Johannadine Posted October 24, 2013 Share Posted October 24, 2013 I want to change my 3.9 V8 EFI to carburetor. What wires do i need to change and do i have to put another petrol pump in. Thanks Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 24, 2013 Share Posted October 24, 2013 You'll need a low pressure petrol pump, not the high pressure one. Spark should operate fine without the petrol ECU - just disconnect the EFI wiring harness. May I ask why? Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 24, 2013 Author Share Posted October 24, 2013 We are battling with the fuel injection too much. and here in south Africa they asking us so much for spears. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted October 24, 2013 Share Posted October 24, 2013 I see all sorts of issues: what happens when the signals from the lambda-sensors go out-of-range because the ECU's no longer able to control fuelling and so it switches to 'limp-home' open-loop retarded-ignition-timing mode? Glowing-red cats are impressive to see. I'd suggest you fix the electronics - if only because they give you at least 20% better fuel-economy over carbs. Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 24, 2013 Author Share Posted October 24, 2013 I see all sorts of issues: what happens when the signals from the lambda-sensors go out-of-range because the ECU's no longer able to control fuelling and so it switches to 'limp-home' open-loop retarded-ignition-timing mode? Glowing-red cats are impressive to see. I'd suggest you fix the electronics - if only because they give you at least 20% better fuel-economy over carbs. im so tied of trying to find the problem im ready to convert. they want to charge me R5000 for a gasket set what are they going to charge me for the rest. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 24, 2013 Share Posted October 24, 2013 Gasket set for what? Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 24, 2013 Share Posted October 24, 2013 I see all sorts of issues: what happens when the signals from the lambda-sensors go out-of-range because the ECU's no longer able to control fuelling and so it switches to 'limp-home' open-loop retarded-ignition-timing mode? Glowing-red cats are impressive to see. I'd suggest you fix the electronics - if only because they give you at least 20% better fuel-economy over carbs. I believe (although I have assumed) that this is a hotwire system with a clockwork distributor. Nothing that advanced. I agree with the above - try and keep the EFI. Nothing is unfixable and there's great knowledge about these systems on here. What issues are you having? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 24, 2013 Share Posted October 24, 2013 Have you been through the diagnostics as I suggested in PM? Any results? Quote Link to comment Share on other sites More sharing options...
deep Posted October 24, 2013 Share Posted October 24, 2013 I put a Disco 3.9 in my Stage One V8 and chose not to use the fuel injection (for legal reasons and because I didn't want the hassle). I just reused the inlet manifold from the older (Range Rover sourced) carburettor V8. It's a totally bolt-on conversion and went together with no trouble whatsoever, though I obviously didn't have to change my fuel pump. A little attention to ignition timing and mixture settings and the result is a very sweet running, easy starting and economical (20m.p.g. on a run) motor. It's way more powerful than the old engine was but I would think probably down a bit on peak power on the full injected setup as the carb diameter and main jet size is set up for a smaller engine with milder cams. I can't recommend doing this enough, provided it is legal where you live. There are no problems with the ignition because they are independent systems on the 3.9. You will have to do something about air filtration, of course. Previously, I have had two very similar 3.5 Range Rovers. One had carbs and a 4 speed manual, the other injection and a 4 speed auto, which was higher geared. Same driver, same driving style etc, I consistently got 10% better fuel economy out of the injected car. One little glitch I had with the fuel injection more than wiped out that financial saving. It's really worth thinking about that! Certainly, if I was working in remote areas again, I would much prefer the reliable simplicity of the Strombergs. The injected engines are in no way smoother or easier to start than a well set up engine with carbs. That's my experience anyway! Don Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 25, 2013 Author Share Posted October 25, 2013 Have you been through the diagnostics as I suggested in PM? Any results? yes went through everything. cant seem to find the problem. Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 25, 2013 Author Share Posted October 25, 2013 I believe (although I have assumed) that this is a hotwire system with a clockwork distributor. Nothing that advanced. I agree with the above - try and keep the EFI. Nothing is unfixable and there's great knowledge about these systems on here. What issues are you having? My land rover 3.9 V8 when i want to pull away from a stop street its like it has a flat spot and the engine wants to stall. and it does not have any power tell i push the petrol flat down. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 25, 2013 Share Posted October 25, 2013 What have you replaced/tested so far? Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 25, 2013 Author Share Posted October 25, 2013 we have been through the diagnostics test and every thing seems to fine. we did change the throttle position sensor, changed the ignition coil, change the coolant temperature sensor. But when we bought the land rover we sew they had taken out the oxygen sensor and they fiddled with the air flow meter. And here by us these things are very very expensive and you can only get it by land rover agents here by us. Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 25, 2013 Author Share Posted October 25, 2013 Gasket set for what? Its leaking oil. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted October 25, 2013 Share Posted October 25, 2013 This sounds all very wrong to me ! The hotwire EFI system is not super complex, and a garage that you are paying your hard earned to should be more than capable of sorting, if they are not then find someone who is !. There is a full diagnostic manual on here I shoved on years ago, if it passes ALL tests then maybe, it just maybe, its not the EFI system, and you / garage need to find what it IS. You could end up changing to carbs (a daft idea and not hassle or trouble free) at a fair cost and still find you have the issue. Do you have emmissions tests as if you go carbs you may then fail on testing ? Far far better is to start back at square one and logically snsibly and methodically go though the basics rulling them out and working then through the diagnostics etc until the issue is found. For starters, what is the Dizzy Cap, and Rotaor arm - are they GENUINE and not pattern parts ?has anyone checked the timing, and also what are tghe plugs and when changed What state is the air filter in, whats the pressure in the fuel rail Is this a standard 4x4 or a fit into something ?When diod it start misbehaving, or has it never been right, if just then what if anything was touched ? Up to you but I think your starting on a road full of pain and it might make things worse................ Nige Quote Link to comment Share on other sites More sharing options...
Nigelw Posted October 25, 2013 Share Posted October 25, 2013 I was going to do something similar with my V8 Disco when I had it, by the time I worked out the costs for conversion it was just not worth the effort and by doing as suggested with following through the trouble shooting guide the EFI is a basic and simple system, you quote costs as a reason to ditch the EFI but I can tell you that setting up carbs to run properly and efficiently aint no picnic either, and it could just end up costing you way more in fuel than you might realize as you just keep pouring it in when needed and it won't be until you work out how much MPG you are getting you don't see how bad it can be. I did on my V8 Disco and glad I did, the extra economy and power more than paid for the parts with todays fuel prices!!! Please do as suggested and work through the trouble shooting manual as HfH put on here and put one thing right at a time. Although my money is on a worn out cam personally. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 25, 2013 Share Posted October 25, 2013 Although my money is on a worn out cam personally. This, or I am beginning to lean to blowing head gaskets..... Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 25, 2013 Share Posted October 25, 2013 Have you tested the AFM as described in the manual. If so, what were the results? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 25, 2013 Share Posted October 25, 2013 It was my first thought, AFM, but I've been assured by PM that it was tested and OK. It does smack exactly of what it is like to drive when you leave it unplugged accidentally Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted October 25, 2013 Share Posted October 25, 2013 My first thought too. Followed by CTS and TPS. Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 25, 2013 Author Share Posted October 25, 2013 The Garage is asking me a arm and a leg everything here is so expensive they want to charge me R25 000.we did the full diagnostic manual test and everything seems to be fine thats why we giving up and doing the carbaratorsthe Dizzy Cap, and Rotaor arm - they are geniue partshas anyone checked the timing (is fine has been checked), and also what are the plugs (we changed the plugs) What state is the air filter in,(a new air filter)whats the pressure in the fuel rail (Pressure fine)It is a standard 4X4Just after we bought it, it started with the problems so then we sew they took the oxygen sensors out and they fiddled with the Air flow meter.Then when we stop by a stop street it reves high 2500 rpm for 5 min. then it only comes down. The stepper motor closes but not fully. when i put it off it has a flat spot and back fires through the air cleaner. and when it stalls in gear it floods and wont start after 20 min. Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 25, 2013 Author Share Posted October 25, 2013 My first thought too. Followed by CTS and TPS. I replaced the TPS but what is the CTS Quote Link to comment Share on other sites More sharing options...
Johannadine Posted October 25, 2013 Author Share Posted October 25, 2013 could it be doing this because the Oxygen sensors are out? soooo stressed Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted October 25, 2013 Share Posted October 25, 2013 Cts is coolant temp if it fails then engine runs rich and boggy basic thing to check Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 25, 2013 Share Posted October 25, 2013 'they fiddled with AFM' Ugh... How and with what knowledge? And find a different garage! Quote Link to comment Share on other sites More sharing options...
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