redrock5432

fyi to those working on misfires: I had a continuous 1 cylinder misfire and after much diagnosis, changed the coil and solved that problem. Then I had an occasional misfire on another cylinder, every 20 seconds or so and only at idle. Code was set and engine check light came one. After discussion locally with others the most likely suspect was fouled injector. I first tried 'brand 1' of fuel system cleaner then I tried 'brand 2'. I am not sure which one really worked but after about 40 miles on the 'brand 2', the miss is gone.

brand 1 was Berryman - Fuel Treatment. Part Number: 2616
brand 2 was Chevron Techron Concentrate Fuel System Cleaner (20 oz.) Part No. 65740

Goldynwun

I was getting ready 2 order all new coils for my 5th gen, now that I read this I am gunna test each individual coil and actually have an idea what to look for. Thanx a bunch bro. Hopefully things aren't as bad as they seem.

HotRod11686

this thread saved me a ton of time. I've been searching on others but you've pretty much got it all down in one single place.

Printed! I've already replaced coil #1 and #3 on the 00 max and I am still going to test out the rest of the coils just to be safe

Thanks again!

Brl24

How much different do you think this would be for a 3.5?

redrock5432

Not sure what you mean by "this" but I can give my view:
1. Start with codes, especially P030x (x is 1...6 = cylinder number)
2. Confirm and individual cylinder by disconnecting each coil one at a time to determine if it is contributing to engine power. If not, it is a suspect.
3. Read the forum for a whole bunch of good ideas.

The hard part of the 3.5 is access to odd number coils (closest to firewall). Requires removal is intake collector, or at least raising is up several inches. There are threads on this process. I used this one to start my 'journey'.
http://www.greghome.com/Greg%27s%20G...eplacement.htm

Good hunting.

redrock5432

11/26/11 update:
Neither fuel treatment solved occasional misfire (time between misfires was 20 to 30 secs only at idle). I had been talking codes and then erasing them to have a fresh start each time. I went back and looked at codes history. (should have done this earlier) I noticed that there was a code p0302 and then later a p0304. It turns out that had move a recently purchased coil from cyl 2 to 4. I replaced cyl 4 coil with a new one. Now there there are no misfires. I was surprised that a coil would be so intermittent, but evidently they can be. Just another data point for me. Others, good hunting for those misfires.

remifenta

I have a P1320.

I have tested all my ignition coil resistances, and they are all equal.

I replaced my spark plugs with OEM NGK's.


I would like to test the other aspects of the P1320 workup from the service manual, including the ECM relay and the ignition condenser.

I have tested the ECM relay, and I have gotten absolutely zero "continuity" from all the plug leads. However, I am questioning these results. Does this mean my ECM relay is bad? Or do I need to continually supply a 12V voltage across plus 1 and 2 in order to test the other plugs as the manual instructs? The manual is not clear on this point.

Also, to test the condenser, I will need to remove lots of electrical tape from the ECCS (EGI) wire harness. What is the function of this tape? Do I cover it back up with generic electric tape?



My theory on P1320 is that if coils are not obviously bad (with missing resistances), then poorly functioning ignition components will cause misfires with marginally-performing ignition coils. This is why only a generic P1320 is showing up and not a specific cylinder, because all cylinders are misfiring at one point. This is why replacing all ignition coils fixes the problem temporarily, because the ignition coils have a "fresh start" before the poorly-functioning ignition components can take their toll to cause a misfire. This is why replacing all ignition coils with new ones will not permanently solve some owners' problems.

redrock5432

model year and engine?

remifenta

2001 i30/maxima 3.0L.

I also tested the coils individually by disconnecting each one to gauge engine noise change. The engine sound changed equally with each ignition coil disconnected.

remifenta

I think people who label their ignition coils as "bad" are mistaken. Unless you have 0 resistance between the #2 and #3 spot according to the service manual, you should still have a good coil.

Electrical circuitry is more likely to blame for the P1320.

I find it hard to believe that so many people are encountering so many problems with the ignition coils themselves but nobody is doing the investigation into their ECM relays or ECM or condenser or wires.



