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starion acting up


gibbon
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I've never had this car running really so not too sure what the deal is. it's rich, it's lean, it cuts out on anything more than half throttle... the issue is explained in the YT blurb but here it is again

car starts and idles easily, the AFR gauge shows it getting progressively richer, but i suspect it's rich from the get go and is just getting more accurate as the probe heats up? i've changed the fuel filter and checked the pickup sock, I don't have a pressure gauge but I tapped a sender into the throttle body and it's showing in the realm of 50psi which is probably in the ballpark but which highlights another issue entirely, this is the 12v starion engine that nobody knows anything about or has any manuals for

anyway so it runs pretty rich and doesn't seem to lean out as RPM increases unloaded. on backing off it leans out quite a bit momentarily. really stabbing the throttle causes it to abruptly cut out, on recovery it runs off the gauge lean, but a blip on the throttle returns it to running reasonably rich. at the end of the video i floor the accelerator, you can see it cuts out before it makes any boost

it seems to be more load related than RPM related, the TPS seems to be functioning normally. the car has a knock sensor, optical dizzy with no vacuum advance. won't rev, wont build boost, running very rich, these are probably hallmarks of limp mode but i have no idea if this car even has it. read a few fault codes but they make no sense whatsoever, they don't correlate to any of the codes in manuals for the other engine models. i have swapped out an airflow meter and ecu but nothing has changed. what should i look at next? got a speeduino here but it'll kill me inside to rip back into the wiring

 

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Airflow meter

I think I've just confirmed that the secondary injector isn't getting a signal to fire which would explain the cutting out.. going to try measuring again straight off the ecu

whether there's an actual issue with the ecu or if not firing the second injector is part of limp mode, I'm not too sure. Perhaps it's upset about something else 

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The fuel pump is an unknown quantity but there was good pressure at the tb and the return line from the regulator was wet so I think it's getting fuel OK

The engine cuts out at any rpm with enough throttle input, or at 3500rpm if I build revs slowly at low throttle 

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Im not familiar with the EFI system on these, but is the coolant temp sensor for the ECU good? If its reading wrong the engine could be dumping in more fuel. The service manual might give the resistance ranges at certain temps for testing.

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OK the good news is that i seemed to have fixed the major problem - i pulled the secondary injector, it was all clean, reinstalled it, pressurized the rail and put some power to the injector and it sprayed like a champ. put a test light across the wires at the back side of the final plug and suddenly it's lighting up and the car is revving out.. so i'd say either a shitty connection somewhere which i've made right with vigorous plugging/unplugging, or maybe the injector was seized up and i've freed it up when i tap-tap-taparoo'd it into place because it didnt quite want to go in

she's still running rich as shit at idle, @bigfoot i checked the return line from the regulator, it was full of fuel so it's at least the valve itself is opening. i agree the rail pressure does seem high though, the return might be full of fuel but maybe it's fuel that isn't going anywhere thanks to a blockage further down... is it safe to disconnect the line and just blow it back with compressed air? when i pressurised the rail i could see that there were no leaks from the injectors or their little housing doodad

@kws i wouldn't have a clue what it's nominal figures are supposed to be for the temp sensor... i guess i could pull it and bench test it with a heat gun to see if it at least changes values.. i've never found a service manual for this particular engine and don't really want to take figures from the closest other manual as there does seem to be quite a few differences.

what air fuel ratios would you expect from an auto choke function? is there a chance it's rich as shit just because it's still trying to warm up?

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3 hours ago, gibbon said:

OK the good news is that i seemed to have fixed the major problem - i pulled the secondary injector, it was all clean, reinstalled it, pressurized the rail and put some power to the injector and it sprayed like a champ. put a test light across the wires at the back side of the final plug and suddenly it's lighting up and the car is revving out.. so i'd say either a shitty connection somewhere which i've made right with vigorous plugging/unplugging, or maybe the injector was seized up and i've freed it up when i tap-tap-taparoo'd it into place because it didnt quite want to go in

she's still running rich as shit at idle, @bigfoot i checked the return line from the regulator, it was full of fuel so it's at least the valve itself is opening. i agree the rail pressure does seem high though, the return might be full of fuel but maybe it's fuel that isn't going anywhere thanks to a blockage further down... is it safe to disconnect the line and just blow it back with compressed air? when i pressurised the rail i could see that there were no leaks from the injectors or their little housing doodad

 

If you blow back against the reg, no air will pass. Best bet will be to take return line off outlet of reg and blow back into tank

