2G Wont idle and runs rough. Tried almost everything

[red_devil]

Car lost power and started vibrating while driving. Pulled over and checked the wires and noticed it was running only from cylinder 1 and 4. So I figured power transistor. Well while I was there I figured I'd do a few things such as new gaskets, test and clean injectors, new knock sensor and check wiring.

Everything together fine but now the car will not start without gas. It will not idle at all when cold and runs rough below 2000rpm. Above that it revs fine. Afrs are around 20:1 and you can smell fuel like crazy. I'm getting both spark and fuel to all 4 cylinders.

I've checked almost everything
Boostleak-no leaks up to 10psi (stopped because that was enough for the issues)

Exhaust leak-has a tiny leak near the wastegate but it's been there in the past with no issues and it will stop after it heats up.

Tps is properly adjusted

Switched wires and plugs, tested coils

Coolant temp sensor is working

Cams are aligned at tdc

Connected to Link and found o2 was running flat at .02v so I replaced it with a spare one with no change. ISC reads dead at 0 and does not move. Removed the ISC to check coils. All were fine but then with movement test it does not move or make a noise. Replaced it with a new spare one and it doesn't move either. So I'm down to ECU. Pics included. Anything else I'm missing before I send it out for testing?

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[twicks69]

Did you replace your coil pack for 2/3 at all?

 

[red_devil]

Did you replace your coil pack for 2/3 at all?

I switched it with a spare yes. Nothing changed.

 

[twicks69]

Ok you just only said the Ignitor in the first post, wanted to make sure you actually tried a different coil pack as well.

 

[red_devil]

Ok you just only said the Ignitor in the first post, wanted to make sure you actually tried a different coil pack as well.

I can't keep up with the crap I've replaced . If I plug the old igniter in it will not run at all anymore. So it was dead but I just don't understand what else is going on

 

[twicks69]

Confirm your firing order is correct.

 

[red_devil]

Confirm your firing order is correct.

Yep. Wont even try to start if i switch them. Is the lack of working isc really causing all this?

 

[twicks69]

That shouldn't do this, you check your plugs if they are soaked?

 

[shellhouse]

That shouldn't do this, you check your plugs if they are soaked?

Curious if one plug looks different from any others.

Maybe a stuck injector or something like that? I've never had such a problem, but if one plug is wet, could swap injectors around to see if the problem moves.

 

[JeffGS-T97]

Mine won't run without the ISC, installed the block off plate on the TB and spit sputter die every time. Put in the bypass plate started fine.

 

[waltah]

This is the maybe-a-dumb-idea department but what about a good-size air leak in the intake? PCV hose off (or bigger) size leak? That could (a) happen suddenly while on the road, (b) make idle impossible and operation at medium RPM very rough, (c) make mixture very lean so 02 sensor voltages ~0.0 V, and (d) might (hard to think about this) drive ISC toward 0.

Check out the EGR valve too. There's a potential big hole in the intake.

If the usual big air leak tests (I like starter fluid spray starting at air filter and if that makes idle much better then go over everything under vacuum) don't find anything I'd do a compression test before sending off the ECU.

My hardest ever too-lean diagnosis: A 'stroker' engine in one of our 1.8L Expo LRV's: Everything seemed perfect but would not run worth anything until I stuck in the injectors for a 2.4L engine. In desperation I measured the stroke through the spark plug holes: 6mm too long. Some long-ago prior owner had stroked it to 2.0L. You don't see that much in frumpy family cars ...

 

[waltah]

Yep. Wont even try to start if i switch them. Is the lack of working isc really causing all this?

I'll bet if it stalls wide open because of an ECU problem that would be possible. On the non-turbo Mitsus I know better the normal idle range is 2-20 steps but the thing will go to 137 (I think). And if the ECU is at fault you can hardly trust the number it reports -- the failure could be in the counting logic so it's lying to itself as well as to you.

 

[shellhouse]

Maybe check the wiring to the ISC too.

 

[red_devil]

That shouldn't do this, you check your plugs if they are soaked?

They look black but don't appear wet. I cleaned them off then ran it for 10secs (first pic) then ran it for a 1 min.

Think I'm going to order all new plugs and wires again and see if it clears up

Curious if one plug looks different from any others.

Maybe a stuck injector or something like that? I've never had such a problem, but if one plug is wet, could swap injectors around to see if the problem moves.

They all look kinda similar. Injectors were just tested and cleaned at FIC

Mine won't run without the ISC, installed the block off plate on the TB and spit sputter die every time. Put in the bypass plate started fine.

Thinking it may be the same. It will not run at all when it's cold unless I bury the throttle. But after warming up some it starts to idle somewhat normal.

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[Diamond Star Werks]

Did you check fuel pressure? Isc should not read zero with key on engine off, if it does resync ecm and isc by disconnecting battery for 10 min. If the car stays running with throttle and runs smooth another set of plugs and wires arent going to change anything.

