Jakers

Just took the beast to emissions...didn't do so well...

Here are the previous emissions tests:

11/16/2012 (220k Odom)
HC 6.91 - FAIL Applicable Standard 2.00
CO 157.30 - FAIL Applicable Standard 20.00
NOx 0.90 -PASS Applicable Standard 4.0

12/28/2012 (220k Odom)
HC 0.33 - PASS Applicable Standard 2.00
CO 7.20 - PASS Applicable Standard 20.00
NOx 1.90 -PASS Applicable Standard 4.0

03/20/2014 (224k Odom)
HC 5.72 - FAIL Applicable Standard 2.00
CO 79.91 - FAIL Applicable Standard 20.00
NOx 1.90 -PASS Applicable Standard 4.0

The first two tests were from the previous owner and the report online does not show what was done to the vehicle (repair wise) to correct the first failed test.

I did the following tune ups when I first purchased the vehicle (April 2013)
(221k Odom)
Spark Plugs/Wires
Distrib cap/rotor
Vac lines
New IAC
New TPS
Clean Throttle Body
O2 Sensor

With having done those repairs I'm leaning towards it either being the cat the or the EGR valve. I KNOW that the EGR valve is bad so but could it throw off the testing by that much? Any advice would be appreciated.

Thanks everyone!
Jake

Jakers

Pity bump..

TwoXJS

My brothers '89 had the same problem at the last two SMOG tests, first was four years ago and most recent was two. Due again this year, but should pass fine. PO put on one of those crappy universal cat's and it was okay until the next smog. Then it put out numbers VERY similar to yours. Replaced with (due to short funds at the time) another universal to get by because of same problem at last smog. Finally got a GOOD cat under there now, so it should pass just fine.

I know the cat isn't what you wanna be thinking about to have to replace, but it's very possible to me

Jakers

Ya I was afraid of that. I figure it would be the cat. Rats

TwoXJS

It might not be, there's still other things to check out first. For instance, maybe the O2 sensor(s). How long ago were they replaced?

highmileage

I would replace the O2 just on gp with the new cat.
my last smog #s' were very similar and that's what I had to do to pass.

DFlintstone

I'm pretty cheap. The slightest miss will send the HC up. I'll clean the dizy cap, rotor and wires in the sink like any dirty dish. (then dry well). I'll re-gap the plugs back down to .035 a couple of times at least. (the gap gets bigger every mile). Your problems are likely over if you find a flaw in the MAP tube.

> There is a brittle little tube. It comes out of a rubber plug, low on the engine side of the throttle body. It runs back to the firewall, then up to your MAP sensor sort of high up there near center on the firewall. CRUCIAL!! The MAP will tell the ECU to dump fuel with less/no vacuum. Any crack or blockage and it will be rich.<

>
Vacuum leaks suck. I go around with short little shots of starting fluid, if you hit one the sound of the engine will change. Small little shots! You don't want that stuff to accumulate. It's a fire hazard, but It evaporates right away. Also with a tube, or a section of hose you can listen for it. Don't forget the lower O rings on the injectors need to seal as well. (uppers would leak fuel).
The manifold bolts have a habit of loosening, especially that rear one. On anything like that you never want to tighten only one. It can warp/bend, even crack things. If I found that any that where easy to reach where loose, I'd pull the air cleaner and tighten them all, starting in the middle and working out towards the ends. I go over about three times. It's a bear of a spot to get a torque wrench on them all. Just don't ape on it. If its firm and not turning, no point in going on to break it, a REAL *****. The rearmost bolt underneath takes a little doing, but it can be done with the right extension. For that very back one by the firewall I use way long extensions (18"), with a swivel at the socket. Anyway, that's a good thing to check on any old Jeep. ALSO, there is a large line coming off the intake, rear of the TB that goes back to the firewall, across, then forward down to the vacuum ball behind your right front bumper. You can pinch that off or unplug it and cap the nipple to test if you have a leak there. <


>Anyone with an 87 to 90 Renix Jeep has two or three minutes to see that their
CPS is putting out at least .35 AC volts. I don't mean to come off rude, but if you can't connect a meter and turn the key, we may not be much help.
AC voltage CPS test; Small clips on the meter leads really helps. (you need contact with those little pins while it cranks)

Unplug the connector at the back of the manifold with wires going down to the bell-housing/cps. (it's a three wire plug, with only two wires)
Probe the two wires to the cps with the meter set on AC volts. (a 200 scale on mine).
Crank the engine and note the voltage. (jump it if your battery is low)

Mine somehow works with only .3 my wiring/grounds must be pretty spiffy. .5 seems to be a good mark. One article talked of .5 to .8. **Update, it soon failed. I installed Napa #css980 in my 90, that part will work back to 87. You can also check for 200 Ohm's resistance, +/-- 75, but the ACV is what the ECU is using. <


You can find Cruisers tips in my signature. The sensor ground resistance check is a must!