My plan is to replace at least the ECM relay, and then I will undo the tape around the ECCS (EGI) and get at the condenser harness. Does anybody know what the condenser part number is?

redrock5432

Is the misfire noticeable or are you just getting the p1320? If noticeable misfire, under what conditions? (idle, cruise, cold, hot, acceleration, ac on/off, etc.)

I looked up p1320 in A33 and A34 service manual and could not find it. Would you post description of P1320?

remifenta

The misfire is very noticeable, like a very rough gear shift, without any change in throttle sound or change in tachymeter. It happens during highway driving predominantly but can happen during slower speeds as well. Happens more in cold weather. The SES light came on during a string of these "misfires", and code read shortly afterwards indicated P1320 as well as P0430 and P0420 which indicates to me a true misfire because more O2 is being dumped into the exhaust.

I also occasionally have a hard time starting the car, as if the condenser is failing (or the upstream ECM relay, or the upstream ECM itself).

I will post the pages from the service manual when I get home from work.

redrock5432

Your conclusion on p0420/30 seems most plausible. These codes are a symptom of the 'upstream' misfires.

I have not seen description of condenser but my guess is that the power transistor in the coils initially draws high current for a short duration. The condenser is connected to 12 vdc supply to these transistors and supplies the this initial inrush of current to each coil and recharges in between cycles. If you had another condenser, you could wire it temporarily in parallel with the existing one, one side to engine ground and other to 12 vdc line common to all coils. (make sure to use wire size at least as big as existing wires, make good connections, and use engine ground.)

remifenta

Hopefully the following will help.

Ironically, the LAST step in the workup of a P1320 is replacing the ignition coils.

What do most dealers and mechanics recommend? Skipping to the last step. And even then, they don't even test the resistance as instructed. They just replace all six ignition coils without identifying which could be bad.

This is lazy. And more expensive than it ought to be.

And, what happens if it wasn't really the ignition coils but instead a spark plug? Or a condenser? Or an ECM segment? Or a specific wire? Those will have to be addressed later, on top of the cost of unnecessarily replacing the ignition coils.

PDF: http://www.quantexlab.de/forum/show_file.php?fid=6679

http://img408.imageshack.us/img408/3881/p13201.png
http://img94.imageshack.us/img94/9560/p13202.png
http://img62.imageshack.us/img62/8082/p13203.png
http://img811.imageshack.us/img811/3990/p13204.png
http://img403.imageshack.us/img403/751/p13205.png
http://img853.imageshack.us/img853/2847/p13206.png
http://img411.imageshack.us/img411/2931/p13207.png
http://img560.imageshack.us/img560/708/p13208.png
http://img193.imageshack.us/img193/4483/p13209.png
http://img72.imageshack.us/img72/6234/p132010.png
http://img338.imageshack.us/img338/1386/p132011.png

redrock5432

Reference URL (pdf) above.

At step 4 in diagnostic. This is checking for 12 vdc at condenser connector, which is after the ECM relay. If this is good,then the ECM relay is good. You could also check for this voltage at any of the coils, pin 3. But the fact that your engine runs but misses indicates you are getting 12 vdc to the coils at least most of the time. Maybe you could attach a voltmeter to pin 3 and check the voltage while driving (long wire for pin 3) and see if the voltage fluctuates when the engine missfires.

Back on my condenser explanation, looking at the circuit again,there would not be large inrush of current, but the current would turn off quickly causing a high frequency pulse superimposed on the 12 vdc (pin 3) wire. I suspect this is what the condenser is doing is filtering out this high frequency pulses. I don't know the size of the condenser, in mfd and voltage rating.

If step 4 is 'ok', then it is time to go to step 10.

This all looks like a good process so far.

Good hunting.

remifenta

Looking at the wiring diagram on EC-508, I think the condenser is a capacitor that is charged up to store excess or extra charge that can be distributed to the collection of 6 ignition coils (distributor vs modern distributorless ignition systems). You might be right about the condenser functioning like a high-frequency attenuator, but I think it has to do with storing extra power for the ignition coils to make sure there is no sudden drop in spark plug energy in case there is fluctuation of the input from the ECU. (The condenser is rated at 0.47 microFarad, which I could see after removing all the excess dielectric grease and sticky tape residue.)

