Mach30SiR

As the title states, about a month ago, i drilled out the intake manifold and cleaned it, reset the ECU. The CEL for this code comes on about 500-600 miles after the ecu is reset......

Let the creative juices flow: thoughts/comments/questions/suggestions

asianspec

iTrader: (1)

cool now do a DYI

Mach30SiR

HAHA, i have pictures, i could, but they are all blury. If enough people hound me about here i will eventually, i get enough pm's about it all the time.

TexasHonda

P1491 (Insufficient EGR Valve Lift) is not impacted by cleaning the EGR ports. This fault indicates the EGR valve is not opening to the ECU-commanded lift amount. Check vacuum supply to the EGR vacuum control solenoid valve, check vacuum control solenoid valve and wiring, EGR vacuum line, and EGR lift sensor. Most likely is a vacuum line fault, or EGR vacuum control solenoid fault.

You will likely need an Acura shop manual to run through all the diagnostics for this fault

BTW, I hope you didn't literally drill out the EGR manifold ports. You should only clean the EGR ports w/ care to avoid enlarging the openings. The port sizes are actually slightly different to balance the EGR flow to each manifold arm. If you enlarge the holes by removing metal, the EGR flow may be too high and you may have drivability problems. However, this should not cause P1491, IMO.

good luck

Mach30SiR

Thanks, i'll have to flow all the vac lines, but i swore i plugged everything back in as per the honda service bulletin. I used a 7.9 drill bit to drill it out, lots of oil to lube, it fits snuggly in, never removed any metal shaving from the actual manifold. There was only one port to be drilled out, clearly the one on the right side that was clogged with carbon. I hate going to the dealer, unless i really have to. Yay, sounds like egr replacement might be due

Mach30SiR

anyone else think of anything i might be missing, could the EGR valve be broke?

TexasHonda

The EGR lift transducer could be defective.

You can test the EGR by jumping vacuum directly to the EGR w/ engine running. The EGR should open and cause the idle to change or engiine to stumble.

good luck

Mach30SiR

your saying hook up a different souce of vac to the egr and see if it lifts?

TexasHonda

A direct vacuum source to the EGR will confirm the EGR opens w/ vacuum and is not blocked.

It will not diagnose a defective lift transducer.

good luck

gtflash

What's up Mach? I drilled the EGR Port using the same method you did. However at the time I did it, it was showing insufficient lift at the same time so I changed the EGR valve too. 1200+ miles since then, NO CEL since.

Mach30SiR

you put a new egr on? The method i told you was word for word from the honda service bulletin, so i know the whole is clear, now wondering about the EGR unit itself. I'm going to do a what texashonda said, and go from there. Glad to hear your CEL is off, hope it stays that way.

Mach30SiR

So I was out poking under the hood tonite with full intensions of hooking up another vac source to the EGR, when to my suprise, i couldn't find anywhere on the EGR to hook it up to. (Very much unlike my experences with h23a and jdm h22a and even b series). Theres no vacume to the EGR, nothing even listed on the sticker on the hood. Does everyone elses EGR look like this??




now what? did the previous owner put on a wrong egr trying to fix the problem, does anyone elese 3.0 have a vac line to it?

I just detailed the engine 3 weeks ago so its still squeeky clean.

TexasHonda

Apparently the valve is driven by an electrical solenoid. PM me w/ your email and I'll send a file for P1491 that indicates how to check the EGR. You may have a failed solenoid that is not lifting, hence lack of lift from the sensor. It could be a wiring or other issue, but failed solenoid is more likely.

good luck

Mach30SiR

::incomming:: thanks alot for the lead....all the other EGR's i've seen in the past were vac and electric, not just electric. oh well, i'll have a read at what you send me when you can. Appreciate it.

TexasHonda

The EGR solenoid may be OK and the EGR is sticking or the solenoid may be open. It should be possible to repair the first w/ throttle body cleaner. The 2nd will require a new EGR valve.

good luck

Mach30SiR

Thanks, i'm going to read what you sent me today at work (gotta love gov't contracts) and pick up some carb cleaner and clean that baby out tonite. I had it off about a year and a half ago to clean it out, we'll see, i'm keeping my fingers crossed.

Mach30SiR

i used a set of jumpers to supply direct power to the egr, and it opened right up, and the engine almost stalled. So that means th EGR is good - now what? where are you at tex?

TexasHonda

I would suggest removing the EGR and cleaning/exercising the potentiometer on the EGR. I've seen linear potentiometers get dust and debris that cause a short circuit. I have no idea how yours is constructed or whether it's possible to blow out any dust and clean w/ contact cleaner. It may be worth a shot, since a new EGR is probably well over $100. Bottom line is a new EGR may be needed.

You can remove the EGR, connect to wiring harness, turn ignition to ON, and check for output from the potentiometer. This may show that you are not getting the voltage variation that is normal. If you can't fix, a new EGR is necessary.

You might be able to find one at a salvage yard but I think they are prevented by law from selling emissions parts on the used market.

good luck

Mach30SiR

I had it off the other day (friday) and it wasn't very dirty at all. what tells the egr to lift? the EGR selanoid? ( i didn't get a degree in spelling)

TexasHonda

Typical control is the ECU supplies ground to constant voltage supply. Valve intermittently opens/closes. However, I'm not familiar w/ the EGR in your car.

good luck