×
ScannerDanner Premium Customer Support (15 Mar 2019)

Please add This email address is being protected from spambots. You need JavaScript enabled to view it. as a contact in your email system. I am having a very hard time communicating with some of you because my reply messages are ending up in your spam folder! So please check your spam folders too!

× Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!

Possible bad ECU

  • rudolph.palm
  • rudolph.palm's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Dont Limit Your Challenges, Challenge your Limits!
More
26 Mar 2019 18:01 #28129 by rudolph.palm
Possible bad ECU was created by rudolph.palm
Hi, maybe you guys can give me some advice with the following situation. As you might know, its always hard to know for sure if the ECU is bad, since there is a lot of other factor which may give a "false" sign that the problem is the ECU. The car I working on is a Mitsubishi Lancer 2008. VIN: JMYSRCY2A8U000844 Engine 4A91 1.5cc. The car starts fine when cold, after a few seconds it start misfiring. the misfiring is due not working of injector number 1. Injector is fine. ECU will not enter Closed Loop. It stays in open loop. O2 sensor stuck at 0.02vlts and no fuel trim data! O2 sensor is OK. DTC Stored: P0122, P0223, P1233, P1234, P1235, P1238, P0350, P1235. P0350 again, ignition coils are ok. Based on my experience, since so many DTC are present with no obvious reason, the ECU may be bad. Further, the car may stall, and not able to idle. Throttle may become non responsive. When cycling the key, after a few seconds, car may start fine and start misfiring again shortly after start up. I was almost convinced that the fuel injector driver chip in the ECU is bad. But since it start up firing all the four injectors fine and short after that only the number 1 stops firing, made me doubt about my diagnosis. I am about to call this a bad ECU. ECU Part No: 1860A799 it seems to be very hard to find a used one. Any help suggestion will be highly appreciated. Best Regards, RP

Please Log in or Create an account to join the conversation.

  • Tyler
  • Tyler's Avatar
  • Offline
  • Moderator
  • Moderator
  • Letting the magic smoke out since 2011
More
26 Mar 2019 18:17 #28131 by Tyler
Replied by Tyler on topic Possible bad ECU
Nice list of codes! :woohoo: I'd say stick with the P0350 code, as it's an ignition system circuit code, and could very easily explain why the #1 fuel injector is getting turned off.

For example, if the ECM sets the P0350 for something it recognizes as wrong in the #1 ignition circuit, it's common for ECM's to respond by also turning off the #1 injector to save the catalytic converter. Intentional shutdown. The fact that you can bring the #1 injector back to life after a key cycle supports this.

SD covers this very phenomenon in one of his videos:



If the P0350 resets immediately after clearing, then that's the place to start. ;) What kind of ignition system does this engine use? Waste spark, COP? Can you move coils around and get the disabled injector to move with them?

Please Log in or Create an account to join the conversation.

  • rudolph.palm
  • rudolph.palm's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Dont Limit Your Challenges, Challenge your Limits!
More
26 Mar 2019 18:37 #28132 by rudolph.palm
Replied by rudolph.palm on topic Possible bad ECU
Thank you so much for your reply, it make sense what you told me about the injector being shut down due P0350. It refers to the primary side of the ignition coil. I will try swapping see what will change. I am still concern about the ecu not entering the closed loop and no ST data. When the engine just start up with no misfire, the O2 is cycling and ST data is present! only a few seconds and when the injector #1 shuts down (car starts misfire) the O2 values jump immediately to 0.02vlts and no ST data is gone! 0 value.

Please Log in or Create an account to join the conversation.

  • Tyler
  • Tyler's Avatar
  • Offline
  • Moderator
  • Moderator
  • Letting the magic smoke out since 2011
More
26 Mar 2019 19:03 #28133 by Tyler
Replied by Tyler on topic Possible bad ECU
Cool, let us know what you find. :cheer:

The O2 and trim reaction you saw is anther typical reaction to a primary ignition failure or dead misfire. The ECM will usually give up fuel control and lean things out in hopes of preventing the cat from melting down. :silly:

I don't believe we get the 4A91 in the US market? Correct me if I'm wrong. I'm gonna figure it's pretty similar to most other Mitsu aluminum block DOHC engines.
The following user(s) said Thank You: rudolph.palm

Please Log in or Create an account to join the conversation.

More
26 Mar 2019 22:33 #28135 by guafa
Replied by guafa on topic Possible bad ECU
Do you have any readings from downstream O2 sensor?

Please Log in or Create an account to join the conversation.

