Multiple misfire codes

Good idea take a day off and regroup . Turning the ground conn. around and reversing the module plugs ,not a good idea . When you replace the crush washers tighten to spec.( banjo bolts 21 lb.ft. , 6mm service bolt 8) . Next I would back step and check everything you did to this point . If possible you could try and replace the module (not buy, maybe borrow one ,they are expensive) as you stated you found the ground loose ,electronic devices do not like to lose ground and this would rule out the module. Good luck
ralph

ralph cerbone said:

Good idea take a day off and regroup . Turning the ground conn. around and reversing the module plugs ,not a good idea .ralph

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No worries here as I stated. The connectors have different sized pins and there was no way they were going to plug into another socket. I was just hoping it would be like the real ignitor and you could switch them around to see if one side was bad.

ralph cerbone said:

When you replace the crush washers tighten to spec.( banjo bolts 21 lb.ft. , 6mm service bolt 8) . ralph

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Yep, torque is your friend. I might have been over-tightening them and crushing the crush washers!

ralph cerbone said:

Next I would back step and check everything you did to this point . If possible you could try and replace the module (not buy, maybe borrow one ,they are expensive) as you stated you found the ground loose ,electronic devices do not like to lose ground and this would rule out the module. Good luck
ralph

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Yeah, I've double checked all of this. I'm hooking up with a fellow Primer tomorrow so we'll swap his module onto my car and see if the codes go away. If they do I'll start to look for somebodies parts car so I don't have to pay full price. I can only imagine what they go for.

Ok, your in the right direction ,take your time , always remember "measure twice cut once " . As far as the fuel fittings , heres the deal ,because they are so hard to break loose many guys over tighten them . The reason they seem tight is not the installing torque but is a function of the copper sealing washer. When fuel or brake fittings are tightened in production vehicles it is done in one continuous motion until spec torque is reached and then stopped . Not like I'll tighten it a little more ,this is where the overtighten takes place and they start to leak. When you break the fitting you can see how the washer is disfigured ,spread and results in a leak . you can retighten it but it will still leak .
Regards
Ralph

I'm here with John Martin. Looks like it could be a blown head gasket. Hard to believe with an entire motor rebuild by DA just 9 months ago. At least I'm in good company, Eddie's car is parked next to mine. We'll know for sure in an hour

Good news, it's not the head gasket. I've got good spark so John doesn't feel it's ignition related so that brings up fuel delivery. But I'm pushing 10 lbs more than stock due to the Walbro 255 install. He's still at it. We'll keep you posted.

Valhalla said:

Good news, it's not the head gasket. I've got good spark so John doesn't feel it's ignition related so that brings up fuel delivery. But I'm pushing 10 lbs more than stock due to the Walbro 255255 install. He's still at it. We'll keep you posted.

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Good to hear. Hope you get this resolved quickly!

Valhalla said:

Good news, it's not the head gasket. I've got good spark so John doesn't feel it's ignition related so that brings up fuel delivery. But I'm pushing 10 lbs more than stock due to the Walbro 255255 install. He's still at it. We'll keep you posted.

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Whew! Shad knows NSX.....its not him:smile:

Oh I know Shad knows his NSX. Just eliminating what might be causing the codes & coolant entering the cylinders through a bad gasket could cause these error codes on one bank. I am thrilled we don't have to pull the motor. That being said, we still haven't found what IS causing the codes.

And we still don't. Spent the whole day there. I'm taking it back next week when John is back. He feels there maybe something up with the injector loom on the rear bank. So, I'm still looking at damn flashing lights. I'm really learning to not like my dash:frown:

Dropped the car on Monday morning and had the head service guy give me an update this afternoon. This is what they have checked;

• Fuel system - everything checks out better than OEM
• Valves adjustment - Looked good but possibly a little tight on the rear bank exhaust so they adjusted them.
• Timing - Dead on balls perfect.
• SMOG - passed with no issues
• Plugs/coil packs - moving them around makes no difference in where the misfire codes are.
• Compression and Leak Down - I'm at 175 on all cylinders and 90%. No issue there.

That leaves the ECU as their next point of interest. They are at 5+ hours under the hood ($$$$$) and don't have any more idea what is wrong than we do. Granted they have spent probably twice that amount of time searching for this but damn. I'm getting real close to just taking the car back and unplugging the freaking dash lights.

