Random Misfire
#1
Random Misfire
So I finally got my oil pump replaced. PITA.... After I got everything back together, I started her up, and WINNER, I had oil going to the cams. Problem is, she is running fairly rough. Idle is low, around 500-700 RPM, and if I rev to around 2000 RPM the CEL light flashes for about 30 seconds, the goes solid. So I pul out my trusty ODB-II scanner and it pulls a P0113 and P0300. No real power to either (i drove it about 3 blocks). The day I was driving it when the oil pump shattered (will have to post pics of that later on), aside from the obvious rattle caused by the broken oil pump. It still had normal power. (thankfully the oil pump died only about a mile from my house).
Any ideas as to what my issue could be? I did spray the MAF with MAF cleaner while I had the TB off, so I think that is what is causing the P0113. Also replaced all the IM gaskets, and spark plugs while it was tore down. I am a bit stumped here guys and need some more help!
Any ideas as to what my issue could be? I did spray the MAF with MAF cleaner while I had the TB off, so I think that is what is causing the P0113. Also replaced all the IM gaskets, and spark plugs while it was tore down. I am a bit stumped here guys and need some more help!
#2
Sounds like the chain might be off a tooth. If it's off by a tooth it will cause a P0300 misfire condition, and will not have much power to speak of at all. Especially if you just replaced the oil pump, it's possible that the chain jumped a tooth on start up, or the chain could have been set one tooth off. I've done that a couple times myself actually. Once on a 240SX, and again on a 350Z.
Being off one tooth on the VQ is not going to cause any damage to the engine or anything like that, so don't worry too much. Hope I could help. Cheers.
-Nathan
Being off one tooth on the VQ is not going to cause any damage to the engine or anything like that, so don't worry too much. Hope I could help. Cheers.
-Nathan
#3
In the past for me, p0113 was a bad IAT and I fixed it by replacing the thermistor. This may or may not be your issue.
I recently had a p0112 which also means a bad IAT. This time however, it wasn't the thermistor at fault. Rather, it was the MAF Connector. Turns out my wires on the connector were frayed. At times, this didn't really cause an issue other than me having a p0300 and a p0112. However, eventually the car felt like it had no power at all and I had a flashing CEL if I drove the car harder than 1800 or 2000 rpm.
Since it is very easy to check either of those things, I suggest you start there. I would assume it has something to do with the MAF, whether its the thermistor, a bad maf, a bad connector or possibly the harness. Good luck.
I recently had a p0112 which also means a bad IAT. This time however, it wasn't the thermistor at fault. Rather, it was the MAF Connector. Turns out my wires on the connector were frayed. At times, this didn't really cause an issue other than me having a p0300 and a p0112. However, eventually the car felt like it had no power at all and I had a flashing CEL if I drove the car harder than 1800 or 2000 rpm.
Since it is very easy to check either of those things, I suggest you start there. I would assume it has something to do with the MAF, whether its the thermistor, a bad maf, a bad connector or possibly the harness. Good luck.
Last edited by OnOiShNo0dl3Z; 05-21-2012 at 05:41 PM.
#4
Sounds like the chain might be off a tooth. If it's off by a tooth it will cause a P0300 misfire condition, and will not have much power to speak of at all. Especially if you just replaced the oil pump, it's possible that the chain jumped a tooth on start up, or the chain could have been set one tooth off. I've done that a couple times myself actually. Once on a 240SX, and again on a 350Z.
Being off one tooth on the VQ is not going to cause any damage to the engine or anything like that, so don't worry too much. Hope I could help. Cheers.
-Nathan
Being off one tooth on the VQ is not going to cause any damage to the engine or anything like that, so don't worry too much. Hope I could help. Cheers.
-Nathan
#5
Proper gap should be .44, and from what I understand, these VQ engines don't react well to other brands of spark plug besides NGK. Not sure exactly why, but I have read that several times throughout these forums.
In any case, they should be pre-gapped, but I always check the gap on mine anyways, because you just never know.
-Nathan
In any case, they should be pre-gapped, but I always check the gap on mine anyways, because you just never know.
