coilpack, injector, or ignitor...?

[evolution23]

So my car has been misfiring lately. It will run great then out of no where a cylinder just shuts down. the engine shakes badly and struggles to rev up and get the car going. I thought it was the wiring harness so i replaced it, still have an issue. swapped around all the plugs and coilpacks, replaced 2 coilpacks (each was thought to be the problem) but its still misfiring. Then i started looking at injectors, i put injection cleaner in and the next day, the car ran great, every cylinder was running, worked for about 3 days then today i put just straight 94 octane gas in with no injection cleaner, got home, let the car sit for about an hour, maybe 2, went outside and started it to go to town and all of a sudden it was misfiring right away. it went away after a couple minutes of driving, picked up some injection cleaner, put it in, and the misfire came back once again, drove the car for about an hour with it missing, really bad back fires when letting off the gas, let the car sit for about 20 minutes while i researched online wtf i can do about this to try and narrow it down, grabbed a metal pole to listen to each injector, started the car (had only sat for maybe 20 minutes) and all of a sudden its running again without a misfire.. anyways i went ahead and listened to each injector, i can hear them all clicking.

2 months ago i replaced the fuel filter, cleaned the MAF and resoldered it, cleaned the AAC. I know i have a TPS issue because every once in a while the slightest touch of the pedal will make the difference from almost bogging down to smoothly accelerating, enough to jerk your head back and with just the slightest touch of the pedal. new coilpack wiring harness, swapped 2 coilpacks, new plugs 2 months ago, new battery terminals, grounded coilpack harness and ignitor harness directly to the battery.

i have absolutely no ******* idea what this is anymore and no one seems to be able to help at all. no shops willing to even take 3 seconds to look at the car cause its an import and that deams it impossible to work on i guess. Anyways, i would just go ahead and swap coilpacks, ignitor, another new harness, new injectors and a new injector harness BUT i dont have the money to do that unless someones willing to part ways with all of those for about $100.

Is there ANY way i can check a coilpack to see if its ****** or not? is there anything that the spark plugs might be able to tell me? is there any way to tell if an injectors ******? how can i check my ignitor? could this be a ground issue? i found a loose ground but no one cares enough to help tell me where the **** it goes. i just need some helpful opinions on this, anything i can do to check coilpacks, ignitor, injectors, etc.. i am 100% out of ideas and almost out of money all because of this stupid issue. im sure its either a coilpack, injector, or ignitor. I dont have the money to replace all 3 though so i need a way to test them.

Video of how the engine sounds at idle and revving, also how the car starts. It usually only struggles the first time i start it in the day but sometime struggles a tiny bit when starting like in the video. This is how the car sounds when its running good.

[evolution23]

checked the ECU, im getting fault code 55 which if i am correct means no codes. So if my ECU is telling me nothing wrong, would that mean its not electrical, meaning not a coilpack or ignitor or wiring harness? I am thinking its an injector sticking open, thats how far i am though, any help?

[beacher1B0]

You should of by now downloaded the R32 engine manual. It has lots of helpfull info, such as how to test your coilpacks and diagnosing problems.
Testing coilpacks - disconnect coilpack, facing the coilpacks connector(looking at the pins), test for resistance between the left and center pins, should be 0.6-0.9 Ohms. Remove coilpack and check condition of boots and spring inside boots. A cracked boot may leak spark(also can check for this while car is idling with everything connected and coilpack cover off in the DARK, watch for spark leaking from boots). A broken or missing spring will create no spark or weak spark.
Also, to isolate a missfiring coilpack, when engine starts to missfire, disconnect a coilpack, engine should stumble and try to maintain a idle, if disconnecting the coilpack makes no difference, then that is the missfiring coilpack. Go one coilpack after another to find bad coilpack.

As for the ignitor box, its pretty involved to check the operation of it. But it is covered in the manual.

What ground was loose? Did it make a difference when you tightened back down?
What spark plugs are you running? Search the internet for a Spark plug diagnosis chart to see problems?

Please keep in mind that it is Summer, most of us are out cruising or fixing our cars. Or like me, helping other people which in turn takes time away from working on my own car. Its not that no one wants to help, the helpfull are busy.

[Skym]

Failed coilpack would make engine miss throughout when reving engine.

If there's a airleak behind MAF (loose intake hose clamp on MAF), it can make engine stutter (similar to failed coilpack). If rev engine enough it usually goes away. Since you have cleaned the MAF, that's where I would look.

Also clean MAF with CRC MAF cleaner.

Leaking injector, leaking intake manifold gasket are other common problems that make engine miss.