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OK some new developments; i pulled the coolant temp sensor and checked it, it seems to be functioning, 2k ohm at ambient down to about 700 at boiling temp. I tested the internal resistance of the inlet temp sensor and there's something there at least, no idea what the nominal figure is. i have three airflow meters and they all gave the same result.

i also blew back through the fuel return line, there was a bit of resistance there but i could hear it bubbling back in the tank so don't think it's a problem

however i did notice something - the meters seem to have some kind of calibrated bypass tube? and some have a single, and some have a double. the one that was previously installed was the single unit. i have no idea if it's the correct one. but if the ECU is anticipating a load of additional unmetered air from a second tube that isn't there... that could well be why its running rich as buggery

 

20220327_200558.jpg.2a0688e10db22d5a6b8c3af45e799e63.jpg

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There will be an "E5Txxxx" number printed on them somewhere (usually on the top). In my experience, if the numbers are the same they should be interchangeable. The diagrams for your car show it as a twin tube AFM, but the images are indicative only. The AFM the parts diagram says it should be is MD077636, but i dont think that will be printed on the AFM anywhere. I can check tomorrow if its available out of Japan, but I doubt it and it'd be MEGA bucks if it were.

https://partsouq.com/en/catalog/genuine/unit?c=Mitsubishi&ssd=%24*KwH-ytuwuqyHqoOCvprAwqaykpWL-vX4-ev4x7fvvun275Dqubnk7vf7trK4irO376X275Dp4O-pprehpY39-_3_-frx1Lmr7q6j6fb85urgub3u_P_m_Pz66rm57u736Pr9-OX5pK7Y_Pz6_vz9-vujz6Wxs7yupI2x6vy5ve6M-_P_jP_4pKuy9fjo5-6u6PK32rf9-_n__PSL6rm56u736Ir99fmJt7elr6Ho8e6AhJ_GufoAAAAA7TmtJg%3D%3D%24&vid=0&cid=&uid=9514&q=A183A5010595

That Speeduino is sounding pretty appealing tbh... Old EFI systems without any diagnostic ability suck.

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The twin tube one is E5T00272, the single ones are 171. If it's supposed to be the twin tube one then there's an obvious problem right there, so thanks for that... I'll swap it out the moment I find motivation 

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Speeduino would be great because I could finally ditch the godawful airflow meter, but then there'd be the temptation to go MPI off the back of that, and that means off the road again for a decade 

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I wonder if the single tube one doesn't have the air temp sensor? The one for your car should have an air temp sensor, but one type doesn't have it and I can't tell how to identify. 

As suspected MD077636 is obsolete in Japan. 

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From my googling (honestly I don't know if I'm helping or not, I just have time up my sleeve and like a challenge) I have found the following. 

The car should run without the afm connected. It'll run rich, bit if it runs better with it disconnected you have a bad afm. 

The coolant temp sensor should read approx 220-270 ohm when at operating temp, and can be substituted for a correct value resistor for testing. 

Fuel pressure should be about 36psi, so maybe your regulator has packed a sad since it's way over that. Apparently it's common for the return hard pines to get crushed and dented under the car too. Maybe take the return line off at the regulator and run it into a gas can and see if the pressure changes?

If you take the intake pipe off the throttle you should be able to see the two injectrs spraying a nice fine cone at idle, and should shut off completely when the engine is off. If they aren't spraying a cone and leak when the engine is off, no bueno. 

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On 28/03/2022 at 09:22, kws said:

I wonder if the single tube one doesn't have the air temp sensor? The one for your car should have an air temp sensor, but one type doesn't have it and I can't tell how to identify. 

As suspected MD077636 is obsolete in Japan. 

You might be on to something there. My Lancer has a single tube air flow meter and it looks exactly the same as the one above (I'll have to get part number to confirm). It has an external air temp sensor located on the inlet pipe after the turbo, but before the injector unit.

I'm interested in how you get on with this as I've had on going issues trying to get my Lancer going properly. Still not figured out after 5+ years of ownership as nobody can get their head around how the systems work.

I have some info on the Lancer 2000 Turbo and Cordia Turbo. Let me know if that might help and I can try look stuff up. I think I saw calibration value for the intake temp sensor somewhere, but not sure if it would be the same for Starion.

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My wiring diagram shows an inlet air temp sensor in the AFM and both the styles of airflow meter that I have seem to have it

However I ALSO have some kind of sensor in the pipe before the throttle body but no idea if it's temp or pressure, the diagram makes no mention of it

There is a wiring diagram that makes mention of two inlet air temp sensors, I'll have to dig it out though. It's not the one that's applicable to my engine. Below is inlet pipe sensor 20220329_181538.thumb.jpg.c4880f2e1174929f460801f219ae8646.jpg

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