What happens if you take the car on a long trip and forget to fill up on meth or just run out? I'd rather have a mechanical self replenishing system like recirc exhaust gas instead of a system that can be depleated.....but that's me
uh oh EGR :p
- Thread starter northwestsupra
- Start date
IJ.;1351924 said:
I don't think that will make it better though as this is still a risk in n/a cars....although lower compression would help a turbo car but I still think the very real risk is still present with or without boost on a usdm ecu.
I see what you're saying ij but that's a fail safe for over boosting not a fail safe for egr type issue...
I ran without EGR for two years on a built 7M (Lex, 550's, 3" exhaust) because the SOV coil was open circuited. Had no issues. As the intake manifold pressure comes up to atmospheric and then goes to boost, no EGR happens anyway since no vacuum is applied through the vacuum modulator to the EGR valve diaphragm. The knock sensors should retard the spark if detonation is a problem. I set initial timing to 13 degrees, run 17 PSI boost with a 57 trim turbo, and have never had codes set, and run BP/Amoco Ultimate gas.
BernieK
BernieK
jdub;1348337 said:Guys - The USDM TCCS is tuned for the EGR timing/fuel map wise. The countries where the EGR was not installed are different...i.e. Japan for example. Running without an EGR risks mid-throttle detonation under load...there is more air in the A/F mixture with no EGR.
Northwest - the best option is a stand alone for that motor
You can run without the EGR, but you are going to need to be very careful at cruise about dropping into boost going up hills.
"Runs great" really doesn't mean squat in this case...your friend is taking the same risk by removing the EGR. The engine will run great right up to the point where detonation induces a BHG
Then, your friend will blame the "POS 7M" as the cause...he did everything right after all...LOL!
berniek;1351949 said:
You are confused on how the EGR works Bernie...it does not work at idle (the EGR vac port is forward of the TB) and above ~4000 RPM the ECU shuts off vac via the VSV. With the TB plate open, coolant temp above 145 deg F, and in the EGR ops range (>idle, < 4000 RPM) the EGR vac modulator is closed to atmosphere causing the EGR valve to open. This will occur under boost and if exhaust gas pressure is low.
The problem is at mid cruise in the EGR ops range and you put the engine under load (i.e. going up hill and go into boost). With the EGR removed, there is no exhaust gas displacing air in the A/F mix...you have a lean condition. The sudden increase under load can (and will) cause the cylinders to detonate. The ECU is setting timing and injector duration expecting the EGR to be there...this is not a good situation.
By the time the knock sensors react, it is too late. Think of knock sensors as "explosion" detectors...once the boom has occured, well, you get the idea. By advancing the timing can make this worse, not better...keep something in mind, the ECU is controlling timing. When you set timing with a light, you are setting base timing and that is all. High octane gas will help.
Regardless of what you may think your experience is, you do not know how it is really affecting your motor. It's going to depend how often you put it in the high risk area. I will bet you that a lot of BHG's have occured because of this and were blamed on something else. You do not know if you have had issues or not...I do know how the EGR works and it's purpose is more than just emissions on a 7M. The Toyota tech articles even mention an inop EGR can cause detonation issues.
Do what you want...it is your engine after all
so no egr is bad?:sarcasm:
cause i took mine off and put block off plates on it, i still have the sensors hooked up but i just ran a vaccume line from the intake to the sensor and then another line to the other sensor and then back to the intake. could this be why my car runs super rich at wot?
cause i took mine off and put block off plates on it, i still have the sensors hooked up but i just ran a vaccume line from the intake to the sensor and then another line to the other sensor and then back to the intake. could this be why my car runs super rich at wot?
erics3000;1356572 said:
Yes, as it's a piggyback. If you had it piggybacked to a JDM ECU then it would be fine...
The engine is running closed loop, so it won't be lean no matter what you do. However, the mixture will be more susceptible to detonation without EGR even though it is stoich.