[evolution23]

i will have to check what the plugs are, they were the recommend NGK plugs, gapped at .8, running 12psi. swapping in the old ones tomorrow to try.
I am going to resolder the MAF tomorrow, clean it again (i am using MAF cleaner)
today while the car was running like crap i took a long socket extension and put it on each injector, they were all ticking.
ill go through the hoses and lines i can find. Revving the engine sometimes makes it clear up, but only about 50% of the time.
This is the ground wire i found thats just hanging there...



also i can hear a tick coming from around the injectors.
i dont hear any air leaks, dont see any, still getting 12psi boost, dont see any fluids coming out from anywhere..
im sure this is a simple thing that i am way overlooking....Anymore suggestions on what i can do will greatly help, ill download the manual if i can find it tonight.

[Skym]

Just noticed the BOV recirculation pipe is blocked off. If running a atmosphere BOV and is not tight enough, it can make engine run rich when accelerating, back fire when deaccelerating, etc. My guess is it is probably as simple as adjusting BOV or fitting a stock BOV with recirculation hose.

To set BOV properly you need to drive and get BOV to go off. If engine starts to stall, stop car and pop hood, adjust nut on top of BOV a little bit towards hard setting (usually has a hard / soft sticker on top of BOV, so know which direction to turn it in). Then repeat this process until BOV goes off, but engine doesn't stall.

Can remember 100%, but I think that ground wire / earth goes from chassis to Jpipe (under the corner nut / mount for brass hardpiping on side of J pipe). Or from chassis to turbo which I think how it is currently on my car (would have to check).

Here's it connected to corner of Jpipe (how it's done at factory) -

[evolution23]

Yeah i wasnt sure where it went because it was wedged down beside my turbo.. i checked all my air lines, i cant find any leaks, tightened any that could be, as for the BOV it just has a big screw on the top, no hard/soft written on it, i know the engine has always been running rich and when i come to a stop just after accelerating sometimes the engine starts to stall out and i need to tap the gas but usually it doesn't. I looked everywhere i could, sides, under, top, i wiggles everything i could to try and make the engine run like crap, i tried seeing any sparks coming from the boot of the coilpacks, i listened to every injector again.. i checked my ECU again, still code 55 which is odd because my Hicas light comes on after highway driving because of the aftermarket wheel.. i did notice however today for the first time, i had the light that looks like the chevy logo steaming come on, i believe its a heat sensor or some sort? (sorry its never come on before so i never looked into what it is) but i noticed it came on today very briefly then went on while turning right (when my engine is running crappy, when i turn right or go down a hill it usually clears up until uphill or on a straight again) so i thought id mention that incase thats got something to do with it.

Also i tried wiggling the MAF, if i push down a bit on the filter, the engine drops (because of constricting the tube after the MAF) but when i pull up on it a bit, the engine picks up a bit? i can try tightening the BOV screw and see what happens.

Also ill just add this, at first we thought it was the coilpack wiring harness so i swapped in a different one, problem went away for a day, when it came back i started unplugging coilpacks, found number 4 was the issue, moved them all around, and the plugs, ran for about a day. next time it happened i unplugged coilpacks again, still number 4. so we made a brand new wiring harness that has been very carefully created, directly connected to every coilpack with a solid connection. car ran for about a day. so when it came back, we started wiggling the harness, we could make it change anymore, so now we know its not the harness.. so anyways i changed the coilpacks in cyl 4 and 2 because 4 had no idle change, 2 had slight idle change, car ran for about a day, now its still coming back so i grounded each wiring harness directly to the battery for the best possible ground, when it still came back i started looking at fuel. but when its running crappy, i heard all of my injectors ticking...

[rak123]

i did notice however today for the first time, i had the light that looks like the chevy logo steaming come on, i believe its a heat sensor or some sort? (sorry its never come on before so i never looked into what it is) but i noticed it came on today very briefly then went on while turning right (when my engine is running crappy, when i turn right or go down a hill it usually clears up until uphill or on a straight again) so i thought id mention that incase thats got something to do with it.

. If that is your exhaust temp light then your exhaust is running really hot which means your engine is running lean. Is it ever hard to start? And does it not like boost along with higher rpms? If so I would guess based off that that your stock fuel pump is on it's last leg possibly.

[beacher1B0]

Have you replaced the ignitor box? Can u borrow one from someone?
Did your car have this problem from Day 1?
It is defintely wierd that you can get rid of the problem by turning right or goin downhill. Which leads to believe you have a break somewhere in the harness. It could be a break in the harness that goes from the ignitor to the ECU.
Also, could it be possible the cat sensor is causing the missfire?
With ignition ON the cat temp sensor light should be OFF. With ignition in Start it should be ON, then turn off when car starts.
Unplug Cat Temp Sensor harness from module under Passenger Seat. Looking at the HARNESS PLUG( not module) head on, the locking tab should be at the top. Ground the bottom right terminal, Turn Ignition ON, The light should go out. If light is OFF, it was the sensor that was throwing the code. Also im sure you could just permanently ground the Terminal on the Harness Plug.
If the light is ON you have a problem else where(harness etc).

