Misfire.... Please help.

[Gregory]

Hey guys. Sorry if this is long, but I felt the need to be very descriptive. I've been dealing with the same problem since I've owned the car (about two years). Under full throttle, at about 5.5-6.5k, the engine will lose power and it seems like I'm pushing it way too hard. It's not fuel cut. It still is accelerating, but seems to lose power greatly in the rpm range that I'd thought it would be strongest. If I get off of it or shift right as it's starting to do it, it pulls through the next gear fine up to about that range. If I continue to go through that hesitation range (up to about 6.5k, not even to redline), it throws the CEL and will diagnose as misfire in cylinder four. I bought whatever pep boys recommended for new plugs and wires, but it still did it. I switched those Bosch plugs out for the NGK BPR6ES, and it still does it. Checked gaps and still were where I left them at .28. I dropped gaps down to where I am now at .24, and it still does this. Do you think the wires I have are causing this? They still are very new. I forget what brand they are off the top of my head, but it's the stock replacement they recommend. I've searched this topic greatly many times, and refrained from starting a thread on it, but every time it seems that someone has this problem, the thread just drops off and ends like no one knows what to say. I'm running 14psi with an EVO III 16g. Thanks for any help.

 

[jking29]

Have you logged it to see if you are pulling timing from knock? Have you ran a compression test? Also, cheap plug wires are not a good idea on a turbo car as they have too much cylinder pressure and will misfire under boost. Get back to us with more info on any logs and compression numbers and we will try and help more.

 

[Gregory]

I'll run a compression test and I just bought a logger, but hasn't been shipped yet. Thank you buddy. I will most definetaly get back to you.

 

[Gregory]

Ok, I'm working out the deal for a used logger and safcII. I just got back from doing a compression test... From the timing belt over, they read 135, 130, 135, 135... Or as if you were looking under the hood, from left to right. 135,135,130,135. I think I have the right plugs. The wires though, I don't know about. What wires do you guys run? I'll update you with any more progress.

 

[SlickGSX]

I have seen a problem like that before, it turned out to be the coil pack, switch with a friends car and see what happens.

 

[Gregory]

Thanks man... I'll try to see if I can find someone who is willing to switch. Needs to be a GST or GSX? Right?

 

[nates6969]

hey man, I have the exact same problem myself. It used to only do it under serious boost like 22psi but now it does it at even 8psi. Im almost possitive its my coils, they just can't provide the energy needed to create a consistant spark.

Also you said you replaced the plugs with NGK6ES, these plugs are perfect for the boost your running, not sure what that one guys was talking about cheap plugs. Just make sure you gap them correctly to ~0.028".


I'm going to be swapping in some other coils sunday so I'll let you know how that turns out if you haven't got around to it yet. As for the coils, I believe the 2g coils are different then the 1gs so you will need coils from a 2g gst or gsx

 

[Gregory]

Thanks man, I really appreciate it. I searched the forums for this problem so much, and never found anything, so now atleast I don't feel so alone . Coils are something I should buy new, huh? Where are you getting yours from? Thanks again Please let me know how it turns out sunday.

 

[nates6969]

I actually have a spare set at home off my old talon which I believe are still good...if it fixes the problem I'm probably just going to go buy new. Weak spark is not something you want in our applications. Im going to test another power transisitor if that doesn't work as well...I doubt this is my problem but I have it to test so might as well.

 

[kenamond]

If your profile is up to date, your FP is stock and not rewired. At 14psi boost, you might be leaning out near the top end. I'm not saying to ignore the coil pack suggestions, but I think you need that logger. Some folks get away with 14psi on stock fuel, some don't. I run my FP B28 at 14-15psi, and I lean out pask 6k even with a rewired FP, and I see timing pulled past 5k rpm.

A logger is the easiest way to see if you're leaning out and/or knocking.

What octane gas do you use?

 

[drmcstroks]

I had the same problem as well.. turned out i needed the NGK BPR7'S. Other things to check though.... the TPS, coil pack, and make sure your not getting any oil by your spark plugs. You might have to replace your valve cover gasket. Also do a boost leak test. Hope this helps.

 

[adamsdarin]

I just fixed that exact problem with my car it was a rather lengthy process. I would encourage getting a multi meter and testing the resistance of your wires, plugs, and coil packs to determine if they are still functioning properly.

There is a set range for the coil pack but I do not remember what it is. As for the plugs and wires as long as they show aprox the same numbers then they are most likly still operational. After that if you are using NGK plat plugs REMOVE THEM and get coppers they are much better for our cars.

Last but not least DOUBLE CHECK your firing order from left to right on the coil pack its 4321 the cylinders its the same order. So make sure your firing order is 4123 and not 3214 which would allow the vehicle to still operate but at high lvls of boost it will cause serious misfires.

hope i helped

good luck

 

[Gregory]

Wow, thanks for all the input guys. Here's where I stand:

I do have the stock fp in the car not re-wired. I have a wally 255, but no fpr, so it's not on yet. The car also had the same problem at stock boost though, so that sorta points me somewhere else I suppose.

I'm not sure if the deal with the logger is going through because it's seeming a little scammy right now, but it might just be in my head. He is supposed to call me tonight, so we'll see what comes of that.

I've done a boost leak test recently, and everything is holding good.

I'm running 93 octane from Sunoco.

I'm running NGK bpr6's, not 7's, so maybe at that price, I should give them a try if that fixed your probelm.

No oil on spark plugs.

