NJ emissions, '90 GW

[DjD]

Great forum, have been reading this place non stop for 2 weeks. Hope you folks can give me some advice.
After a lot of work, got the CO and HC's under the limits, but the NOx is out of line. Got it down a little bit by pulling and cleaning the EGR valve. Evidently the NOx has to do with too much heat somewhere between the spark plug fire in the cyl. and the end of the exhaust pipe. The tech guy? at the inspection station finally had a long talk with me to diagnose the problem (guess they've seen too much of me, 3 times one day 5 times total). He says high NOx is probably the catalytic converter. But from what I've read I don't have the symptoms of a blown cat. (I could be wrong). Symptoms are supposed to be no power during acceleration, and stalling after it is warmed up?

The law in NJ is that after you spend $200 on emission problems, all you have to do is pass the idle test instead of the dyno (driving on rollers about 25 mph?) and if the numbers pass the lower standards you get a kinda 2 year exemption. The guy says based on my numbers on the driving test I would probably pass the idle test, but he didn't look real sure. But I've only spent about $180 so far. So I'm thinking of putting a few bucks into general tune up stuff (plugs, etc.), which I should do anyway and say it is for emissions and get the $200 exemption.

If I knew a cat. would solve my problems I would gladly put one on, but I just don't want to keep throwing money at different things with no results. And, of course, I'm Mr. Parsimonious.

GAS-----STD------READING------RESULT
NOx-----1076-----1477---------FAIL
HC-------159-------42---------PASS
CO%--------1.42-----0.00------PASS
CO2%---------------12.6
O2%-----------------3.2

Does anybody think if I richen the mixture it will bring the NOx down under the 1076 number. Screws are now 1.5 turns out after rebuild on the 2150.
I'm a newbie, not very mechanically inclined, well I just don't have the tools but have some great family and friends. Just bought the vehicle and trying to get it on the road.
Sorry if a bit long.
Thanks for any advice!

[ August 27, 2001: Message edited by: DjD ]

[reddog]

Welcome!!

Not an expect here but I do have some experiance with my 87. How does yor truck run? I would suggest checking all the vacuum lines to make sure they are intact with no leaks. Second thing that came to mind is looking at your HC reading you could go a little richer which MAY help lower your NOX readings - richer = cooler combusion temps. You could try turning your idle screws richer but I don't know how much the idle circuit is still working at the speed run on the dyno. I think that raising your float level may also richen up your mix some also. The tune up is not a bad idea especially if that puts you over the $200 limit.

Kerry

[mahlmann]

This topic comes up regularly on Jeep forums. Changing spark plugs on these dinosaurs is such a snap you should do it just for the FUN! Here's some other info that might help.

Smog Check Tips from California.

Baseline tips: make sure you don't have any vacuum leaks. Premium fuel and cold air won't help. You want your idle mixture set about 1/4 turn leaner than maximum idle speed and your engine fully warmed up. Set timing and idle speed within factory specs. Take it out on the freeway (turnpike? - whatever) and warm it up completely before you take it in for test. I got the following from a vendor on ebay who was selling this as a guaranteed way to pass the smog check. The short version is, run your car down to just 2 or 3 gallons of gas left and add 5 bottles of "SILOO" gas tank additive. It's mainly isopropyl alcohol which is a main ingredient in any of the gas "dryer" or water removal additives. It comes in a white bottle with an orange label. I don't think there is anything special about this particular brand, but it's what was recommended. Drive it a couple of miles to make sure the "new stuff" is going through the carb and get it tested. Then, fill it up with regular gasoline ASAP.

So far, my '87 has always passed with very low emissions without using the gass additive since I dumped the Motorcraft 2150 and switched to an Edelbrock, but these suggestions are not carb specific.

Good luck with it! Let me know how it turns out.

[Rolling$Pit]

Wow, you just scared me. I've got an 87, due for NJ inspection next month. First time for me taking it through. Is anyone familiar with the NJ rules? I've read where you CA guys can't do much to the engines, even if the changes pass smog. I'm planning on doing some upgrades like carb, manifold, possibly EFI but don't want to screw up emmissions testing. Any thoughts?

[mahlmann]

Keep the stock air cleaner, cold air hose, and all somg stuff in place and you should be OK. These things don't make much smog when they are tuned properly and all the equipment is in place and working. I'm running an Edelbrock intake manifold and 4bbl carb on my Waggy and the visual inspection guys have never noticed because they can't see past the air cleaner and all those vacuum and water hoses!

[DjD]

Got under the jeep today to see if cat. was welded or u-bolted onto exhaust system. Turns out it is bolted so probably not the original?

But, more importantly, there is a metal hose that runs from the air pump to a little tube coming out of the cat. Well, the air pump tube was cut and folded forward with a kink and the tube coming out of the cat. was squeezed flat/shut at the end. So I hack sawed both tubes back to a good round spot. Tomorrow I plan on inserting a piece of copper flexible tubing in there with some exhaust sealant and hose clamps. This should get it through, providing I can get an air tight seal.

Anybody see any flaws in my plan of attack?
Anybody know of a good liquid/paste exhaust sealant?

Rolling$Pit, from what I've read here, CA inspectors actually crack the hood to make sure everything is in order. NJ people don't open the hood, they just care about what's coming out of the back. They do look all around under the vehicle with a mirror, for I don't know what. Originally they also failed me for "steering wheel lash", too much play in the wheel. We fixed that with a $10 kit.

[jeepguzzi]

They are looking for a converter and muffler with the mirror. I just had mine passed in Illinois after failing the first test. One other simple thing to check is the timing. If it is off, it will have a big effect on the test.