[DarkCaporaL]

It is defintely wierd that you can get rid of the problem by turning right or goin downhill. Which leads to believe you have a break somewhere in the harness. It could be a break in the harness that goes from the ignitor to the ECU.

Manual mentions engine inclination in the troubleshoot for engine breathing.

"Increased tension of harnesses or air duct due to inclination of engine during acceleration can also be a cause of poor contact."

[evolution23]

the car takes about a second then it fires up, in the mornings the idle jumps between 100 and 300 for a few seconds then jumps up to around 1500 for a couple minutes the drops to around 1000, sometimes to 700 (it sounds like its struggling when at 700) and as for the exhaust temp light, it has only come on once and it went off at the most 2 seconds after i saw it, while turning right. im quite positive the engine is running rich and not lean, its always given me little backfires while cruising when i let off the gas but when it starts misfiring, the backfires are very frequent and much louder. and no, this problem first happened a little over a month ago, i was getting onto the highway, as soon as i hit 5th it started misfiring so i stopped and shut it off, started it back up and it still did it so i slowly limped it back home, went online to search about it, went back out 15 minutes later and it started up fine and didnt do that again for about a month. but now lately in the last 2 weeks its been doing this almost everyday, it didnt do it for 3 days straight (when i had injection cleaner in) then i fueled up without injection cleaner and the problem came back, i just put injection cleaner in again yesterday and today it seems to be running alright. but when it was missing, i took a long extension and listened to every injector, they were all ticking.. iv tried messing around with the wiring harness for the coilpacks, it wont change the idle anymore, i tried messing with the MAF. its really hard to catch the problem because when it is misfiring, i have at the very most a minute to get under the hood and start messing around before it clears up again. Every time i take it to a shop, it doesnt misfire at all. we can make it misfire while driving but not while parked. it sometimes does continue misfiring while parked but never when iv had a chance to jump out, last time was at an intersection, the time before that during lunch at a drive through...

[amnash]

you should try find someone close to you with another skyline and try swapping out a couple thing like maf and ignitor. you might have cleaned and re-soldered the maf but it could still be dead. its what i did to mine. i bench tested it before and after i cleaned/soldered it and failed both times.
i feel for you man im having issues with my car that i cant figure out too. electrical snags are the worst. and unluckily for me there's no one(that i know of) on gtrc that lives close to me

EDIT: did you try looking for vacuum leaks with a propane tank? there only like 25 bucks at can tire

[evolution23]

you should try find someone close to you with another skyline and try swapping out a couple thing like maf and ignitor. you might have cleaned and re-soldered the maf but it could still be dead. its what i did to mine. i bench tested it before and after i cleaned/soldered it and failed both times.
i feel for you man im having issues with my car that i cant figure out too. electrical snags are the worst. and unluckily for me there's no one(that i know of) on gtrc that lives close to me

EDIT: did you try looking for vacuum leaks with a propane tank? there only like 25 bucks at can tire

Yeah iv tried, took a torch, turned on the gas and went around connection i could. Its weird though that my ECU is telling me everythings fine, even right after it misfires.. but yeah idk iv been trying everything i can think of to figure this out, if i had some extra money i would just start swapping parts cause it wouldnt hurt to get some new parts on the engine but i dont have the money to do that which is why this is such a pain to figure out. Ill see what happens when i fuel up next time. I have a feeling its an injector so im going to run straight fuel again with no injection cleaner and just see, if it starts missing im going to assume its an injector and hope that when i get some new one, it clears up.

[Skym]

Cat light acts as an overheat light for catylitic convertor or engine check light for ECU. I had it come on due to screw on side of ECU wasn't properly in run mode and hitting bump in road would make it light up (switching between run, diagnostic).

Injector cleaner could make fuel higher octane, so I suspect engine is knocking due to low octane gas or running lean.

Try running some octane booster or higher octane gas. In some cases it's a bad batch of fuel at service station that's a lower octane. Switching service stations can confirm this.

One thing I noticed is a missing exhaust manifold stud on 6 cylinder in that photo. If so, 6th cylinder (maybe 5th cylinder as well) can run leaner and higher octane gas helps to prevent knock from happening. Also can drop compression in 5th, 6th cylinder due to running too lean. Compression test, low compression in those cylinders would confirm.

[evolution23]

i run 94 octane, only one place in town that sells 94.. i can try some 91 from a different fuel station and see what happens, ill pick up some octane booster as well and try that out.

checked out the exhaust manifold, also missing the first one... Would i need to get them off another member or is there a specific exhaust manifold stud i can get from another vehicle that will work or locally at a shop? and would that cause the car to randomly run crappy, then instantly run great again? it can switch between running great and running crappy instantly, itll run crappy for a few seconds then run great again.. i thought it was electrical because of how quickly it changes then started thinking injector