Misfire codes, Dealer wants $1230.00

[comtec]

Those are all on one side so they have something in common. My guess is you have a sensor going bad and there are lots of them. I would start doing the checks from the repair manual for the PGM sensors and also do the noise consenser. My first guess would be to check the crank / cylinder position sensor.

Intermittent failures like yours are hard to diagnosis because it seems they like to hide when your looking for them :wink:. Doing the manual checks is much better then throwing parts (money) at it.

Mike

 

[heathbar0]

Drove the car last night.

15 minutes of normal driving...

I could feel the beginning of the hesitation, but the CEL did not come on until i was at a traffic light, idling. Continued to drive another 15 minutes and felt the hesitation, but the CEL would not blink unless I was at a stop.
At one point the CEL flashed constantly (30 seconds +/-) until I started to accelerate again.

Car sat for 2.5 hours, started up home and made the drive home(30 min) without a problem.

 

[heathbar0]

Update, and looking for some help.

After trying some suggestions and replacing a few things, I am still having problems.

I first checked the battery cables. I found the ground movable, and the positive slightly corroded. Upon removing the battery to clean it I found that it was leaking, so I replaced the battery.

Last night after waiting for a while for the Ignitor to arrive, I replaced it.

After replacing it, I started the car. At idle, standing behind the car, it seemed as though the car was missing.

After the car warmed up I went for a drive. Not a long one. After 10 minutes I come to a stop light and I get a CEL and TCS.

I drove the car a little more and then let it sit. Be aware, I could not get the car to reproduce the sputtering between 2500, and 4500 RPM as it had done in the past.

After an hour I drove the car again, and after 10 minutes I come to a stop and again CEL and TCS.

Codes:
P1204
P1206
P1300

Those are all on one side so they have something in common. My guess is you have a sensor going bad and there are lots of them. I would start doing the checks from the repair manual for the PGM sensors and also do the noise consenser. My first guess would be to check the crank / cylinder position sensor.

Intermittent failures like yours are hard to diagnosis because it seems they like to hide when your looking for them . Doing the manual checks is much better then throwing parts (money) at it.

Mike

http://nsxprime.com/forum/showpost.php?p=1481193&postcount=31
This post comments on a problem with 3 bad BRAND NEW coils, and a "igniter on lower bank" and from all my searches, the closest to the symptoms I am seeing.
I was unaware of an ignitor for each bank, can anyone elaborate?

The common denominator is all codes every time I read them are on one side.

I replaced the plugs and coils about 2 months ago and about 400 miles.
I can't imagine that I would put 3 bad coils on one side...
Is there anything I could have messed up while replacing the coils and plugs?
Is there an additional Ignitor for each bank of coils?

Help is appreciated.

 

[Old Guy]

Because you seem to have addressed the obvious sources of the misfire codes, my suggestions are probably going to fall into the 'hail Mary' category!

As noted by Comtec, the 1204, 1205 and 1206 codes all suggest some kind of common mode failure associated with the ignition components on cylinders 4, 5 and 6. From the wiring diagram, the only common mode components that I could see are the +12 v supply to all 6 ignition coils and the wiring from each individual coil to the spark plug voltage detection module.

The wiring diagram I was looking at indicates that the +12v supply to the coils comes from the same fuse (#13 in the engine compartment fuse box) as the FI main relay (but it is not switched by the FI main relay so a faulty relay would not create this problem). The diagram implies that the 12v supply is a common connection to all 6 coils with no connector separating the front 3 cylinders from the back 3 cylinders. Unfortunately, my car is zipped up in an air tight plastic bag in a secure storage facility for the winter, so I couldn't get access to it to check the actual wiring arrangement. The fact that you are not generating codes on cylinders 1-3 suggests that it is unlikely that there is a problem with the common 12 v supply. Also, a short to ground on this common supply should kill all 6 cylinders at once and likely blow fuse 13, which hasn't occurred. However, there might be a remote possibility that the the wire connecting the back 3 coils to the front 3 coils for the +12v supply has chaffed on something and is giving you an intermittent connection to cylinders 4-6. The wiring diagram indicates that this commmon 12v supply to the coils is a black/yellow wire if you want to check it out. It might also be possible that there is a connector (not shown in the wiring diagram) that separates the 12v supply to the front and back sts of coils. If this connection was bad, it could cause the misfires on cylinders 4-6 because the wiring diagram implies that the 12v connection from fuse 13 goes to cylinders 1-3 first and then round to cylinders 4-6. However, I would expect that this would cause a simultaneous problem on cylinders 4-6 which you would definitely notice in terms of power loss. The service manual states that the misfire codes are generated when the voltage sensor located in each ignition coil "detects the long duration high voltage which occurs in case of unfavorable combustion or misfiring." This suggest that if you are generating the P1204-P1206 codes, I don't think that it is a lack of supply voltage and as such, my gut feel is that it is unlikely that the problem is with the 12v supply to the coils; but, if other things don't check out, it might be a last resort.

As noted, the other common ignition component for cylinders 4-6 is the wiring for the spark plug voltage detection module. There are 6 wires that run from this module to each individual coil. The wiring diagram indicates that the wires for cylinders 1-3 and 4-6 are grouped together in two shielded cables (up to some point where they have to split to the individual ignition coils). The wiring diagram doesn't show where they split apart. If the common shielded cable that runs to the voltage sensors on the coils for cylinders 4-6 was chaffed and you were getting cross connections between the signal lines, you might be geting some kind of screwed up signal going to the spark plug voltage detection module fooling it into thinking it has a misfire on those cylinders. If the ECM gets a false misfire message from the module, it might take a preventive strategy to avoid engine damage which could result in a power loss. The latter is a pure guess on my part as I know zip about the code built into the ECM. I have read somewhere that you can detect a failure of the voltage detection module by unplugging it and starting up the engine. The ECM will generate a bunch of error codes; however, the engine will run normally if the problem is with the module.

