Resolved Troubleshooting rough idle

[Eclipsefin]

Hi! I'm having a problem with my 2G. It has had a rough idle for a while now and here is what i have done already. Change MAF, air filter with a box, change ignition coils, change spark plug wires, change spark plugs (this was little over year ago), clean carbuerator, clean idle motor.... Still has rough idle and getting worse now.

Top of that we have yearly inspection in my country and now i didn't pass because of emissions. Inspector said he hears a snapping noise from engine bay and thought it might be spark hitting the wrong place but don't know how its possible since everything is new on spark side.

Non turbo version btw.
Please help

 

[chrysler kid]

Is there a check engine light?

Is the motor oil level good?

Is it possible the engine has internal damage and the internal damage is causing the motor to run poorly?

 

[Eclipsefin]

Check engine light has appeared maybe 4-5 times during 6 months and always stays on for just a minute. Oil level is good and oil change was about 6000km ago (1,5 years though) and i doubt its internal damage because the problem comes and goes randomly. Only connection i have regognized is maybe the fault happens more on rainy/extra humid weather

 

[Justin DuBois]

a 420a - hmm
Other normal things you should check - compression - and vacuum leak.

 

[chrysler kid]

a 420a - hmm
Other normal things you should check - compression - and vacuum leak.

Technically he could have a 4g63 non turbo since his screen name may imply that he is from Finland

 

[Eclipsefin]

a 420a - hmm
Other normal things you should check - compression - and vacuum leak.

Yea mine is non turbo version. And i have traced vacuum leak few times with brake cleaner (smoke machine would be great) but cant shut that option out totally either. Could that cause faulty spark then?

 

[m1nd64m3]

Test the resistance between the pins on your IAC, it could have bad coils in it.

 

[Eclipsefin]

Test the resistance between the pins on your IAC, it could have bad coils in it.

I did a rough test on IAC by disconnecting it when car was on and also removed it and made sure it opened when ignition is turned on. Seemed to work fine but could that still cause problems? You have any idea what kind of readings i should get from it?

 

[steve]

Yea mine is non turbo version.

But the question is still unresolved. Is your car a Euro NT with a Mitsubishi 4G63 or a USDM NT with a Chrysler 420A? There are two different non-turbo 2G cars depending on the original market.

 

[Eclipsefin]

Oh my bad, 4g63. And btw checked IAC valve once more. No fault there

 

[chrysler kid]

Oh my bad, 4g63. And btw checked IAC valve once more. No fault there

Can you post a picture of the engine bay so I can have an idea of the overall condition of things. There are several ground cables that could be bad to cause the issue, the main one on the intake manifold to the firewall and one from the starter to the negative post on the battery

 

[Eclipsefin]

Sorry i had to rush it since it was raining out there.

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[Justin DuBois]

Wish we had these in the states - we could have converted a bunch more blocks to turbo builds

 

[Eclipsefin]

Wish we had these in the states - we could have converted a bunch more blocks to turbo builds

So this is easier to do? Good to know since that is in to do/wishlist

 

[Noranuzoki]

So this is easier to do? Good to know since that is in to do/wishlist

As far as I know the major differences between the turbo and NA 4g63s are the oil squirters. I believe the heads are the same, might be a bit bigger coolant ports (correct me if im wrong). You'd need a turbo eprom ECU and maybe some different pistons (depending on how much boost you'd want to run). There is probably more stuff electronically for auto DSMs but as far as manual its pretty simply done.

If you want oil squirters you'd have to machine them in. But for the most part I don't think they're super necessary. I would recommend them always but obviously being bothered to machine in oil squirters is a hassle and at that point you might as well buy a turbo block.

And obviously, all turbo stuff (injectors, piping, turbo, BOV, as well as sensors, etc, etc).

Thats what I know from the minimal amount of research I did because the 1gs that have NA 4g63s.

