EGR Readiness Achieved with EGR Removed!
- Thread starter SuperHatch
- Start date
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Just following up to see how this mod has performed for you. Any ill effects and has it stayed consistent?
-Phil
-Phil
- Thread starter
- #23
No ill effect at all... forgot I did it until this thread was bumped. 
No ill effect at all... forgot I did it until this thread was bumped.
Any chance you took pix of this contraption while you were doing it? ;p
I'll even say, if OP makes a DVD like headgasket and front axle rebuild, I'll buy it.
Removed blueprints as they need to be revised...
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Reposting my blueprint now that it has been corrected.
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So I performed the mod outlined above in my blueprint, mostly as a test to see if I can get my readiness monitor to pass, as since my battery died the ECU has not shown ready, even with the EGR system in place and functioning. I'm beginning to think something else might be up that is preventing me from passing readiness despite following the drive cycle as best I can.
I've checked and re-checked my wiring for the relay, the proper continuity of my spliced connections, and the resistance for both circuits (all good). Here's some things I noticed that someone might help me in figuring out:
- When I first plug in the relay, I've noticed that the ground trigger is ON when the truck is off. As soon as I power the truck on, the ground trigger turns OFF until the ECU tries to enable EGR. Not sure if this is normal or not.
- I've noticed even driving around town, the EGR cycles on and off often (I can hear my relay clicking). Like every 30 seconds to 1 minute, dependent on speed (all below 45mph), sometimes at longer random intervals.
- I have a ScanGuage II, all it shows when I scan is:
No Codes Found
- Not Ready -
Is there a method on the ScanGuage to find out what the actual readiness failure is?
And a drive-cycle related question - I'm having trouble performing the requested test with ECT below 107º F - I mean the only place I can drive ~50mph is the highway, and that's about 3 miles away. By the time I get there, the truck is too hot per the drive cycle instructions. Unfortunately, I can't put it up on all fours right now due to not having a garage, otherwise I'd run it in the garage off the ground.
Any thoughts on where to go from here would be helpful.
Thanks!
-Phil
I've checked and re-checked my wiring for the relay, the proper continuity of my spliced connections, and the resistance for both circuits (all good). Here's some things I noticed that someone might help me in figuring out:
- When I first plug in the relay, I've noticed that the ground trigger is ON when the truck is off. As soon as I power the truck on, the ground trigger turns OFF until the ECU tries to enable EGR. Not sure if this is normal or not.
- I've noticed even driving around town, the EGR cycles on and off often (I can hear my relay clicking). Like every 30 seconds to 1 minute, dependent on speed (all below 45mph), sometimes at longer random intervals.
- I have a ScanGuage II, all it shows when I scan is:
No Codes Found
- Not Ready -
Is there a method on the ScanGuage to find out what the actual readiness failure is?
And a drive-cycle related question - I'm having trouble performing the requested test with ECT below 107º F - I mean the only place I can drive ~50mph is the highway, and that's about 3 miles away. By the time I get there, the truck is too hot per the drive cycle instructions. Unfortunately, I can't put it up on all fours right now due to not having a garage, otherwise I'd run it in the garage off the ground.
Any thoughts on where to go from here would be helpful.
Thanks!
-Phil
Dave 2000
Not all Land Rovers are useless!
Great mod but not much good to us diesel owners 
One thing I would point out is be careful with relays and ECU's. Relays give off a discharge when changing over or releasing. The discharge from the relay coil can destroy delicate electronics. Open up the relay and check you relay has a small diode connected across the (NORMALLY) 85/86 terminals, if not then use a typical diode perhaps a IN4001.
I know you mentioned not being electronic savvy so I found this:
Relays
Hope it helps?
regards
Dave
One thing I would point out is be careful with relays and ECU's. Relays give off a discharge when changing over or releasing. The discharge from the relay coil can destroy delicate electronics. Open up the relay and check you relay has a small diode connected across the (NORMALLY) 85/86 terminals, if not then use a typical diode perhaps a IN4001.I know you mentioned not being electronic savvy so I found this:
Relays
Hope it helps?
regards
Dave
Update on my end - I could not get my truck's ECU to go ready based on the street layout where I live, and I don't have a garage to run it up on stands.
I tried the OP's solution and could not get the truck to go ready before throwing a P0401 (happened after about 20-30 minutes of driving). I checked and re-checked all of my connections. The problem for me was that I simply could not complete the drive cycle before the ECU realized there was an issue with the EGR.
My solution was to set up a similar solution that eliminated the mod at the sensor and had both inline and controlled by the relay:
My thoughts were that this would still show the ECU a "cool" (200k ohm) EGR temp sensor when the truck first started up and then show the appropriate "hot" (4.7k ohm) when it cycled on. I was hoping this would enable me to drive the truck normally and let the drive cycle naturally complete without tripping the P0401 before the readiness cycle completed.
I implemented this today and drove around for a bit, and lo and behold I got P0401 again! Wondering if anyone had any thoughts?
I tried the OP's solution and could not get the truck to go ready before throwing a P0401 (happened after about 20-30 minutes of driving). I checked and re-checked all of my connections. The problem for me was that I simply could not complete the drive cycle before the ECU realized there was an issue with the EGR.