You might want to adjust that new TPS, if you haven't already.

Jakers

O2 was replaced a year ago but I never I drive the Jeep (its not my daily just my project/toy so it only has 4,000 miles on it.)


Ya I just checked my shelf and no starter fluid haha, have plenty of degreaser/brake cleaner/electronic cleaner but no more starter fluid. Gonna pick some up tomorrow and start testing for leaks. I've done prolly 90% of cruisers write ups so the TPS and CPS and all of that are good. Ya know I haven't done my manifold bolts yet either so I guess I'll start there and check for vac leaks, registration isn't due till end of April but I'll also be out of town in April so hopefully I can work on it here and there so I won't be stuck getting those damn 3-day permits.

cruiser54

Even if the O2 sensor is new, if it's not grounded well, or getting low heater voltage, it will be lazy.

Jakers, refresh my memory on which of my Tips you've done.

I've got an idea.

Neighbor bought an XJ recently. We immediately hooked it up to my DRB scanner. Everything looked great but the O2 sensor switched real slow, almost appearing that it failed.

We refreshed the grounds, added some, and then eliminated the C101 just cuz he wanted to.
Gave me the opportunity to make a write-up with photos, too. Post 27....

After that, the idle stabilized, O2 sensor switched quite quickly.

Jakers

1-Ground refreshing* Done
2-C101 connector refreshing** N/A
3-Connector and relay/receptacle refreshing** Done
4-Coil/ICM contacts* Done
5-Checking sensor grounds* Done
6-Sensor ground upgrade** Done
7-CPS testing and adjusting** Done
8-TPS testing and adjusting** Done
9-ECU connector refreshing* Not Done
10-Trans plug connector refreshing* Done
11-Throttle body and IAC cleaning* Done
12-Setting your 4.0 to #1 TDC** Not Done
13-Renix Distributor indexing** Not Done
14-Restoring throttle butterfly adjustment* Done
15-Rear main seal diagnosis* Not Done
16-Vacuum test for exhaust restriction* Not Done
17-HO engine into Renix* N/A
18-Improving the instrument panel ground** Done
19-Headlight harness installation* Not Done
20-4WD shifting tips* N/A
21- Renix EGR valve test* Done (Needs to be replaced still)
22- Renix vacuum harnesses** Done
23- CPS timing advance mod** Not Done
24-4.0 Engine date codes** N/A
25-Valve cover mod** Done
26- Oil Filler cap Mod* Done
27-C101 Connector Elimination** N/A

Any way to test the O2 sensor on not getting enough voltage with the multimeter?

Edit:
If it makes any difference I can smell unburned fuel in I beleive the engine bay.

Here's a shot of what my plugs look like

cruiser54

I see your problem.

Those are the worst POS plugs you can use in a 4.0!!

Seriously, get some standard NGK Coppers FR5. .

To answer your question about the O2 sensor, the ground can be checked by probing the unplugged harness to engine ground.

Voltage can be checked at the connector with the key on .

9 and 13 at some point.

DFlintstone

Check that the gap on the new plugs is .035. Myself, I might call it done, take it back.

You should not smell gas. Stock injectors? They are known to leak at the crimp. With an up-grade, even a 1 MPG gain will eventually pay for them.

Jakers

Ya, I bought those plugs BEFORE researching around the forums haha. Could have saved $30 too. I'm off Tuesday so Monday I'll replace the plugs and check the O2 sensor voltage and ground.

Ya stock injectors, I got the new injectors (the ones in your write up and have had them for a few months now) I just haven't had the time to put them in. So maybe Monday or Tuesday I can replace them and tighten all my manifold bolts down and take it back through emissions and see what the verdict is.

cruiser54

I actually got a REFUND on the Platinum plugs when I returned them.. Worth a try. If it works, you're driving a six-pack of a good IPA up to Prescott for me..........

Jakers

Haha, nice time of year for a Prescott trip too. Maybe I could just use your address and skip emissions completely? I'd say that's worth a few sixers