SHADY280

pulling #5 makes it run not too bad, i tried the others and the idle is effected more, so #5 it is, least effect so the tester doesnt notice, it even has decent power still, i call #5 the incase cylinder - incase you need to win against a mustang

jfairladyz

Yeah I noticed that too. Some cylinders have a bigger impact on how the engine runs then others. Not exactly sure why, but it just happens that way.

thxone

That is true, when I first got my car the number 2 and 3 spark plug wires were crossed and it sucked off the line but it would still pull hard top end. Much better with them correct though.

Just to add to this I noticed it also shifted harder when they were crossed...I can't figure out why.

NismoPick

J... didn't you say that the injectors all spray at the same time on the 280zx?

jfairladyz

yeah they all fire at the same time. But the spark plugs dont. he had sparkplug wires crossed, which isnt really relevant to whats being discussed here though since we're talking about killing fuel to a single cylinder.

Crossed sparkplugs can do damage. You've got the cylinder firing at the wrong time and that HAS to be corrected. At higher speeds the misfire isn't so bad cause the pistons are moving so fast so thats probably why it sucked at lower RPM's but wasn't noticeable at higher RPM's.

thxone

Yeah it is fixed now, I know it would have messed up an emissions test for sure cause you could smell raw fuel at the tail pipe but it is all gone now. Plus no emissons here in Fl.

NismoPick

ah yeah... for some reason I thought he said injectors... not plugs. my bad.

WildmaN

Well I failed again, worse this time. Here are the readings:

Hydrocarbons HC 3.56 limit 3.00 Fail (Closer)
Carbon Monoxide CO 33.91 limit 25.00 Fail WTF?
Oxides of Nitrogen NOX 2.34 limit 3.50 Pass (Lower)

So since I am off tomorrow, I am gutting the other cat, because as you can see. It is useless, and shot. And I am putting a few gallons of high premium fuel with pass a emissions bottle. And go either Saturday or Monday. Then if I don't pass, I am getting a new cat, and try again. The damn smog ***** are not winning this battle. I refuse to get rid of my old cars.

entropy31

man that sucks. keep at it. and i think i read somewhere that using premium fuel actually hurts you on a smog test. i think thats the reason they only get 91 in cali. not 100% sure, but someone else should be able to confirm this.

WildmaN

91 here in AZ, but I have done the trick before, and passed great with my '81. And considering it is the same motor, it shouldn't be any different. I am also leary on unplugging my #5 injector, as Shady has suggested. That they could see that, and maybe question it. I don't want to hassle with that. Like I said, I am gutting the cat, and dump the bottle in. If I fail again, I am getting a new high flow cat, or regular depending. And as soon, as I pass, the cats get switched back over.

jfairladyz

Higher octane is harder for your engine to burn and so you're more likely to have unburned hydrocarbons left over after combustion. That will have a negative impact on your emissions. It sounds to me like your cat is the culprit now. The cat is the main controller of CO output which is where you failed. And just so you know, removing the #5 injector is probably EXACTLY what you need to do at this point. By acting as an air pump it will significantly lower your CO output.You dont have to remove it completely. Just pull it off the connector and then rest back on the connector (but dont plug it in). Then use electrical tape or something to hold it in place til the test is over. I wouldn't waste your money on high octane fuel or that pass emissions stuff.

EDIT: And if your cat is going bad then gutting it will only make things worse.

SHADY280

j hit that one right on the nose, its looks your after, there too stupid to notice, also put in some mythel hydrate, about 500ml to 1 liter, it will help drasticly in emmisions and is untracable.

Fast240Z

If you want to pass emissions, do not gut your cat! What you need to do is warm up your Z before you take it in to get it smogged, such as driving it around town for a good hour or so before having it tested. I had to have my 94 Ranger tested 3 times before it finally passed here in Cali, all because I failed to warm the truck up properly. The cat needs to be piping hot in order to pass emissions.

SHADY280

drive around in 1st gear in town at like 30mph, thatll get it right hot, and keep your engine reved up if your sitting in a line waiting

NismoPick

Hey Wildman... You didn't pay that shop the some $80 if your car still doesn't pass did ya? I'd be pissed as hell if a shop charged me & it still doesn't pass.

jfairladyz

Thats why I dont pay a shop for anything. If I can't fix it then chances are they cant either.

