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I just had my LTs, y-pipe and catback isntalled but my mechanic said that I have a misfire in cylinder 6 after the install but I didn't have it before hand, would this just require a tune to fix or is there some other reason for it?
Any information would be helpful. Thanks.
did you replace the plugs and or wires when you did the install. make sure the wires arent touching the header and melting. also make sure that they are properly plugged onto the spark plug and coil
cracked plug from install, i think i had the same plug broken on my swap too! lol, change the plug and enjoy!!
No I did not replace them but one cause i broke that plug by accident. Should I just replace them all? I just don't want to end up replacing them and it ends up being something else.
i think most change them all out when doin headers but you can probably get by with changin #6. Scan again and hope the misfire is gone
99% chance it is a plug/wire connection issue, if you had no problems before the headers.
for NGK TR55 plugs and MSD wires brand new for $75, whats 75 when you probably spend $1000.
Agreed with everyone else here. During LT installs, most shops change the plugs. Check that plug out.
99.99999999999% its the plug. I had the same problem when I did mine. The MSD wire's got to close to the heat sheilds and it started to melt. (Actually I was a dumbass for not keeping the stock metal boots from the stock wires). Install went fine and a few days later it started to missfire and the SES light came on. Did a scan and it came up as "Cylinder 6 missfire". Pulled the plugs and the #6 plug was melted beyond recognition.
Alright thanks for the info I'll check that plug out. Also I'll post some pics up at soon and maybe a video.
Had to top my 99% prediction, eh?Quote:
Originally Posted by rajiv1998
Might try simply re-seating the plug wire. Apply pressure until you hear one "click" at the plug and two "clicks" at the coil.
I checked my plug and wire and they both look fine. Would it being gapped wrong cause this issue? Just to check do you guys know what the correct gap is?
start car in a dark place and look for spark jumping.
Mark
I just HAD to :lol:Quote:
Originally Posted by Too Fast
Another question, since I have a miss in cylinder 6, would my rough idle be related to that? I am pretty sure I already know the answer just wanting some comformation on it though.
any results yet? altho the plug may look allright, change it out and see what happens, if problem persists then swap plug wires with another cyl and see if the problem follows the wireQuote:
Originally Posted by 98TransAmWs-6
Yes, it certainly can and most likley will. When my plug wire burned, the idle was really bad. It kept on surging and popping. The car would never idle properly and you could clearly hear it missfire in the exhaust. It never rolled outta 1'st without popping and jurking, kind of like if you release the clutch to quickley.Quote:
Originally Posted by 98TransAmWs-6
mine was a bit different, it idled fine and ran fine till i got on it, then it backfired like a machine gun. Every situation is different tho. Op, your car might need a tune after the header install also, could be runnin a little rich now. get the misfire figured out first then go from there.Quote:
Originally Posted by rajiv1998
Mine never ran good at WOT either. I doubt the missfire is due to the tune. Headers shouldnt change the A/F ratio, timing, spark etc... too much. People go months without tuning after LT install. This sounds like an internal problem. Pull out all your wires/plugs and make sure they are ok. Recheck all your ignition connections. Try to run a scan if you can. Go to 2 or 3 places and get it looked at (most are free) to make sure they are all pointing to the same thing.Quote:
Originally Posted by razer900
Well I'd like to try to figure it out first without having it scanned because where I live its $85 per scan. Even though I could just buy a scan tool myself for just a little more.Quote:
Originally Posted by rajiv1998
Quote:
Originally Posted by 98TransAmWs-6
Yes, for sure.
And a +100 on this, this is how I isolate which cylinder has the misfire, and to see if it is spark/spark plug/fuel injector related or other. I swap the easiest thing from the suspect cylinder to an easy to access cylinder, and see if the misfire follows, or stays at the same cylinder. Process of elimination.Quote:
Originally Posted by razer900
Do what we mentioned. Pull the wires and see if they are melted/damaged. And swap the plugs to differant places and see if it follows. If it does, you know its not a cylinder thats acting up, its just bad plugs.Quote:
Originally Posted by 98TransAmWs-6
I never drove my car much after this happened. Didnt want to screw things up more. But if you must andits your dd, try and fix it fast. It shouldnt take you more than 1 hour max.
Swap the #6 coil with another and see if the misfire follows.
Pickup a used predator for around 150 and that will tell ya evrything you need to know as far as codes and datalogging. I used mine for a tuner also till I got a frost tune but I still use it to datalog with, works great and clears codes too.... Just a thought.Quote:
Originally Posted by 98TransAmWs-6
Autotap is more useful than a Predator.
