Disable the EGR system the (mostly) Toyota way (2 Viewers)

[alaskacruiser]

Add me to the P0402 list. I put BBs in all the vac lines since I wasn't sure which should be blocked,and I jumpered the temp sensor on the ECU side. After 110 miles and about 10 starting cycles, I got the code. This makes 4 of us so I think it is more than a coincidence. Ideas, anyone?

 

[IdahoDoug]

Bummer. I was set to do this mod soon. Anyone having success with it for a while now??

DougM

 

[trapper92]

long term?
yes......its been over 18 months since I disabled mine.

used a 5k ohm resistor if I remember correctly....no codes whatsoever.

never noticed much of a difference with detonation, and my timing is set at about 6-7 degrees advanced. Slight ping on mild acceleration which isn't hurting anything, I could back my timing off a degree or two to cure this. Overall the truck just runs smoother and has slightly better throttle response with this mod.

I know that in the newer generation of vehicles the ecm works very closely with the egr, taking advantage of the cooler combustion temps by advancing the timing and adjusting fuel injector duration, in so doing getting rid of the negative performance caused by the egr to begin with and actually improving the engines overall efficiency and performance.
I think the 80 series is a less advanced and simpler system (at least the OBDI versions) and it seams to benefit from the egr being diabled. I have owned and disabled both a 92 and a 94 cruiser with positive results and no ill effects.

My father was a ford tech for over 35 years and he is a firm believer in disconnecting the egr on the vehicles he has owned where it is possible to do so. In newer vehicles though this is not always an option or beneficial to do.

On the OBDII 95-97's it sounding like its not that simple.

 

[alaskacruiser]

trapper92- you used a 5k resistor across the terminals of the temp sensor on the ECU side, correct? Has anyone done this mod on an OBD2 (95-97) 80 series with a resistor and without any problems?

Does anyone know the expected range of resistance values provided by the temp sensor? Perhaps just shorting the sensor isn't providing a valid reading under all the circumstances required to not trip the CEL.

 

[Ebag333]

Bummer. I was set to do this mod soon. Anyone having success with it for a while now??

DougM

Doug,

I'm starting to suspect that this will only work for OBD-I trucks.

No idea why I ran it for almost 1k miles and no CEL (and everything flagged green), but I can't replicate that lately.

trapper92- you used a 5k resistor across the terminals of the temp sensor on the ECU side, correct? Has anyone done this mod on an OBD2 (95-97) 80 series with a resistor and without any problems?

Does anyone know the expected range of resistance values provided by the temp sensor? Perhaps just shorting the sensor isn't providing a valid reading under all the circumstances required to not trip the CEL.

This may help:
https://forum.ih8mud.com/80-series-tech/43028-po401-defeated.html

 

[alaskacruiser]

This may help:
https://forum.ih8mud.com/80-series-tech/43028-po401-defeated.html

Funny how much opinions can change over time- my own included

Anyway, I've gleaned the following from the above post:

1. it looks like Bear80 ('97 80) was using a 1k (0.25W or 0.5W rated would work) resistor without any problems

2. zipastro ('94 80) had his working for 2 years on a 1 OHM (not 1k) resistor, which is possibly further evidence that the OBD1 trucks are less sensitive to this mod

3. scoop ('97 80) did the 1k resistor mod and it apparently caused a "not ready" ECU condition (NOT a CEL) when it came to emissions testing, even after 1,000 miles

4. BrettinSanAntonio posted this info on expected resistance values of the temp sensor:
According to the FSM the ranges are:
122 (F) - 64K -97K Ohms
212 (F) - 11K - 16K Ohms
302 (F) - 2K - 4K Ohms

Does anyone (CDan?) know if a temp-sensor-like connector is available with open terminals to make it easier to insert a resistor in it? I'd rather not cut the temp sensor probe off to do this mod.

 

[trapper92]

trapper92- you used a 5k resistor across the terminals of the temp sensor on the ECU side, correct?.

Yes...resistor goes in the female (ECM) side of the connector.

What Kup99 is doing by jumping the male side (Temp sensor)of the connector will not accomplish anything. The ecm wants to see a certain resistance or it will throw a code.

The 2-4K ohm range is telling the ecm that the temp sensor is hot... so the ecm 'thinks' the egr system is functioning normally and is happy. So to speak.

 

[kup99]

So I need to use a 5K resistor on the sensor side? anyone have a pic of this done?

 

[kup99]

What Kup99 is doing by jumping the male side (Temp sensor)of the connector will not accomplish anything. The ecm wants to see a certain resistance or it will throw a code.

I am not jumping the resistor side, it is the ecu side ... I'll take another pic!!

 

[brian]

just tagging till i can sift through all the "extra" stuff.

