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Great, it's going to turn into one of these threads. Egr does not enrich the mixture, it's inert....so it cannot enrich the mixture. It has an actual AFR of 0, but the computer reads the AFR of the egr gasses as whatever they were when they were ejected from the engine before introduction to the intake. This is because the o2 sensor reads only post combustion "o2", it has no idea that what is going into the intake manifold is inert and thinks the reading of the Egr gasses (let's say 14:1) are a result of the combustion process, but those gasses are not 14 parts air, 1 part fuel. Egr gasses are essentially 0:0 . So, as anyone can clearly see, this is not enriching the mixture, it's *polluting* the mixture (10% of what the computer is reading has an absolute AFR of 0:0, but it is reading it as ~14:1)
Not having egr keeps the intake side of your engine cleaner, longer. Egr also decreases your displacement by 10%. Parasitic losses, so often touted as a benefit of egr circulation, are insignificant with egr vs without. The most efficient modern engines do not have an egr cycle.
I'm such an idiot.
Exhaust gasses taking the place of oxygen changes the ratio of fuel to oxygen.
Come on man, if you have two sticks and two stones you can kill four rabbits for dinner.
Computer is calibrated for the inflow of EGR gas, without it you are more prone to part throttle detonation.
Exhaust gasses taking the place of oxygen changes the ratio of fuel to oxygen.
You said it enriches the mixture....changing your tune to "changes the ratio of oxygen"? Egr gasses displace volume with an AFR of 0:0, a volume that could otherwise be filled with air OR gas.
Originally Posted by HardScrabble
Come on man, if you have two sticks and two stones you can kill four rabbits for dinner.
If I had two sticks and two stones, I can kill dozens of rabbits.
Originally Posted by HardScrabble
Computer is calibrated for the inflow of EGR gas, without it you are more prone to part throttle detonation.
and the potential for ping when Egr has problems or is deleted has nothing to do with air/fuel ratio and how the Egr effects it.
And by pursuing your own agenda, you've turned this man's thread about getting his truck running right into your own personal discourse on the validity of the EGR system.
And by pursuing your own agenda, you've turned this man's thread about getting his truck running right into your own personal discourse on the validity of the EGR system.
Happy?
when he needs info, here or elsewhere, I'd be happy to help him. The thread largely had already evolved into what it is before I put in my piece.
The most efficient modern engines do not have an egr cycle.
You're absolutely right my man, but unfortunately that's not any of us in here. I'd like to think the engineers put these systems in place for a good reason, else they wouldn't exist in the first place. I guess every machine is different and deleting it has no harm in some cases, I just can't advocate for that at all because men far greater than me taught me that 'you are to trust the engineer that built the machine, he understands it better than you as a technician ever will'.
You're absolutely right my man, but unfortunately that's not any of us in here. I'd like to think the engineers put these systems in place for a good reason, else they wouldn't exist in the first place. I guess every machine is different and deleting it has no harm in some cases, I just can't advocate for that at all because men far greater than me taught me that 'you are to trust the engineer that built the machine, he understands it better than you as a technician ever will'.
Egr was the only way to comply with the nox requirements at a time when there were no other practical options. 3 way catalytic converters have changed that, the engineers of this system would have been happy to have affordable 3 ways at their disposal. You called anyone who thinks deleting their Egr is beneficial is an idiot....which is an idiotic statement to say the least, especially when there are plenty of us out there who actually understand how the stuff works, why it's there, what the "engineer intent" was, and why we don't want it.
Hardscrabble, ill save *you* the google search. Again, ping as it relates to Egr either malfunctioning or being deleted has nothing to do with air/fuel mixture as it relates to the introduction of egr. Short and sweet version: The computer advances timing when egr is commanded. Since an engine with egr into the combustion chamber tolerates more timing, engineers added more timing to combat the loss of power inherent with an egr cycle. When the eg's are no longer present, the computer is still commanding the advanced timing. It's timing, not AFR.
.... I just can't advocate for that at all because men far greater than me taught me that 'you are to trust the engineer that built the machine, he understands it better than you as a technician ever will'.
Why do people always want to think it's ONE THING?
It's probably everything you can think of and some more that is beyond your scope. OK, good, timing too.
Look at it this way:
If you introduce NOX without additional fuel it leans the mixture. Introduce N2 without reducing fuel it richens the mixture.
Another one: Two stroke premix. More oil in the mix leans the AFR because the oil replaces fuel. Since it turns the plug black, smokes and blubbers, most people think it richens the mix.
After all of this having been said I think EGR is a stupid system. Scavenging exhaust out of engines has been the target of much research and development at tremendous expense. So after we manage to scavenge the cylinder clean of exhaust, what do we do? Dump it back in the intake were it can soot up the engine. Likewise keeping engines clean of soot has been the target of much effort. Around and around we go.
But our engines are designed with EGR and we are better off with a properly working system than without. These are low tuned engines anyway and practically speaking you gain nothing by removing all of the pollution controls.
Besides they say people who breath exhaust have the same health problems as people who smoke three or so packs of cigarettes a day. So keep your engine clean 'cause momma don't need no breast cancer.
I have a '95 F250 with a 351W that has GT40 cylinder heads, exhaust headers, and cat-less exhaust with no oxygen sensors, and the EGR port on the intake manifold is blocked off. The truck was set up like this when I bought it. It's running OK but the fuel mixture at idle is so rich it's nearly enough to make you barf. I have a new, remanufactured computer (see my other threads on this site) and I know the ECM regulates fuel mixture but mine isn't t getting all the inputs it expects, like O2 sensor and EGR and I'm guessing this is why the mix is off. So, is there a way for me to manually adjust the fuel mixture?
I don't have time to read the whole thread so if this has been covered please forgive me.
Yes there is. The O2 sensor floats around 1.5 volts to continuously adjust the mixture. You can make a circuit with a potentiometer to feed 1.5 volts into the ECU inputs for the O2 sensor.
Wow...don't check your email for a few days and an EGR argument pops up. Well, whatever the truth is about EGR my truck doesn't have one and probably never will. But back to the original problem:
I dropped the front tank this weekend and fixed it. The lock ring wasn't installed correctly.
Reinstalled it properly, drove to the gas station and filled up....no leaks. Now I can go back to the welder this week and get my O2 sensor installed. I'll let you know how it works out. In the meantime, play nice guys.
Finally made it to the muffler shop today and got my O2 sensor installed into the collector on the driver's side exhaust header. I only drove about 10 miles home but it already seems like the truck is running better. It seems a little quieter and it accelerates from a dead stop smoother than it didn't before. We'll see whether anything happens with fuel economy. I've only been getting about 8 miles to the gallon around town.
10-19-2017, 12:03 PM
Well, whatever the truth is about EGR my truck doesn't have one and probably never will. But back to the original problem:
