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.

 

[nates6969]

hey Gregory, do you have a logger? I'd be sweet if you could pull a log paying close attention to o2s to see if you have extremely high o2s as well. mind you those large values I was having could be caused by a boost leak or just poorly ignited mixtures, who knows...as for the 7es you are running, it is over kill for 14psi but it should be fine...I ran my turboed N/T talon at 8psi (9:1 pistons) with 8es's and it ran like a champ.

I also pulled my plugs tonight to see their shape and they are perfect. I didnt have my gap tool on me so Im going to do that tomorrow and also take the advice of the one guy and swap on some plug wires from a buddy...the ones i had put on are at least 2.5 years old now.

 

[Gregory]

The only reason why I'm running brp7es's is because the problem went on with the bpr6es's, and someone said they had a similar problem which was solved by this. I just put them in yesterday. It was the cheapest thing to check. I'll put the gap back to .028. Do you think I should run the 6's or 7's? They are both about new. And I don't have a logger. I was going to buy one from somone on here, but I think he was scamming me. I obviosuly can't drop any names at this point because I'm only speculating.

 

[nates6969]

Ya man I'd definitely get yourself a logger. At 14psi the 6 or the 7s should both work fine. Without a logger though it's hard to tell whats going on in the motor. I'd try to find another guy selling one. You're obd2 right? I made my obd1 logger cable and just went out and bought a palm for 30 bucks new, don't know if this would work for your car though

 

[Gregory]

I have no idea . I suppose I could give it a look. I'm trying ro see if I can find a used palm logger since there are always people upgrading to dsmlink. And I gapped the plugs back to .028, and no difference, but atleast they are back where they should be. I guess this thread is on hold untill I can find a logger. Thanks everyone. I'll let you know how it all works out.

 

[jshuman]

I had a similar problem that I just got fixed. I had a cel for a missfire in cylinder one. I lost serious power at just over 5k. I had a few boost leaks that I am sure were contiributing to the problem. I tried plugs, wires, and tested the coil packs. I ran compression and boost leak tests, but nothing fixed the missfire. I posted my problem and a few people told me to check injectors and connectors. The connectors were all tight, so I tried switching injectors next. When I pulled the fuel rail, I found the seals for injector one were in very bad shape. I replaced all injector seals and the missfire was gone. Hope that helps! Good luck.

 

[nates6969]

Well great news for me anyways! I realized that since my o2s were so high, this could not be an ignition problem...o2 sensors measure oxygen and if the mixture is not being ignited there would be an overwelming about of air coming out of the cylinder, much more than the raw fuel which would therefore give you a lean mix. mine were pig rich...did another boost leak test today but made up a better tester and found a HUGE leak on my LICP where it meets the front mount. pipe had blow back about an inch but was hard to see where the pipe is mounted. Readjusted the coupler and good bye misfire! it must have blown off when I tuned up to 22psi! haha

 

[kenamond]

I have no idea . I suppose I could give it a look. I'm trying ro see if I can find a used palm logger since there are always people upgrading to dsmlink. And I gapped the plugs back to .028, and no difference, but atleast they are back where they should be. I guess this thread is on hold untill I can find a logger. Thanks everyone. I'll let you know how it all works out.

Maybe I missed it if you said you did, but have you done a boost leak test?

 

[drmcstroks]

ya he said he did and it held strong. well let us know when you get your logger.

 

[Gregory]

Okay... I decided to go with a used coil-on-plug setup. Please don't ask why coil'on'plug. So anyways though, it is not throwing the cel anymore at all, but can the ecu know a misfire once you re-wire for coil-on-plug? Or does this ruin a loop that it runs to detect misfires? Is seems a little stronger, but not what I was expecting I guess since the problem was occuring to where my peak power should be. Please let me know what you guys think. Thanks!

 

[Gregory]

Oh, and the logger is in the mail. I payed a guy over paypal for a used one a few days ago. No tracking number though... hmmm

 

[Gregory]

Does anyone know if the coil-on-plug setup would keep the computer from throwing a check engine light?

 

[drmcstroks]

i dont think it should

 

[Gregory]

Okay. I've slowly performed almost everything i could think of to my car to fix this problem. I just changed the fuel filter and the other day I cleaned out the intercooler untill it looked new. Now, the problem still persists. I have a logger and have posted logs. I personally don't know much about logger/tuning, so I only know that I'm told something is wrong. It's always a misfire in cylinder 1. Someone told me to just put in the upgraded fuel pump. Any more ideas? Thanks to any replies!

 

[drmcstroks]

if you cant figure out the problem, i'd say take it to a mechanic so they can check out the whole ignition/ fuel system... 99% of the time its something stupid and easy to fix.

 

[Gregory]

I'll consider doing that, thanks.

 

[drmcstroks]

yup... i'd say just make sure you checked EVERYTHING first... boost leak test, correct plugs/wires, coil pack, etc...

o yeah if you are running the 16g, its probably definatly your fuel pump, set the boost to 12psi MAX, anything over 12psi the fuel pump and injectors cant supply enough fuel for the 16g to function properly..

 

[Gregory]

I've been running like 11psi and it still does this. I don't know what else to check besides injectors and fuel pump. btw, I have COP now, and it doesn't help. Thanks for the reply.

 

[drmcstroks]

ok, Ohm the coil pack, do a boost leak test, pull out your #1 plug and make sure theres no oil covering it, check the seals around your fuel injectors, and do a compression test. If you do all that and everthing is fine, i'd say take it to a local shop it'd be your best bet.

o yea... make sure you have the plug wires connected properly haha. you dont want to pay a mechanic $70 to tell you that

 

[Gregory]

I've done everything there except check the injecot seals. That's an area I've never pried into. That's easy to check?

 

[Spyder4g64]

I take it your mods list is up to date, and is correct?

 

[drmcstroks]

just take the injectors out and visualy look at them, make sure the seals arent cracked/ dryrotted, etc..

 

[Gregory]

Thanks, I'll do that. And yes, my mods list is up to date and correct. Thanks!

 

[Gregory]

Okay, so here is the update. I took out all of the injectors and to my surprise, the injector seal in the misfiring cylinder (#1) looked the best. The injector itself looked and proved to be fine. I replaced the o-rings in all of them, and I also switched the number 1 and 4 injector to see if it was an injector malfunction. I did a pull, misfire in cylinder 1 still. When the fuel rail was off, I also went ahead and put on the aeromotive fpr and set it to 43.5psi with the vacuum hose off. Needless to say, that didn't change anything. So, I have a Wally 255 in the box still, but is it possible to be fuel since it is always cyl #1. I figured it made sense since it was the farthest from the fuel feed line on the fuel rail. Does that make sense? Could it be something bigger like a valve not sealing or something wrong with my engine? I'm getting more nervous as I'm running out of things to check. Any ideas? Throw in the fuel pump, huh?

 

[loveTOspeed]

I used to have a misfiring problem along with a sputter. I found out it was my Barometric Pressure sensor, Might want to check that out too.

 

[drmcstroks]

also remove and check the TPS sensor. if you dont want to take the throttle body off.. you'll need a footlong extension with i believe a 8mm socket on a rachet wrench. very easy to check, i forgot the numbers exactly, but they're in the hayens book.