 

[trapper92]

sorry Darren...yes you have it right then.
Its been a while since I did this, so I think I got confused between the male and female ends. Maybe try the resistor in there instead. I believe I picked mine up at a radio shack or something. The 5K has been working for me. It was Bear80's thread that inspired me to try this and I basically copied what he did except, I thought a 5K ohm resistor was more in the range that was needed.
Don't know what else to tell you.

 

[kup99]

Trapper92
Thanks for helping me trouble shoot this!

How did you get it to stay on the male side? Glue? Solder?

Thanks again!!

 

[zukinut]

Ok, So im a newb on the 80s. I know a ton about the 60s and 62s and i want to know the same amount about the 80s. I dont wanna bother yall with bs questions so ill study as much as possible.

This is the first ive read about the egr system and the first ive read about the harness melting. I dont have to worry about emissions, so ill just remove the egr completely.

If i completely remove the system do i need to "jumper" the plug, or can i just leave it unplugged. It looks to me that i need to "jumper" it. But i thought it wouldnt hurt to ask.

Thanks in advance,
Will

 

[medtro]

sorry Darren...yes you have it right then.
Its been a while since I did this, so I think I got confused between the male and female ends.

You were not confused. ECM side has the female connector for OBDI system.

 

[kup99]

Ok, So im a newb on the 80s. I know a ton about the 60s and 62s and i want to know the same amount about the 80s. I dont wanna bother yall with bs questions so ill study as much as possible.

This is the first ive read about the egr system and the first ive read about the harness melting. I dont have to worry about emissions, so ill just remove the egr completely.

If i completely remove the system do i need to "jumper" the plug, or can i just leave it unplugged. It looks to me that i need to "jumper" it. But i thought it wouldnt hurt to ask.

Thanks in advance,
Will

Yes, you would still need to jumper cause the ecu will still be looking for the signal!!

 

[trapper92]

Trapper92
Thanks for helping me trouble shoot this!

How did you get it to stay on the male side? Glue? Solder?

Thanks again!!

I believe I crimped on little connectors (like Bear80 did in the first pic of his thread) then wrapped it in heatshrink. Its not stealth, but it doesn't matter because for our aircare testing I just put it back to stock anyways, as I need a functioning egr system to pass.

 

[kup99]

I believe I crimped on little connectors (like Bear80 did in the first pic of his thread) then wrapped it in heatshrink. Its not stealth, but it doesn't matter because for our aircare testing I just put it back to stock anyways, as I need a functioning egr system to pass.

Cool Thanks.. I'll buy one tomorrow, and some BB's to disable the egr !!

Thanks,

I'll try to post some pics!! So according to you I need a 5K resistor!

 

[trapper92]

Yeah Darren...I think I used a 5K, but anything between 2-10K would probably fly as its in the 'hot' range that the ECM wants.
I believe I used little spade type connectors and had to modify (shape) them a little to fit them in snugly. The resistors that I bought were very small, like the ones below(except 5k), so get more than one in case you should break them accidently.

5 pack -- 1 watt 5% carbon film resistors - 7.5k ohm - eBay (item 150378480456 end time Dec-05-09 16:16:29 PST)

BTW..do they have emissions testing in cowtown like they do in vancouver?

 

[kup99]

Thanks again Trapper,

No emissions in Calgary!! nice option!! I will buy a few from the source electronics today and try to get this done tonight!!

 

[toylndcrusr]

I finally got around to removing my EGR system. I ordered some 2K resistors that haven't come in yet, so for now I have bridged the ECU side of the temp sensor. The operation of the EGR system is all vacuum controlled, the only way to disable the EGR is to disable the vacuum lines from the TB. The computer monitors input from the temp to see if the EGR is working properly. There was post earlier in the thread about checking the temp of the EGR pipe to see if it is operating. If the vacuum lines are hooked up, it is operating.

As far as destroying this delicate little snow flake we call planet earth by removing my EGR, please do not insult my intelligence or the intelligence of anyone else on this board by making a suggestion as patently stupid as this. The EGR is just a half inch diameter orifice that allows a minuscule amount of very hot exhaust gas to be pumped into the intake runner of the #6 cylinder. It isn't Three Mile Island or Chernobyl. All I have done is change the intake configuration to mirror that of ever other Land Cruiser sold in the world that wasn't destined for commuter duty in North America.

The way I did this to my truck, I fashioned a couple of block-off plates to cover the holes where I removed the EGR pipe from the back of the cylinder head and the intake plenum. The one on the back of the head was a real bear to get to, and I had to get my wife to place the block-off plate on that one and get the bolts started because my arm won't fit back there.

One last thought on EGR. This bunch of crap was stuck on engines destined for North America in order satisfy a stupid and arbitrary requirement put in place by Congress and certain state legislatures. Who knows more about automotive engineering and internal combustion engines, Toyota or Congress? Congress so far has a perfect track for exacerbating every single problem they address. Toyota on the other hand supplies the world with the best vehicles ever made, and the only ones with this retarded EGR bullsh!t are the ones that come to America.