  • rudolph.palm
  • rudolph.palm's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Dont Limit Your Challenges, Challenge your Limits!
More
26 Mar 2019 22:39 #28136 by rudolph.palm
Replied by rudolph.palm on topic Possible bad ECU
Ok thank you so much for your advices. It all make more sense for me now. I will keep you posted when I have some updates after checking out the root cause for the P0350. Its gone take some time since the code does not specify which coil. What weird to me is when the injector number 1 is shut down the ignition coil is sparking normal. I took it out and use a spark tester on the coil and at the same time a test light connected on the B+ and the signal wire of the injector. While my test light is not giving any activity and the engine is misfiring, the ignition number one is firing fine on my spark tester. You are right, I don't believe you will have this engine in the US, its a Korean engine made for export. The VIN number is not even valid for most of the online decoders.

Please Log in or Create an account to join the conversation.

  • rudolph.palm
  • rudolph.palm's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Dont Limit Your Challenges, Challenge your Limits!
More
26 Mar 2019 22:45 #28137 by rudolph.palm
Replied by rudolph.palm on topic Possible bad ECU
Well.. that is another strange case with this car. There is only one O2 sensor on this car. Only one before the CAT. Its a 4 wire O2 sensor. # 1588A192. Its actually the first time I am seeing only one O2 installed on a car.

Please Log in or Create an account to join the conversation.

More
27 Mar 2019 01:50 - 27 Mar 2019 01:53 #28141 by Andy.MacFadyen
Replied by Andy.MacFadyen on topic Possible bad ECU
Only an upstream O2 sensor used to be normal, the downstream O2 was introduced as a check that the cat was working. It is still the case on the vast majority of cars that the downstream exists only to flag up a fault code if the cat isn't lighting up for whatever reason.

"It is the nature of every person to error, but only the fool perseveres in error." Marcus Tullius Cicero
Read more at: www.brainyquote.com/authors/marcus_tullius_cicero



Last edit: 27 Mar 2019 01:53 by Andy.MacFadyen.
The following user(s) said Thank You: rudolph.palm

Please Log in or Create an account to join the conversation.

More
27 Mar 2019 08:15 - 27 Mar 2019 08:32 #28151 by guafa
Replied by guafa on topic Possible bad ECU
In open loop at idle and for the first injection shots, ECU stays focus on LTFT, MAP/MAF, IAT, ICT and engine speed (CKP/CMP)

For instance siemens sim32 ECU at 23°C, shots for every injector 32,21,16,13,10,9 ms. Then stays adjusting pulse width according to desired engine speed.

At aprox. 13°C injection schedule is 51,37,24,18,15,11 ms.

I still cannot explain whyu is not switching to closed loop (neither why only cyl #1 is misfiring), but i would discard first all sensors mentioned before and check injection pulse width in every injector.

This could just explain no misfire at start.
Last edit: 27 Mar 2019 08:32 by guafa.
The following user(s) said Thank You: rudolph.palm

Please Log in or Create an account to join the conversation.

  • rudolph.palm
  • rudolph.palm's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Dont Limit Your Challenges, Challenge your Limits!
More
27 Mar 2019 18:25 #28160 by rudolph.palm
Replied by rudolph.palm on topic Possible bad ECU
Here some update regarding this issue. After verifying the wiring, injectors and coils I did not find anything wrong. Good continuity from coil and injector connectors to the ECU connector. So, as last check, I decided to take the plugs out for visual inspection and some measurements, (I have seen plugs gone bad before) There was nothing wrong with the plugs but what I have noticed that cylinder number one plug came out like it was soaked in engine oil!! that was not oil dripping from the valve cover. The piston at cylinder one is completely wet of engine oil while the rest are dry!!! I believe that might be giving the P0350 code, since the oil is preventing the plug to spark or spark as It should be. P0350 refers to a primary OR secondary abnormality detected. So in this case it might be a secondary issue. Pls advice what you guys think of this. I did not start the car after this findings, I will re assemble everything back tomorrow and focus on the oily cylinder number 1 issue. Unfortunately, this might be worn rings related.

Please Log in or Create an account to join the conversation.

More
30 Mar 2019 10:01 #28232 by juergen.scholl
Replied by juergen.scholl on topic Possible bad ECU
A compression and/or leak down test will give you a clue about the rings etc. It might be a damaged head gasket as well, especially if this started all of a sudden.

An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
The following user(s) said Thank You: rudolph.palm

Please Log in or Create an account to join the conversation.

  • rudolph.palm
  • rudolph.palm's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Dont Limit Your Challenges, Challenge your Limits!
More
30 Mar 2019 10:44 #28233 by rudolph.palm
Replied by rudolph.palm on topic Possible bad ECU
well... last night I was working on this car again and there is nothing wrong with the cylinders, compression reads Ok. Leak Down test OK. After that I checked the crank position sensor since it has a main role in the ignition system. I found that the connector is broken and the three wires were very loosen and wiggling freely. Although the car starts fine, Its very obvious that there might be a connection issue. I am now fixing the harness connector in the best way possible. What I found is just the three bare metal plugs which are supposed to be locked in a housing. I believe this might affect the ignition system and make the ECU throw the P0350 code and disable the injector. What is not so clear to me is why the ECU always shuts down only the number one injector. I will put an update when so far today. Thanks

Please Log in or Create an account to join the conversation.

