Mike-e Posted August 21, 2007 Share Posted August 21, 2007 could always go to a aisin carb with a fuel cut off soleniod - heaps of them have them on toyotas and mitsi uses alot of aisins as well? Quote Link to comment Share on other sites More sharing options...
fuel Posted August 21, 2007 Share Posted August 21, 2007 Yup I'm pretty sure that EX will have an Aisan carb factory (as did all 80s and early 90s Mitsis other than Aus spec ones), just not sure if the early ones had fuel cut off solenoid Quote Link to comment Share on other sites More sharing options...
Scrubb Posted August 21, 2007 Author Share Posted August 21, 2007 I've always used 91 and never had any problems.. a bit confused why it would just start randomly after I increased the idle and then I put the idle down and it still does it.. weird..We'll see hat happens when it gets some fresh fuel in it.. Running 91 is false economy dude, sure it's cheaper at the pump (by only a few cents) but the engine will run like complete shit compared to 95 or 98 with the ignition timed to take advantage of the higher octane fuel. 91 has a quick flash point, ie it ignites a whole heap easier and faster than 95 or 98 - something in the combustion chamber (whether it be carbon build up, too hot a spark plug, hot exhaust valve due to being stuck open or incorrectly set tappets) is igniting the fuel (other than the spark plug sparking itself). This in turn keeps the engine running, pumping the fuel pump, drawing fuel back into the cylinder (igniting on something other than a spark) - it's basically running like a Diesel engine! Adjusting the idle screw could have richened up the mixture (causing excess carbon build up), or you could have adjusted the fuel mixture screw instead of the idle screw (it happens). Do you know what the timing was set at? It should be around 5deg BTDC if running on 91, but if you run on 95 or 98 you should be able to adjust it higher. If the timing is too far retarded, the engine runs hotter than usual causing hot spots. If the tappets on the exhaust valve are too tight not allowing the exhaust valve to sit on the valve seat for long enough to dissapate heat, the hot exhaust valve could be igniting the fuel There are many factors which can cause running on, I suggest you run it on 95/98, get the ignition timing set properly, run NGK BP7ES plugs and check the valve clearances (should be 0.15mm inlet, 0.25mm exhaust when hot). Hope that helps Some very good points! The timing was set at 5 degrees. We recently got new spark plugs but it was late at night and nothing was open so just got whatever they had at mobil (probably the wrong ones) The Tapperts were adjusted when the engine got put back together and I was told after its done some driving to get them adjusted again which hasent been done yet.. Mike-e, Its got a factory aisan carb on it. Ive always wanted to run it on higher octane as my friend says he gets ALOT better milegae and performance out of it in his primera but I want to get everything actually working like it should before I change anything (if I can) Problem is.. I know nothing so I have to get other people to do things for me so usually not alot happens when it comes to fixing the car lol Quote Link to comment Share on other sites More sharing options...
fuel Posted August 21, 2007 Share Posted August 21, 2007 It's a 1980 SOHC carb Mitsubishi - I can't seriously think of anything more basic. Pull plugs out and check what they are, if they are BP7ES chuck them back in there, if not put some in. It's a shame there's no haynes manual specific to the EX lancer but the 4G32 that's in there is the same as in the Sigmas, Galants, Chariots etc. I have a 4G37 manual in PDF form if you want it, covers fuel injected Galant engine but things like tappet adjustment procedure and setting the timing is all the same. Quote Link to comment Share on other sites More sharing options...
RWD4G62NZ Posted August 21, 2007 Share Posted August 21, 2007 Couldn't agree more with Fuel on this one. When I was refuelling Aircraft for a job we got to go through both Marsden Point Refinery and then the Depot at Wiri in Auckland where the Fuel from Marsden's Pipeline ends up and the whole thing made me sick. All the grades of Fuel from Jet A1 to Diesel to Petrol all come down the 1 pipe and guess what gets used to flush the pipe out before each Fuel type change? 91 and 95! Petrol. When the petrol goes into the trucks to go to the servo's it's as contaminated as Government Regulations allow it to be! We tested 91RON and found it to be 87RON and 95 struggled to make 91. And we pay top doller for that shit!!! My sugesstion is to use BP 98 if available and reset your static timing to factory and advance to a safe level as like most have been saying "Run On" is usually due to incorrect timing. Quote Link to comment Share on other sites More sharing options...
CaMpylobacter Posted August 21, 2007 Share Posted August 21, 2007 They're likely designed to run at least 95RON fuel as mostshit was back then. just chuck it in Quote Link to comment Share on other sites More sharing options...
Scrubb Posted August 21, 2007 Author Share Posted August 21, 2007 I'm confused.. says in the user manual that its designed to run on 91 octane.. the static timing should be set at 5 degrees which is factory and dosnt it advance by vacuum? So whats required to run it on the higher octane? I really want to try and get it running properly on the 91 fuel first though cuz it shouldnt have any problems as far as I understand because it didnt do it until a few days ago.. nothings changed except idle speed a little.. If I can I want to be able to get it running properly with the fuel its always been running on first so I think I'll wait untill I've put some fresh petrol and see what happens.. if its still the same I'll get timing and that sorta thing checked and then try the different fuel.. good idea or not ya think? Quote Link to comment Share on other sites More sharing options...
fuel Posted August 21, 2007 Share Posted August 21, 2007 Well up to you really. I personally would run it on 95/98 and up the ignition timing until it pinks slightly then back it off a degree or so until it stops - right there is the optimum point to have the timing. As you said you've adjusted the idle speed, this in turn could have altered the fuel mixture. At least pull the plugs out and check they are the correct ones... Quote Link to comment Share on other sites More sharing options...
RWD4G62NZ Posted August 21, 2007 Share Posted August 21, 2007 Like I said before Cuz our 91 is not 91! It's more like 87RON so your poor old engine is havn to contend with not enough OOOPMH from the petrol. Chuck her on 95 which is closer to 91 anyway and do the timing and see how she goes. Even early low compression motors have trouble running on anything below 90RON. Just as a footnote: When I run my car on a mix of 95 and Avgas I get better milage than I've ever got on pump gas alone! Quote Link to comment Share on other sites More sharing options...
Mike-e Posted August 21, 2007 Share Posted August 21, 2007 Mike-e, Its got a factory aisan carb on it. could always go to a aisin carb with a fuel cut off soleniod not all have fuel cut off solenoid. carb with fuel cut = no run on Quote Link to comment Share on other sites More sharing options...
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