Smog Dilemma

[Guest brian peterson]

O.k., now I'm obsessed with getting my 87 with 212k mi. Pathy to pass Calif. smog! I've spent about $3,000 on four different shops (including the Stealer) and none can get it to pass smog.

 

I've rebuilt several engines myself, but never have ventured into the emissions control systems...seemed like too much hocus-pocus. But now that I've been tapped out financially, the wife says fix it myself or it goes to the scrap yard.

 

Help!!!!! I rebuilt engine about 10k ago (at which time it passed smog with flying colors). But now my HCs are way off the charts at idle. Everything seems to be within norms at 2500rpm.

 

I've read all the threads on this site...many were very helpful, but was hoping to get one more piece of advise that will solve this.

 

This is what I've done so far:

 

1. New (reconditioned) computer ...under passinger seat

2. New O2 sensor

3. replaced bad air inductor reed valve and canister

4. degunked the PCV valve

5. New air injector

6. New Throttle Position Sensor

7. replaced a few vacuum lines that were marginal

8. new air filter

9. new plugs

10. new injector seals (were leaking)

 

Have not changed the Cat conv. as a couple mechanics said that's probably not the problem.

 

What can else can be done? I can't tell you how grateful I'd be for any of your thoughts that give me a shot at holding onto my precious Pathy!

 

Thanks!

[BigMike]

have you tried bribing the attendent?

[88pathoffroad]

EGR system all clean and working properly? Mine was completely clogged before I took it off.

[MatterHorn]

some states will sometimes pardon your emmissions testing if you show that you spent a certain amount on it in an attempt to show you tried to fix it ... would be worth a look anyways ...

[transworldmoto]

Hey, I just bought an 88 Pathfinder, but I can't seem to get the backup lights to work, but all the other lights work. Brake and Turn Signals work, but not the reverse. It sucks. I fanyone knows why, please give me a hollar. Thanks!

[robinasu]

Hi Brian,

 

I saw cats online for 80 bucks, I would change that out if my ideas below don't work.

 

I didn't pass CA smog the first time as well. I found that the cylinder head temp. sensor was fried and giving bogus feedback to ECU based on ECU fault code and measurement with a multimeter.

 

Look for fault codes on the ECU. I just ripped off the plastic cover from the ECU under the seat. Flip the switch from normal position till the lights flash 3 times together, then flip back to normal position. If all is well you will get 5 red then 5 green flashes. If you get any other combination there could be a problem. I think the temp. sensor was 1 red 1 green, but forgot at this point.

 

Based on the factory manual, the inputs for mixture control include the cylinder head temp. sensor.. I found that when the temp. sensor was malfunctioning the ECU never would get into closed loop mode (i.e. never used the o2 sensor to control mixture) proved by putting the ECU into mixture ratio diag. mode.

 

The temp. senor I am talking about is buried under the distributor, not the coolent temp. sensor on top of intake. It is a MF bastard to get to. I am talking about the V6 here as well, but the 4 cylinder works on the same concept. Invest in the factory manual if you have not already. Don't mean to preach if you know this already.

 

Long story short is I disconected the temp. harness and put in a $1 300 ohm resistor and the sucker passed the 2nd smog try.. it was close though. I have the auto and I made the guy keep the tranny in power mode to keep the revs up. I am confident that a new cat would have helped the old beast easily.

 

Bottom line is mixture control is key, make sure all inputs are working correctly.

 

Maybe check the EGR solenoid, too. I think the main component of failure is ECU malfunction due to bad inputs.

 

Hope this helps.

[LINDERS]

I'm having a similar issue with my '97. So I understand the frustration. However, after spending 600 bucks I applied to the CAP (consumer assistance program). They offer financial assistance to help smog vehicles. It's a rather long and annoying process but they will provide a voucher for 500 dollars worth of assistance at an authorized mechanic. There are two versions of the CAP program. 1) poor people-you need to prove that you are financially needy with a w-2 or 2) if you've already spent, i think it's 500 bucks and have the receipts to prove it.

 

The information can be found on the Cal DMV website.

 

I figure heck- if the state will give me money I'll fill out a form.

[transworldmoto]

Yeah, so today i got my pathy for good. (I had a little trouble with the previous owner the past few days). Anyways, I can't seem to get the back-up lights to work, so I was wondering if anyone knew what was up with that. Also too, the darn fuel guage don't work neither, so i don't know what's up. ALSO, the hood latch doesn't push the hood up so i can open it unless me and another guy , one pulling the release, and the other pulling the hood up, work at it. Can anyone tell me what might be up with all of this. thanks!

 

Pathy love-

[hardwaretoad]

Not into sidetracking posts BUT, twm ~ sounds like a simple backup switch replacement, head to NAPA or somewhere & change it out. Have you even bothered to check your bulbs ? Might even be a loose connection on the switch. Crawl under there & look. -thnkboutit-

 

As far as the fuel guage, could be a sending unit, could be the guage itself, could be wiring, could be a relay, could be a fuse, start with one thing 'til you eliminate that then move on to the next until you solve the problem. ALL probs can be fixed with process of elimination, just be patient & use some common sense to try & track it down. Try a search on the forum for guage probs or something, chances are you're not the first one here to have a problem with their fuel guage.

 

The hood's not that hard to solve... next time you have it open, try adjusting the actuating cable where it hooks into the latch. Chances are it's stretched a little over the years, take up some of the slack and your in business. While you're under the hood, on either side of the front next to the fenders you'll see 2 black rubber bumpers. Give them each a twist a little at a time to raise them up closer to the bottom side of the hood. Close your hood, try the release ~ your hood should pop up. If it doesn't, tweak 'em a little more, but not too much.

[transworldmoto]

Sweet, thanks for the info. I've checked the bulbs and the connections and they are all good, but I'll try those switches and things you were talking about. As for the fuel guage, I took apart the guage cluster and found that four bulbs are missing from what looks like little indicator lights. I couldn't tell what symbols were on the film they're supposed to shine through, but I need to get those replaced. Do you know where I can get some V-2 Toshiba bulbs from? I'm thinking if I get those, maybe they connect a circuit that might get the fuel guage to work. Idk, but we'll see. I got a bull nose front push bumper for it today and now I gotta make mounting brackets for it. Hopefully everything goes smoothly!

[robinasu]

I forgot to mention above that my AIV system is totally disconnected and the beast still passed. If I remember correctly the AIV comes on during certain situations.. decel and idle?? I think it comes on during typical rich mixture situations and adds air in the exhaust to burn off the fuel that escapes combustion in the rich situations. I forgot exactly and I don't have the book in fron of me.

 

My point is that the AIV is not a main player in the emissions control game. I think it is there to shave off a couple of % points.. same with the PCV.

 

Even leaky injectors may not be a main component assuming the ECU is getting into closed loop mode because the O2 sensor should detect the rich condition and adjust the injector PWM frequency. Although, if the leaking injectors are just DUMPING fuel the ECU may only be able to adjust the PWM a fixed amount.

 

I think it is either the cat is bad of the ECU is not getting into closed loop mode.

 

I am curious what happened in this case, give us an update if you can!