Cyl 1 missfire need input/ help!

Chris02mp5

Member
:
2002 protege5
Recently I have been experienccing a missfire at idle with cyl 1. The car runs fine under load and will have a very slight intermitent miss at idle but not enough to stall the car. I have replaced the plugs, wires, coils, and injectors. I have recently done the 1.8L coil conversion and am wondering if it could be caused by the signal wire to the coil. Only question is would cyl 4 also be experiensing a missfier if this were the case? The car is running high compression (~11.5:1) with heavy cams, double valve springs, adj. cam gears ect... I tired pulling the cyl1 wire and it it has to be very close to a ground source before it will arc to ground where as cly2 will arc from 1-2 inches awy. This is consistant when I switch the coils as well. I tried just a regular compression test and it was fine, but I have yet to try a leak down test. Any ideas? I am starting to lean towards the possibity of a burnt intake valve but being so new and having not seen rpms over 4500 I dont know if this could be the problem. any ideas? I may pull the intake tonight check the intake valves, I had the headers off yesterday and the exhaust valves looked fine, other then the extra carbon build up from running rich.
 
Did you get the misfire before or after the conversion?

How is your intake hose? I only ask because I just got a misfire on my Cyl 4, and I did a coil/wire swap, but it came back. Turns out my intake hose was cracked, letting in air after the MAF.
 
Intake is all good, I'm still going to check leackage with my torches tomorrow. Thing thats. Infusing me is that the spark from cyl 1 seems weaker then the rest yet cyl 4 has no miss (but it does have a much shorter length of wire to travel) I have some other plugs I may try as well... To be honest idk know when this started... Prob. Since I installed the motor, at first I had a problem with my cams and valve springs being too heavy for my timing blew tensioner spring. They were stretching the s*** out of it at idle (as the car loads and unloads) this was throwing my timing out and making the car run like s***. After I came up with a solution to make the tensioner manualy adjustable it ran 100x better. However when I fixed the timing belt I also did the 1.8 conversion so I'm not 100% sure when it actually started (lucky me) the car is leaner then it should be because of my inability to tune closed loop. I do have my 02 pulled out so the car would run a little richer closed loop but I can't see that causing a single cyl. misfire.... I'm really at a loss I might have to start at square one and do every test.
 
I dunno man. Thats a lot of stuff to change at once, and sounds like you have a lot of customization there that might hinder any "easy" trouble shooting. Do you have another wire you can try for cylinder 1? I know its new, but that doesnt mean it isnt bad.
 
New wire's on it, also new plugs, and coils. I even tried adding an additional ground strap to the that side of the motor incase it was a grounding problem. I did a compression test again and i'm 205 accross the board. I know they can be missleading but there'd have to be some difference even if it was only a couple psi. instead im right on 205 on every cyl. I tried the spark test agian also and for cyl one to arc to ground you basicly have to touch the end of the boot to a grounding point. Cyl 4 I can pull the wire and it'll literaly arc to any ground source for 2 inches away :s... tired different wires on both cyl 1 and 4 and still the same results....
 
Then that would lead me to believe that the ignition coil is faulty. You should be seeing a similar spark on both outputs. Either the wire isn't making good contact at the high-voltage connector or the ignition coil is somehow damaged internally. Check for corrosion on the ignition coil's connector and make sure that the wire has a relatively snug fit. If that doesn't help, hopefully you can exchange the part from wherever you bought it...
 
when you did the 1.8 coil conversion, did you also replace the cam cover to the 1.8 version? if not, its entirely possible that the plug wires are not getting a good seat on the plugs. the 2.0 cam cover has ridges around the plug holes which prevent the 1.8 wires from reaching all the way down to the plugs.
 
