009 I have actually (just yesterday infact) connected the MAP to the take-off on the rear of the manifold. This is behind the drivers side carb, and is basically a mirror of the point at the front for the servo vacuum. Mine was blanked off with a bolt, but i found another old mainfold we had lying around had a banjo in this position. I fitted the banjo and some nylon tube last night. However.... In this position my MAP is seeing a lot of pulsing, with it fluctuating around 5kPa (i.e at idle i see 30-35kpa spikes...) At the moment i just have a straight tube to the Megajolt, so i will be investigating using a small air reservoir to smooth in the signal. I will let you know how i get on. Quote Link to comment Share on other sites More sharing options...
RangeyRover Posted September 16, 2009 Share Posted September 16, 2009 I have actually (just yesterday infact) connected the MAP to the take-off on the rear of the manifold. This is behind the drivers side carb, and is basically a mirror of the point at the front for the servo vacuum. Mine was blanked off with a bolt, but i found another old mainfold we had lying around had a banjo in this position. I fitted the banjo and some nylon tube last night. However.... In this position my MAP is seeing a lot of pulsing, with it fluctuating around 5kPa (i.e at idle i see 30-35kpa spikes...) At the moment i just have a straight tube to the Megajolt, so i will be investigating using a small air reservoir to smooth in the signal. I will let you know how i get on. Raid a Rangey! Go and find an infamous black sphere. They are vacuum reservoirs anyway for the heater system, so should smooth out the MJ pulses. Mine certainly does. RR Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 16, 2009 Share Posted September 16, 2009 A plastic inline fuel filter from a carb engine can work to smooth things out too. Quote Link to comment Share on other sites More sharing options...
m&mv80 Posted September 16, 2009 Share Posted September 16, 2009 ok ive done it , i had actually done the same as quagmire in the end, there is indeed the said plug at the rear of the manifold, just for reference and if it helps anyone else in the same position, i removed the vacuum take off adaptor from an efi plenum as per rangeyrovers pic, its the same thread so just screwed straight in to the manifold and its the correct size hose tail, quagmire; interesting to see the reading your getting, with mine in the same place and hose connected direct im getting 40-43kpa at idle approx 650rpm (i think the idle is a little low), good tips about using a sphere or fuel filter to smooth the signal ill report what i find cheers for the advice chaps martin Quote Link to comment Share on other sites More sharing options...
m&mv80 Posted September 17, 2009 Share Posted September 17, 2009 i tried the fuel filter trick to try and smooth the signal, i was quite suprised with the results, i first tried a small filter approx 35mm long and 2omm dia, no difference then a filter just over twice the size, still no difference i then thought maybe a restrictor would help so used a plug with a 1mm hole in placed in the vacuum hose, still no difference i then had a rummage around and found a big fuel filter, about the size of a coke can, this made a difference, the reading was then fluctuating 41 - 42kpa i fitted everything i had tried inline and still the same result, so now im not sure what to do, how important is a stable map reading? at the end of the day its not affecting the advance so surely it doesnt matter that its not 100% smooth, 1kpa is nothing really is it? looking forward to any comments you may have cheers martin Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 17, 2009 Share Posted September 17, 2009 1kpa seems fine to me, even the 3kpa you had before was probably ok. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted September 17, 2009 Share Posted September 17, 2009 Unless your engine is running like the proverbial sewing machine the vacuum is never going to be 100% steady, that would require every cylinder to have exactly the same compression, even fuel & air distribution, identically flowing heads & valves, the same lift on every lobe of the cam, etc. etc. If you're running direct coil drive you can detect misfires and even cylinders with slightly different compression from the microsecond variations in pulses from the crank sensor... Quote Link to comment Share on other sites More sharing options...
Quagmire Posted September 18, 2009 Author Share Posted September 18, 2009 Just beware that the bigger the reservoir you are using to damp, then (i think) the more the MAP reading will lag behind what the engine is doing... Quote Link to comment Share on other sites More sharing options...
m&mv80 Posted September 18, 2009 Share Posted September 18, 2009 Just beware that the bigger the reservoir you are using to damp, then (i think) the more the MAP reading will lag behind what the engine is doing... i did wonder about this but it didnt seem to make any difference, i was only testing with these filters anyway to see what would happen, its back to being direct feed at the moment, ill have a bit more of a play but might just leave it as is to be honest Quote Link to comment Share on other sites More sharing options...
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