Royal Nonesuch
NAXJA Forum User
- Location
- Pasadena, CA
I was hoping to solve this issue on my own using the huge amount of data from similar threads, but after reading them all twice and doing the steps I am still not getting anywhere. So, here I am, another poor bastard with a RENIX running rich (in California, of course :shiver: )
A little over a year ago I bought a 1988 XJ. It had about 185,000 miles and ran alright. Of course it was leaking everywhere but the price was in my range, and I was looking to increase my mechanical knowledge while building a reliable offroad rig for overland/camping excursions.
Here were it's passing SMOG numbers at time of purchase:
Here are it's failing numbers now:
In the year between those two tests I touched pretty much everything except the bottom end in my process of fixing the XJ up and learning about it. Obviously somewhere I screwed something up because it's running very rich in the CO% dept.
1988 XJ Pioneer 4x4, AW4, np231. Bone stock when I got it.
Since then:
~3.5" lift w/ 1" tcase drop
Replaced stock D35 with a 29spl 8.25 from a 2001 (3.55) (replaced driveshaft at that time with a correct, kastein-reccomended length)
31" Cooper ST MAXXs on stock wheels.
Head was pulled and taken out for hot-tank/valves/deck (new felpro 530HD head gasket + new head bolts torqued in sequence to spec)
Every goddamn gasket replaced new with FelPro. Freeze plugs replaced once, and one again when one failed.
Sensors I have replaced & How They Tested according to LungHD testing numbers:
02 - NTK 23553 (reads 6.5ohm)
CTS - Standard Motor TX28 (reads 450ohm @ ~200deg)
original MAT (cleaned) - (reads 480ohm @ ~200deg)
MAF (new hose to TB) - ACDelco 213-3205
EGR - Standard Motor EGV608
CPS - Standard Motor PC87T (reads 236ohm)
Knock Sensor - Delphi AS10093
Thermostat - Motorad 2000195
New cap, Champion copper plugs, wires, ignition coil. New 2AWG battery cables cut & crimped to fit. She starts right up without struggling (at least by renix standards). It's had several oil changes, but currently running Castrol GTX high-milage 10w30 + 1qt MMO. Doesn't burn any oil that I can see since I changed it 500 miles ago.
New radiator, hoses, HESCO high-flow waterpump/thermostat housing. (Jeep runs steadily at 210 on streets in 95degree weather, ~215 under load uphill, and ~190-200 coasting downhill.
Transmission cooler installed (bypassing radiator heat-exchanger).
When I pulled the head, I noted some hairline cracks on the exhaust manifold in the usual collector area - wirewheeled them clean and had a friend booger-weld them. Removed all the sensors from the intake manifold and had it high-temp pressure washed clean (inside & out). Reinstalled both with a new gasket and torqued new bolts in the proper sequence to spec (front and rear bolts present/not sheared off). Muffler had some leaks and was replaced at a local shop.
At the time of the failed smog check, the only fueling/engine modifications I was running was 703 injectors and a 60mm bored throttle body from StrokedJeep. After the fail, I swapped back my original OEM injectors (w/new o-rings) and it failed again with essentially the same numbers ( left the bored TB on....mistake?).
I did almost everything but the head rebuild myself, and was relying heavily on archived
threads/various jeep forum renix-specific searches. With that in mind and to answer your next question, here's the relevant Cruiser54 tips I have completed:
(disclaimer: I am a complete novice at electrical systems and multimeters. Please let me know if you think I'm screwing up a test)
1 Grounds refreshed + new grounds added: fuel-rail>firewall, Batt Neg>radiator support, Instrument panel
2 C101 refreshed Cleaned that thing meticulously, but haven't eliminated it
3 Connectors/Relays cleaned
4 Coil replaced, contacts cleaned
5 Checking sensor grounds TPS B terminal to batt. neg. = 4ohm @ 200ohm multimeter dial setting ( no variation while wiggling harness)
6 Sensor Ground Upgrade Began this today. I was able to find the brown/white wire splice near the MAP sensor, but there were no wires with that color code near the harness side of my MAT connector?
