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RogerD

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  1. It turned out to be a dry solder joint on the ign live feeds to the coil packs and edis. Runs sweet now. And yes,the VR sensor connector came loose too. Just to confuse the issue !
  2. Thanks guys - I've changed the map to go up to 100 now. Idle, once the engine has wamed, settles around 65. (might be something to do with the cam I have etc - not sur ewhat I have, I know the engine is tuned to some extent. Now when you floor it, the green box runs along the bottom of the screen, then returns in a big circle (anti clockwise) as you would expect it too. I just expected idle to be further up the screen (lower KPA) but some quick googling suggest certain types of cams can change this. I run the vac of the non timed port on my eddy carb - i've tested the other port and it's timed (100kpa at idle, then jumps back down when you touch the pedal) - which I don't want. I undertsand the idea of it all now. The MJ manual confused me as I though the legends on their engine map were descriping the axis, but they are not, they are explaining what causes the green bar to go in each direction (confusing, but you might know what I mean!). Incidentally, I set the map to max at 78 as at the time, that was my idle tickover and I assumed the map went in the other direction when you floored it. My mistake!
  3. Looks like I had a loose VR sensor cable - made the mistake of cable tieing the lead to the chassis - which was a bad idea as when the engine torques.....
  4. I've got my 4.3 V8 (carbed on Eidelbrocks) running on MJ. Drived fairly ok, a little missfire under heavy load at times but mostly ok (there IS a rythimic pulsing of the engine in the mid rev range but that must be something else...) I'm analysing my spark table which is basically a safe map from this site, and Im a touch confused as I don't totally inderstand how the carb vacuum relates to engine load. My Map is: (that was taken with the engine at tickover) Now, on the MJ instructions PDF it shows an example map with, on the left, an arrow going up with "Vacuum increases or throttle closes), then an arrow down with "Pressure increases or throttle opens". Advance increases with rpm and increases as Vacuum increases or throttle closes (their words). So that tutorial seems to tell me that the higher KPA readings - at the bottom of my map, represent.the engine "under load", and the lower KPA readings higher up in the map represent the engine "coasting" ("Vacuum increases or throttle closes"). This tallies with what I've read about engines needing less advance under load and more when coasting. So from this I assume that the KPA figure is high when the "pressure increases or throttle opens" and drops off when you back off the throttle. This is where I get confused. On my car, at tickover, the green square floats around the bottom left of the map. Should it not be the top left as that is where it should be for "closed throttle/vacuum increase". Or is it because, revving the engine at standstill is not a "load" and you have to actually strain the engine for teh figures to be right? When I blip the throttle (standstill) the green square starts bottom left and then , naturally goes right as the revs increase, and also it climbs up the screen (to lower KPA figues) So it's doing kind of the opposite of what I'd expect from the MJ tutorial diagram. It's also confusing as the MJ diagram talks about both vacuum increasing and pressur eincreasing. Which is it? Do you start with a vacuum that turns to positive pressure under load? (p.s. I'm using the non timed vac port on my carb - I've tested it, and the timed port to be safe)
  5. Thanks for that. I know very little about RV8's to be honest. I'm currently running on one of his safe maps. She drives ok but it clearly not totally ok. The engine kind of "pulses" between around 2k and 3.5k - I'm going to check my VR sensor bracket is tight and sturdy too. I did notice that with a timing light she ticks over at 10 degrees advance as she should but she kind of flickers down 1 degree rythmically. Must be linked to the above.
  6. I really don't know much about the engine history. I know is was built as a racer and then the builder changed his mind (it's a Westfield but there seems to be a lot of knowledge on here re. Megajolt). I've had to have a larger crank pulley made as mine was too small so it under drove the water pump and alternator. The floor is all ally, the chassis is lightened. So a fair few racing hints. But I really don't know too much about the engine. I have some unverified history (a letter than came with the car from the original builder) which tells me: Engine was overbored 20 thou, new pistons, bearings, ported cylinder heads, uprated cam shafts, Rhoades lifters, carb spacer and velocity stack.... but then he says he ripped it out and replaced it with a cross-bolted 4.2 - so I really have no idea! PLus, the history is for a car of a different reg!! Still, I have a recent verified dyno print out from the previous owner who I do know and trust, and it shows 249.1Bhp peaks as 5400 but then carries on flat to a recorded 6100. Torque peaks at 265 Ftlb at 4450rpm then falls off as the power carries on. When I got it it woudl cleanly push through over 6000 - I thought it was around 6200. Now it splutters at 5800.
  7. Hi - I've seen a fair few example maps on here for 4,2 and 3.9 rovers but , according to the chap who sold me my car, I have a 4.3 (which from quick research tells me it must have been bored and stroked - it's not got TVR on it anywhere). I can't check the CC easily but I can tell you I have a dyno showing 250/250 bhp/torque at 5,8k, it develops power cleanly to 6.2k (or did, not 5.8k which is part of the reason I'm going EDIS/MJ) - if any of that info helps. I'm looking for a 4.3 V8 map. I've seen 4.2 suggested maps so I assume trying one of those is the way to go? Cheers
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