scott1111

I recently had the head gasket changed for my Honda FR-V 2005 (1.7 VTEC petrol). Since the work was done I've been getting a P0401 (EGR insufficient flow) error code. I've taken off the EGR valve and cleaned it with a cleaner spray. I've also attempted to clean the passages using the spray and a pipe cleaner but they seem to go into the engine block.

When I start the engine there is no suction on the EGR port which is supposed to feed the exhause gas back into the cylinders so it appears the blockage is deep inside the engine block. What is the best way to clean it?

toivolaZACK

I am not sure if every Egr system is the same on every make and model car, but from what I know and have read the EGR system only operates under certain conditions, one being heavy load, such as hard acceleration or at certain vehicle speeds, if I am remembering properly at about 40 to 70 mph. So not having vacuum at idle in your driveway is not a problem. I know it's a completely different vehicle, but I spent crazy amounts of time and money chasing an EGR trouble code on my 1989 Ford F-150. I replaced the EGR valve, the EGR valve position sensor, and the EGR vacuum solenoid which I guess actuates the valve itself. Still was getting the code. But the truck ran great and got good gas mileage, for a big truck, so I think I kind of wasted my time.

So I guess if your vehicle is running well then don't worry about it, and since you used the word "petrol" I'm assuming you may be in or from the U.K. so I'd have to say "Bob's your Uncle" on that problem, mate.

scott1111

Haha thanks. Yes you are right I'm based in the UK. At the very least I need to get the engine management light off for my MOT (yearly vehicle certiication) due next month. After being hit by the cost of the HG change the last thing I need is another big repair bill. I'm annoyed the mechanic who did the HG change didn't clean the EGR ports, I would have thought it was standard procedure.

toivolaZACK

Well good luck with that. It's hard to find a good mechanic these days, usually they only do what you pay for, nothing else. A possible explanation is that a wire or sensor may have been damaged during the repair, which could be triggering the light, even though everything MAY be operating okay. Hopefully a connector or harness is just unplugged somewhere. Makes me miss my old 1978 Ford Granada with the carburetor and basically no sensors or computer at all.

scott1111

I'm quite new to how modern engines work so may not understand this correctly, but I thought for EGR the Exhaust gas normally flows through the EGR valve back into the intake manifold where the air is mixed with the fuel to be injected back into the engine?

But in my car the passage from the EGR valve goes straight into the engine block. I'm wondering if it goes through the head gasket for each cylinder and feeds the inlet valves directly?

In either case I would expect if the passages were not blocked, the EGR port would be sucking air in.

holmesnmanny

exhaust gas runs from the 4th cylinder in the block through the egr valve through the intake to the combustion chamber

scott1111

For the benefit of people following this thread: The FR-V 1.7 has a D17A2 engine and there is quite a lot of information about cleaning the EGR passages online for Civics with the same engine. I have a suspicion that when the garage changed the HG they may have fitted the wrong intake manifold gasket, since the gasket is available with and without the EGR holes (both have the same part number 17055-PLD-004).

My plan is to take off the intake manifold to clean out the EGR passages and I'll also fit a new gasket.

toivolaZACK

you know the vacuum port on the egr valve is an output, not an input. The hose that is attached to it runs from an actuator that is controlled by the computer. It sucks on the egr valve which lifts the diaphragm inside the valve and pulls air through the valve, the actuator itself, then to the intake manifold or perhaps an air plenum, as is the design on my 92 Accord. You can follow the vacuum lines to get a better understanding. You can also test if the actuator is doing it's job and opening the valve by testing it with a hand held vacuum pump and a GOOD ohm meter. Don't buy the cheapest one you can find. If the actuator is not opening the valve, you would be getting that insufficient flow code. It would probably be much easier to test that than to take apart the intake. Although your idea of the wrong gasket sounds possible.....I can't believe the two that you found had the same part number. I'd have to imagine that unless the mechanic was totally asleep at the wheel he would not have done that.

Just don't ever take your car in on a Monday...those guys often enjoy a good time let's say and mistakes are made while hungover.....

scott1111

I've confirmed now that they did put the wrong intake manifold gasket in my car. The gasket didn't have the EGR holes so it was never going to work. Since replacing the gasket with the correct one from Honda the car has been fine. I don't know how they could make such a mistake.

toivolaZACK

That's crazy, man....I hope they reimbursed you for your trouble....good instincts by you as well