Scrubb Posted April 11, 2017 Share Posted April 11, 2017 Is someone able to fill me in on what the deal is with the sensors I have on my engine, what sensors do I have and how can I test them? Car is 1987 Mitsubishi Lancer EX 1800 GSR with 4G62T engine. The reason I ask is that it's suffering from a very bad misfire which is progressively getting worse and I've replaced all the ignition components with no change and reading online leads me to possible the O2 sensor. It looks like I potentially have 4 sensors from my quick look today, but I don't know what they are. It looks like there could be 2 on the exhaust - one before and one after the cat converter, there's a wire coming out of the air box so I assume there's one in there but I haven't taken the air box off to check, and there's one on the intake right before the injectors. I've attempted to check the one on intake and exhaust just after the turbo by connecting my multimeter to the terminals and measured both voltage and resistance across the pins, or between ground and pin for single wire sensor and I can't get any reading at all, so I'm not sure what to do. Is someone able to fill me in on what sensors I probably have and how to test them? I can get pics if needed but I thought maybe someone on here would be able to decipher my mumbling and know what I'm talking about Thanks! Quote Link to comment Share on other sites More sharing options...
Scrubb Posted April 11, 2017 Author Share Posted April 11, 2017 After some more research I found the pic below which looks like the one on the exhaust just after the turbo - oxygen sensor http://i.ebayimg.com/images/g/cZEAAOSwAL9UbW5k/s-l1600.jpg I assume from my research on the net that the one after the cat will be the same. Don't know what the others are though. Quote Link to comment Share on other sites More sharing options...
fuel Posted April 11, 2017 Share Posted April 11, 2017 The O2 sensor before the cat helps the ECU know what mixture the engine is being supplied but it is a narrow band and only really helps for closed loop on-cruise running and not acceleration etc. Even if it's faulty or non-existent it doesn't really affect the running of the engine. I have run mine without an O2 sensor and it's fine. The sensor after the cat converter is just a temperature sensor, if the cat clogs up and runs hot it will trigger an overheat lamp on the dashboard. That's all it does. The sensor on the intake pipe right before the injectors is the air intake sensor - usually there is an air intake sensor built into the air flow meter but I guess on a turbocharged engine the ambient air temp is going to be different from the actual intake air temp due to the turbo heating the charged air up. I gather being an '87 it's an intercooled model? I would be looking at the ECU coolant temp sensor telling the ECU it is still cold and therefore running overly rich and mis-firing, or look at the injectors as they are known to leak, dribble or block up. Does it just mis-fire under boost/acceleration or at all times including idle? if at all times I would be checking for a vacuum leak too. 1 Quote Link to comment Share on other sites More sharing options...
Scrubb Posted April 11, 2017 Author Share Posted April 11, 2017 Wow fuel. That's everything I needed to know, and more! Thanks! Yes, it's an intercooled model and it misfires at all times, but gets worse as the engine heats up, to the point where every time I come to a stop, the engine stalls and when starting it back up, I have to hold my foot on accelerator so that it doesn't stall - The idle speed is fine when it decides it doesn't want to stall, though. I've also checked the ECU coolant temp sensor and I assume it's working as I checked it's resistance when cold and when hot and it's resistance had changed dramatically. You suggest looking at the injectors, and I will do, but I just wanted to make sure I had all my sensors in order first before getting in to anything else. Do you know if the sensors and injectors are available to buy? Probably not OEM, I would assume... There's so many vacuum lines I'm not sure where to start, but I'll pull some off when the weather is better and check for vacuum. I did pull a couple random ones off last night and couldn't feel any vacuum. I just assumed it was because it was at idle. Quote Link to comment Share on other sites More sharing options...
AllTorque Posted April 11, 2017 Share Posted April 11, 2017 There is no point checking the resistance of the temp sensor unless you know what to expect at what temp. 2 Quote Link to comment Share on other sites More sharing options...
fuel Posted April 11, 2017 Share Posted April 11, 2017 At idle there would usually be the most vacuum an engine is subject to (other than de-acceleration). Most of the vacuum lines control things like EGR and extra idle-up when A/C is on etc. I would make sure there is vacuum source going to the distributor vac advance diaphragm and to the fuel pressure regulator. Mine was a complex mess of vac lines most of which had perished and were leaking somewhat but even then it still didn't mis-fire - I just had inconsistent idle speeds and poor fuel economy. Quote Link to comment Share on other sites More sharing options...
fuel Posted April 11, 2017 Share Posted April 11, 2017 Go see Brett at Don Campbell motors - he is an EX Lancer nut and probably has 5-10 old Mitsubishis at any given point of time. Quote Link to comment Share on other sites More sharing options...