Found the problem. Just got back from the dealership and I'm headed right for the tequila. Don't even need a glass. The engine wiring harness is fried. The wires that go to the rear injectors got so hot that they are brittle as can be. Looks like there was some extra resistance in the line and the wires got hot. The loose ground that was found would not have affected this, so I'm told. They also found that the plug that goes into the spark plug indicator box was missing some prongs, so they replaced them and that is when they could tell the circuit was not complete.

So anybody out there have an engine wiring harness in great shape for a '97 NA2? They think they can source one from one of their (Honda) warehouses but it might also only be in Japan. You don't even want to know how expensive this is. Where is my freakin' lime wedge....

I sourced an engine wiring harness for a '97 that has never been hacked into. Being sent out to Jon Martin tomorrow. With a little luck....

Shad at Driving Ambition is the bomb. Fantastic to deal with. You guys in NoCal are so lucky to have him.

Problem solved. I doubt anyone will ever want to archive this thread as the issue(s) were so off the wall it's not funny. But after robbing a bank and handing a sack of money over to Power Honda, the car now runs as it should. Here are some of the gory details.

To summerize, Jon and crew went over the misfire codes. They looked at the ignition, the fuel system inclusive of pressure. They looked at compression, leak down tests and overall motor health. They placed it on the SMOG tester twice to verify the ECU was functioning properly. They inspected the cooling system to make sure there were no leaks. They started testing wires, circuts and connections and that is when things got interesteing. While inspecting the engin harness for the rear bank injectors they found a ground wire that was fried. They dug a little deeper and found the frequency insulator wire that wrapps around the injector wires was all brittle and broken. Then when they inspected the actual injector wiring they too were all very hard and easy to break. There was a heavy resistance in these wires causing them to over heat. But from where?

They installed the new harness but before firing up the car and frying another loom, they went back through the whole circuit and tested every pin and connector. What they eventually found was the pins and connectors at the spark firing module (the part I initially thought was bad) had very loose connections and this is what caused the resistance and extra heat. This also caused the module to die further adding resistance and more heat. It was just a question of time before there could have been a small fire.

So a like-new engine wiring harness, a new spark indicating module and two weeks of diagnostics and replacement and the car runs like new. I forgot what it felt like. Jon also played with the numbers due to the amount of time he and his guys invested in this. It wasn't cheap but they did a good job in the end. I am now whole again.

Is there anything else you guys want me to diagnose? I'm starting to get too good at this!

You helped remind me that faulty wires is as good a culprit as any. Thanks for that.

You can now help diagnose why i'm so slow and why LMR is even slower...

I'll be noticing that more and more as you get smaller in my rear view mirror:biggrin:

Yes, I can help you. But it will take many Benjamin's to remedy. Are you ready?

Valhalla said:

I'll be noticing that more and more as you get smaller in my rear view mirror:biggrin:

Yes, I can help you. But it will take many Benjamin's to remedy. Are you ready?

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track day on the 31st. Bring it! :biggrin:

RYU said:

You can now help diagnose why i'm so slow and why LMR is even slower...

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No gifts for you now:wink:

Valhalla

Thanks for your detailed analysis and communication of your issues. I recently purchased a 98 nsx-t with the exact symptoms you had. Rear bank misfires and TCS light. Idles pretty crappy with a slight boom. Just had a new ECU installed under recall and new plugs going in shortly. Was going to do full bank of rear coils but will start to investigate wiring.

I'm wondering if I should go straight to the spark detection module and replace it right away?

Steve

I wouldn't. A new ignitor is $450. I'd check the wires first with an ohmmeter before replacing the entire car piece by expensive piece.

shern said:

Valhalla

Thanks for your detailed analysis and communication of your issues. I recently purchased a 98 nsx-t with the exact symptoms you had. Rear bank misfires and TCS light. Idles pretty crappy with a slight boom. Just had a new ECU installed under recall and new plugs going in shortly. Was going to do full bank of rear coils but will start to investigate wiring.

I'm wondering if I should go straight to the spark detection module and replace it right away?

Steve

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Bump for the month.
I'm getting similar symtoms, got random misfire with multiple codes.
Have you fix this issue yet besides Vahalla?