The test of the condenser in step 11 is to ensure that the capacitor is functioning properly, with hopefully an infinite resistance between the two capacitor plates. If there is damage, then there may be a communication between the plates causing insufficient capacitance for the ignition coils. I passed this step in my diagnostics.

Step 4: passed
Step 5: passed for continuity (part 1), but I do not know how I test for "short to ground" and "short to power"!
Step 6: skipped
Step 7: passed
Step 8: skipped

Step 9: no continuity between 1 and 2, 3 and 5, or 6 and 7 I am not sure about the purpose of applying 12V DC current to terminals 1 and 2 before testing continuity between 3&5, 6&7. I will buy banana clips and test this soon by connecting it to the battery. I did the same test on a non-ECM relay, and I had the same results in terms of no continuity.

Step 10: FAILED. I do not know why this is the case, but I suspect there could be a short between terminal 2 of the condenser and the actual ground of the car. I will need to test this again because I am not sure if I put the ECM relay back on before testing previously. Also, what does it mean to test for short to power?

Step 11: passed
Step 12: passed x6 ignition coil terminals
Step 13: skipped
Step 14: passed x6 ignition coil terminals, and resistance measured all equal 1.7x200,000 ohms
Step 15: UNKNOWN HOW TO TEST
Step 16: passed x6


If step 10 is indeed failed for me, I think I am in trouble. Taking apart the harness and finding where the ground wire broke will be a nightmare. I will definitely take apart the tape and test again before I head down that road.

Does anyone have any idea about how to test "short to ground" and "short to power"? The manual mentions it several times but with no further explanation.

remifenta

All the causes listed for the P1320 are:

Harness or connectors (the ignition primary circuit is open or shorted.)
Power transistor unit built into ignition coil
Condenser
Crankshaft position sensor (REF)
Crankshaft position sensor (REF) circuit


Further exploration will require me to check information about the Crankshaft position sensor (REF) and REF circuit since I haven't even thought about those yet, but I have never received any error for that and it's on the lower order of probability for causing my P1320.

redrock5432

By your paragraphs:

0.47 ufd is not much for power storage but would be effective for high frequency filtering.

There should be infinite resistance between terminals on capacitor. This means it is not 'leaking' or shorted but does not confirm it is working, it could be 'open' inside unit, for example.

On the ECM relay, continuity between 6 and 7 and 3 and 5 would only occur when the relay is energized, ie. 12 vdc applied between pins 1 and 2. In relay language this is called a double pole single throw normally open relay, ie. DPST-NO.

In the circuit diagram, pin 2 of the capacitor is connected to ground, so you should measure zero ohms between pin 2 and engine ground. So your finding is correct.

If you had a 'short to ground' or 'short to power' you would not be running at all.

My opinion is that the component that is failing intermittently is one that is common to all cylinders. Otherwise I would expect a P030x code indicating a particular cylinder. Here is my candidate list with (probability of being cause)

1. Outputs from ECM or Power to coils: 12 vdc power or ground to coils is intermittent. (high)
2. Inputs to ECM : various timing sensors, camshaft and crankshaft. (med)
I rate this medium because of the way the malfunction is defined "Malfunction is detected when the ignition signal in the primary circuit is not sent to ECM during engine cranking or running." I interpret the primary circuit to mean power/signal/ground to coils. Apparently, the ECM can determine if a wire is connected and the power transistor is working by monitoring the voltage on the signal (pin 1) to the coil when the ECM signals that particular coil. I can go into detail here if needed.

You may be able to add temporary power and/or ground wires to coils and then drive car to test for misfires.

RR5

iTrader: (6)

Short to ground implies what that means in the name. You have a wire running between two points. If you test both points for continuity, you'll get 0 resistance. However, if the wire has a short to ground, it means there is a break in the wire touching bare metal. This will mess with the continuity. It shorts the connection to ground.

A short to power is nearly the same thing, only the power wire has a break and the expected voltage isn't seen.

See this page for a much better explanation http://rsandas.com/P1_Session_10-1.html

remifenta

Thanks for the information about shorts to ground and power, it was very helpful.