WildmaN

The thing is they didn't have a dyno, to test the emissions part of it. They just said I had the #3 plug bad, and also the cat was bad. Plus the o2 sensor was no good. I know the cat was bad, because even after I leaned out the A/F mixture, today, it still was putting out wet black smoke, and soot. So I switched back to the hollow cat. No more black smoke, but still I smell a rich smell. It is drving me nuts. I am going to drive him tonight, and see if he clears up better.

And yes I did pay the $90 for the shop to look at it. And believe me, I am really irritated right now.

lww

If you're running rich, it'll ruin your cat and any cat you replace it with.

Before you spend another $90 on smogging this thing, we need to figure out what's wrong with your Z.

WildmaN

Yeah I am running rich. I am going to try the AFM rebuild on the '81's I currently have in my Z now. And see if that helps, it is boggling me. And I have leaned it out as much as I can. And it still is running rich. So that is why I am going to attempt the rebuild of the AFM. Will let you know, how it goes, and thanks everyone for the support. I am not sure how many more 3 day permits I can get, before I get the limit. I think I have 1 more, I can get, after that. I will have to park the Z, until I can figure out what is wrong with him. I hope I don't get to that point though.

Dashibhs2004

Hey man I don't know if you have access to one or not, but if you can get an air/fuel ratio meter, after alot of fighting a friend and I learned that the best air/fuel ratio is 14.7. It provides the most power. Now I know a number that high sounds dangerous but after many years of testing on a 350hp turbo charged 4 banger and his dads 550 hp turbo charged eclipse (FAST) I have learned not to doubt his advice. At 14.7 to one the fuel is completely burned and there is no excess air/fuel or something like that I can not remember exactly what he told me, but it would probably be good for an emissions test. If you have solid state valves make sure they are in adjustment also, bad adjustment on those things can make your Z run like complete crap

jfairladyz

Yes 14.7 is good for emissions. But it NOT good for power. Too lean.

WildmaN, do you have a multimeter? If so check to make sure your cylinder head temp sensor is working. If your car is stuck in warm up mode cause the sensor is bad then it will run rich full time. Make sure the connector is good too.

WildmaN

Yes I have one J, but what should the readings be? And also, I bumped the head temp sensor yesterday. And the car bogged, so I know it is important. It is located on the passenger side head correct? Anyway like I said, I am going to try your AFM rebuild, and see if I can't get my Z to run leaner. If it doesn't, he is parked after I run out of permits for the year. And when somebody that knows these cars, much better than I do. Helps me with it, that is how it stands now. But I hope the AFM rebuild does the trick.

lww

Your cylinder head temp sensor and water temp sensor will control whether or not your Z thinks the engine is fully warmed up or not.

If either of these are faulty or reading 'cold' due to corrosion or additional resistnace in the line, you will get a rich mixture.

I think you can still get the CHTS from Courtesy Parts for about $35 and the water temp sensor for about $25.

Before buying new ones, use electrical contact cleaner to clean the contacts on both and then seal them with dielectric grease. Both can be had at Radio Shack for cheap.

Good luck dude!

lww

Either your friend doesn't know what he's talking about or you mis-heard what he said.

14.7 is WAY to lean for best power. The accpeted 'standard' for maximum power is in the 12's.

WildmaN

Allright, now I have a crappy update at the moment anyway. I took my AFM off, and did the simple rebuild on the carbon track. Now the ECU won't read it, and I cleaned the contacts, and everything else. Now I wish I didn't mess with the AFM at all. And get this, the one I thought was no good, on my motor or Carl's. Works in my '82 now, go figure. So now, my Z is running like crap still. And running real rich, and missing like crazy. WTF? I am going to try, and clean up the '82's AFM. And if that doesn't work. Try to figure out why the '81's took a crap. And why the ECU won't read it. But I am struggling right now. And trying to keep up with my bills. And my other vehicle needs a tune-up bad. But it still runs and drives, just kicks a high idle.

Now I believe I need another AFM for a N/A motor. So if anybody has one, for cheap. I would really appreciate it. And I will also post it in the wanted section.