FridgeFreezer Posted January 12, 2006 Share Posted January 12, 2006 Sorry, but how does something that has no idea what the airflow is into the engine, nor any clue about whether the driver has his foot off the pedal or the pedal welded to the floor, make any even remotely accurate assessment of how much fuel to stuff in...? It uses a Manifold Air Pressure (MAP) sensor in the ECU and the RPM to work out how much air is being sucked in, as well as coolant & air temperature sensors. AKA the speed-density method. It can also run Alpha-N (RPM, temperature and TPS only). The Lucas system is Mass Airflow (MAF) so the AFM is directly measuring the air flow into the engine. Quote Link to comment Share on other sites More sharing options...
Hillbilly Rebel Posted January 12, 2006 Share Posted January 12, 2006 No nice burble, no go... Nasty smell and a horrible rattly noise I'll stick with a V8, thanks - even if it doesn't work in the rain You can't of heard the "VERY NICE" Burble that comes from my exhaust, the best sound which can swim under water!! All thanks to a Ford Transit Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted January 12, 2006 Share Posted January 12, 2006 in the rain....you lucky lucky lucky Bas*ard....Mine coughs and misfires if a mouse sneezes within 500 yards of it on a summers day If it makes you feel any better mine doesn't make any noise at all at the moment It's still at robhybrids with a knackered engine. Quote Link to comment Share on other sites More sharing options...
minivin Posted January 12, 2006 Share Posted January 12, 2006 All thanks to a Ford Transit so if you were to polish your truck a bit could we start calling you White Van Man Quote Link to comment Share on other sites More sharing options...
Hillbilly Rebel Posted January 12, 2006 Share Posted January 12, 2006 No thats Tonks job, I'm just the crash test dummy. (Winch Bitch) Talking of crashing, came across three young lads today, whom 30 seconds earlier had parked their car head on into a tree, turned out the driver had just past his test this Tuesday, not bad going, writing the car off with in two days. Quote Link to comment Share on other sites More sharing options...
minivin Posted January 12, 2006 Share Posted January 12, 2006 did better than my friends son then, he only lasted 6 days before skidding on ice and stoving sideways into a parked car Quote Link to comment Share on other sites More sharing options...
Jon White Posted January 12, 2006 Share Posted January 12, 2006 Yeah BUT..... The 3.9 system has a "get you home mode" built in so you can even take the airflow meter off, chuck it in the boot, and the engine will still run (admittedly badly) enough to get you home. You still end up having to chop about a wiring loom to add in the extra sensors, remove the ones you dont etc. Joints in wiring looms are asking for trouble. Megadribble may be easy to fix if you've access to all the bits from RS, circuit diagrams, soldering irons etc etc, but who carries them round as spares? If you break down at the side of the road what chance do you have of fixing it to get you home? Ask Ash about getting home from Wales for example. At least with standard parts its easy to carry a spare ECU and AFM if you so desire. They're cheap and easy to get hold of. I dont deny all the benfits of injection (for my daily driver I'd chose nothing else). However for something I dunk in the mud I want something I can fix in the mud. I couldnt care less about fuel economy as my truck does less than 500 miles a year. I still dont see the point in replacing a perfectly good injection system when theres a perfectly good off the shelf system thats matched to the engine. If the AFM's pack up, then replace them with new not 2nd hand! Lets face it you wouldnt expect a set of carbs to still be in perfect order after 150000 miles, so why expect an AFM will be? In my opinion the only sensable applications for Megasquirt are for fitting to engines that were never equipped with EFi from the factory, or for substantially modified engines where the custom mapping is required. Otherwise unless there is an inherant problem with the EFi system I do not see the point in changing it. Jon Quote Link to comment Share on other sites More sharing options...
Hillbilly Rebel Posted January 12, 2006 Share Posted January 12, 2006 Talking of "Crashing" you gotta test date yet Rob? Quote Link to comment Share on other sites More sharing options...
minivin Posted January 12, 2006 Share Posted January 12, 2006 Talking of "Crashing" you gotta test date yet Rob? nah not yet, must get on the site and book the theory, work is getting in the way of everything at the moment as working lates and saturdays (when the instructure is free!), however been driving dad around in the Metro so thats a laugh Quote Link to comment Share on other sites More sharing options...
minivin Posted January 12, 2006 Share Posted January 12, 2006 weird, just tried to book my theory test and it tells me I am either not allowed or don't need to take the test, just emailed to ask them to confirm that I don't need to do it Quote Link to comment Share on other sites More sharing options...
minivin Posted January 12, 2006 Share Posted January 12, 2006 umm... yeah, what was the subject here again oh yeah, MS bad, carbs good Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted January 12, 2006 Share Posted January 12, 2006 I still dont see the point in replacing a perfectly good injection system when theres a perfectly good off the shelf system thats matched to the engine. If the AFM's pack up, then replace them with new not 2nd hand! Lets face it you wouldnt expect a set of carbs to still be in perfect order after 150000 miles, so why expect an AFM will be? How much is a new AFM, then? Probably as much as an entire Megasquirt installation... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 13, 2006 Share Posted January 13, 2006 Ash's ECU was a pre-production one, built some years ago before there was such thing as an official kit. The resistor that died was uprated in all the ones that followed. I replaced the resistor and it's fine now. The V3 prototypes have been tested for that fault by connecting the input to mains voltage for a week The MS will limp home in any number of configurations, there's no direct comparison to your example because there's no AFM to disconnect. There's no real chopping into the loom: You lose the AFM and replace the air temp sensor that's housed in there with a standalone one instead. The TPS, coolant, RPM, Injector wiring, idle valve stepper motor, fuel pump relay all stay as they are. If you want a Lambda sensor you add wires to that. The only chopping is when you chop the Lucarse ECU plug off and replace with the new one. You don't actually gain any extra "points of failure" as you're suggesting. Electrical connections are only unreliable when they're done badly (for example with a hammer...) Rob - there's a reason we don't use mechanical computers anymore Quote Link to comment Share on other sites More sharing options...
MogLite Posted January 13, 2006 Author Share Posted January 13, 2006 Andy,as from the vioce of sanity AFM £30 - £40 top, ECU £70-£80 Nige Nige - Brilliant - an on-topic post. For all you thread hi-jackers out there - carry on I'm going to stick with the stock EFI system, for the moment. Its all there on MogLite, and just needs wiring, I've got a spare 3.9 Rangie in the back-garden should I need to compare and contrast. I probably will go MS in the future, but with ignition and nitrous Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted January 13, 2006 Share Posted January 13, 2006 Are those new (as Jon specified) or second hand prices? Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted January 13, 2006 Share Posted January 13, 2006 You are having a laugh. From memort ECUs range dependant on part numbers from £450-£590 approx, AFMs again there were last time I looked (and that was some time ago) a couple of options fiotr3.9s, ......ranging arouind £420+ mark Many sh AFM are damaged, there is a very fine wire that is often broken, and a small hole often blocked with mud, so be very carefull ! Nige Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted January 13, 2006 Share Posted January 13, 2006 From memort ECUs range dependant on part numbers from £450-£590 approx, AFMs again there were last time I looked (and that was some time ago) a couple of options fiotr3.9s, ......ranging arouind £420+ mark That's what I thought... I did a bit of digging around when I was deciding whether to go for Megasquirt, and found that the major components of the hotwire system where more each than an entire Megasquirt'n'EDIS installation. So I'll see your spare AFM Jon, and raise you an entire spare fuelling and ignition system Not that I'll actually bother carrying the spares of course, so you'll still get to laugh at me if I ever do break it Quote Link to comment Share on other sites More sharing options...
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