92 Ranger failed NJ Emissons Inspection... Any helpful hints to fix?

[Arquest]

I would like to bounce a couple of ideas off you guys...

My '92 Ranger 3.0 just failed the NJ DMV inspection for high NOx. (185,000 miles).

- High NOx is related to high combustion temps and/or lean fuel mix - correct?
- No EGR on '92 3.0... That would have been too easy

Here is the list of parts I am planning to replace:

Spark Plugs / Wires
Fuel Filter
O2 Sensors (2 before Cat)
Clean MAF
Clean Injectors
?? Anything else ??

I am going to avoid replacing the CAT if I can.

Any other suggestions?

FYI - The truck has an almost totally new cooling system (rad, lines, core) and runs nice and cool.

NJ has a waiver available if you spend at least $450 on repairs... I normally do all my own work but this time I may just farm it out to a local certified shop with a $450 cap on the work order... I am thinking this for three basic reasons - 1) they can test NOx as they go so perhaps not all the parts will need to be fixed (ie: I MAY spend less than $450) - 2) I hate trying to get O2 sensors out if they were not installed correctly - and 3) ever try changing the rear sparkplug one the passenger side - yikes...

What do you guys think? Any other parts that I should be going after?

Thanks in advance...

 

[slownis]

I cleaned my MAF just yesterday. If you have the correct bit (tamper resistant T20 torx bit) its literally a 5 minute affair, after you get the spray can of cleaner. If you have the bit, I'd do it myself anyways, and then have them run down the list, because I wouldn't be able to stand the thought of paying someone else to do it.

I don't really understand your reasoning behind number 2. Are you worried the last person installed it incorrectly? If so, gotcha.

 

[racinranger]

I have had good luck with NJ inspection and using a product sold at parts stores and walmart called Guaranteed to pass or GTP in a bottle you add to your fuel. you run the whole tank through and go through with a fresh tank right away. I've got through a 88 minivan, a 88 bronco II and a 95 f250 with a 351w in it. so i say give it a shot and then run it through

 

[Arquest]

Well new plugs/wires and a bottle of GTP didn't work - actually NOx went up not down. Actually I kind of got messed over when I was at the DMV Inspection - the coffee truck pulled up and they left my truck running sitting inside the inspection station while they went for their break. Not Happy!

As I was running out of time, I then took it into a local repair facility and paid them for the 'inspection'. Sticker is now on the window and all is good now...

 

[4x4fun]

get the engine nice and hot (easy to do if you have an electric fan.) or you can put some rubbing alcohol in your tank.

 

[fixizin]

FYI - The truck has an almost totally new cooling system (rad, lines, core) and runs nice and cool.

Umm, hopefully you didn't replace the thermostat with a lower temperature rated one, thinking it's "good" for your engine--it's NOT. Running your combustion chambers TOO COOL can have adverse effects on your engine, and no doubt your emissions too.

 

[Arquest]

Stock temp. thermostat was put in (don't have the temp on hand at the moment)... Engine does run at a normal temperature...

The issue was high NOx which is a function of a lean running engine. Fix is likely related to the coolant temp sensor for the computer or a new Cat. After all the truck has 185,000 miles and I have no idea how it was maintained or what has been replaced over the years. It looks like it may be the original Cat (complete with hose clamp around the shroud which was Ford's answer to a common problem with rattling cat's)...

Either way - I decided to go under the table and pay for the sticker. That will be good for two more years which may be longer than this baby has left...

 

[McCormack]

FYI - The truck has an almost totally new cooling system (rad, lines, core) and runs nice and cool.

Umm, hopefully you didn't replace the thermostat with a lower temperature rated one, thinking it's "good" for your engine--it's NOT. Running your combustion chambers TOO COOL can have adverse effects on your engine, and no doubt your emissions too.

That's a MYTH... the cooler (within reason) you run an engine the longer it will last. Of course for emissions purposes you are going to need some heat in the engine, but scads of us Ranger owners run 180* thermostats in our 3.0's and we have no problem what-so-ever passing emissions, our engines run better, and like I said they're going to last longer to boot.

 

[TomB1269]

FYI: I had a 92 grand am 3.3 liter...IE no EGR either, NJ inspection one year 1 point from failing NOx, 2 years later, pulled in with fresh oil change and nice warm motor, NOx 300-400 points lower. (may have change plugs, but do not think so), and the mileage on the cars was about the same as yours. Remember the crank case gets vented to the intake. With an old engine and old oil lots of crude going out the tail pipe.