Ok so I replaced the spark plug, switched wires around, and switched coils around, and so far I still get the code for a cylinder misfire. Any idea what might be wrong now? Also just to make sure I am doing the correct cylinder, if I am standing infront of the car cylinder 6 is the 3rd from the front on the passenger side right? I did some research and I found a site that said this can be caused by faulty o2 sensors, is that true cause my rear ones do need to be replaced. Also could this be caused by one of my fuel injectors? I would find that odd since all of these were fine before the install. Oh and also I scanned my car today and got another code p0174 too lean (bank 2) what exactly does that mean and how can it be fixed?
It shouldn't be the 02 sensor, but u never know. The other code isn't a big deal, a good tune should fix your A/F ratio. Just double check to see if none of the sensors or anything are broken. I don't think it's your injectors. People with cams are still on stock injectors, so I doubt it's due to a lack of fuel. Also what are the chances your injectors went bad right after a header swap? (if that's the issue).
I didn't think it was my injectors but I have no clue what the problem could be now.
But is the misfire code the same cylinder, or did it move to the cylinder you put the suspect plug/wire/coil to?Quote:
Originally Posted by 98TransAmWs-6
And yes, , cylinders # 2,4,6,8 are on the passenger side.
Have you checked your fuel pressure? (Should be 58-62, key on engine off with the 2 second prime.)
Also, have you cleaned your MAF sensor?
Usually fuel pressure/MAF problems would set codes for lean both banks, not just bank 2 tho.
The problem stayed in cylinder 6. 2 codes pop up on the scanner for being too lean but it's the same code for being lean both in bank 2.Quote:
Originally Posted by Too Fast
Could the code p0174 be caused by a faulty o2 sensor? Otherwise I kinda Its weird how that code popped up after the header install since the headers shouldn't have changed the air to fuel ratio too much. No I haven't checked the fuel pressure. I am going to check my MAF and clean it.
Any chance you over-revved the engine and bent a pushrod? That would cause a miss. Not a lean code, tho. I've never changed my O2 sensors, but some here have reported that they got dirty/skewed after a header install, due to an inside coating in the headers. That could cause the O2 sensors to report wrong, with a false lean code.
Shouldnt you be able to hear a ticking sound if you bend a pushrod?
Yes usually.
The only sound I hear besides the miss is a rattling sound but that is just from the rough idle and it's my exhaust. I am going to try and replace my o2 sensors and fuel filtr tonight and see if that fixes it. If not I am at a total loss as to what's causing the codes.
Bone stock MAF?
Yes except the screen was removed before I bought it. But it was fine before the the install so why would that cause problems now?
Quote:
Originally Posted by 98TransAmWs-6
Descreening the MAF will skew its output... not tremendously, but enough to alter fueling.
Yes but why would it do it all of a suudden when its been that way for years? It may explain the lean but not the misfire or atleast I don't see how it would.Quote:
Originally Posted by pajeff02
If your MAF was de-screened prior to the header install and wasnt causing a problem, then I doubt thats the problem. Again, the A/F ratio shouldnt be off that much to throw is off. Change the fuel filter first. No point in changing parts if you dont know for sure. You could screw it up and be at a loss. Why dont you just do a compression test and see if there is actually anything wrong with the 6th cylinder. Each should be within 10% of each other. Doesnt really make sense to change the 02 sensors if you are not 100% sure thats the problem.
This may sound like a stupid question but how do I do a compression test or is that something a shop has to do? Also, if there is nothing wrong with cylinder 6 then why would I have the rough idle and can hear the cylinder miss?
I ran a Granitelli maf way back in the day for about 5 months and it worked fine. Put Mac headers on the car and started getting misfires. I put the stock maf back on and sold the Gmaf, no more problems. Try running a stock maf.
Know where I can get a screen for mine then? Cause I really don't want to buy the whole unit if I don't have to. But I am going to try replacing the fuel filter first before I do anything else.Quote:
Originally Posted by INMY01TA
no...Quote:
Originally Posted by 98TransAmWs-6
If you are getting a lean on both banks I almost guarantee that is a vacuum leak.
Its two codes for bank 2 so no not in both banks. But if it was a vacuum leak how would I fix that?Quote:
Originally Posted by 35th-ANV-SS
Well, I didn't read the entire thread :lol: I should probably do so real quick then report back.
You said you were going to clean your MAF....did you? P0174 code is most like a MAF or vacuum leak.
