range rover failed the emission test...bad

[bandit86]

1992 Range Rover with a 3.9L, way off course on everything, probably about 1-300% over both the idle test and 2500rpm test.<br /><br />I will retard the timing, (I think it's way too advanced but runs a lot better this way), I'll throw in a new air filter and change the oil <br /><br />Anything common on these trucks, like egr or something to try? how to check if cat is working properly?

 

[bomar76]

Re: range rover failed the emission test...bad

Yeah, they eat 02 sensors due to running way rich.<br />Did you ever pull the codes?<br />The actual results of the emmissons test should point you in the right direction. <br />100 to 300% over what??<br />CO?<br />NOX?<br />???

 

[bandit86]

Re: range rover failed the emission test...bad

hc idle limit 200, mine 757ppm<br />hc @2500rpm limit 200, mine 651ppm<br />co idle limit 1.00, mine 5.45<br />co @2500rpm limit 1.00, mine 6.25<br />for nox it's all Not availible<br /><br />it has no engine codes stored right now, I'll go out later and chack again, just came back from a 4 hour drive

 

[DJ]

Re: range rover failed the emission test...bad

It's running VERY RICH. It is probably in "limp mode".<br /><br />Got any vacuum leaks?

 

[bomar76]

Re: range rover failed the emission test...bad

I agree on the vacuum possibilty....check intake vacuum...<br />High HC are normally ignition related.....change plugs, wires, cap, rotor, etc. I'd also suspect the MAF sensor is gummed up with garbage, clean it with the CRC cleaner for coated MAF's.<br />High CO is too much fuel....again, I'd clean the MAF.<br />I'd bet the CO reading was so high it's hiding a NOX problem too....look for problems with the EGR or way advanced timing..if they are ok, time to think about your Cats....

 

[bandit86]

Re: range rover failed the emission test...bad

I tried retarding the timing, but the truck seems to run worse. I'll clean the maf tomorrow.<br /><br />Now, when I bought the truck, there were 2 sparkplugs in the wrong place, 5&6 were mixed up. since then it had a tune up, but I think having the wires like that for a long time should have melted the cats down.

 

[dolluper]

Re: range rover failed the emission test...bad

Here,s some things to check when you have high Hc and high Co do a fuel pressure test ,timing, check your fuel vapor canister for fuel loading,PCV and hosing,ignition compontents, Cat ,O2 sensor voltage check,engine warm enough to be in closed loop and the loney coolant temp sensor .Usually in that order unless you spot something not right

 

[bandit86]

Re: range rover failed the emission test...bad

I'm starting to suspect the water temp sensor, everything else seems to be working fine... I know timing is still off a bit, but not the amounts I'm over.<br /><br />and it runs a whole lot better cold and starts easier too

 

[dolluper]

Re: range rover failed the emission test...bad

If you have a vaccum guage,throw it on a intake port and adjust your timing very very slowly giving your motor time to adjust untill you get the highest vac reading with the vehicle at operating temp,hopefully your above 18lbs closer to 20 lbs.Don't have one get one 10 bucks at any auto store.Vac guages can tell you alot about the motor

 

[bandit86]

Re: range rover failed the emission test...bad

duh, I should have thought of that... <br />Now why is it that engines rev higher when the timing is advanced, is that because of less vacum or more?

 

[imported_KLR]

Re: range rover failed the emission test...bad

Although it may be cheating........

When I lived in Phoenix (Maricopa county) AZ. , I had to pass emissions tests to get my tags.

I had a 1972 Duster (318 2 bbl. ) that was over all their limits and I got it to pass.

I ran the gas very low leaving about 3-4 gallons in it and dumped in about 10-12 bottles of Iso-heat fuel treatment.
This stuff is Isoprohol alcohol and burns EXTREMELY clean. It will not hurt the engine and drops you emission readings way down. The Duster passed easily.

Just my .02....

 

[bandit86]

Re: range rover failed the emission test...bad

thanks, may need it later

 

[sloopy]

Re: range rover failed the emission test...bad

thanks for the tip KLR