  • rudolph.palm
  • rudolph.palm's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Dont Limit Your Challenges, Challenge your Limits!
More
30 Mar 2019 19:18 #28260 by rudolph.palm
Replied by rudolph.palm on topic Possible bad ECU
Hello, unfortunately fixing the crk sensor connection did not fix the issue. I don't have a automotive scope yet. But I used a old school conventional Oscilloscope used back in time to repair electronic devices. What I could see is a normal square wave pattern for the crank sensor and for the cam sensor. I also look at the control wires of the coils, the number one coil looks different than the 3 others. Numbers 2, 3 and 4 has a flat on top pattern while the number one coil has a slight larger amplitude and like a drop of voltage at the top. Its very hard to see any further details with the scope I used. I am not sure how a input to the ECU can bring a abnormal wave for only coil number 1 but I believe the ECU is bad in this case. Switching the coils and injector did not change anything, it keeps killing the number one injector circuit. Cycle the key, will bring it back to life just to kill it again after about 20 seconds. P0350 keeps showing up persistently. Any comment will be appreciated, I will call the customer on Monday and tell her she needs a ECU.

Please Log in or Create an account to join the conversation.

More
30 Mar 2019 20:05 #28264 by guafa
Replied by guafa on topic Possible bad ECU
What about the oil issue?

Compression and leak down test can be fine, even if you have oil inside cylinder.

Please Log in or Create an account to join the conversation.

More
31 Mar 2019 08:50 #28284 by Dtnel
Replied by Dtnel on topic Possible bad ECU
Where's the oil coming from would be interesting to know. I'd be interested to know what he finds. With the oil in the cylinder could it be a cam related issue? I'm just giving it a shot in the dark as I'm learning from this post.

HE never mentioned that he watched the scannerdanner video that one of the replies refers to.

Which video would this be by chance as I do want to watch it and see what I can glean from it in regards to this guys situation.

Sent from my SM-N960U using Tapatalk

Please Log in or Create an account to join the conversation.

  • Tyler
  • Tyler's Avatar
  • Offline
  • Moderator
  • Moderator
  • Letting the magic smoke out since 2011
More
31 Mar 2019 10:10 #28290 by Tyler
Replied by Tyler on topic Possible bad ECU
Would it be possible to post the ignition coil waveforms you saw? #1 and one of the others, preferably. I dunno that it's gonna change your diagnostic direction? :silly: But I think it'd be beneficial for the group to see what the PCM is seeing.

I was going to suggest using a spark tester on the #1 coil to see if it was something about the spark in the cylinder that the PCM doesn't like, but I see you've already done that. :silly:

You might be down to a PCM? I'd love to know more about the exact criteria on this P0350 code, but I can't see that the US market Mitsubishi's use that code. Before you pull the trigger, it's worth trying a hard reset. Disconnect both battery cables, jumper them together and have a cup of coffee. Come back and see if the symptom remains.

Please Log in or Create an account to join the conversation.

  • rudolph.palm
  • rudolph.palm's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • Dont Limit Your Challenges, Challenge your Limits!
More
31 Mar 2019 12:58 #28304 by rudolph.palm
Replied by rudolph.palm on topic Possible bad ECU
Hi guys, thanks for your attention on this issue, well to be honest, I don't see the oil on the number one spark plug anymore. My first guess is that the oil I saw in the beginning of my diagnosis was just oil build up during all the days/months that the customer kept driving this vehicle with the engine running on 3 cylinders.. No combustion firing, no oil burning! hence the oil observed earlier on the spark plug and the wet piston top. Since I cleaned up the spark plugs and swapped them, no oil was observed. This car went to several service centers for this issue without any success. Even the local Mitsubishi dealer kept this car for a week long and called a bad ECU! Many cars drove in my shop having the same call out from dealers and other service centers and drove out fixed without replacing the ECU. This one is kicking me in the bud!!. I watched the video of ScannerDanner Tyler sent me earlier. As a matter of fact I watch all the scannerdanner videos and learned a lot of him, he is a great teacher!! The video is about the same situation I am having with this car, but in his case there was an obvious issue which was a bad/damaged spark plug. In my case, I am no seeing anything wrong that could be affecting the ignition system what so ever!
The following user(s) said Thank You: Tyler

Please Log in or Create an account to join the conversation.

  • Not Allowed: to create new topic.
  • Not Allowed: to reply.
  • Not Allowed: to add attachements.
  • Not Allowed: to edit your message.
Time to create page: 0.951 seconds