So the check engine light goes on in my car today. I check the code and it comes up 72 and 73. Any specific reasons this could happen? The only thing I did recently was regap the spark plugs yesterday that are only a 15 months old. I drove around yesterday and this morning with no problems. Light came on when I got in it the second time today. Car is still under dealer warranty. Any input or advice would be appreciated. Thanks in advance....

BTW - No engine mods. Just a Comptech intake...

 

looks like your second and third cylinders are mis-firing

 

Could it have anything to do with the spark plugs I removed and regapped yesterday? I hope I didn't do anything wrong. Would switching the plugs to different cylinders prove or disprove anything?

 

well hey..at least i know im not the only one with a cel code 73 problem. i still havent tried to take care of it since i cant drive the R yet. it came on last wednesday and i havent drivin the car since. hope someone can help u out. worst comes to worst, go to the dealer since its still under warrenty. but dont leave the R over night.

 

does it sputter at all? could be the inject0rs

 

No sputtering. Sounds fine. Just feels a little sluggish. Besides that, it idles and revs fine.

I just think it's strange that it came on the day after i pulled the spark plugs.

 

make sure everything is tightly placed.. you didnt' wash your engine bay any chance did you?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kicker773 &raquo;</TD></TR><TR><TD CLASS="quote">make sure everything is tightly placed.. you didnt' wash your engine bay any chance did you? </TD></TR></TABLE>


I do wash my engine bay every couple months. It's probably been over a month since I did that.

BTW - If I switch the plugs around and for some reason the problem is fixed, will the engine light go off by itself, or will I have to manually reset the ECU?????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Leo &raquo;</TD></TR><TR><TD CLASS="quote">


I do wash my engine bay every couple months. It's probably been over a month since I did that.

BTW - If I switch the plugs around and for some reason the problem is fixed, will the engine light go off by itself, or will I have to manually reset the ECU?????</TD></TR></TABLE>

not to sure about that.....

 

the engine light will go off by itself, but it won't go off right away. just reset the ecu everytime you try something to fix the problem. it'll come on if the problem is still there. anyway, why don't you try buying some regular spark plugs that will work and put them in to see if it fixes the problem. if it does, buy some new OEM NGK Platinums.

 

Just for ***** and giggles, last night I pop off the spark plug wires and put them back on. This morning I reset the ECU and notice that the check engine light is off. I then take it out for a ride for about 15 minutes, and the light is STILL OFF. The car feels as good as it ususally does. I'm rather pleased, but in the meantime, I cant' help but think that it'll probably come back on since I really didn't do anything.

If it does come back on, i'lll try switching the spark plugs around and see what that does. Thanks for all the input guys.

 

What did you re-gap the plugs to, and what were they before you gapped em?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tomakit &raquo;</TD></TR><TR><TD CLASS="quote">What did you re-gap the plugs to, and what were they before you gapped em?</TD></TR></TABLE>

I regapped the plugs to .04 inches. They were at approx .043. Just a really small difference. This is all according to the cheapo spark plug gapper.

Something I noticed on the gapper tool. .04 inches is NOT the same as 1.1 mm according to the tool. It appears that .04 inches is .95 mm on the MM side. It's strange. Am I splitting atoms here or could this maybe be the problem?

 

If I were you I'd recheck the gap on the plugs and make sure all of your wires are firmly in place.

Couldn't hurt, ya know?

 

Well I knew it was too good to be true. After a few trips out with the car and around 25 miles, the check engine light came back on. So I decided to switch the spark plugs around. Since 2 and 3 seem to be the cause of the light, i moved 3 to 1, and 2 to 4. Then reset the ECU again. Now so far, so good, again... I put about 30 miles on it since, so time will tell. Thanks again for all the input/help.

 

when i had a 7x code
i did valve adjustment
and it went away

 

Ive had a few friends come to me with the same problem....and every time it seems like the spark plug wires are not connected all the way either at the dizzy end or the spark plug end. That can cause the CEL. Check those next time, and buy new plugs, they aint that expensive

 

new plugs usually solve this problem. A tip : if you got a loud exhaust, you can know if your spark plugs are worned out when you release the gas pedal at high rpm, If you heard a lot of littles backfires, your spark plugs are misfiring...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BassBoy19 &raquo;</TD></TR><TR><TD CLASS="quote">new plugs usually solve this problem. A tip : if you got a loud exhaust, you can know if your spark plugs are worned out when you release the gas pedal at high rpm, If you heard a lot of littles backfires, your spark plugs are misfiring...</TD></TR></TABLE>
That doesn't sound like a good way to tell at all. Free flowing exhausts make a popping/back firing sound when all it is turbulence.

 

So one day you gap the plugs, and the next day you've missfired in 2 and 3.

Seems to me there is a direct relationship going on here. Re-gap the plugs, re-set the ecu and see what happens.

And no, the CEL will not go out by itself, the ecu must be re-set.

 

I am not talking about one back fire I am taliknig about like 10 of them in less than one second....

 

OK, the check engine light is back on again. But this time it only reads code 72, not 72 AND 73. Now my question is, which order do the cylinders run? When looking at the engine, is it 1-2-3-4 or 4-3-2-1? Sorry for the bonehead question, but I just want to be sure before I pull the spark plug out and check it. Thanks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dr Pooface &raquo;</TD></TR><TR><TD CLASS="quote">
And no, the CEL will not go out by itself, the ecu must be re-set.</TD></TR></TABLE>

the CEL will go off by itself IF you have fixed the problem. my 98 GSR threw a 74 a few days ago(wire on #4 disconnected from the plug), and before i checked the code via the diagnostic plug the lights had turned off

zer0

 

I got the same code too, but i haven't got it fix yet becoz my car has been store for the winter. I find some information (from helms manual) on what are the possible cause to it.
code 71 - cylinder 1, code 72 -cylinder 2, code 73 - cylinder 3, code 74 - cylinder 4. The possible cause might be coming from fuel injector, fuel injector circuit, ignition system, low compression, valve clearance, fuel line clogging, blockage or leakage.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Leo &raquo;</TD></TR><TR><TD CLASS="quote">Well I knew it was too good to be true. After a few trips out with the car and around 25 miles, the check engine light came back on. So I decided to switch the spark plugs around. Since 2 and 3 seem to be the cause of the light, i moved 3 to 1, and 2 to 4. Then reset the ECU again. Now so far, so good, again... I put about 30 miles on it since, so time will tell. Thanks again for all the input/help.

</TD></TR></TABLE>

Well that didn't seem to work either. I still keep getting code 72.

Since the problem seems to lie in Cylinder 2, I decided to replace the plug wire in that cylinder just for the hell off it. Same result. Light comes back on after a day or so. Same code.

Final solution. I replace the distributor cap with a new one that i've had since last summer. I put that on and low and behold, it's been 3 days now and over 120 miles and still no damn check engine light (knock on wood). The old dist cap looked fine accept for a couple hair line cracks right were the bolts are. Hardly noticable. Could that really have been it? Very strange. Hopefully now the light will stay off and I can consider it a victory and my car will be happy.