7 CPS Testing Sparks easily, haven't tested
8 TPS Testing/Adjusting resistance tested fine, adjusted as per instructions. Also tested TPS for dead spots with analogue multimeter; needle swept smoothly
9 ECU connector refresh Done, everything was already clean as a whistle
10 Trans Plug refreshing refreshed engine bay connectors, have not done glovebox connector
11 IAC Cleaning Replaced with new IAC
12/13 TDC + Distributor indexing Set to TDC, windowed a spare cap, reinstalled and examined it. The rotor tip was already dead-on with the trailing edge leaving #1.I figured it was good there - do I still need to pull out the whole distributor/cut locating tabs/etc?
14 Throttle butterfly Adjustment Done, and cleaned perfectly by Jeff @ StrokedJeep when the TB was bored from 52 to 60mm. This is currently the only modification done to the fuel/air system - maybe that's enough to cause the system to run rich but I doubt it?
16 Vacuum test for exhaust restriction Haven't done
18 Improving instrument panel ground done
21 RENIX EGR valve test New valve, tested OK
22 RENIX vacuum harnesses new front harness, rear OK
I've shot starter fluid at every vacuum hose junction I can think of with no change in idle.
:banghead: Sorry about all that text but I know that's the stuff you guys are gonna want to know. Here's some purely observational stuff I think is important:
When starting on a cold engine, the Jeep turns right over and idles nicely at the desired 750rpm for about 10-15 seconds. After that, over a period of about 5seconds or less it drops to 500 RPM and begins stumbling/seeking for approx 2minutes. RPM at idle remains fairly consistent at 500 in P or ~600 in D after that. Exhaust does smell very rich and plugs turn black rapidly. It does this pattern no matter what combination of 703/stock injectors/bored or stock TB I give it. The damn thing runs great aside from the low idle. This seems like an open/close loop situation to me, but I don't have one of those Snap-On bricks to read things.
Fuel milage on the 703 injectors was consistent at 10.5 city - I don't do much highway, but the one time I tracked it I was getting 19mpg. I don't have any relevant numbers since I put back in the stock injectors.
I love this stupid Jeep more than any of my other vehicles. I've got 2 months before I have to pass, but it depresses me every time I look at it so I really want to figure this one out. My only remaining ideas are to eliminate the C101, replace the cat (my smog guy doesn't think it needs a new cat), maybe find some stock-size shitty takeoff tires for the dyno test to reduce load on the engine under acccel? Do I need to track down a spare ECU? I know I have to be missing something here for the numbers to be so far off after an overhaul.
:hang:
A little over a year ago I bought a 1988 XJ. It had about 185,000 miles and ran alright. Of course it was leaking everywhere but the price was in my range, and I was looking to increase my mechanical knowledge while building a reliable offroad rig for overland/camping excursions.
Here were it's passing SMOG numbers at time of purchase:
Here are it's failing numbers now:
In the year between those two tests I touched pretty much everything except the bottom end in my process of fixing the XJ up and learning about it. Obviously somewhere I screwed something up because it's running very rich in the CO% dept.
1988 XJ Pioneer 4x4, AW4, np231. Bone stock when I got it.
Since then:
~3.5" lift w/ 1" tcase drop
Replaced stock D35 with a 29spl 8.25 from a 2001 (3.55) (replaced driveshaft at that time with a correct, kastein-reccomended length)
31" Cooper ST MAXXs on stock wheels.
Head was pulled and taken out for hot-tank/valves/deck (new felpro 530HD head gasket + new head bolts torqued in sequence to spec)
Every goddamn gasket replaced new with FelPro. Freeze plugs replaced once, and one again when one failed.
Sensors I have replaced & How They Tested according to LungHD testing numbers:
02 - NTK 23553 (reads 6.5ohm)
CTS - Standard Motor TX28 (reads 450ohm @ ~200deg)
original MAT (cleaned) - (reads 480ohm @ ~200deg)
MAF (new hose to TB) - ACDelco 213-3205
EGR - Standard Motor EGV608
CPS - Standard Motor PC87T (reads 236ohm)
Knock Sensor - Delphi AS10093
Thermostat - Motorad 2000195
New cap, Champion copper plugs, wires, ignition coil. New 2AWG battery cables cut & crimped to fit. She starts right up without struggling (at least by renix standards). It's had several oil changes, but currently running Castrol GTX high-milage 10w30 + 1qt MMO. Doesn't burn any oil that I can see since I changed it 500 miles ago.
