misfire on #1 cylinder

[the hunter]

I have been chasing a rough engine problem on my 93 NSX for a long time. She has 92,000 miles and has run great since purchase a year ago. Intitally diagnosed as failed O2 sensors, these were replaced but no improvement. Then new plugs and a suspect rcoil eplacement but no change. I replaced all the injectors, no difference. Then the dealer did a full electrical check and confirmed no issues with the wiring or ECU. So I am left with a misfire on #1 which the dealer's mechanic thinks could be a burnt valve. However, the compression test was OK. Cleaning the fouled plug cleared the problem for a short while before the misfire came back. My dealer started to make $4,000+ labor quotes for an engine stripdown so I need a second opinion. Any ideas what could be causing this? If it is a burnt valve, why is the compression test good?

 

[drew]

Is the #1 spark plug fouled or something

Some reasonable guesses:

Bad ignitor? 30120-PR7-A01

Clogged injector? Get them cleaned.

or bad connections to either of them.

**

I kinda doubt you have valve issues, but a leak down tool is nice to play with.

Maybe a flat cam lobe could cause a misfire error.

You are probably due for a valve adjustment, which can't hurt.

Drew

 

[Daedalus]

the dealer's mechanic thinks could be a burnt valve. However, the compression test was OK. My dealer started to make $4,000+ labor quotes for an engine stripdown so I need a second opinion.

Change the mechanic. Not a burnt valve. They want to charge you $4,000 to tear down the engine and inspect piece-parts, but the needed preliminary diagnosis is best performed on an assembled, running engine. Do a 5-minute (or less) vacuum gauge check. If the vacuum response is good a tear-down is not needed.

 

[RON98]

dont trust dealers worth sht. they dont work on these cars enough and have no idea where to start.

quit throwing $ at the car when you dont know the problem.

The injectors can be easily tested with a volt meter in about 5 minutes so you didnt need to waste your money there.

the ECU harness test is also pretty straight foward and should take about 5 minutes.

also im not sure what they mean by full electical check.. but it sounds like bull shit. They checked the battery and alternator? or did they acturally test the wire harness? my guess is they would be too lazy to acturally do the work. coming for a shop that would suggest to charge you 4000$ for a tair down, im not suprised if all they did was check battery and alternator.

With the coil packs, you could do an easy test too to determine if they are within factory specs... which takes another 5 minutes.

whats your compression check figures? im not sure what OK means but i would not be suprised once again if they didnt do the work

there is only three things that can go wrong, fuel, spark and compression.

test your injectors and injector harness to make sure right signal is getting through.... so your fuel should be ok since you got new injectors and they said they did the "harness test", spark..... new spark plugs and coil packs.... so that should be alright..... so leaves us with compression... do a preasure leak test... takes about 10 minutes to setup and do for on cylinder. thats your best bet to see if the valves are burnt... i dont know why they need to fken strip your engine.... if anything, they could stick in a fiber optic scope through the spark plug hole to see whats up from the back side, if there is a chunk missin off the exhaust valve then we know what you need.

stay the hell away from these fken retards. btw tell them mr ron said their mechanics are retards who cant trouble shoot with out a scan tool.

go else where , you already gave then enough of your money.

 

[the hunter]

PROBLEM SOLVED THANKS TO BEN AT DAISY IMPORTS​

After months of trips to my local dealer I was facing a potential engine strip down and a huge bill because they suspected a bent or burned valve. (I had replaced the O2 sensors, all the plugs, all the fuel injectors and a coil with no improvement at all). I finally got this problem solved thanks to Ben at Daisy Imports in Maryland. This guy is a real NSX expert. Withinin a few minutes he confirmed the engine had perfect leakdown results and he then looked behind the CEL codes to track down the real cause of my misfire. (something my dealer just could not do!) It was just a simple case of replacing the air inlet and water temperature sensors. Ben also made some other adjustments and my 92 NSX is running like a dream. He is very reasonable and I will certainly go back for more work in the future.

So all you NSX owners in the DC, VA and MD areas or anybody else on the east coast looking for an expert NSX service and repair shop which is run by an NSX owner just head to:

DAISY IMPORTAUTO CARE CENTER
2878 Daisy Road
Woodbine, MD 21797

ask for Ben or Shawn 410-489-9334 or 410-292-9259​

 

[Daedalus]

That's good to hear. So was the problem not actually isolated to the #1 cylinder only? Or was there something else that made the particular cylinder problematic?

 

[redbird92]

Hello,it was a combination of the Igniter, TW sensor and a very dead MAT,coeds set also , I think NSX's with mileage and years of service , these sensors etc are damaged with age and Heat soak. Something to think about;] Car also needed a valve adjustment, probably never done from what I found.

 

[53heloFE]

Hello,it was a combination of the Igniter, TW sensor and a very dead MAT

What are the TW sensor and MAT exactly?

 

[Daedalus]

TW is water temp sensor. I assume MAT is manifold air temp sensor, which is referred to as the TA sensor in the manual. There's also a MAP sensor--manifold absolute pressure. The MAP plays a much larger role than the TA sensor in adjusting A/F and is a likelier culprit for poor performance.