If o2 doesn't ever change off .02 the sensor ground is missing, heater circuit is open and sensor is not hot enough (though even cold sensor don't normal stick at .02), or engine is actually very lean due to low fuel pressure or large vacuum leak. Look for missing injector seal.

Temporarily rule out o2 by locking in open loop then diagnosing the issue. Temporarily add deadtime till afr get to 14.2-15.5 it should idle with that afr. Also regardless of open or closed loop the o2 sensor should still report voltage to ecu so if afr drops below 14.5 by adding fuel via more deadtime and the o2 sensor never switches there is an issue.

However from cold starts ecu is in open loop anyways so ecu isn't even using the sensor for fuel adjustment right away. So a bad or even unplugged o2 sensor will not even affect a cold start no idle issue. Even a hot start would be unaffected by a bad or unplugged o2 sensor at least until it switched to closed loop which it won't do if the primary o2 is unplugged.

 

[Diamond Star Werks]

If the problem didn't exist before working on it then likely its something that is related to what was done.

Also you have ecmlink and Internet access so you should post a good log capturing all relevant data.

 

[Vegas Smith]

My dude those plugs appear to be fouled.

 

[pauleyman]

Car lost power and started vibrating while driving. Pulled over and checked the wires and noticed it was running only from cylinder 1 and 4. So I figured power transistor. Well while I was there I figured I'd do a few things such as new gaskets, test and clean injectors, new knock sensor and check wiring.

Everything together fine but now the car will not start without gas. It will not idle at all when cold and runs rough below 2000rpm. Above that it revs fine. Afrs are around 20:1 and you can smell fuel like crazy. I'm getting both spark and fuel to all 4 cylinders.

I've checked almost everything
Boostleak-no leaks up to 10psi (stopped because that was enough for the issues)

Exhaust leak-has a tiny leak near the wastegate but it's been there in the past with no issues and it will stop after it heats up.

Tps is properly adjusted

Switched wires and plugs, tested coils

Coolant temp sensor is working

Cams are aligned at tdc

Connected to Link and found o2 was running flat at .02v so I replaced it with a spare one with no change. ISC reads dead at 0 and does not move. Removed the ISC to check coils. All were fine but then with movement test it does not move or make a noise. Replaced it with a new spare one and it doesn't move either. So I'm down to ECU. Pics included. Anything else I'm missing before I send it out for testing?

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This is the biggest clue for me. Car lost power while driving. Have you ruled out boost leaks? Mechanical timing? What were you doing right when this happened. WOT? Or just cruising along.

 

[steve]

It's time to send your ECU back to ECMTuning. There is corrosion starting in the center around R4 and R5 from the C205 capacitor leaking. Given the other posts there may be much more going on but the ECU needs some work.

 

[red_devil]

If the problem didn't exist before working on it then likely its something that is related to what was done.

Also you have ecmlink and Internet access so you should post a good log capturing all relevant data.

Laptop took a dump . Try to get one after black friday.

This is the biggest clue for me. Car lost power while driving. Have you ruled out boost leaks? Mechanical timing? What were you doing right when this happened. WOT? Or just cruising along.

No leaks at 10psi. Timing is lined up.

It's time to send your ECU back to ECMTuning. There is corrosion starting in the center around R4 and R5 from the C205 capacitor leaking. Given the other posts there may be much more going on but the ECU needs some work.

Agreed. With zero isc movement the car will probably struggle to start now its getting cold.

 

[waltah]

My dude those plugs appear to be fouled.

Yeah and that kind of throws everything I thought right out the window. In fact it's hard to think how a fuel-injected/computer controlled engine could do that: All the cylinders are running far too rich so the usual sorts of injector problems wouldn't be the cause.

Fuel pressure regulator not working? But the way they're built that's almost impossible -- they'll leak but not jam shut running the rail pressure up to whatever the pump will deliver. Unless maybe the return line is kinked shut or something like that.

The ECU does pulse all the injectors at once -- 4x normal delivery -- when the engine is cranking but not yet started. I don't remember how that ends -- how the ECU knows the engine has started AND whether that process could fail causing continued injection of far too much fuel. I wouldn't think that could happen but who knows.

This isn't some kind of feedback loop problem though because as others have pointed out it's happening while still running open loop and in any case I don't think loop adjustments are big enough to make plugs look like that.

This may indeed be a sick ECU. A stock spare is a good thing to have but if you don't I'd say get that checked out. Changing other parts right now will just add more variables.

 

[red_devil]

Finally got this figured out. Sent the ECU to ecmlink and they identified that the damage from the leaking cap had caused 2 problems. First it was preventing the ECU from reading battery voltage and causing the ISC to remain fixed. The second, was preventing battery backup voltage to the processor. They stated the initial damage would of created extremely rich mixtures and caused all kinds of running issues....

The ECU is back in and it now runs smooth. I still need to do some biss adjustments and such but she will idle and rev now

Thank you for the help and shout out to ecmlink.com as they identified the problem and fixed it on a Friday and was delivered back to me on Tuesday!!!