New radiator, hoses, HESCO high-flow waterpump/thermostat housing. (Jeep runs steadily at 210 on streets in 95degree weather, ~215 under load uphill, and ~190-200 coasting downhill.
Transmission cooler installed (bypassing radiator heat-exchanger).
When I pulled the head, I noted some hairline cracks on the exhaust manifold in the usual collector area - wirewheeled them clean and had a friend booger-weld them. Removed all the sensors from the intake manifold and had it high-temp pressure washed clean (inside & out). Reinstalled both with a new gasket and torqued new bolts in the proper sequence to spec (front and rear bolts present/not sheared off). Muffler had some leaks and was replaced at a local shop.
At the time of the failed smog check, the only fueling/engine modifications I was running was 703 injectors and a 60mm bored throttle body from StrokedJeep. After the fail, I swapped back my original OEM injectors (w/new o-rings) and it failed again with essentially the same numbers ( left the bored TB on....mistake?).
I did almost everything but the head rebuild myself, and was relying heavily on archived
threads/various jeep forum renix-specific searches. With that in mind and to answer your next question, here's the relevant Cruiser54 tips I have completed:(disclaimer: I am a complete novice at electrical systems and multimeters. Please let me know if you think I'm screwing up a test)
1 Grounds refreshed + new grounds added: fuel-rail>firewall, Batt Neg>radiator support, Instrument panel
2 C101 refreshed Cleaned that thing meticulously, but haven't eliminated it
3 Connectors/Relays cleaned
4 Coil replaced, contacts cleaned
5 Checking sensor grounds TPS B terminal to batt. neg. = 4ohm @ 200ohm multimeter dial setting ( no variation while wiggling harness)
6 Sensor Ground Upgrade Began this today. I was able to find the brown/white wire splice near the MAP sensor, but there were no wires with that color code near the harness side of my MAT connector?
7 CPS Testing Sparks easily, haven't tested
8 TPS Testing/Adjusting resistance tested fine, adjusted as per instructions. Also tested TPS for dead spots with analogue multimeter; needle swept smoothly
9 ECU connector refresh Done, everything was already clean as a whistle
10 Trans Plug refreshing refreshed engine bay connectors, have not done glovebox connector
11 IAC Cleaning Replaced with new IAC
12/13 TDC + Distributor indexing Set to TDC, windowed a spare cap, reinstalled and examined it. The rotor tip was already dead-on with the trailing edge leaving #1.I figured it was good there - do I still need to pull out the whole distributor/cut locating tabs/etc?
14 Throttle butterfly Adjustment Done, and cleaned perfectly by Jeff @ StrokedJeep when the TB was bored from 52 to 60mm. This is currently the only modification done to the fuel/air system - maybe that's enough to cause the system to run rich but I doubt it?
16 Vacuum test for exhaust restriction Haven't done
18 Improving instrument panel ground done
21 RENIX EGR valve test New valve, tested OK
22 RENIX vacuum harnesses new front harness, rear OK
I've shot starter fluid at every vacuum hose junction I can think of with no change in idle.
:banghead: Sorry about all that text but I know that's the stuff you guys are gonna want to know. Here's some purely observational stuff I think is important:
When starting on a cold engine, the Jeep turns right over and idles nicely at the desired 750rpm for about 10-15 seconds. After that, over a period of about 5seconds or less it drops to 500 RPM and begins stumbling/seeking for approx 2minutes. RPM at idle remains fairly consistent at 500 in P or ~600 in D after that. Exhaust does smell very rich and plugs turn black rapidly. It does this pattern no matter what combination of 703/stock injectors/bored or stock TB I give it. The damn thing runs great aside from the low idle. This seems like an open/close loop situation to me, but I don't have one of those Snap-On bricks to read things.
Fuel milage on the 703 injectors was consistent at 10.5 city - I don't do much highway, but the one time I tracked it I was getting 19mpg. I don't have any relevant numbers since I put back in the stock injectors.
I love this stupid Jeep more than any of my other vehicles. I've got 2 months before I have to pass, but it depresses me every time I look at it so I really want to figure this one out. My only remaining ideas are to eliminate the C101, replace the cat (my smog guy doesn't think it needs a new cat), maybe find some stock-size shitty takeoff tires for the dyno test to reduce load on the engine under acccel? Do I need to track down a spare ECU? I know I have to be missing something here for the numbers to be so far off after an overhaul.
:hang:
