emissions related question

[the_chief]

Howdy. I found a guy with an 88 4.0. He just brought it here from california and can't get it to pass emmissions. I think if it's an original cali jeep, it might have some funny emissions stuff going on. I haven't seen the emissions report, but does anyone here have experience with this? Any heads up would be appreciated. thanks in advance.

edit: on second thought, would cali regs make lower emissions?

 

[5-90]

I'd be willing to help, but I'll need some more information - like an emissions test report...

Seriously tho - since CARB requirements are tighter than the rest of the country, a CA vehicle should have no trouble at all passing smog anywhere else, if it passed in CA...

One RENIX issue I run into all the time is "meatware" related tho - seems the "techs" (I'm using that word advisedely...) don't understand that the XJ was pre-OBD until the end of 1990... I take my FSM with me when I get smogged, with the part about "pre-OBD" marked, so I can show it to them when they try to fail me for "CEL out..."

5-90

 

[YELLAHEEP]

Yes, one would think that that a California emissions compliant vehicle should pass with no concerns here.

However, we are dealing with a higher altitude and that alone can cause issues with those flat-lander vehicles. Some ideas:

First, check to see how long ago it passed CA inspection - could be a mechanical problem that developed since then.

How much has he driven the vehicle here in Colorado? Does he say it started running funny or noticibly less power when he got here with it? Could be that it simply needs more drive time in this altitude to allow the computer to adjust the tuning. If he trailered it out, then I'd definitely encourage him to drive it a few days and see if that takes care of the issue.

If he drove it out from CA, it's also very possible he burned the catalytic converter just driving over the Divide. If it's the original cat, that could be a good place to start if the computer seems to have adjusted to the altitude.

 

[old_man]

While you should get it running correctly, in December, the emissions for gas powered vehicles expires here in Colorado, at least in the outlying areas. I don't know if that pertains to Denver or not, since they always had a dyno based instead of tail pipe based test.

 

[Fred]

I don't think it will effect emissions, but it will effect drivability and gas mileage. Check to see if the CPS is the high altitude version. High Alititude versions will have the sensor body rotated counter clockwise to the mounting bolts. The low altitude will appear centered between the bolts. Shine a flashlight down from the drivers side rear corner of the valve cover, and look for it at 2 o'clock on the bell housing.

Fred

 

[philip_g]

got any info on the high altitude CPS? My jeep came from VA and I'm sure doesn't have it.
Does it just advance timing a little?

 

[old_man]

Do you have the emissions numbers? That will go a long way towards telling us what is wrong.

The high altitude cps advances the timing a few degrees.

 

[philip_g]

nifty, learn something new every day.
anyone happen to know where I can get one and be certain it's a high alt aside fromt he dealer?
the online shops just list one.

 

[Fred]

They are only available for the 90 and earlier 4.0's. AFAIK, the dealers in CO only sell that CPS when you request a CPS. I would just go to a dealer for it. The high altitude CPS made more improvement in the MPG performance of my 90, than any other mod.

If you do have an HO engine, there is an aftermarket CPS that advances the timing 2 degrees.

Fred

 

[philip_g]

nah, I have a renix.