I plan to, I want this to become my DD and if it needs some work done with the head off I'd rather do it now than later.

O2 sensor is DONE! I just got done changing it and oil about an hour ago. It was remarkably simple. I had the torch out and ready to go and everything. It came right out. The unit that I took out looked almost identical to the Bosch unit I was installing except for the connector was slightly different, and the sensing part on the one I removed didn't protrude as much as the one I was installing. In fact, on the one I removed it looked as though it had been pushed back into the sensor body, and the little holes (that I'm guessing air go into) are even partially obstructed. Perhaps a defect?

I'll test the EGR valve tomorrow afternoon. I'll start by applying vacuum straight to the EGR valve and then work my way back. Are you absolutely certain that it'll want to die if the EGR is opened at idle??

 

Yes that is how the test is done during the inspection,the tech will apply a vaccum pump to it and if it does not cause the engine to stumble it is failed,you will be able to see the stem move also.

 

You have a high temperature exhaust gas problem.
Possible causes:
Lean mixture, check closed loop operation (O2 sensor)
EGR valve stuck closed, replace and check vacuum feed
Inefficient cooling system, check temp to be lower than 210 farenheit, fan, fan shroud, electric fan, clogged radiator, thermostat valve etc.

 

Ok, I messed with it some tonight. Being at work for all of daylight frickin sucks. But I applied vacuum DIRECTLY to the to valve and it opened and she almost died. I have vacuum going into the front of the EGR electronic control on the driver's side fender. I applied vacuum to the vacuum line comes from the back (the middle, not the furthest back. The furthest back on mine is capped.) of the EGR electronic control that winds all over and plugs into the transducer. No effect. How does that transducer thing work? Either the transducer doesn't work properly, or that line is plugged.


NOx is generally caused by a lean condition. I just replaced the O2 sensor. EGR valve opened when I applied vacuum directly to it and I'm checking the the rest of the system leading to it.
Temp never hits close to 210 on factory gauge. Fan shroud is broken, but in place. The Jeep seems to run at reasonable temperatures.

 

Ok, I need help. How exactly does that transducer thing work? I applied vacuum directly to the transducer and no bogging, it just seems completely normal. I apply vacuum directly to the EGR valve and the Jeep wants to die.

What does that line going from the transducer to the base of the EGR valve do? Should vacuum directly to the transducer be passed to and open the EGR valve?

 

The line going from the base to the transducer is for back pressure,when you apply vacuum to the egr it wanted to die,that means it is ok,now trace your vacuum line according to the sticker under the hood and make sure it is hooked up just the same way.

 

It is routed properly, is there anyway I can check that transducer thing? Or the vacuum control thing?

 

The solenoid on the firewall should be going to the transducer,make sure you have good vacuum to the solenoid inlet and no vacuum on the outlet,then unplug it and see if you get vacuum on the outlet,if you do it is working. The solenoid is operated by the ecu,to see if it is opening at cruise you would ave to have the shop check it on the dyno,it will open it when it thinks it is cruising,newer cars actually use exhaust gas readings to vary how much to open the egr.

 

Ok! I do have good vacuum on the front side of the solenoid, I didn't know how or when to open it. I'll pull the plug and try it tomorrow.

One last question... the thermostatic air valve on the front of the airbox is hooked up, the vacuum lines are all properly routed, but I failed visual because the piping back to the hot air source wasn't in place (I've always called this the heat riser). I looked for some sort of heatshield or holder that this would go to on the exhaust manifold, but I can't see one. Where should my heat riser tube to the airbox go??

BTW, Abovethetimberline, you've been immensely helpful with your consistent responses to this thread. It's greatly appreciated, and if you're ever in the LA area let me know and it'll be my pleasure to get you a beer or other beverage (in case you don't drink).

 

You can see the egr valve stem move when you accelerate the engine. It should slowly open when RPMs rise and cycle open/close when RPMs decrease.

 

RENIX HEGO sensors are (per data gathered and reports from the field) good for 120-160Kmiles before total failure. Possible cause there.

If the cat is original, you'll probably want to change it first - since it's a RedOx bed meant to finish the combustion of HC and CO (the "Ox" part - oxidise) and break the NOx down into N2 and O2 ("Red" - for Reduction.) The NOx is broken down first to supply the O2 for the Ox bed next.

Given that you've got spikes for all three major pollution components, I'd look at the cat first.

Using higher-octane fuel is not a good idea. As mentioned, higher octane fuels burn more slowly - this means you're going to spike HC and CO even further. Higher octane (AKI) fuels are suitable for high-compression engines or engines that run lean or at high altitudes (this is why the AKI rating for aviation gasoline is 100 or higher - I've seen up to 120LL, with 100LL and 112LL being fairly common.) At that point, it's more a "performance number" than an "octane number" - since it burns more slowly than 100% octane (which has an 100 RON and 100 MON by definition.)

The EGR valve is supposed to control NOx (doesn't really - we don't have a high enough SCR or DCR to make it actually useful...) but does so at the expense of increased HC and CO emissions - which are then oxidised by the catalyst bed. The cleanest any of my RENIX rigs have ever run has been with the EGR failed/disabled - but CA sez I have to keep it because it's original equipment (despite the fact that I've proven that it causes more harm than good - using their test and equipment they've approved!)

For replacing your catalytic converter, any replacement you source (that isn't OEM) is going to be physically smaller than the unit you remove. Cut the four-bolt flange off of the old unit and weld a pipe stub to it (having that joint being something you can break comes in very handy!) and get a single "universal replacement" cat spec'd for a SBChevvy or BBChevvy truck or van. This will give you a greater catalyst bed area (making for greater catalyst efficienty) and higher through flow (in case you do a stroker or something later) - and should run you under $100 for the converter and pipe stub.

Yes, it will pass smog - it has for me on three rigs so far. (Santa Clara County, in case you're wondering.)

 

What's that?

 

Believe static compression ratio and ???? compression ratio?

 

static and dynamic compression ratio

 

SCR - Static Compression Ratio. CR calculated using the full length of the stroke.

DCR - Dynamic Compression Ratio. Actual compression, calculated using remaining stroke after the intake valve has closed.

DCR is always lower than SCR. SCR can only be changed by altering the cylinder head, piston, crankshaft, or bore; DCR is altered by changing the camshaft.