Regarding my condenser harness, testing for continuity between terminal 2 (ground) and the actual engine ground fails (Step 10). Doesn't this mean that there is a break in the ground wire for the condenser? If the condenser doesn't have perfect grounding, it will be unable to build up a high enough capacitance in the condenser, and so it may not be able to attenuate high frequency impulses from the ECM before going to the ignition coils. This may be the reason why the ignition system is misbehaving and causing misfires in a few of the cylinders (especially since the condenser is common to all cylinders' ignition coils). I think it's possible to have an ineffectively running condenser which causes intermittent misfire without preventing my car from running at all.

redrock5432

By fails, I think you mean that it should read zero ohms but instead is open or reads infinity. If this is the case, then add your own wire from engine ground to pin 2 and test for changes in misfires.

remifenta

My voltmeter buzzes for continuity if the resistance is less than 50 ohms. It was closer to 800 ohms if I remember correctly. I will check again soon.

I am tempted to try splicing a new ground cable, but it would be tricky to run it to the other engine ground without having the wire touch against the engine block causing it to melt.

remifenta

Driving home, I got P0133 (o2 sensor) and P0420 (cat) codes with no associated jolting or misfire.

This car is driving me crazy.

redrock5432

"stay on target"

remifenta

I tested continuity this time with the ground being the negative terminal of the battery, and the wires passed the test. I don't know why it's continuous with the ground of the battery but not the engine block or the ground wires into the engine block, but that's how it is.

I'm stuck. I passed all steps of the P1320 workup minus those which require testing continuity with the ECM. Since the ECM is in the passenger wheelwell, I don't have the capability now to see what I am doing there or the voltmeter cables long enough to test this.

http://img850.imageshack.us/img850/4307/itb011.png
http://img843.imageshack.us/img843/4309/itb012.png

If the ECCS harness is intact, and it looks like it is at this point (minus the possibility of ECM intermittent faults), then I may have to replace what appear to be good ignition coils.

This does not make any sense, but I can't explain it otherwise.

redrock5432

The engine block should be grounded. There should be a ground strap somewhere eventually connecting to ground of battery. This might be 'out there' but I would check why the engine block is not grounded before digging into the ECM or other wiring.
Here is a picture from a 2002 A33 Series service manual. This is in electrical section, ground distribution. Note connection of coils to engine block.

remifenta

I saw both sets grounding wires in appropriate areas of the engine block and metal frame. I will post pictures when I get home from work.

If I remember correctly, only some grounding tests using the engine block failed, but others worked well. I wonder if the ground that is not working is the "F40" ground listed in the wiring diagrams. What is F40 and how do I test that specific wire?

Also, when I was getting my car looked at by a mechanic, he said the ground strap by the exhaust was broken. It's probably nothing, since I think the ground strap has more to do with attenuating (or "grounding") the vibrations of the exhaust, and not really something to do with grounding the electricity. I am not sure though.

remifenta

Actually, looking over the electrical section in the service manual, EL-26, it looks like F40 is a specific ground wire. I will need to look over the diagrams more carefully to see which grounds I was looking at and if F40 was included in that. I know that one of the grounds I saw was a "body ground", but an engine ground.

Edit:
It looks like B27 (condenser) plugs into B30 (body ground).


Edit 2:
But, it also looks like F34 (condenser) plugs into F40 (engine ground).


This is confusing. Are the two grounds just redundant?


Edit 3:
Does it truly matter that the coils and condenser are not grounding directly into the engine block or the body? As long as it's grounded to the battery, it means there is a ground at some point for these circuits.


Edit 4:
At what point do the ground connections get connected to the negative terminal of the battery? How is it labeled in the service manual?

I really do not want to go into the ECCS (EGI) harness to find the broken wire. If the above results do indeed mean a break somewhere, I am more inclined just to throw an extra wire between the two end points (between terminal 2 of condenser and battery, and between common ignition coil ground cable and battery), wherever those two points are. I just don't know where to throw the wires.


Edit 5:
I may just end up tracing the cable of the negative end of the battery, and seeing where that leads. Failure of grounding from engine block to battery makes no sense when there is successful grounding of ignition coils and condenser to battery, unless there are multiple cables plugging directly into the negative terminal of the battery. Perhaps the condenser is grounding via the secondary method of the body which then grounds into the battery? Do I really need to test between terminal 2 of condenser and the body ground?