Does anyone know if there were metal tubes running to the cat on a 1985 J10 with the 360?? :confused:

[reddog]

<BLOCKQUOTE>quote:</font><HR>Originally posted by DjD:
But, more importantly, there is a metal hose that runs from the air pump to a little tube coming out of the cat. Well, the air pump tube was cut and folded forward with a kink and the tube coming out of the cat. was squeezed flat/shut at the end. So I hack sawed both tubes back to a good round spot. Tomorrow I plan on inserting a piece of copper flexible tubing in there with some exhaust sealant and hose clamps. This should get it through, providing I can get an air tight seal.

Anybody see any flaws in my plan of attack?
Anybody know of a good liquid/paste exhaust sealant?<HR></BLOCKQUOTE>

Sounds like a good idea but I don't know how much it will lower NOX. I have seen some exhaust sealer that is a kind of tape you put over leaks. When the exhaust gets hot it melts and seals.

Kerry

[FlakeyJake]

<BLOCKQUOTE>quote:</font><HR>Originally posted by mahlmann:
. . . I'm running an Edelbrock intake manifold and 4bbl carb on my Waggy and the visual inspection guys have never noticed because they can't see past the air cleaner and all those vacuum and water hoses!<HR></BLOCKQUOTE>

Wow! I'm impressed. Edelbrock told me not to try the manifold & carb on the jeep 'cause it would NOT pass the Denver emissions. But from what you are saying, it works just as clean as the 2BB setup? :confused:

[Rolling$Pit]

Well, I failed. Brakes aren't quite right, so here comes a brake job. Fine. But I also failed smog.

Req'd Me
NOx 2238 53 ok
HC 159 496 oops
CO% 1.42 8.75 not good

Guess I've been making the world a little hotter. any suggestions?
:(

[DjD]

Rolling$Pit, wow, your NOx reading was like my first go-through.

From what I've learned, the NOx reading is so low because you are dumping so much fuel down the cylinder which keeps everything cool (high NOx = high heat in combustion and exhaust chambers). So the mechanic says I need a carb. rebuild (Your gas mileage must be around 7-8 miles/gal.) That diagnosis cost me $50 which, I negotiated down from $65.

While into the rebuild I find out the PO had the power valve vacuum hose plugged with a screw. Therefore, the power valve, without vacuum to keep it closed, was open all the time. That cost me $75 plus a couple of lunches for the kit and labor (I know cheap, and should be done anyway, thanks to family and friends). My gas mileage went from like 7-8/gal. to 11-12/gal.

Check to make sure your power valve vacuum hose is connected to manifold vacuum. Some years are connected to the front manifold some to the back. If it is connected properly and the hose is in excellent shape, then maybe your power valve is blown. You can pull the hose off the power valve and if there is gas in it, then it is blown. That hose is for vacuum, not fuel. I understand they can be replaced without doing the whole carb rebuild. That knowledge cost $0, IFSJA.

If the power valve, Haynes manual calls it the "economizer valve", checks out OK, I suppose the next easiest check is to make sure your mixture screws aren't too far out of whack. Should be somewhere around 1.5 turns out (counter clockwise), but there is a proper way to set them.

But, if the carb has never been rebuilt, you might want to go that route. I went with the Borg Warner kit from Mechanic's Auto Parts item# 10748 for $45.44 with shop discount. It had the 2-stage power valve included. I'm talking about the 2150 carb.

All the fuel you're burning is causing the high HC and CO readings.

But, I could be wrong, I still haven't passed. Now looking into how the EGR works. As per my original post, my numbers are now the opposite of yours and my first go through. I wish I only had to pass the NOx numbers for an '87!

Know anything about EGR's?

[WINGO]

I just took my '84 through the NJDMV inspection station in Millville, NJ and was failed for not having my air tube conected from the cat to the air pump. With this lacking, they wouldn't even put me on the dyno.

Maybe I will just connect the tube. I have the kit but never put it on. Put on the new carb and be over the $ 200.00 limit.

Do you NJ guys think this will work?

[DjD]

WINGO, how bout that. I had about a 9 inch gap from where the air tube came down and wasn't connected to the cat. They never caught it on the 5 times I went through. I found it and corrected it myself with a piece of flexible copper tubing and 2 hose clamps, but it didn't help my emissions, still failed again.

Probably saw it cause you're jacked up so high. Yes, Millville inspection station, they should know me well by now.

Sounds like you have to fix the air tube or you'll never even get tested. I don't know if I would bother with the new carb until you see where the numbers are.

The $200 has to be spent on emissions which in your case, air tube and carb, would be true. But you still have to pass all of the safety issues and the emissions idle test.

My buddies over there (not really) tell me that they raise the numbers on HC and CO for the idle test and don't even check for NOx. NOx is my problem.

So fix the tube and let them run all the tests to see where you stand. Doesn't cost you anything but time to take it through. I really want to get mine through legit and will use the $200 waiver as last resort. I believe you have 45 days from your first failure and then they check you all over from scratch. I've been through 6 or 7 times, starting to lose count. I'm trying to find something to spend the last bit to get me over the $200. Maybe an EGR.

Let me know if I can help.

[<Jeff>]

We have a 87 J-10 in NJ as well as a newer car. I dont trust the folks to do dyno tests and any other of the new messing about with my car tests for inspection. I have found that my mechanic can do it for a check of 80$ for private inspection and we paid an additional 50 for exhaust/ vacuum pump work...

[WINGO]

Hey DjD:

Where's EB, NJ?

[<DjD>]

WINGO, "you've got mail". East Brunswick, hate to say this being from New J"o"rsey but, exit 9 off the Trnpk.