[RESOLVED] multiple cylinder misfire

[srtkiller]

I am getting a multiple cylinder misfire code and I can't figure out what's going on. I replaced the plugs and wires also checked the coils it is getting a very strong spark to the wires. Also when I plugged it in the code reader it shows the timing was bouncing between 4 degrees and all the way up to 19 degrees. The idle is very rough and my wideband bounces from very rich to lean. I have also done a boost leak test. I really need some help I can't figure this out. Thanks

 

[srtkiller]

Here are the pictures of the sensor I was talking about. It is making a really loud ticking all the time and when you touch it you can feel it when it ticks. What is this and could it cause my problem?

 

[Noogabox]

Is is really needed to gap them all the way to .28 ? I gapped my iridium NGK to .35 and I have not had any misfires that I know of. I currently and running 5 psi boost and I am about to jusmp to 7.25 psi

 

[Burnett03]

Is is really needed to gap them all the way to .28 ? I gapped my iridium NGK to .35 and I have not had any misfires that I know of. I currently and running 5 psi boost and I am about to jusmp to 7.25 psi

We are talking about the 4g63 motor, it's different than yours. .028 is needed on ours due to higher boost.

 

[srtkiller]

I just went out and disconnected the maf sensor while it was running and it completly smoothed the idle but when i hit the gas it still kind of bogged. ould it still be the maf sensor?

 

[meliketoball]

The MAF sensor is the MAF sensor. If you're misfiring, then again look @ your plugs, plug wires, coil pack etc.

 

[srtkiller]

Again I have replaced the plugs, the wires are good, and the coil is good. I was just wondering if the maf could possibly cause this problem. I have also checked for vacuum leaks.

 

[PieEyedPiper]

I gotta ask the easy ones,

What plugs did you use?
What did you gap them to?
( I know this has already been touched, but please humor us and be very specific, I even want to know which model of NGKs you used )

When did this start, and what events surround the advent of this P0300 issue?

When are you getting the P0300 code? Highway? Idle?
What are the symptoms? None? Feels like its running on 2 cylinders and is very reluctant to accelerate?

Also, try cleaning your MAF. I used 90% iso and a Q-tip to do mine, but some people like to use the "MAF Cleaner" available in a can sold at many auto parts stores.

Also try cleaning your TPS and your CAS.

 

[srtkiller]

I used NGK BPR6ES plugs and I gapped them at .28. It kind of started out of nowhere one morning I started the car and it was running like crap it was very rich. When I got home I did a boost leak test and found two small leaks I fixed them and checked again everything was perfect. It was still not perfect and it was about time for a spark plug change and oil change so I used the seafoam then changed the plugs and oil and the car ran perfect. Then one day I was on my way to parts store (go figure) and I got into the throttle pretty hard and then when I got to a stop light all of this started just came back out of nowhere. When I got home I did another boost leak test and everything is just fine. The car has a very rough idle and is pretty hesitant under light throttle it almost feels like there is a flat spot in the signal from the tps but I am not getting a code for it and it is not showing a voltage drop. Also when you say cas do you mean cam or crank angle sensor?

 

[PieEyedPiper]

I mean Cam Angle Sensor.
For me and many others CAS = Cam Angle Sensor and CPS = Crank Position Sensor. But they're often and easily confused.

The CPS has also been speculated as cause for this behavior, but since you need a timing belt job to get to it.. well lets just say I'm trying that one last.

Try the MAF cleaning.

Yours is the only case I know of that throws a P0300 code at idle ( not saying you're the first). This leads me to believe that your issue is somewhat different than mine, other 7bolt P0300's and certainly different than the 6bolt in a 2g P0300.

Is it possible to switch wires with a buddy or anything? What wires are they and how many miles?
You can test your wires easily. At night, open your hood with the car running. Now use a spray bottle filled with water and lightly mist the wires. You should see a bit of a light show if they are bad, and nothing if they are good.
Not a definitive test, but it will certainly tell you if they are bad.

Also, can you describe how you determined that your coil packs were good?

So test/clean your:
-wires
-CAS
-TPS
-MAF

Report back so we can give you another list of things to try!

 

[srtkiller]

The wires are the blue NGK wires and they have maybe 1500 miles on them. Also it being a 95' my cas is behind the intake cam sprocket. How would I go about cleaning it and checking it. One thing I did notice is it seems there is some white corrosion on the back of intake cam sprocket I wonder if it may not be getting a proper reading. If that is all it is that would suck. I will test and clean all of this when I get home and repost. Thank you for your help thus far.

 

[srtkiller]

I did all the tests and everything looks good. I even did a compression test 179-179-180-179 and I believe factory spec is 178 so I will assume the gauge was off a little. I took a look at the timing belt and I am going to check the timing marks again tonight I think it have jumped a tooth. Would that cause a misfire code.

 

[Captain D]

I had a similar problem because of plug wires. One of my wires was shorting out against the mounting bolt for the timing cover. They were fairly new wires. I couldn't see or hear the wire shorting during the daytime. I found the problem by observing the wires at night with as little light as possible. Also, one of my repair manuals has a warning about improper arrangement of spark plug cables will induce voltage between the cables causing misfire. Cylinders 1 and 4 plug wires should never be close to wires 2 an 3. Also none of the wires should stick up and possibly short out against the hood.

