| homey |
My '03 (88K miles, past recall) developed the initial bad EGR valve problems a couple months ago. I read the threads here, replaced the valve and cleaned out the Intake Manifold.
No dice. Problem was actually worse with the same MIL/VTM-4 light show. Confident the indications were exactly what most other EGR sufferers described, I sent the EGR back for a replacement (checked the old one and no improvement).
New valve arrives and by this time I can do the job blindfolded. I have a little trouble getting the jumper plug back on the valve, but don't force it. Take it for a spin and same crap. This time I just unplug the damn harness for the ride home. Runs like brand new! No stuttering off the line or constant hesitation at constant speeds, gas mileage back to normal.
Alas, the damn lights came back and stay on. Personally, I have no problem staring at the lights so long as the truck runs fine, but the VTM-4 doesn't work while it's malfunction lamp is on. Priced the harness and it was $361.00 (entire engine harness only, of course). Could it be the ECU? Plug looks fine.
Just want some opinions and feedback before I do anything. It's rainy season in Florida and I bought it for the AWD - family car. I'm a better than average mechanic when teamed with my father and I'm sure I could find the harness for less on line but would hate to drop that kinda dough on a hunch.
Thanks to all those that carried me through this on the 10 other EGR threads. |
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| N_Jay |
Buy the electrical manual;
Check the wires to find if that is the problem;
Check the ECU signals to see if they are correct.
OR
Take it to a good dealer. |
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| homey |
So check the voltage when plug is back on EGR with truck running?
How do you troubleshoot the ECU?
Anybody got the electrical manual pages to upload?
Anybody want to trade 03's? |
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| belundy |
| Make sure the EGR valve gasket is oriented correctly and not torn--it's easy to get it 180 turned, and not apparently not uncommon for it to tear when removing the EGR. |
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| homey |
quote:
Originally posted by belundy
Make sure the EGR valve gasket is oriented correctly and not torn--it's easy to get it 180 turned, and not apparently not uncommon for it to tear when removing the EGR.
Installed new gasket each time and it was on correctly. |
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| harley909 |
I have a 2003 Pilot EX-L with 170,000km on it.
I have had problems with the VTM4 and Service Engine Light coming on lately and oddly mainly when it rains. It runs fine so I know the EGR valve is working well...I have experienced a bad one on a chevy so I know how they can run with a bad EGR.
I have an OBDII reader which gave me the P1491 (if i recall correctly) code which referred to a 'sticking" something or other in the emissions circuit.
I was just going to change the EGR but I was so sceptical because it only did it in the rain, so I did not bother. The EGR valave was also about $200 here so I preferred to experiment first.
I ended up taking the plastic off the motor to have a look at the egr valve. I took some WD40 and sprayed it inside the valve where the openings are and I tapped the valve with a wrench a few times (yeah I know sounds too simple) and I have not have a code since. It's been about 2 weeks and we had a load of rain...but no codes at all.
Time will tell if this a long term fix or a short term fix.
As for changing the egr and still having the codes I would suspect the vacuum passages to it must be plugged up. I read somewhere that it's a matter of taking things apart on the intake and carefully picking away with a vacuum in hand to suck all the debris out carefully as you go. |
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| homey |
| The EGR was replaced. Just to be sure, I sent the 1st replacement back for a new one. Cleaned out all the intake manifold passages with a shop vac and rat-tail file. All in the first post. My problem is deaper and is there all the time, not just when it rains. |
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| belundy |
Have you had the MIL codes read? It may tell you what the engine computer is complaining about (i.e. insufficient flow P0401 or insufficient lift P1491.). Apparently the actual failure mode of a bad EGR is a sticking actuator, and when it finally pops open, overshoots the target valve positions, the computer backs off, realizes the flow is low and repeats the cycle.
More info..
There is a position sensor and of course actuator drive in the EGR valve. Wires:
Yel/Blu - voltage to position sensor (5v probably)
Grn/Yel - sensor ground (body ground near the ECU)
Wht/Blk - sensor signal to ECU
Pink - ECU drive to EGR valve.
Blk - valve drive ground (body ground).
If you are handy with DVM measure voltages and/or continuity back to body or ECU. You can back probe the EGR connector or pin probe the wires at the EGR while the engine is running. If you have Scope DVM, you could even extend the sensor and drive lines to the passenger compartment and meaure/log during a drive.
I the bad EGR reportedly acts the worst between 40 and 55, level road, in the 5th gear with very light throttle.
Before I did that, I might be sure the EGR ports are clear from exhaust side and then to the intake manifold. A clog anywhere in the path will cause problems. I might spray carb cleaner down both holes, wait 15 minutes, then blow through with compressed air. |
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| homey |
thanks, belundy.
The original codes were the 1491's that most EGR victims get.
Since the replacement and IM cleaning the codes are "CYL. 1 MISFIRE/CYL. 2 MISFIRE, etc./ MULT. CYL MISFIRE", something along those lines with a misfire code for all cylinders. Resetting with reader just clears temporarily.
I'll troubleshoot the harness with the specs you listed. |
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| homey |
can anyone post the part # for the complete engine wiring harness. It would be the one including the EGR leads.
Thanks |
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| Blkblurr |
quote:
Originally posted by homey
thanks, belundy.
The original codes were the 1491's that most EGR victims get.
Since the replacement and IM cleaning the codes are "CYL. 1 MISFIRE/CYL. 2 MISFIRE, etc./ MULT. CYL MISFIRE", something along those lines with a misfire code for all cylinders. Resetting with reader just clears temporarily.
I'll troubleshoot the harness with the specs you listed.
My 04 did the cylinder misfires as well and after Honda replaced the egr valve, they found out the injectors were misfiring. MIne was covered under warranty but it took 3 trips to the dealer to fix it. I also got the check engine and VTM-4 lights when I got the misfire codes. It has not happened since and I've put on 70,000 more miles. |
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| harley909 |
| I just came off a long road trip (over 3000km) and to date, no more codes at all. Looks like i got lucky and the wd40 spray on the actuator rod freed up the sticking. I have been through rain and lots of heat and no probelms at all. |
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| homey |
quote:
Originally posted by Blkblurr
My 04 did the cylinder misfires as well and after Honda replaced the egr valve, they found out the injectors were misfiring. MIne was covered under warranty but it took 3 trips to the dealer to fix it. I also got the check engine and VTM-4 lights when I got the misfire codes. It has not happened since and I've put on 70,000 more miles.
Thats interesting. Were they 'misfiring' or clogged? I've cleaned injectors before and older cars love it.
Unfortunately, I don't think that can be the problem since the truck runs great when I un-plug the EGR sensor lead. I've got the new wiring harness and it's pretty intimidating (tons of wires and connectors). I'm hoping this is it because it would be a $270 mistake.
If this doesn't do it, I could only assume it's the ECU. |
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