Checked firing order and everything is correct.

so, I guess that leaves me with trying different plugs and maybe a coil pack first. Hopefully it will be solved before I have to replace a head gasket. And is TPS throttle position sensor? I don't know how to check that, so I'll look it up or do a search. Thanks guys. You rock. Please let me know how the coil pack works out, and I'll keep you guys updated on everything. And what wires should I be running for those of you who think the stock replacements aren't sufficient? Thanks again.
-Greg

 

[VicBoost]

I had misfire problems and it was just the spark plugs, i got the ngk's and problem was fixed

 

[Gregory]

I had misfire problems and it was just the spark plugs, i got the ngk's and problem was fixed

Yea, I have those plugs. Problem persists.

 

[drmcstroks]

well the BPR7'S are cheap ($2-3 a plug) so try that before you spend a bunch of money on the coil pack. If your plug wires and coil pack are good, check the TPS, if the TPS is good... check the in-out play on your turbo. and if all of that is ok, then the most extreme case is that you fried part of your ECU. Let us know how it goes.

ps NEVER NEVER EVER go with platnum plugs they suck for our cars. cheap little ngk's are all we need

 

[nates6969]

Results:

Well I put in my other coils and transistor pack tonight and no change. I tested the coils I put in and the primaries are out of spec by about .3ohms. Does anybody think that will cause any issues? They boosted well in my other car so I don't think this pack is messed up. I went on to pull a log tonight and noticed my car was running super rich! I don't have a wideband but I had tuned the car for .92 o2s and now its 0.98!! I'm tuning it with an eprom emulator and I haven't changed any of the maps so its either a boost leak or my spark plugs just arent firing the complete mixture all the time. I'm just about to pull the spark plugs, I am running 8ESs gapped to 28, I might have fouled them already...I will get back to you with the results


Now this doesn't rule out your coil pack, you may want to see if you can pull one from the wreckers just for test, you can probably lie what car's its out of and get it for next to nothing, haha

 

[Gregory]

yea, I'll try the BPR7's. I'm looking into possibly buying the coil on plug setup from SBR. I'll try the plugs tomorrow even though I wouldn't think I'd need a colder plug yet. And the turbo shaft play is non-existant. Thanks. I'll let you know how the plugs work out tomorrow.

 

[Gregory]

Okay, It was hell to find 4 bpr7es's in a shop in my area. Everyone either didn't have any, or they had three of them..?? So anyways, I put them in and gapped them all really small from the get-go. .22 on everyone except cylinder 4 which I gapped to .20 because that's the cylinder that is always mis-fireing. It ran different (and a little better I thought in the high RPM range where it was normally dying). BUT, the CEL light still threw, so I know it doens't solve the problem. I suppose coils are next

 

[nates6969]

shitty man! its up to you about the coil on plug, if you plan going big with the car then it may just be an investment you'd want to make anyways. If not, try to get some used ones for test if you can. Im starting to think our prblems are a bit differnent as you car is throwing a code.

When you pull in my car it feels like its hitting a rev limiter and the power just diminishes. Im about to go just my plugs now and if that fails I'll do a boost leak test tomorrow when I have access to an air compressor.

Damn dsms! I just want to drive fast again! I had to let a ricer integra walk all over me the other day!!! hahaha

 

[Gregory]

"I had to let a ricer integra walk all over me the other day"

haha. well, that's certainly not good news.

 

[boostnbuds]

i had a similar problem. If i went full boost i would misfire all over the place and i found myself having to smoke integras at part throttle...I thought it was a tps sensor or cam sensor, because i had done a tune up only 8 months prior. everything tested good, did a coil pack swap for shits and giggles and still nothing....i then said to hell with it and bought a new set of wires and sure enough problem solved. I was using 8mm msd wires and they were only 8 months old but they couldnt handle the voltage, you may want to just try new wires....

 

[drmcstroks]

Oh yea, heres the big thing that happened with me. I had the misfire problem you guys were having for about 8 months until I finally got tired of the problem and took the car to AMS. It took them all of about 15 minutes to figure out that fu#*$(% autozone gave me the plugs for the 420a instead of the 4g63... as you can imagine I was beyond pi$$ed . My point here is that if you cant find the problem soon, try taking it to a shop that knows the car, you'll save yourself alot of time, money and agravation, trust me. Chances are that your problem is something REALLY stupid and simple to fix, but theres just to many things on a DSM that could cause a misfire like that.

 

[Gregory]

Well, you bring up a really good point. I'm really thinking coilpack now though. It's the one thing I havn't checked. I know the recommended plug gap is .28, but is there a disadvantage to running smaller than that? My guess is that the idea is to run as big as you can without misfire caused by plugs, right?

 

[kenamond]

Well, you bring up a really good point. I'm really thinking coilpack now though. It's the one thing I havn't checked. I know the recommended plug gap is .28, but is there a disadvantage to running smaller than that? My guess is that the idea is to run as big as you can without misfire caused by plugs, right?

I'd bet a dollar that there is a reason you don't run too small of a gap, but I can only speculate. The fact that your car doesn't run right when the correct plugs are used and gapped to spec indicates you have a problem (I know, "duh!"). I'd suggest setting the gap properly before you forget.

And why aren't you running BPR6ES instead of BPR7ES? You shouldn't need 7s for 14psi on a E3B16G.

My speculation on spark plug gap is that you need a certain length of sufficiently hot spark to properly ignite the fuel/air. You got my curiousity. Maybe I'll Google it.