Edit 6:
I will probably make a master diagram of all the grounding connections, because apparently different grounds are grounded into each other, such as on EL-24 which shows body grounds grounding into the engine ground (or is it the other way around?)

It doesn't help that these grounds are mostly attached to their insertion points via rusted screws.


Edit 7: interestingly, based on the large diagram I compiled, there should be continuity between F34/B27 (condenser ground side of capacitor, terminal 2) with (B30 OR F40). Because there is continuity with neither of these points, there must be a break in the condenser ground wire between the #2 terminal end (where the capacitor plugs into the harness) and the point where this wire breaks off to head to F40 or B30.

Strangely, the ignition coils have the same issue with grounding only to battery and not to the engine ground, which indicates a disconnect between F40 (engine ground) and ignition coils. Since F40 is the shared connection that is faulty, the ignition coils must be grounding over the MUCH HIGHER RESISTANCE route of B30 (body ground) which is then grounded back to the engine and then to the battery. Bypassing the engine and going straight to battery results in zero ohms of resistance.

When I get the chance, I will test continuity between the engine block and the battery.

redrock5432

Perhaps a quick test. With one battery jumper cable attach one end to negative terminal of battery and one to good metal connection point on engine. Coil it up and go for a test drive and see if misfires are gone.

Also, numbers like F40 in the diagram I posted are for 2002 maxima and may not match your car. Use your own manual to find numbers and locations. I didn't mean to make things confusing.

All ground straps are important. They don't have to be elegant or the original part numbers just the same size with good electrical connection at both ends.

My suggestion is to fix to easy stuff first, who knows it may help.

remifenta

Thanks. I addended my more recent post:

"interestingly, based on the large diagram I compiled, there should be continuity between F34/B27 (condenser ground side of capacitor, terminal 2) with (B30 OR F40). Because there is continuity with neither of these points, there must be a break in the condenser ground wire between the #2 terminal end (where the capacitor plugs into the harness) and the point where this wire breaks off to head to F40 or B30.

Strangely, the ignition coils have the same issue with grounding only to battery and not to the engine ground, which indicates a disconnect between F40 (engine ground) and ignition coils. Since F40 is the shared connection that is faulty, the ignition coils must be grounding over the MUCH HIGHER RESISTANCE route of B30 (body ground) which is then grounded back to the engine and then to the battery. Bypassing the engine and going straight to battery results in zero ohms of resistance.

When I get the chance, I will test continuity between the engine block and the battery."

The F40/F34 applies to my car as well, along with B27/B30, according to my service manual.

remifenta

Any idea what the "wire loop" means in the wiring diagrams right before ignition coil #1? I see a set of looped wires coming out from my ECCS (EGI) harness right around the alternator area. One loop of wire is secured by white tape, making me wonder if there was a break or disconnect in that wire that was repaired previously.

redrock5432

I saw the wire loop also and do not know what it is.

Also, if the coils and condenser are grounded poorly that would fit with all your data, p1320 and misfires.

You mentioned rusty screws/bolts. Definitely check those connections, if possible loosen and check for rust or corrosion. clean up these connection points, especially if any of them deal with coils. Clean others if you can. These grounds are needed to complete the circuit on these electrical components, ie. just as important as 12 vdc and other signal wires and connections.

remifenta

While driving around, I kept the OBD-II reader plugged in and I have been checking for DTC codes every so often. I got codes P0304 (cylinder 4) along with a P1320, and later a P0132 (heated oxygen sensor) with a P0420.

I will keep checking codes while driving. If I get the same misfire code for a specific cylinder, I will change out that ignition coil, though the workup in the service manual suggests a million other things that could be operating incorrectly.


So far I have received codes P0133, P0132, P0420, P0430, P0304, P1320.

redrock5432

In my service manual for A33 (2002) the page for ground of O2 sensors is EL-25. It looks like the same area on the engine block where the ground wire exits the harness and is attached to the engine. I would re-do those connections to make sure they are good. So far, all your symptoms seemed to be explained by poor grounding. The cat codes are downstream of misfire and may clear once other issues are fixed.