Scrubb Posted April 11, 2017 Author Share Posted April 11, 2017 1 hour ago, fuel said: Go see Brett at Don Campbell motors - he is an EX Lancer nut and probably has 5-10 old Mitsubishis at any given point of time. Funny you mention that. The car in question is his GSR I bought from him! I left it with him to go over and he said he checked the vacuum lines and couldn't reproduce the problem, but that was when it only played up when hot. Also, I know the idle speed control is controlled electronically by a motor which moves the throttle linkage which I have confirmed isn't working as I understand there should be movement when turning the key ON, but I couldn't get any movement out of it. I bumped the idle up to compensate and it idles at a good speed when hot, but a little low when cold. Quote Link to comment Share on other sites More sharing options...
0R10N Posted April 11, 2017 Share Posted April 11, 2017 Could the fuel pump be failing? Speaking of G62BT fueling issues I recently picked up a Cordia turbo for someone that seems to only randomly die around left hand corners, and when coming to a stop after cruising for a while. Initial diagnoses indicated either a bung fuel pump, or crap in the tank interfering with fuel flow. Quote Link to comment Share on other sites More sharing options...
fuel Posted April 12, 2017 Share Posted April 12, 2017 18 hours ago, Scrubb said: Funny you mention that. The car in question is his GSR I bought from him! I left it with him to go over and he said he checked the vacuum lines and couldn't reproduce the problem, but that was when it only played up when hot. Also, I know the idle speed control is controlled electronically by a motor which moves the throttle linkage which I have confirmed isn't working as I understand there should be movement when turning the key ON, but I couldn't get any movement out of it. I bumped the idle up to compensate and it idles at a good speed when hot, but a little low when cold. Haha so the plot thickens - I messaged him a link to this post to investigate before you told me you bought it off him, but he couldn't see the thread as he doesn't have an account. I told him the issues you are having and he said it could be the ECU and/or knock sensor and to send it to John at Get It Fixed to be repaired. The idle speed is controlled by both a servo motor and a coolant controlled wax element. I think the earlier cars like mine had further solenoid/vacuum idle control. I know I had a solenoid which triggered when the A/C was on, which had vac lines to increase idle speed. Quote Link to comment Share on other sites More sharing options...
Scrubb Posted April 12, 2017 Author Share Posted April 12, 2017 6 hours ago, fuel said: Haha so the plot thickens - I messaged him a link to this post to investigate before you told me you bought it off him, but he couldn't see the thread as he doesn't have an account. I told him the issues you are having and he said it could be the ECU and/or knock sensor and to send it to John at Get It Fixed to be repaired. The idle speed is controlled by both a servo motor and a coolant controlled wax element. I think the earlier cars like mine had further solenoid/vacuum idle control. I know I had a solenoid which triggered when the A/C was on, which had vac lines to increase idle speed. Bugger, hopefully the ECU is still good, but I'll get the sensors sorted out first so then I know 100% they're good before I start looking at ECU, etc.. Is anybody able to assist me in sorting these sensors? O2 sensor Exhaust temp sensor Air intake sensor Air flow meter Coolant temp sensor Quote Link to comment Share on other sites More sharing options...
0R10N Posted April 12, 2017 Share Posted April 12, 2017 The sensors are available aftermarket. I recently bought coolant temp and O2 sensors brand new from BNT for the Starion. Phone Ant the Mitsi Whisperer at BNT New Lynn and say you are from Oldschool. Note that exhaust temp readings should only really affect things if the catalytic converter is present, and not completely choked up. The Starion seems to be very sensitive to running the correct plug gap - I'm assuming the G62B is similar - have you made sure you're running the correct ones for the engine? Also, I know I've already said it, but have you considered the fuel pump? Quote Link to comment Share on other sites More sharing options...
Scrubb Posted April 13, 2017 Author Share Posted April 13, 2017 53 minutes ago, 0R10N said: The sensors are available aftermarket. I recently bought coolant temp and O2 sensors brand new from BNT for the Starion. Phone Ant the Mitsi Whisperer at BNT New Lynn and say you are from Oldschool. Note that exhaust temp readings should only really affect things if the catalytic converter is present, and not completely choked up. The Starion seems to be very sensitive to running the correct plug gap - I'm assuming the G62B is similar - have you made sure you're running the correct ones for the engine? Also, I know I've already said it, but have you considered the fuel pump? Cool, thanks, I'll contact him as I'm very particular and want to have piece of mind that all my sensors are in working order, even if they're not all 100% needed I've got new NGK plugs in which according to NGK are the correct ones for the engine (B7ES or something like that) but I haven't gapped them as I'm not sure what the gap should be. i'll have a look under the bonnet tonight and see if it says... I'm considering everything at this point, but I'd like to do the sensors first as nearly everything I read online of other people having the same symptoms, their issues were fixed by renewing their sensors, particularly the O2, I think, but Phil has successfully ran his without one with no issue, so I'm not sure what the deal is, but I'll start there for my own piece of mind and then move on to fuel pump, injectors and ECU/knock sensor, I guess. OR1ON, on a side note, does your Starion have the servo ISC motor and have you ever looked at replacing this? Mine's not working and I THINK I've found the part for a 2.6 engine overseas for big bucks (Not sure ifit's the same, will have to get part number), but was wondering if it's available aftermarket here for cheaper and failing that there's a place I found which might be able to repair it as they do ones for later model Mitsubishi's. One other quick question, will BNT be able to look up what I need, do you think? In the past I've had to provide Mitsubishi part numbers for them, but in this case I don't have any. Quote Link to comment Share on other sites More sharing options...