Like I said, both of these suggestions fall into the way out there category!

The crankshaft position sensor is one other common component in the ignition system; however, from my limited knowledge, a failure would not selectively cause issues leading to misfires on cylinders 4-6. I think the CKP sensor would also throw its own set of error codes which you have not detected.

If we make the assumption that the ignition system is OK, is it possible that you could have fuel mixture issues just for cylinders 4-6 causing the misfires? When you changed the plugs, did the insulators all look the same or was there a difference in the plugs on cylinders 4-6 (whiter indicating a potential lean condition, darker indicating rich). However, if you're problem is only occurring briefly / intermitently, it may not be enough to cause a permanent change to the insulator color. I would also expect that you would get a mixture out of range error code P0171 - P0174 which give lean/ rich indications for the front and rear cylinders separately.

In your last post, you mentioned that the TCS light is lighting up. Did you pull the error code for the TCS?

Good luck with it

 

[heathbar0]

When you changed the plugs, did the insulators all look the same or was there a difference in the plugs on cylinders 4-6

In your last post, you mentioned that the TCS light is lighting up. Did you pull the error code for the TCS?

Good luck with it

Thank you for your response.
I do not remember, but I think I would have noticed a build up on the spark plugs.
I will, however pull the one side and see what they look like.

I started the car about 15 minutes ago and it is definitely misfiring at idle now. (Minor miss)

I did not know I could get a code from the TCS, How is that done?

Thanks!

 

[Old Guy]

You retrieve the TCS diagnostic codes using the service check connector. I have attached a .pdf from the NSX Wiki which describes using the service check connector. I have also attached two .pdf files from the sections of the 97+ service manual that describe how to interpret the codes. (You can find the complete service manual on NSX wiki. Its in .pdf form. )

Are you generating any error codes when you get the misfire at idle?

Have you ever had the throttle body cleaned? I would not expect an intermittent problem like you describe to be associated with a dirty throttle body (a dirty throtle body problem should always exist under the same engine load conditions, not come and go). Intermittent problems are usually related to poor electrical connections or failure of electronic components at elevated temperatures. That said, cleaning the throttle body is relatively easy and would eliminate it as a potential source of the problem. If you search the Prime site with that subject line, you should find a number of posts describing cleaning the throttle body. Make sure you clean the vacuum ports on the throttle body.

The fuel pump operates through a resistor which is bypassed above a certain RPM to increase fuel delivery. I have never experienced problems with fuel delivery on my car, so I have no direct experience fiddling with this system. I don't even know where the pump is located. There have been a number of posts describing problems with the fuel pump and the resistor bypass circuit. These might be intermittent electrical problems and the lack of fuel pressure would result in mixture problems leading to misfires although the fuel pressure would have to be really bad to create problems at idle. My recollection is that the check of the fuel pump was fairly simple. You might want to try searching the posts for a description of this problem. The best check would be to measure the fuel delivery pressure which requires a gauge and the proper fittings.

Is your car stock and what is its age? Are the air and fuel filters in good condition?

 

[heathbar0]

Old guy.

Thank you for your help.

If I get a minute this weekend I am going to clean the TB.


I am expecting that not to work, and I just don't have the desire to work on this anymore. I have made an appointment at the Acura dealer for Monday, assuming that the cleaning of the TB will not work.



I own a company with 7 trucks, I have 4 personal cars and a bunch of small equipment. I am the head of maintenance, along with many other titles.... I was working on my forklift yesterday...

Just tired of my hands being dirty, I guess.

I will, however, report back when my problem is solved so those who may have a similar problem may resolve it without such frustration.

 

[heathbar0]

An update for this thread can be found here:
http://www.nsxprime.com/forum/showthread.php/170030-Big-thanks-to-Ben-at-Daisy-Automotive?p=1671012#post1671012

 

[nikey22]

An update for this thread can be found here:
http://www.nsxprime.com/forum/showthread.php/170030-Big-thanks-to-Ben-at-Daisy-Automotive?p=1671012#post1671012

so let me guess.... after all this, it probably ended up costing about hmmmm, $1230 anyways right?

 

[heathbar0]

Well... Just a touch more:wink:

 

[nikey22]

Well... Just a touch more:wink:

that's okay, you learned a lot about the car in the process, and so did we...

 

[charlee]

OH, that is great to hear that your car has been fixed. These types are the best disucssions as these appears to be phantom issues. I would have left the shop just as puzzled as when I pulled in. In trying to understand the problem further.

"After Ben got his hands on it he found that the cam timing was off and the timing belt was loose, something he'd never seen before. Two of the injectors were bad, the TW sensor was bad, and the cam angle sensor was in terrible shape.
In addition the clutch was in horrible shape, the thermostat was falling apart and one of the intake gaskets was leaking."

So which one(s) is/are the most likely culprit?

 

[nikey22]

I'm interested in knowing more about what he did with the cam angle sensor? - how was it bad? Do we need to change ours maintenance wise?

 

[heathbar0]

I'm interested in knowing more about what he did with the cam angle sensor?

So which one(s) is/are the most likely culprit?

To answer your questions, I contacted Ben.

It was not a clear and simple answer, so he suggested that anyone looking for more info on my specific problem, or with a "Phantom" problem, contact him directly.


Ben is an outstanding individual, and ready to help a fellow NSX'er even if they are on the other side of the country.
He cares more about your car than you do...Really, he does.

Send him a PM
Here is his profile:

http://www.nsxprime.com/forum/member.php/14909-redbird92