My solution was to set up a similar solution that eliminated the mod at the sensor and had both inline and controlled by the relay:
My thoughts were that this would still show the ECU a "cool" (200k ohm) EGR temp sensor when the truck first started up and then show the appropriate "hot" (4.7k ohm) when it cycled on. I was hoping this would enable me to drive the truck normally and let the drive cycle naturally complete without tripping the P0401 before the readiness cycle completed.
I implemented this today and drove around for a bit, and lo and behold I got P0401 again! Wondering if anyone had any thoughts?
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Readiness achieved!!!
I reviewed the ECU wiring diagram and found out that the OP either had a different year or something (mine is a '96) - my relay was running off the VSV circuit, but on the FPR side, which would activate at different times. Found out the VSV (EGR) circuit was one wire over (#22).
Rebuilt as outlined below, adding a 100ohm resistor on the coil activation to prevent fluttering of the relay when the idle sensor switches on and and off (low voltage signals running through the ECU were flipping the relay on and off and I was worried about burning out the relay).
Drove around today and finally got ECU ready and no CEL after about an hour or so of driving! Leaving this relay in place would continue to tell the ECU what it wants to see as far as the EGR system is concerned. For me this was a temporary fix that will allow me to verify that the ECU was correctly handling signals from the EGR system. Now on to troubleshooting what's realy wrong with my EGR system.
Note: in this solution, the EGR sensor is DISCONNECTED, as the relay/resistor unit provides the ECU all info that it needs.
I reviewed the ECU wiring diagram and found out that the OP either had a different year or something (mine is a '96) - my relay was running off the VSV circuit, but on the FPR side, which would activate at different times. Found out the VSV (EGR) circuit was one wire over (#22).
Rebuilt as outlined below, adding a 100ohm resistor on the coil activation to prevent fluttering of the relay when the idle sensor switches on and and off (low voltage signals running through the ECU were flipping the relay on and off and I was worried about burning out the relay).
Drove around today and finally got ECU ready and no CEL after about an hour or so of driving! Leaving this relay in place would continue to tell the ECU what it wants to see as far as the EGR system is concerned. For me this was a temporary fix that will allow me to verify that the ECU was correctly handling signals from the EGR system. Now on to troubleshooting what's realy wrong with my EGR system.
Note: in this solution, the EGR sensor is DISCONNECTED, as the relay/resistor unit provides the ECU all info that it needs.
Last edited:
Readiness achieved!!!
I reviewed the ECU wiring diagram and found out that the OP either had a different year or something (mine is a '96) - my relay was running off the VSV circuit, but on the FPR side, which would activate at different times. Found out the VSV (EGR) circuit was one wire over (#22).
Rebuilt as outlined below, adding a 100ohm resistor on the coil activation to prevent fluttering of the relay when the idle sensor switches on and and off (low voltage signals running through the ECU were flipping the relay on and off and I was worried about burning out the relay).
Drove around today and finally got ECU ready and no CEL after about an hour or so of driving! Leaving this relay in place would continue to tell the ECU what it wants to see as far as the EGR system is concerned. For me this was a temporary fix that will allow me to verify that the ECU was correctly handling signals from the EGR system. Now on to troubleshooting what's realy wrong with my EGR system.
Note: in this solution, the EGR sensor is DISCONNECTED, as the relay/resistor unit provides the ECU all info that it needs.
Very nice job!
So this setup, and just swapping the two vac lines will disable the EGR, but keeps the check engine light off?
cool deal, thanks for posting up the solution.
So how often does the relay click? Not sure if I want to put it inside the cab or not.
cool deal, thanks for posting up the solution.
So how often does the relay click? Not sure if I want to put it inside the cab or not.
subscribed, i will try this mod on my 95.
Count me in for a "kit" if anyone wants to put one together. I've had the P0401 CEL on for about a week and would like to resolve it one way or the other.
Appletech, have you still been using this? Still working? I'm about to do the same.Readiness achieved!!!
I reviewed the ECU wiring diagram and found out that the OP either had a different year or something (mine is a '96) - my relay was running off the VSV circuit, but on the FPR side, which would activate at different times. Found out the VSV (EGR) circuit was one wire over (#22).
Rebuilt as outlined below, adding a 100ohm resistor on the coil activation to prevent fluttering of the relay when the idle sensor switches on and and off (low voltage signals running through the ECU were flipping the relay on and off and I was worried about burning out the relay).
Drove around today and finally got ECU ready and no CEL after about an hour or so of driving! Leaving this relay in place would continue to tell the ECU what it wants to see as far as the EGR system is concerned. For me this was a temporary fix that will allow me to verify that the ECU was correctly handling signals from the EGR system. Now on to troubleshooting what's realy wrong with my EGR system.
Note: in this solution, the EGR sensor is DISCONNECTED, as the relay/resistor unit provides the ECU all info that it needs.
Also, could you repost the diagram? It seems to have disappeared!
Ran it until the CEL went away, then disconnected the relay unit and installed a 4.7k ohm resistor in place of the sensor. Didn't seem wise to leave the relay connected long term as it was constantly firing on and off depending on throttle position.
Will repost diagram shortly - sorry my server is in a state of flux.
Here's the diagram. Make sure you check your wiring diagram for your specific year to ensure your trigger is running off the VSV (EGR) circuit, not the VSV (FPR) circuit. Note that circuit is also ground triggered...