0R10N Posted April 13, 2017 Share Posted April 13, 2017 No worries, I'm fairly sure Ant can help you source those bits - he should be able to look everything up without needing the part numbers, but there might be several types listed so you may have to guess or provide the old one as a sample. You could also possibly make some inquiries at Auckland Motors Mitsubishi. Mine's a facelift 2.0 with the non-tophat intake manifold, but I think it still has the same ISC. Haven't had any trouble with it (yet - touch wood) but it's possible that Fuelmiser or someone similar makes aftermarket ones, you might even find they are shared between various models and not just restricted to the turbo ECI ones. Oh yes, knock sensor - forgot about that. The dreaded E-101, haha. If you need to go down that route I can possibly lend you one of my good ones, as I stockpiled a few just in case mine shits itself. Quote Link to comment Share on other sites More sharing options...
Scrubb Posted April 13, 2017 Author Share Posted April 13, 2017 23 minutes ago, 0R10N said: No worries, I'm fairly sure Ant can help you source those bits - he should be able to look everything up without needing the part numbers, but there might be several types listed so you may have to guess or provide the old one as a sample. You could also possibly make some inquiries at Auckland Motors Mitsubishi. Mine's a facelift 2.0 with the non-tophat intake manifold, but I think it still has the same ISC. Haven't had any trouble with it (yet - touch wood) but it's possible that Fuelmiser or someone similar makes aftermarket ones, you might even find they are shared between various models and not just restricted to the turbo ECI ones. Oh yes, knock sensor - forgot about that. The dreaded E-101, haha. If you need to go down that route I can possibly lend you one of my good ones, as I stockpiled a few just in case mine shits itself. Non-top hat manifold - Is that what mine is? Image below is of my engine bay: https://goo.gl/photos/JEF9XuZcFXzPgiZ88 Quote Link to comment Share on other sites More sharing options...
fuel Posted April 13, 2017 Share Posted April 13, 2017 Your '87 intercooled should have the same inlet manifold and injection system as a later Starion, including Ed's one. I believe Ed's is NZ-new so it will be without a cat converter, O2 sensor and exhaust temp sensor and instead has a mixture adjustment trimpot mounted somewhere. Quote Link to comment Share on other sites More sharing options...
Scrubb Posted April 14, 2017 Author Share Posted April 14, 2017 4 hours ago, fuel said: Your '87 intercooled should have the same inlet manifold and injection system as a later Starion, including Ed's one. I believe Ed's is NZ-new so it will be without a cat converter, O2 sensor and exhaust temp sensor and instead has a mixture adjustment trimpot mounted somewhere. Awesome, that should help me in my search for parts! Quote Link to comment Share on other sites More sharing options...
Ranter Posted April 15, 2017 Share Posted April 15, 2017 i'd be swapping the air flow meter for a known good one, then the boost sensor first. Coolant temp sensor is the only other one that would matter I'd probably replace it rather than mucking around. If it comes down to computer I might have one to send you to try somewhere. Quote Link to comment Share on other sites More sharing options...
kempy Posted April 15, 2017 Share Posted April 15, 2017 Watching this with interest as my Cordia GSR is doing exactly the same thing, changing the disty cap has made some progress but I haven't got it hot enough to make sure the problem is fixed Quote Link to comment Share on other sites More sharing options...
Scrubb Posted April 15, 2017 Author Share Posted April 15, 2017 So, I did a little bit of troubleshooting today. I took out the air box and sprayed the air flow sensor liberally with brake clean. It was a bit filthy, and I found the intercooler hose was loose, so I tightened that up while I was there, but none of this made any difference at all. I did notice though, that there was a short period of time where it ran quite smoothly between the needle coming off cold and getting in to hot and only for 30 seconds or so, then it was back to it's normal spluttering. Once it warmed up, I also disconnected the air flow sensor and it caused the car to stall, so I'm assuming that's working. I then reconnected that and disconnected the vacuum hose going to the boost sensor and the idle speed immediately dropped and ran even worse and I could hear the hose hissing so sounds like there's good vacuum there. So would I be right to assume my sensors are probably working okay and to look elsewhere? Quote Link to comment Share on other sites More sharing options...
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