No not yet haven't had a chance to get the cleaner for it since I don't have any electrical cleaner
Try that first. Could very well be a dirty MAF. Get the MAF CR cleaner from Autozone, Pepboys, etc.Quote:
Originally Posted by 98TransAmWs-6
I finally just decided to take it to a shop and they found a vacuum leak in the tube from my egr valve to my intake manifold. I will be finding out what caused the misfire tomorrow.
Try this: pull the spark plug wire and start it up- does it run any different? You need to trace the problem back to the root. By pulling the plug wire you'll see if the cylinder is even getting spark, if there's no change in the idle with or without the wire, then you don't have spark. Check the plug (electrical connector) going into the coil- most will pull the coil packs on the passenger side when they install headers.
I had the exact same problem when i did my headers. after a while motor would die, it had a crapy idle. I was told to look at the spark plug so i did and i found out i forgot to plug the #6 wire back in. tryed it and still misfired, i took a look at the coil connection and wasnt right, took it off and the thing inside was bent. I straightin it out put it back on and worked like a dream. might be your problem maybe not. just thought i would share my experience with the misfire.
The shop I went to said I have a clogged fuel injector and that's causing the misfire. Also, what even causes a clogged fuel injector? I would like to prevent this in the future.
Poor grade of fuel can do it, over a long time. I've always used Shell V-Power, never had a fuel related issue. Also, our cars don't have a return line for the fuel injectors, any "crap" that gets in there tends to go to the end of the line, like the even numbered fuel injectors. You might want to flush all the injectors, or replace them all, or just replace the #6 and have the others cleaned, off the car. Some ideas for you, obviously some cost more than others.
It is strange that it suddenly happened when you had the headers done but it would explain the lean code.
But I thought headers make a car run rich and not leanQuote:
Originally Posted by bberretta
Running on poor grade fuel isn't possible I always use shell v power. I suppose at some point I'll pull the other injectors and clean them.Quote:
Originally Posted by Too Fast
Headers do make it run rich, not lean.Quote:
Originally Posted by silverWS.6
But he said that an injector was clogged, therefore he would be running lean. No fuel coming out = lean. No spark would equal rich.
Also I had a vacuum leak so that would make it lean too.Quote:
Originally Posted by bberretta
Very true. I'd still test the coil- it's strange the FI would spontaneously be clogged when the headers were done.Quote:
Originally Posted by 98TransAmWs-6
Well I already switched it with a coil I know is good and it still misfires on the same cylinder and same with the wire and replaced the plug. Hopefully everything will be fixed on tuesday. The shop couldn't give me prices for the fix until then.Quote:
Originally Posted by bberretta
I find it strange that the injector got clogged right after a header swap. Might as well replace them all when you have them out. Your probably looking at $150-200 in labor. You have to pull the intake out don't you? Unless there is a way of doing it while it's on the car, but I never heard of it.
It was most likely a coincidence. Headers should have nothing at all to do with injector problems.Quote:
Originally Posted by bberretta
Well I'll see on tuesday if that is the fix. I thought it was weird that it came up after the install.Quote:
Originally Posted by Too Fast
Does this cost to fix my problem sound a little high, $800 to fix a fuel injector and the vacuum line? Thats the quote the auto shop I brought my car to estimated.
Either a coincidence or a shop guy just saying it is the injector when something else it going on, which would be a lot cheaper to fix.......like a bad spark plug!Quote:
Originally Posted by Too Fast
It's a big job, but I'd be 100% positive before I go about paying $800 for something you may not need.
Let me get this straight- you've swapped the coil (not just put the coil wire on another coil which would fire it out of time), tested the coil wire, and tested the plug and you have spark at all three place, right? Sorry if I sound like I'm harping on this, but I really don't want you spending $800 and they come back and say that it'll be another $500 because there are ignition problems as well.
$800!!! What a rip off. Just swap out the intake yourself and save $$. Go to ls1howto and read the write up. Once the intake comes off, just disconect the fuel rails and out come the injectors. Dude $800 is a full days worth of labor. You can have a cam installed for less than $800. If you did the header/exhaust install by yourself, you shouldnt have much of a problem with the injectors.
I would narrow it down to EXACTLY whats causing the problem before throwing away hundreds, maybe even thousands of dollars. Find someone with auto-tap or a good scanner and have them run a full scan on your car. Do a compression/leak down test and see if the cylinder is actually not working. All 8 cylinders should read within 10% of each other. Again I dont see how it would be your injectors considering they were fine before the install. Did you get your EGR/AIR block off plates and everything if you bought headers without EGR/AIR provissions???