 

[Eclipsefin]

As far as I know the major differences between the turbo and NA 4g63s are the oil squirters. I believe the heads are the same, might be a bit bigger coolant ports (correct me if im wrong). You'd need a turbo eprom ECU and maybe some different pistons (depending on how much boost you'd want to run). There is probably more stuff electronically for auto DSMs but as far as manual its pretty simply done.

If you want oil squirters you'd have to machine them in. But for the most part I don't think they're super necessary. I would recommend them always but obviously being bothered to machine in oil squirters is a hassle and at that point you might as well buy a turbo block.

And obviously, all turbo stuff (injectors, piping, turbo, BOV, as well as sensors, etc, etc).

Thats what I know from the minimal amount of research I did because the 1gs that have NA 4g63s.

Awesome, you gave me some hope as far as turbo install goes

 

[DogWhistle]

Hi! I'm having a problem with my 2G. It has had a rough idle for a while now and here is what i have done already. Change MAF, air filter with a box, change ignition coils, change spark plug wires, change spark plugs (this was little over year ago), clean carbuerator, clean idle motor.... Still has rough idle and getting worse now.

Top of that we have yearly inspection in my country and now i didn't pass because of emissions. Inspector said he hears a snapping noise from engine bay and thought it might be spark hitting the wrong place but don't know how its possible since everything is new on spark side.

Non turbo version btw.
Please help

Are normal driving speeds okay?

Make sure your maf is clean. Use a specific maf spray cleaner.

Fuel injectors with deposit build up will make a terrible idle. You can try adding fuel injector cleaner to your fuel, or remove and inspect them, or, if your budget allows, just replace them.

 

[Eclipsefin]

Are normal driving speeds okay?

Make sure your maf is clean. Use a specific maf spray cleaner.

Fuel injectors with deposit build up will make a terrible idle. You can try adding fuel injector cleaner to your fuel, or remove and inspect them, or, if your budget allows, just replace them.

There is some stutter/misfire while driving from time to time, specially low rpm. Maf was replaced a year ago but might aswell check that too. I actually have injector cleaner in my garage which i bought for my motorcycle so might aswell use that. But next thing im gonna do is chase is there is exhaust leak which might mess up lambda readings and cause problems

 

[steve]

Make sure your maf is clean. Use a specific maf spray cleaner.

Please read the label on any MAF cleaner, most say not for Karman MAF's. Hot wire MAF's can get dirty and that impacts their measurement, Karman MAF's don't and solvent based cleaners can damage them.

 

[DogWhistle]

Please read the label on any MAF cleaner, most say not for Karman MAF's. Hot wire MAF's can get dirty and that impacts their measurement, Karman MAF's don't and solvent based cleaners can damage them.

So DSM mafs are Karman style? If so, this is interesting news. Ours has been subjected to maf cleaner a couple times.

 

[Justin DuBois]

So DSM mafs are Karman style? If so, this is interesting news. Ours has been subjected to maf cleaner a couple times.

This is where a data log of the airflow signal would help. Maybe its working fine?

 

[steve]

So DSM mafs are Karman style? If so, this is interesting news.

There are two reference manuals I suggest everyone read as well as have a FSM for your year and model.

1G DSM 1990 Technical Information Manual

Part of the promotional material from Chrysler previewing the then brand new vehicle

www.dsmtuners.com

2g DSM Technical Information and Troubleshooting Factory Service Manual

This is the 2g DSM Technical Information and Troubleshooting Factory Service Manual.381 Pages - 13MB -- use the link below to access.Here is the direct link from my Google Drive - You must be registered to see element.

www.dsmtuners.com

This is from the original 1990 Technical Information Manual (DTM).

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The 2G MAF is smaller but works in a similar way as mentioned in the 2G DTM.

 

[Eclipsefin]

Solved! Ended up being slightly malfunctioning lambda sensor, now she runs fine and passed the inspection. Thank you for everyone