-Nathan
#7
I had the P0113 code and it was due to a broken MAF sensor connector wire. Your MAF sensor may be bad but make sure the wires are all intack and not broken. I also got some random misfire after I did my engine swap and it went away after a while.
Hope you have some kind of warranty. Right now i'm dealing with codes after codes after codes. But good luck man
Hope you have some kind of warranty. Right now i'm dealing with codes after codes after codes. But good luck man
#9
#10
Sorry you felt ignored. Was just a bit more worried about having to tear the timing back down again. My misfire is a bit worse than what I would discribe as just random.
#11
nah i just figured since that's what the CEL points to and this issue has been experienced before with the same symptoms mentioned and same CEL, it would make sense to take a minute to inspect what is suggested. Shouldn't take more than 3 minutes and could very well fix your problem for no cost.
And yes, when there are MAF issues or an issue with the connector to the MAF, it is not uncommon to have very bad misfires, bad enough at times to make the car bog or feel like you're running on half the cylinders. Flashing CEL and lack of power are both possible symptoms of this issue.
And yes, when there are MAF issues or an issue with the connector to the MAF, it is not uncommon to have very bad misfires, bad enough at times to make the car bog or feel like you're running on half the cylinders. Flashing CEL and lack of power are both possible symptoms of this issue.
#12
He is indeed correct about the MAF. Faulty MAF's have been known to cause some very odd firing conditions, and can be a prime source for a misfire. Checking the wiring, and testing the MAF per the FSM procedure is a good way to, at the very least, rule it out.
And yes, I did mean .044 on the spark plug gap. My apologies. .44 would be a helluva gap. Lol.
-Nathan
And yes, I did mean .044 on the spark plug gap. My apologies. .44 would be a helluva gap. Lol.
-Nathan
#13
Ok, so I finally got back to my car today to be able to look at it (I travel a lot for work). Cranked her up, and let idle for a few minutes. Still idling fairly rough, but after it got warm, I tried to rev it to replicate the flashing CEL. Today however, it was like the engine went into fail safe mode. Couldn't get it to rev past about 23-2400 RPM. Exhaust had a funny sulfur/gas type of smell (really hard to describe) that I noticed. So I went to checking basic electrical items. Unplugging each of the coils produced a noticable stutter in the engine. Then I went to look at the MAF. Inspected the harness, and it looks to be in good shape. Then I unplugged it. Very slight stutter in the engine, then back to the current "normal" rough idle. Repeating the unplug produced NO change in engine idle. So I pulled out the scanner to pull codes. Still got the 0300 & 0113, but now I have P0102 even after the harnes was plugged back into the MAF. So I guess that means I need a new MAF correct?
**UPDATE: Went back out to try to mess around with it more. Still idles rough, and feels like about half the engine is running. Now when I unhook the MAF, it kills the engine, also no problem revving almost to red line now. Still throws the 0330, 0113, &0102 codes. Still think it might be a bad MAF?
**UPDATE: Went back out to try to mess around with it more. Still idles rough, and feels like about half the engine is running. Now when I unhook the MAF, it kills the engine, also no problem revving almost to red line now. Still throws the 0330, 0113, &0102 codes. Still think it might be a bad MAF?
Last edited by '02 Style; 05-23-2012 at 02:44 PM.
#14
Well I found the problem!!! Seems that when I put everything back together, I failed to tighten a few of the clamps on the air intake system. Also, it seems that I had switched the wires going to the coils. Had #1 & #3 reversed! So I hit the MAF with a little MAF cleaner and switched the coil wires back and viola! No more misfire. I cleared the codes, and drove her around for about 10 miles, still no CEL. Plan on getting it out a little more tomorrow, so hopefully that issue is solved.
Thanks for everyones help and advice!
Thanks for everyones help and advice!
#16
I figured the coil thing out by just unplugging each of the coil packs and listening if it affected the way the engine ran. The front side was a pretty serious stutter (almost died). Unplugging #5 almost caused it to die, but #3 & #1 didn't produce any change. My first thought was great two bad coils, but then I noticed that there almost wasn't enough slack in the harness to re-plug #1. Thats how I figured out that they were crossed. GL in getting your car sorted out!
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