1fz-fe EGR disable ? (2 Viewers)

[OGBeno]

Most current Toyota vehicles do not have EGRs anymore.

All emissions components for the 1FZ as they pertain to the FSM are found in the SFI section. That is the case for all FSMs from this time period. All emissions components are also found right before or right after the SFI components in the parts catalog.

That said, I've had no EGR/cat/downline O2/EVAP/VSV components and temp sensor resisted on my rig for well north of 50K miles.

Onward!

 

[rolliges]

The Toyota text above is easily found on Google. Just cut and paste some portion and you'll find it.

It uses the 95 Camry 5S-FE engine as an example. This engine uses a similar EGR system to the OBD2 80: Egr valve, Egr modulator, and ECM controlled VSV.
( Even has the same electrical terminal for the VSV as our 80).

 

[rolliges]

Tell me, what would "additional spark advance and decreased fuel injection" do to an engine?

 

[kirkm76]

If the EGR was that vital then why do most 93-94 models ECU's have no clue wether or not it is working. Are the OBDII systems that different in how they manage fuel?

 

[Ebag333]

Are the OBDII systems that different in how they manage fuel?

They are, actually. Mostly in that they have better visibility...but the EGR systems are identical, meaning neither ECU has better control or visibility over it.

 

[Pin_Head]

Well, it's physically near the SFI system. So in that respect it makes sense to put it there.
Now show me the evidence that paint code doesn't effect fuel map. I've always thought dark green 80's were the fastest, and white 80's the slowest.

Being churlish is not a substitute for providing evidence. Put up or ....?

All emissions components for the 1FZ as they pertain to the FSM are found in the SFI section!

Not so for the FZJ80. The only two emisions components mentioned in the fuel injection chapter are the EGR VSV and the EGR temp sensor. All the other emissions component are in the emission control (EC) section.

If the EGR was that vital then why do most 93-94 models ECU's have no clue wether or not it is working.

How do you know that the 93-94 models don't monitor the EGR function? There are several ways to monitor EGR flow and MAP (manifold absolute pressure) is another way. When the EGR valve flows the MAP drops proportional to the flow at any fixed throttle position.

 

[rolliges]

Inputs to the EGR modulator:
Exhaust backpressure created by engine load when the engine reaches a normal RPM range.
Port R from throttle body. Doesn't generate vacuum until 3000 RPM. When it does it pulls about 5.0 in/Hg.
The combo of exhaust backpressure and Port R vacuum controls EGR operation according to engine speed and load.

Output from EGR modulator:
Control vacuum flows out of the EGR modulator from Port Q to the VSV.

VSV Operation.
The VSV is a simple solenoid-operated valve. The ECM energizes the VSV by grounding it. When the computor turns on the VSV it vents contol vacuum to the atmosphere so the EGR valve won't open.

From: MOTOR August 2009
By Dan Marinucci
Reference motor: 2000 5A-FE
EGR system: Toyota vacuum modulated (same as on OBD2 80s)

 

[Ebag333]

Being churlish is not a substitute for providing evidence. Put up or ....?

Hey, I'm not the one making the claim here. Back up from the FSM that the ECU uses the EGR system to change fuel maps. Lets see it in black and white. Put up or.....

How do you know that the 93-94 models don't monitor the EGR function? There are several ways to monitor EGR flow and MAP (manifold absolute pressure) is another way. When the EGR valve flows the MAP drops proportional to the flow at any fixed throttle position.

The EGR valve basically acts as a vacuum leak, granted a more controlled than a random leak but it's introducing unmetered air.

Yes the MAP/MAF will register a change when unmetered air is introduced, but you can not determine the amount of unmetered air just by the change of flow in the MAP/MAF. This is why the engine can and will run poorly when unmetered air is introduced, whether it be the EGR system failing open (so dumping exhaust during idle or high load situations), a crack in the intake, or another point of failure.

If the ECU was clever enough to compensate for unmetered air simply off the MAP/MAF, then any vacuum leak wouldn't cause problems. But they do, and that includes the EGR being stuck open at idle.

 

[rolliges]

Why does the VSV have an electrical harness?

