Random misfires CEL codes?
04-22-2006, 01:33 PM
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Random misfires CEL codes?
Hi there, I hope you can help with this one. I've had the following codes come on a couple of times. I allways get the 1399 one and usually a couple of random misfires as well.
P0300 Random Misfire
P0301 No. 1 Cylinder Misfire
P0302 No. 2 Cylinder Misfire
P0303 No. 3 Cylinder Misfire
P0304 No. 4 Cylinder Misfire
P1359 Crankshaft Position (CKP)/Top Dead Center (TDC) Sensor Circuit
Malfunction
P1399 - Misfire
I've had the CEL come on a couple of times. I've reset it without pulling the code with no ill effect. It's mostly come on from coasting to a stop in traffic after normal driving. Happened again today cruising gently at 30mph.
The car runs perfectly. I've got a Nurburgring trip planned next month and am getting a bit paranoid about things like this.
Do I need to change a sensor?
P0300 Random Misfire
P0301 No. 1 Cylinder Misfire
P0302 No. 2 Cylinder Misfire
P0303 No. 3 Cylinder Misfire
P0304 No. 4 Cylinder Misfire
P1359 Crankshaft Position (CKP)/Top Dead Center (TDC) Sensor Circuit
Malfunction
P1399 - Misfire
I've had the CEL come on a couple of times. I've reset it without pulling the code with no ill effect. It's mostly come on from coasting to a stop in traffic after normal driving. Happened again today cruising gently at 30mph.
The car runs perfectly. I've got a Nurburgring trip planned next month and am getting a bit paranoid about things like this.
Do I need to change a sensor?
04-22-2006, 02:30 PM
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These are random misfire codes that are classified as temporary. They relate to misfires that are frequent enough to trigger detection of increased emissions during 2 consecutive driving cycles. If these misfires are frequent enough to damage the cat, then a blinking CEL will ensue and you will have to take more immediate action.
When these codes show up, sometimes they are accompanied by other codes. Those other codes must be pulled and dealt with on an individual basis. They may involve things like MAP sensor, primary heated O2 sensor, fuel metering, crankshaft position sensor, Idle Control System, either one of 2 Top Dead Center sensors or Idle Air Control Valve. DID THE SHOP SCAN FOR ANY OF THESE?
You must determine if these misfires occur ...................................
- only at low ROM and load. Check fuel pressure. This could also indicate low compression and/or low quality fuel.
- only during acceleration. Check fuel pressure. This could also indicate a malfunction in the VTEC system.
- at high RPM and load, or under random conditions. Check fuel pressure. This could also indicate that the valves need adjustment.
The above is the "official line" as given in the service manual. For you at home, you might want to try to pull all the sparks plugs and check for condition and proper gap. When putting them back in, you might also mix up the coilpacks so that they don't go back into the same cylinders. Reset the ECU and go for a test to see if you can get a CEL with the different driving conditions mentioned above.
As you can see, diagnosing this situation may prove very extensive and "could" end up being quite expensive (for the warranty holder). Ultimately, the worst case scenario may involve exchanging of many parts, the final one being the ECU itself.
When these codes show up, sometimes they are accompanied by other codes. Those other codes must be pulled and dealt with on an individual basis. They may involve things like MAP sensor, primary heated O2 sensor, fuel metering, crankshaft position sensor, Idle Control System, either one of 2 Top Dead Center sensors or Idle Air Control Valve. DID THE SHOP SCAN FOR ANY OF THESE?
You must determine if these misfires occur ...................................
- only at low ROM and load. Check fuel pressure. This could also indicate low compression and/or low quality fuel.
- only during acceleration. Check fuel pressure. This could also indicate a malfunction in the VTEC system.
- at high RPM and load, or under random conditions. Check fuel pressure. This could also indicate that the valves need adjustment.
The above is the "official line" as given in the service manual. For you at home, you might want to try to pull all the sparks plugs and check for condition and proper gap. When putting them back in, you might also mix up the coilpacks so that they don't go back into the same cylinders. Reset the ECU and go for a test to see if you can get a CEL with the different driving conditions mentioned above.
As you can see, diagnosing this situation may prove very extensive and "could" end up being quite expensive (for the warranty holder). Ultimately, the worst case scenario may involve exchanging of many parts, the final one being the ECU itself.
Still seems to be a few options to choose from
04-24-2006, 12:19 PM
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Originally Posted by Rawhide,Apr 22 2006, 02:30 PM
Search has been helpful. I've found some info on this from Xviper
Still seems to be a few options to choose from
Still seems to be a few options to choose from
If it's random, it is unlikely to be a plug or coilpack issue. What would make them all go out at the same time?
New or cleaned injectors seem to fix it for most with this problem.
The thing that nags at me though is that why would all the injectors go bad at the same time? Does the ECU cut fuel to all injectors if one or two are fouled? Is there instead a problem with the fuel pressure regulator or fuel pump. Could it be something subltle in the electronics (voltage variation or something?)
Please keep posting and let everyone know what happens.
04-24-2006, 12:45 PM
#5
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I know you are favoring this "fuel system/electronics" kick, and while you're advice and input is welcome, telling people to go straight to the fuel system and injectors is not really the right direction. People like myself, slowS2k, xviper, billman, etc, will tell you the steps you should try in the order you should try them. Most of this is inline with the helm's manual. Far more often, misfires are caused by spark plugs, coil packs, or even valvetrain problems and compression leaks, than the fuel system.
Also, this is not an epidemic. You are in a forum where people post about their problems. If there was a forum where people would post about how they never have any problems, there'd be 100 times more threads.
Also, this is not an epidemic. You are in a forum where people post about their problems. If there was a forum where people would post about how they never have any problems, there'd be 100 times more threads.
didn't even see that when i first skimmed the post. good catch will.
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04-24-2006, 04:19 PM
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[QUOTE=Wisconsin S2k,Apr 24 2006, 12:45 PM]I know you are favoring this "fuel system/electronics" kick, and while you're advice and input is welcome, telling people to go straight to the fuel system and injectors is not really the right direction.
04-24-2006, 05:37 PM
#10
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Cleaning the injectors only fixes the cars with clogged/dirty injectors. It won't fix a injector with shorted windings. (which has also happend)
There is no blanket statement repair that fixes misfire DTC's. They have many causes which need to be eliminated one at time. Typical troubleshooting start with the easiest things to check 1st, such as spark plugs and moving coil packs and fuel injectors.Then moving on to more time consuming checks such as fuel pressure, valve clearance, and cylinder leakage.
Another issue is the PCM's misfire monitor is not always accurate. The PCM is watching fluctuations in CKP signal to deterimine what cylinder is misfiring. On a high RPM misfire, the PCM maynot be able to isolate what cylinder and stores multiple misfire DTC's.
There is no blanket statement repair that fixes misfire DTC's. They have many causes which need to be eliminated one at time. Typical troubleshooting start with the easiest things to check 1st, such as spark plugs and moving coil packs and fuel injectors.Then moving on to more time consuming checks such as fuel pressure, valve clearance, and cylinder leakage.
Another issue is the PCM's misfire monitor is not always accurate. The PCM is watching fluctuations in CKP signal to deterimine what cylinder is misfiring. On a high RPM misfire, the PCM maynot be able to isolate what cylinder and stores multiple misfire DTC's.