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Can anyone scan a RENIX for me?

Hypoid

Hypoid

NAXJA Member
NAXJA Member
Location
Golden, CO
It failed emissions, again. We have 10 calendar days for the free re-test. I'd like to have it re-tested by this coming Saturday. I have evenings free.

If this in not the appropriate place to post such a request, please move it for me.

'89 XJ, 4.0, auto tranny, 24?,000 miles.

HC GPM: 2.4965_____Limit: 3.0
CO GPM: 52.9986____Limit: 25
CO2 GPM: 408.9755
NOx GPM: 1.2254____Limit: 5.0

I have done a lot of work on this Jeep, it runs well and drives well. I'm thinking the CAT needs replaced. Before I dump more money, I'd like to have someone check the real-time stats and make sure the engine management system is operating within it's parameters.

Thanks, Mike
 
I'll have to put some tires on it to drive that far. :)

Maybe a road trip/parts shuttle is just the thing it needs.
 
CO probably isn't going to be the CAT, those normally cause NOX failures.

You have a fueling issue, now dumb question but.... Are you making sure the Jeep is good and hot before taking it in? Make sure the engine is at operating temp and run it down the highway a bit to get the CAT good and warm prior to taking it in. It culd be as simple as the Jeep still being in "cold run" mode.
 
Hypoid said:
It failed emissions, again. We have 10 calendar days for the free re-test. I'd like to have it re-tested by this coming Saturday. I have evenings free.

If this in not the appropriate place to post such a request, please move it for me.

'89 XJ, 4.0, auto tranny, 24?,000 miles.

HC GPM: 2.4965_____Limit: 3.0
CO GPM: 52.9986____Limit: 25
CO2 GPM: 408.9755
NOx GPM: 1.2254____Limit: 5.0

I have done a lot of work on this Jeep, it runs well and drives well. I'm thinking the CAT needs replaced. Before I dump more money, I'd like to have someone check the real-time stats and make sure the engine management system is operating within it's parameters.

Thanks, Mike
Click to expand...
Your numbers look a lot like mine. It turned out that my O2 was the culprit.
 
DutchVDub said:
You have a fueling issue, now dumb question but.... Are you making sure the Jeep is good and hot before taking it in? Make sure the engine is at operating temp and run it down the highway a bit to get the CAT good and warm prior to taking it in. It culd be as simple as the Jeep still being in "cold run" mode.
Click to expand...
Actually that is a pretty good question! A year or two ago, they overheated it. I replaced several cooling system components, probably the thermostat among them. Last November, the new reservoir split the seam, I replaced it with a Volvo reservoir. The whole time I've been working on it, I've seen the temp gauge come up to the 12 O-Clock, but not really stabilize there. Even though she drove it long enough before picking me up, the gauge seemed to stabilize a little on the cool side. Since I tend to replace thermostats just because I'm there, I'll install a "proven" unit and see what the gauge does.

A little more history: The owners took it for emissions without any prep. No tune-up, no oil change, no nothing. The CO failed at 300 GPM! :eek: Amongst all the testing amd measuring, we discovered the fuel pressure regulator leaking fuel on the vacuum side of the diaphram, Aha! That explains the trouble they've had with starting it. :rolleyes: A trip to the junkyard provided a sparkly-clean FPR, vacuum harness, and O2 sensor. We changed oil, air filter, and plugs, replaced a burnt plug wire, cracked exhaust manifold and dealt with a few unrelated issues to get to this point.

I'm hoping the leaky FPR didn't kill the five-year-old CAT. I'd like to find something simple and cheap, like a bad thermostat. :)
 
Not much on the data stream on a renix.
Better off with a DVOM on the 02 signal wire and watch voltage.

high CO is a rich exhaust. The ecm is not leaning it out enough, likely from a lean biased O2 sensor.

You can 'fool' the ecm to switch from rich to lean by using your body. you can become the O2 sensor by holding the signal wire to the ecm with one hand and touching the batt terminal with the other. Touch the pos term to cause the engine to go lean, neg term will cause it to run rich. watching the voltage on the meter while you do this will confirm that the ECM has the ability to change the mixture, and confirm that the O2 can interpret lean and rich mixtures into mv. 0-.5 mv is lean .6-.9 mv is rich.

If you hold the neg terminal for a time, you should be able to tell the engine is running rich..loping and stinky, possibly black smoke. a lean biased O2 will not display a rich voltage.
 
Holding the Pos terminal for a time should cause the ECM to lean the mixture and the engine performance and O2 voltage should reflect that.
If it does not lean out, then there is an external source of fuel.. carbon canister, FPR, leaky injector.....
 
Did your EGR pass function test? I'm assuming it did, since you show elevated HC and CO (those tend to drop significantly when EGR is NF.)

My first impression is the cat as well. Were those numbers for the low-speed or high-speed test? What were the results for the other test?
 
Those results would be from the IM-240 dyno test. We don't do the idle/high test in CO unless its too old, too heavy, or unable to be tested on the dyno.
 
DutchVDub said:
Those results would be from the IM-240 dyno test. We don't do the idle/high test in CO unless its too old, too heavy, or unable to be tested on the dyno.
Click to expand...

Right - but not the old "TSI" (Two-Speed Idle) test, but the two-speed Dyno test, I think they run your vehicle at 15 and 25mph or so on the rollers (that's what they do out here, anyhow.)

Or, do you do more than one speed on the dyno as part of a test cycle, and then give aggregate results? (Frankly, that's a foolish way to do it - having discrete results generated at specific speeds is far more informative...)
 
IM 240 is setup to simulate on road driving conditions. It takes the vehicle up to about 30mph, comes to a stop, accelerated again up to about 30mph, cruises along, and then gets up to about 55mph where it stays briefly before coming to a stop.

Its basically simulating leaving your house, stopping at a light, driving down the road a bit, and then getting onto the highway.
 
DutchVDub said:
IM 240 is setup to simulate on road driving conditions. It takes the vehicle up to about 30mph, comes to a stop, accelerated again up to about 30mph, cruises along, and then gets up to about 55mph where it stays briefly before coming to a stop.

Its basically simulating leaving your house, stopping at a light, driving down the road a bit, and then getting onto the highway.
Click to expand...

Ah. So, a multi-speed test, but only gives an aggregate emissions output number. Bugger - getting results at various speeds is more useful, from the standpoint of actual diagnostics...
 
I picked it up last night, drove it 10 miles on the highway before it finally got to operating temp. I had to drop it into 3rd, on a hill, to get it that warm. Our '90 warms up faster, I think this one used to warm up faster.

I'll get it ready for a road trip tonight. :)
 
When a vehicle fails you also get a print out that shows the levels of each tested gas along the test "route"
 
Hypoid said:
I picked it up last night, drove it 10 miles on the highway before it finally got to operating temp. I had to drop it into 3rd, on a hill, to get it that warm. Our '90 warms up faster, I think this one used to warm up faster.

I'll get it ready for a road trip tonight. :)
Click to expand...

time for a thermostat :viking:
 
Thanks for the help, Flores! Yeah, I could have changed that temp sensor during the week, like you said to. Then, we'd never know that it kept the ECU in open loop.
 
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