Are you still feeling the car misfire?

remifenta

The screws/bolts are rusted on. I am concerned I will not be able to get the ground cables off/on if I strip the screws. I will take a look again when I have more time.

I just ordered a bluetooth OBD-II reader to interface with Torque on my android phone. Maybe it will help me keep track of these intermittent fault codes.

Does it seem strange that I am seeing so many new codes when the engine light is not on?

The sheer number of O2 sensor codes and P0420/P0430 codes that come up during driving is shocking to me. It is as if the cats are constantly receiving too much oxygen from misfires, but I do not feel misfires happening as often as the error code comes up. Cat codes to misfire codes are 10:1.

I will drive more and reassess.


I agree though that the cat codes are likely coming up because of upstream malfunction. I can't rule out O2 sensor error either.



The list of things for me to do:

1) Retest grounding with voltmeter to confirm poor engine grounding
2) Try to identify all ground leads and insertion points to address rust or perhaps even shorted wires
3) Take a look at the "wire loop" that I think was previously patched in my wiring harness
4) Replace exhaust ground strap
5) Test grounding between engine block and negative terminal of battery
6) Identify exactly the ordering of wires that connect to negative of battery so I can test each individual wire segment in the grounding series
7) Drive the car with a jumper cable or any banana clipped wire to engine block and negative terminus of battery (after testing if there is poor connectivity between engine block and negative terminus).

Maybe:
7) Replace ignition coil in cylinder 4 if code comes up again

redrock5432

Testing/measuring grounds may be inconclusive as your symptoms are intermittent. Also, there may be multiple paths to ground but the 'best' one may not be connected, eg., your meter may say OK but the best ground is really not connected. Visual checks may be your best guide.

Relative to rusty screws, I recommend doing whatever you need to address those rusty connections. If the screws/bolts cannot be salvaged you may need to create an alternate connection to the engine block. You also may be able to clean out the screw hole with a tap.

I think your task list is good, just make sure those small wires exiting the harness (coils/condenser ground) get good ground to engine and the engine is well connected to neg terminal of battery.

Just to reiterate, I think all your symptoms can be explained by poor ground connections.

Wish you well in your hunt.

remifenta

The list of things for me to do:

1) Retest grounding with voltmeter to confirm poor engine grounding: engine had poor grounding to negative terminal of battery
2) Try to identify all ground leads and insertion points to address rust or perhaps even shorted wires: Junk and rust over all the leads.
3) Take a look at the "wire loop" that I think was previously patched in my wiring harness Must be manufacturer's way of identifying wires, because it was uninterrupted/untampered on my car
4) Replace exhaust ground strap: not done
5) Test grounding between engine block and negative terminal of battery
6) Identify exactly the ordering of wires that connect to negative of battery so I can test each individual wire segment in the grounding series. I have a comprehensive series of connections on paper, I can attach an image later. Basically, the entire system is very redundant.
7) Drive the car with a jumper cable or any banana clipped wire to engine block and negative terminus of battery (after testing if there is poor connectivity between engine block and negative terminus).

Maybe:
7) Replace ignition coil in cylinder 4 if code comes up again





The interesting thing since fixing all the ground connections is that the number of codes I get has dropped almost to zero. Whereas before I could drive over 10 minutes with the same 4-6 codes coming up, I can drive 20-60 minutes without a single code. Though, one code still comes up occasionally: P0430.

I will keep track of codes and update with my progress.

redrock5432

This is great progress and a lesson for us all on grounding and all those odd straps on the engine, body, exhaust, etc.

P0420 and 430 are cat codes, one for each bank. I read somewhere that if misfires are severe enough the cat could be damaged. This cause/effect needs to be confirmed.

remifenta

Before I knew any better, I took my car to Midas 2 years ago because of a O2 sensor code, and when trying to replace it, they said the threads of the cat were messed up and needed to replace the cat. I found out later that:

1) there are tools to fix the threads so new O2 sensors can be placed
2) the cat they used was a bad aftermarket cat which didn't fit the original exhaust so they used cement to seal the connections
3) they hammered and dented part of the exhaust pipe to make the new cat fit.

remifenta

Based on what the service manual says for a P0430, it's probably the dents in the exhaust or a leak around the cement.