miss fire on cylinder #4

Jim Fairbanks

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Hey Bill....I'm not sure if it is wet after it is fully warm...I think it is 4 valves per cylinder...thanks...Jim
 

nickb2

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Nick...hope all is well with you....Jim
Yeah, so so, I am actually fine, or so so. my sister not so well, bringing club down, but, as long as I feel I have friends, that really want to go somewhere, ok.

You, a long time member, know, I never back down. I might sound funny right now, but I am not your typical lurker. Jim, back in 2008, I didn't know my ass from a pdf, YOU, showed how. Then, I got interested in all the data out there, sadly, forum rules prevented, but now, all is legit. thx to you:eek:
 

NickD

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Just read you have coil on plug, four of them, you switched coils around with still a misfire on cylinder # 4, each coil only has two wires, possible on the #4 harness, either a dirty connector or a broken wire someplace on the harness itself.

Takes me back to one of my kids 2002 Ford Taurus and this present post on a dirty high beam light connector, his one connector was corroded preventing continuity and hence, a misfire. Sure fires up the CEL with excess oxygen in the exhaust, O2 sensor cannot deal with that.

Yeah this new stuff, have a Chrysler T&C to look at, have to remove the top half of the engine to replace a spark plug. 88 Supra is the same was with all that turbo stuff, was fun 32 years ago, but this darn body of mine is also 32 years older and I feel one of my spark plug wires is not firing anymore.
 

Jim Fairbanks

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Hey Nick....yeah it is coil on plug...but there are 3 wires on each coil..I pulled the coils off and put plug in the coil and turned it over...also had a plug in 3...Both of them were firing the same...Looked like they are firing ok....Jim
 

Jim Fairbanks

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OK.....so I decided to go ahead and replace the injector on #4 and it fixed the miss....Got it back together and drove it and no miss came up....Thanks for all the help on this....Jim
 

NickD

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Use to go to a lot of auto shows, even met playmates, looked better in the centerfold, ones I met looked beated out.

Saw a fuel injector cleaner/tester for $7,000.00 Got all that stuff at home, air compressor, various power supplies, pulse generator.

From an air compressor quick coupler, cut off valve, regulator with a pressure gauge to a hose to couple to and injector with a clamp on it. Filled the hose with choke and carb cleaner. Increasing the pressure to an attached injector, typical is 45 psi, but per the vehicle specs, closed the valve, to check of leak down.

Using a current limit power supply, typically 1 ampere flowing into the injector solenoid would open so you could see the spray pattern, but first step was to clean the outside of the injector first. Returning the PCV to the air cleaner deposited a lot of crap on the nozzle, what idiot thought about this.

Of course if one ampere does not open the injector, tells the coil is opened or shorted, typical injectors are fired by 12V with a 12 ohm power resistor in series, if you don't have a current limited power supply could use a 12 volt battery in series with a 12 ohm 15-25 watt resistor.

Can also fill that hose with more choke and carb cleaner and blast it again, takes about 3-4 minutes per injector but for what they cost, your time is well worth it.

6,000 RPM is 100 revs per second, hooking up a pulse generator since the injector fires every other rev, vary the frequency between 0 and 50 Hz, can tell by sound its responding, if it skips or jumps, try recleaning it or replacing it.

Also like to test a new one, could get a brand new defective one from China.
 

nickb2

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Returning the PCV to the air cleaner deposited a lot of crap on the nozzle, what idiot thought about this.
Boy do I have on to make you Nickd laugh. The other day, car comes in, seeing the two codes together and reading live data, nothing here made sense. SO went to TSB, guess what, swap pcv valve, watch trims, tsb said need to reflash. I said no, will swap pcv with smaller orifice, will let the adaptive do work. I told lady, you may have to come back if check comes back on, I will reflash for free if it comes to that. Well she never came back.

This trade is ever evolving. It is hard to keep up, the more I delve into this trade, the more I feel a need to trust my instruments.
 

nickb2

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As long as ICE engines exist, the vac gauge is king in quick check. Couple that with a scope, you don't even need to open a hood, as long as data is precise,

I do a high pressure job, which means it has to get out of bay pronto. No time to hook up, client doesn't have cash for that, ok I say, I throw shyte at your car all day, don't mean it gonna work right if you don't give me time. The problem right now, is not the techs, it is the front desk guys selling a fridge to an eskimo. That is the real problem right now, much like a congressional hearing. :cool::fixed::giveup:
 

NickD

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How do you test a PCV valve, you shake it, if it rattles, its good!

No way, blow in one side of it, should be clear, other side, completely blocked. If not, spray choke and carb cleaner in the free end, same crap builds up in there. Lots of fuel components can be cleaned and the are a heck of a lot more expensive than washing my dishes, but yet those are cleaned constantly.

While you are at it, clean up the crap in your throttle body, if that throttle vane sticks and you are short on brain power not to switch off the key, or even put the thing in neutral you get what you deserved when you drive into a tree.
 

nickb2

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Nickd, if they made an algorithm for the modified pcv, rattle and shake test is way ole. We are not in 1984 on my 302 overbored. :cool:

I especially like the recal on interceptor crown vics. Car may swerve and cause damage or death. I am actually old enough to remeber that one. A few cops flew in to ditches. It was funny. Not so much if you have kids in the car. o_O
 
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