EGR bypass on 1HDFT (1 Viewer)

[Zim80s]

Good day guys....
Looking for some advice please.....How can i best do away with my EGR system. I have cleaned the system and tested all the vacuum lines and solenoids and everything seems to be okay...as soon as i press the accelerator a bit hard the damn glow light comes on and when i checked the code its 71 EGR system error so i was just thinking of doing away with it completely.....Also when the glow light comes on the truck smokes a bit more and performance is very sluggish....any advice at all will be welcome.

 

[gilmorneau]

You might have better luck in the "diesel" section of 'Mud if the moderators will move this, but I'll take a stab at it.

How can i best do away with my EGR system.

There are a few ways to do this. You can just re-arrange the vacuum hoses on the valves as in the photo below. Doing so will keep the EGR valves from opening when the VSV "tells" them to (because they won't be getting vacuum). The emissions computer will still "think" everything's OK, but nothing will actually be happening. That's assuming, of course, that your EGR valve(s) aren't stuck open (which may be the cause of your problem).

If your EGR valve(s) are stuck open, you can remove them and install plates such as in the photo below. You can fabricate them from aluminum or buy some from various online vendors. If you do this, you'll need to add a ground strap (as in the photo) for the pre-heater to operate normally.

Either of the above options shouldn't confuse the emissions computer, since all the wiring and VSV's will still be in place. If you want to remove the whole system, that's a little more involved. It's kind of like a cancer that's entangled with other, more useful cells.

The Toyota FSM for the emissions system of the 1HD-FT is in the "resources" section of 'Mud. You'll find it here:

FSM - Repair Manual for Emission Control 1HD-FT

This manual provides service information for the emissions control systems found on some 1995-1997 HDJ80 that are equipped with 1HD-FT 24-valve diesel motors. Supplement to 1HD-FT Engine Repair Manual RM437E. Included: Positive Crankcase...

forum.ih8mud.com

That's probably the most complete explanation of how it all works.

 

[Zim80s]

You might have better luck in the "diesel" section of 'Mud if the moderators will move this, but I'll take a stab at it.


There are a few ways to do this. You can just re-arrange the vacuum hoses on the valves as in the photo below. Doing so will keep the EGR valves from opening when the VSV "tells" them to (because they won't be getting vacuum). The emissions computer will still "think" everything's OK, but nothing will actually be happening. That's assuming, of course, that your EGR valve(s) aren't stuck open (which may be the cause of your problem).
View attachment 3505719


If your EGR valve(s) are stuck open, you can remove them and install plates such as in the photo below. You can fabricate them from aluminum or buy some from various online vendors. If you do this, you'll need to add a ground strap (as in the photo) for the pre-heater to operate normally.
View attachment 3505721

Either of the above options shouldn't confuse the emissions computer, since all the wiring and VSV's will still be in place. If you want to remove the whole system, that's a little more involved. It's kind of like a cancer that's entangled with other, more useful cells.

The Toyota FSM for the emissions system of the 1HD-FT is in the "resources" section of 'Mud. You'll find it here:

FSM - Repair Manual for Emission Control 1HD-FT

This manual provides service information for the emissions control systems found on some 1995-1997 HDJ80 that are equipped with 1HD-FT 24-valve diesel motors. Supplement to 1HD-FT Engine Repair Manual RM437E. Included: Positive Crankcase...

forum.ih8mud.com

That's probably the most complete explanation of how it all works.

Most appreciated thank you...this method looks simple enough to remove. Thank you. I will need to check online how to check if they are stuck open.

 

[kenavt]

Thanks a ton for this writeup! I followed this and it was a piece of cake on my truck. CAD'd up the blockoff plates and had them made. I made sure they were thick because my exhaust manifold studs are decently chewed up on the lower threads and the crossover pipe's studs aren't threaded for that long. Then I bolted them on, added the ground strap, and re-routed that one vaccum hose. This'll work for a nice long time; then I think maybe I will look at trying to de-entangle more of the system when I get around to cleaning the carbon deposits out of my intake manifold.

Would there be any interest from folks to buy EGR cutoff plates for their 1HD-FT trucks? The only ones I've seen for purchase online have been from Australia for a lot more then they cost me (before shipping).

 

[gilmorneau]

Would there be any interest from folks to buy EGR cutoff plates for their 1HD-FT trucks?

Put an ad in the jdm/diesel classifieds. There aren’t a lot of those motors around, but everyone who has one probably wants to get rid of the EGR.

 

[kenavt]

I've had a bit of interest in these block-off plates, so I wanted to make a detailed set of instructions for how to use them to delete one's EGR (building off of @gilmorneau's post).

Needed items:

• A new ground (GND) strap for the pre-heater; since it's normally grounded through the EGR system to the block. I bought these on Amazon and installed them, but my pre-heater has been disconnected. I expect anything of this size or bigger should be good.
• Some EGR blockoff plates. DM me if you'd like me to sell you a set. If I continue getting one-off interest, I will sell sets for $50. If I could get enough people for a group buy then I could drop the price. I have been using aluminum for the intake side (to match the crossover pipe material), and stainless steel for the exhaust side.
• Optional:
  • New gaskets for the EGR block-off plates. I re-used mine but in general not great practice. 25628-17010 should be the exhaust manifold EGR hole; 25627-17010 should be the crossover pipe's EGR holes.
  • New nuts for the EGR studs if you think the old ones are worthy of replacement. I did not re-use mine.

Prep work:

• Give the exhaust manifold's EGR studs and nuts a few PB Blaster rounds of treatment over the few days before doing this. If it's anything like my truck, they will be awful to come off.

Actual process:

Step 1: Switch over the vacuum hoses as @gilmorneau describes in his post; so no vaccum hoses are connected to the EGR valves.

Step 2: Remove the EGR valves by removing the two nuts on the exhaust manifold's studs; and the four nuts on the crossover pipe (green circles). Hopefully they aren't too rusted for you; highly recommend the PB Blaster spa treatment.

Step 3: Install the 3x blockoff plates on the exhaust manifold and crossover pipe with the gaskets.

Step 4: Remove one of the mounting bolts on the exhaust manifold heatshield (blue circle), and install the ground strap for the pre-heater between that heatshield bolt and an EGR mount stud on the crossover pipe.

Step 5: Torque down the EGR blockoff plates. The 1HD-FT FSM (RM437E, highly recommend if you have a 1HD-FT) gives the exhaust manifold at 26 ft-lbs; no info on the intake manifold torque.

Step 6: Enjoy a beer. Up here in rainy Seattle we'd probably say a Rainier.