Yes I swapped the coil I haven't had a test to see if I am getting spark but I switched the actual coil, wires, and replaced the spark plug. I also tested compression and it is exactly as it should be. BTW hell no I am not paying them to do that I am going to replace the vacuum line and the fuel injector myself. I have access to a military base that has lifts and they will help you with work if not do it and not charge much since they are funded by the government. Also is it bad to run the engine when it has a misfire and the engine light blinks? Cause the base is a little bit away not really far but its like 20 miles away or so.Quote:
Originally Posted by bberretta
I didn't do the install this time myself but I have done it myself before, I bought ones and they didn't fit even though they were suppose to so I had to buy another system. Yea $800 is close to what it cost to have my whole system installed. No I kept all my EGR/AIR stuff to keep it street legal and it is all hooked up correctly. This may sound like a stupid question but I don't really know much about the AIR/EGR but is it possible that the leak in the vacuum line caused the injector to get clogged? Oh btw I was running open headers before I got everything installed I don't know if that makes a difference in getting a clogged fuel injector. Don't see how it would but you never know.Quote:
$800!!! What a rip off. Just swap out the intake yourself and save $$. Go to ls1howto and read the write up. Once the intake comes off, just disconect the fuel rails and out come the injectors. Dude $800 is a full days worth of labor. You can have a cam installed for less than $800. If you did the header/exhaust install by yourself, you shouldnt have much of a problem with the injectors.
I would narrow it down to EXACTLY whats causing the problem before throwing away hundreds, maybe even thousands of dollars. Find someone with auto-tap or a good scanner and have them run a full scan on your car. Do a compression/leak down test and see if the cylinder is actually not working. All 8 cylinders should read within 10% of each other. Again I dont see how it would be your injectors considering they were fine before the install. Did you get your EGR/AIR block off plates and everything if you bought headers without EGR/AIR provissions???
And no, I've never run into a vacuum leak causing a clogged injector. And running open headers shouldn't cause it either. I think it's just some bad timing on the injector going bad.Quote:
Originally Posted by 98TransAmWs-6
I would try a professional FI cleaning (not just the pour in your tank stuff, but one where they hook up the pressurized tank to your fuel rail) before spending the $800 on one injector. You can replace all 8 injectors for a little less than that if you did the labor yourself! ;)
I am going to do it all myself since I am not going to pay that money when I can get an injector for about $100-130 or so and the vacuum line for $170 hopefully replacing both will fix the issue.Quote:
Originally Posted by bberretta
Exactly. I think you gave us all a bit of sticker shock with that quote!Quote:
Originally Posted by 98TransAmWs-6
Well I just wanted to make sure I was right in thinking it's a crazy price.Quote:
Originally Posted by bberretta
Being an ASE Master, L1 certified tech has saved me untold $10,000s over the years, I'm positve! If you can do some work yourself, you can save money.
What we don't like is when people try to do something themself, then expect a bailout from us, when it would have been way easier for us do the job had someone not broken something/screwed it up then come to us and say can you fix it.
If I'm current on your issue, I understand your still getting a code of misfire on #6 and a shop says you have a clogged injector/bad. Why not flip flop the #6 injector with another and see if the code changes to the other piston you move it to prior to purchasing another injector?
I will probably try that once I pick up my car from the shop.Quote:
Originally Posted by MeGoFast
I got my car back today and when I started it at the shop the engine light was on. I figured they deleted the codes. There was no rough idle like before and no cylinder miss that I could hear. Almost all the way home then the engine light came back on and I started to hear the miss but the rough idle didn't come back. Once I got home I scanned the car and only the p0306 code came up. My question is do I still have a vacuum leak and will the codes come back or are they gone for good?
Start by clearing the code yourself, fix the vacumn leak, and then running it again to trip the code- that way you're getting a clean set of codes. I don't think a vacumn leak would focus on a specific cylinder- that's got to be either injector, plug, plug wire or coil- I think.
The short answer is yes, most likely you still have a vacuum leak. Lean codes take more time to set, usually, than a misfire code. It is possible that you have a mis-diagnosed injector, and the vacuum leak is mostly at/near #6 injector. I would swap #6 injector with #2 and see if the misfire goes to that #2 cylinder. Also, it would be a good idea to fix the misfire code before looking for a possible lean code, it could be a bogus code since #6 is not firing.Quote:
Originally Posted by 98TransAmWs-6