 

[srtkiller]

Okay I checked my timing marks and they line up perfect so it didn't jump a tooth, thank god. Last night I took it for a drive and when I got going I had a major loss in power and the car sounded like an STI with exhaust, not cool. I shut it off let it sit and when I started it up again it stopped the subaru thing. When it did that it was studdering very bad and there was almost no power. This thing has really thrown me for a loop. Hey look at that this gave me my 100th post thanks to my broken DSM.

 

[ranger2339]

Not sure if its been said, I dont want to read the whole thread. Did you try a known working ECU?
Maybe a dirty fuel filter,bad pump or bad injector?? seems like you hit most of the ignition stuff, maybe try fuel and ECU?

Josh

 

[PieEyedPiper]

What were the results of the boost leak test? How long did you hold 20psi for?

 

[srtkiller]

The second test I found an injector seal leak, I replaced the seal and checked it again and it held pressure but I didn't time it. How long should it hold 20 psi for? I'm sure that's been addressed before.

 

[srtkiller]

I just though since nobody else has posted a resolve to this problem I would be kind enough to. I finally gave in and took it to the Mitsubishi dealer by my work and I got a call back about a two hours later. The front honeycomb in the maf somehow came loose fell into the filter then when I got on the gas again it got sucked back into the sensor and lodged itself in there crooked so it was not reading properly. So the tech who also owns a very nice dsm put the honeycomb back in as a temporary fix and now the car runs perfect although it is temporary I guess it's just time for a gm maf setup I call it a good excuse.

 

[PieEyedPiper]

srtkiller, thanks for updating this thread and letting me know via PM.
I'd suspect not everyone with this issue has their honeycomb stuck in sideways, but at least we now have confirmation that a bad MAF will cause this, be it old and fried or messed up honey combs.

Glad you got it all fixed up. I've not seen the P0300 code in some time now, but if it returns I will check my MAF first thing.

 

[Artago]

I just replaced my MDP and Transistor pack. I had codes P1400 and P0300. I got the codes several times a day.

After replacing the MDP and Transistor pack I haven't had the codes yet. It's only been 2-3 days but so far no codes. If they come back I'll let you all know.

PS: My airflow sensor reads 0.18 lbs/min when the car is OFF. Is this normal? Shouldn't it read 0.0 lbs/min?

 

[srtkiller]

If you haven't gotten the code again there is a good chance that the problem is fixed but, it still is possible that the car has not gone through a complete drive cycle. How is the car running? Also yes the air flow sensor should read 0 when the car is off.

 

[Artago]

If you haven't gotten the code again there is a good chance that the problem is fixed but, it still is possible that the car has not gone through a complete drive cycle. How is the car running? Also yes the air flow sensor should read 0 when the car is off.

The car is running stronger and sounds cleaner. Under accel and decel it's smoother. It's been 3 days and no P1400 or P0300.

I still have a P0136 (Rear O2 circuitry failure) code but that's because my rear O2 wires are cut (bought the car like that).

I have a warm high idle issue but that's due to existing vac leaks and new vac leaks I most likely created when I removed the fuel rail and injectors (to get the coil out).

BUT the car runs a lot better and no P0300 or P1400.

If you want a regular update for the next several weeks then PM me, but so far it looks good.

I think my Mass Airflow Sensor is bad or on it's way out but I wont replace it because I going to be upgrading to FMIC and GM MAF.

Do you know of any good tech articles about running a GM MAF? (I'll be getting DSMLink shortly after that)

Thanks,

Tom

 

[1992awdlaser]

To run a gm maf you just take off your old maf sensor. Put the gm maf where your stock maf was or put it on the upper intercooler pipr between the bov and throttle body. Then you have to hook up a maf translator. It has two connectors on it. The one goe to the plug that would normally connect to the stock maf. The other plugs into the gm maf. Since your going to be tuning with Dsmlink you would keep all the maf translator settings to stock. Here is a couple picture of my gm maf in the upper intercooler pipe.

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[Artago]

^^ Yeah I know all that. What I don't know is how cheap I can do the setup. Since I wont be using MAFT for tuning all I need is the translator functionality. Unfortunately the MAFT is $200 and it wont even be used to tune. Is there a cheaper translator I can use / build? I really don't wanna fork over $200 for something I wont be using for it's 100% functionality.

Basically I'm asking... what's the cheapest way to translate the GM MAF signal?

Thanks,

Tom

PS: And yes I will run my GM MAF between the BOV and TB.

 

[srtkiller]

Insted of going with DSMLink you should look into ECU+ you can a GM maf without the translator and it is also a little cheaper and you don't need an eprom ecu to run it. I just got off the phone with Will at MachV and he provided some very usefull information you can also go to theur website at ecuplus.com. That way you save some money can still run the GM maf and have a very useful tuning tool.

 

[1992awdlaser]

You will still need a maf-t unless you wait for V3 of Dsmlink to come out.