Ya I replace the valve cover with the 1.8L cover and the wires snap on good. The coils are new and have no corrosion... I'm thinking it could be a bad coil, and I'm prob. Going to exchange them (since I can with no problem) I'm also going to re-wiree the coils just to be sure that's not the problem. if anyone else has any ideas let me know
 
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Update... So I rewired the coils and even warranted them an got new ones... Still no luck!!! the only code that comes up is cyl 1 misfire. An it only shuters at low rpm ( aroun and below 1000 ) I checked the valves when I had the intake plenum off and everything looks good and the ports and valves are as clean as the day I put the motor in. The exhaust valves also looked good, with cyl1 having a little bit more carbon then the others because of the incomplete combustion. This is leading me to believe that it it is a timming issue..... Because my cams have the integral stage 3 specs I'm wondering if the ignition timming is just too retarded to fire properly with that long of duration and I creased overlap. Only question I have is, can this cause a single cyl misfire?
 
It still seems a little weak and will only arc when the plug is about a half an inch away, I going to try hooking up a spark plug to it and see what the spark looks like from the plug. As for the gears they are modified stock gears, so i know its not the pickup.... Im going to try running cyl 1 and 4 on seperate coils using an extra one that I have lying around. If that solves the problem I just buy four aftermarket individual coils and call it a day. If it doesnt work a budy of mine told me to take the mettal cover off of my cam sensor so i can see the meginent inside and then check its alignment with the pickup on the cam when cyl 1 is at TDC. He's thinking that it could be off. It could also just be that maybe because of the .040 head shave and the size of the cams the motor just doesnt like slower engine speeds. knowing that the exhaust cam was also repined also means that there is going to be at least a couple deg. of error with that. It could just be that everything combined is just enough to through my ignition timming out, but only to the point that cyl one is noticing it. Ether way I hav a couple new things I can try.
 
you are running all those mods on a stock ECU? "THAT" could be your problem, and i would worry about the life of the engine. 11.5:1 with aggressive cams are too much for the stock ecu to handle.
 
yes stock ecu but im running an emanage piggyback for open loop tuning and a innovate LC-1 wideband for closed loop a/f control. I'd understand if i was running nothing that the car would run like s*** but this is a problem that is happening with adjusted a/fs and only on one cyl. Because the exhaust cam was a repined cam and because the head is shaved .040-.045 Im thinking that the most plausible cause is my timing.
 
So an update... I turned the idle up to about 800-900 and noticed about a 80% difference. I also moved my cam position sensor closer to the pickup ~.020 I think the cam gears are a little further away because the specs werent exact when they were made. It was still within the acceptable range but I mover it closser anyway. I just baught a set Of the long reach ze plugs in regular copper and am going to give them a shot aswell.
 
Replaced them already... I could be throwing the knock sensor for a loop as well because of how heavy the cams are, does anyone know if you can bypass the knock sensor?
 
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so the cars been running good but is still pulling the code. I pulled the plugs the other day and cyl one still has a slight darker color. the only thing I have left to check is my enjector wiring and firing system. Everything on the ignition side is good. I even added a grounding kit to make sure the head had a good ground. One other possibility I came up with is that the cams I had made have a lobe that is off center and that's causing less air to be able to enter cyl one. Only prob. With that theory is that it should cause the compression to be lower in that cyl. Any more thoughts pass them on
 
So i've put aprox. 17,000km on the new motor, and still pulling the cylinder one missfire code. Ignition is out of the question and so is the injector and injector wiring. Cyl 1 is running richer then the other three but the miss fire is so subtle that after reseting the computer the missfire code will not come back till the car is shut off and restared. Once it is restarted the car has to idle for a bit before it throughs the code. Doesnt matter how long i drive around for after reseting the computer the code only comes back after the second start. Since the timing is good (both cam and ignition) the sensors are all good, ignition is good, fuel delivery is good, and the injector and wiring is all good im stuck thinking that the ECU might be the problem. Another thing to note is that when it throughs the code the CEL just turns on, maybe once every two months it'll actualy flash the CEL to show that a missfire had just occured, other then that it is only giving me the solid CEL to tell me that a miss had ocurred at some point. Just trying to bring back this thread to see if anyone else has some input.
 
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