 

[rolliges]

Hey, I'm not the one making the claim here. Back up from the FSM that the ECU uses the EGR system to change fuel maps. Lets see it in black and white. Put up or.....

Perhaps the FSM is not the only source of information.

 

[rolliges]

The EGR valve basically acts as a vacuum leak, granted a more controlled than a random leak but it's introducing unmetered air.

.

The exhaust gas is carefully "metered and varies significantly as engine load changes."

It is not air. Exhaust gas has no oxygen.

You cant base an argument on a false statement.

Try to keep an open mind.
I'm out....

 

[Ebag333]

Perhaps the FSM is not the only source of information.

Sure, but it's specific to the 80 series. What your posting is not.

Once again, why would Toyota detail how the MAP/MAF and O2 sensors effect fuel maps, but neglect to add the EGR system? That makes zero sense, and it makes even less to believe that because it's not included then it must.

 

[Pin_Head]

The FSM is good at describing how to test and repair parts, but it does not tell much about how things work.

You made the claim that the EGR has nothing to do with the fuel system. I provided unequivocal evidence that Toyota thought that the EGR was relevant to the fuel system. It is your turn to put up. The ball is in your court.

 

[Ebag333]

The FSM is good at describing how to test and repair parts, but it does not tell much about how things work.

Actually it does talk quite a bit about how things work. If you read the appendixes, it goes into quite a bit of detail on how they function, the better to be able to troubleshoot things.

For example, it talks about how the O2 sensors affect STFT and LTFT. It does not talk about how the EGR system effects either of those.

You made the claim that the EGR has nothing to do with the fuel system. I provided unequivocal evidence that Toyota thought that the EGR was relevant to the fuel system. It is your turn to put up. The ball is in your court.

No, you provided unequivocal evidence that Toyota put it in the same section, which as Beno pointed out they do for those components and similar.

You've shown zero evidence in the FSM that the EGR system directly changes fuel maps. You have a tenuous link that they are connected....but one might as well connect the seat belts and fuel map because they're both in the same FSM.

No where does it say anything along the lines of "effects or changes fuel mapping."

 

[Pin_Head]

I'm still waiting for evidence rather than conjecture.
You can have the last word.

 

[semlin]

this is getting a bit childish guys.

 

[MoGas]

Note the head in the 15th post of this thread. I know it is Aussie, but it is fuel injected and no EGR.

 

[alaskacruiser]

Another piece of data from autoshop101's Toyota Manual on Ignition- Electronic Spark Advance:

Because the manual is not 80-series-specific, this is not definitive proof the 80-series advances timing for EGR, but it's pretty darn close. Why? Because all of the signals required are inputs into the '95-97 ECU, specifically:
- Engine Speed (NE)
- TPS (VTA, IDL)
- Intake air (VG)

 

[Ebag333]

Think about what it's saying though.

When EGR is operating....when does the EGR system operate? Cruising speeds, low load, high air volume, etc.

The timing is advanced according to the....EGR? No. It specifically states "intake air volume" and "engine RPM."

The EGR system can reduce engine knocking, which allows the timing to be advanced. The ECU knows what situation the EGR is active in, so yes, it will advance the timing in those situations. But guess what, even with the EGR system disabled (or never there in the first place) the ECU will advance timing in that scenario regardless.

And the relevant signals are absolutely the ones that the ECU uses to advance (or retard) timing, no matter what scenario you're in (if EGR would be active or not).

Timing isn't the same as fuel maps either. It's very possible that the ECU has some conditions that assume that the EGR is active in a certain scenario and tries to bump up the timing. The dual knock sensors will prevent it from bumping it up the timing too high regardless.

Someone (Brian?) posted an article once about how the ECU in the 80 series would change the timing based on the octane of the fuel it was running. Surely if the ECU can compensate for an octane difference, it can compensate for an EGR system being not active when it would otherwise be.

 

[rolliges]

I have mild pre-detonation during the conditions when the EGR should be active. The cause: VSV for EGR is venting all EGR vacuum.

This "pinging" started around the same time as my PO401 CEL.

I was about to delete the EGR (mistakenly) until I was curious and investigated if the two conditions are related.

All signs point to Yes.

I expect the pinging to stop after replacing the VSV.