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It would help if i put my codes here, duh....
They are as follows:

P0300 - random misfire
P1201 - cylinder number 1 misfire detected
P1202 - cylinder number 2 misfire detected
P1203 - cylinder number 3 misfire detected
P1204 - cylinder number 4 misfire detected
P1205 - cylinder number 5 misfire detected
P1206 - cylinder number 6 misfire detected

Prior to this happening, car had been service for new timing belt/wp & new clutch put in.
2 days later this happens...Was driving on highway at about 70 & all the sudden wham!.. got a hiccup, what the hell just happen??? i ask myself....

Then i decide to turn around & head back home that's when first green blink TCS came on & then CEL, stopped immediately at a nearby gas station, turn off the car, then turn car back on, CEL still there but TCS cleared, car started fine until i started heading towards the road & stop at the red light, then bam....

Car died...Started right back up, thought the AC maybe draining the battery so turn AC off, started car again, stayed on for 10 secs then bammm.. died again, started it back up again, this time gave it some major revving & no more dying... since then it's was fine driving home....

Could this be early symptoms of some other issues similar on this thread or this happens to be coincidence right after dealer touch it??

I know i will have to have dealer answer this, but, would be good to know if someone here had this issue & was able to solved it....

I am taking it to dealer first thing Monday morning but any insights, suggestions, exact or similar experiences would help before i take it to the dealer (stealership) & make sure they are not trying to pull a fast one.

Thanks..

timeless1 said:

Bump for the month.
I'm getting similar symtoms, got random misfire with multiple codes.
Have you fix this issue yet besides Vahalla?

- - - Updated - - -

It would help if i put my codes here, duh....
They are as follows:

P0300 - random misfire
P1201 - cylinder number 1 misfire detected
P1202 - cylinder number 2 misfire detected
P1203 - cylinder number 3 misfire detected
P1204 - cylinder number 4 misfire detected
P1205 - cylinder number 5 misfire detected
P1206 - cylinder number 6 misfire detected

Prior to this happening, car had been service for new timing belt/wp & new clutch put in.
2 days later this happens...Was driving on highway at about 70 & all the sudden wham!.. got a hiccup, what the hell just happen??? i ask myself....

Then i decide to turn around & head back home that's when first green blink TCS came on & then CEL, stopped immediately at a nearby gas station, turn off the car, then turn car back on, CEL still there but TCS cleared, car started fine until i started heading towards the road & stop at the red light, then bam....

Car died...Started right back up, thought the AC maybe draining the battery so turn AC off, started car again, stayed on for 10 secs then bammm.. died again, started it back up again, this time gave it some major revving & no more dying... since then it's was fine driving home....

Could this be early symptoms of some other issues similar on this thread or this happens to be coincidence right after dealer touch it??

I know i will have to have dealer answer this, but, would be good to know if someone here had this issue & was able to solved it....

I am taking it to dealer first thing Monday morning but any insights, suggestions, exact or similar experiences would help before i take it to the dealer (stealership) & make sure they are not trying to pull a fast one.

Thanks..

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certainly sounds like the timing belt was not installed properly & timing is perhaps off on all cylinders. maybe it wasn't tensioned properly and skipped a tooth or more in the days after the replacement. Personally I wouldn't drive it until that is ruled out.

I agree 100% with vivanshah. You are throwing codes on all cylinders and as it happened after service, I would look at the timing belt as well. Do not drive the car.

timeless1 said:

I am taking it to dealer first thing Monday morning but any insights, suggestions, exact or similar experiences would help before i take it to the dealer (stealership) & make sure they are not trying to pull a fast one.

Thanks..

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are you taking it back to the same dealership? do they have someone there with many NSX major service experience? Probably not otherwise this won't happened as this is a difficult job doing it with the engine in the car. We all think TB is the most likely culprit but the stealership can spin it differently as many do. The tech can check it again but can you trust his work?
AFAIK, cking TB is not a quick 15 min. job and correcting it(if they willing to admit that is the problem) is much longer. I hope this dealership is willing to redo their work right for free and not turn it into a nightmare for you as I am sure someone there has extended B, K experience but not our C engine.
Keep CCC when you talk to them.

I am going to add that I have had many cars come in with this issue and most are fixed by replacing the coils, igniter and plugs.

- However, I have 2 cars that have not been successful. My own and one other, we suspect that it is the MDU and this is an expensive part but shows the same symptoms on RL and TL of the same vintage - I think I am close to cracking the case, we shall see.

I'm with Angus here. Pull the coils and the plugs. I'm not sure why Honda allows it to throw codes for all cylinders, but it is very likely that only one coil is to blame.