EGR weep hole, just an idea....

[honda_vtec2]

I'm loosing boost through my egr weep hole. There seems to be more oil pouring out of there these days. Is it a bad idea to seal that hole up with high temp silicone?. Why is that weep hole needed?.

TIA

 

[schultp]

The weep hole is needed to equalize pressure on the back side of the EGR diaphragm. For a properly operating EGR the weep hole is needed. Folks with the oil problem as you describe drill and thread the hole and install a fitting so that they can attach a tube and run the oil either to the ground or to a collection container attached somewhere in the engine bay.

Could you explain your loss of boost and the amount of oil coming from the EGR weep hole? I'm not a guru but it sounds like you may have other reasons for your boost loss.

 

[honda_vtec2]

The weep hole is needed to equalize pressure on the back side of the EGR diaphragm. For a properly operating EGR the weep hole is needed. Folks with the oil problem as you describe drill and thread the hole and install a fitting so that they can attach a tube and run the oil either to the ground or to a collection container attached somewhere in the engine bay.

Could you explain your loss of boost and the amount of oil coming from the EGR weep hole? I'm not a guru but it sounds like you may have other reasons for your boost loss.

Since i've posted, i came across a thread somewhere on the site of a user tapping the hole and running a fitting/hose back to the ccv assembly. I'm going to look at that and see if i can run something similiar.

I've done the boost smoke test with a cig and noticed a lot of smoke coming out of the weep hole as well as wasted oil. I've cleaned the turbo and actuator where it moves freely in full motion. Cleaned and tested the n75. I still get a 200mbar underboost when viewing my logs of grp 11. It's been like that since i've purchased the car. My maf is slightly lazy due to age but still tracks pretty close. I've checked all vac lines and egr pipes. So based on my smoke test, my boost is leaking out of the egr diapragm due to shaft wear.

 

[Lug_Nut]

The weep hole is about 1/8 inch diameter (.0125 square inch area). The turbo is about 1 inch diameter (.7854 square inch area).
You could rip the shaft completely out of the EGR and still not see a drop in pressure.

This is on a friends car that was dribbling pretty badly. I don't want to see it so I've added a shunt. I'll let him clean off the oil stains that are already present.

 

[honda_vtec2]

Lugnut, thanks for the pic. What exactly did you use to screw/tap into the egr housing and the ccv assy?.

Based on what you said about ripping up the egr plunger. My slight underboost is not leaking due to the weep hole. Is that correct?. I based my theory on reading about how to do a boost leak smoke test, so i assumed that since the smoke was leaking out of there, so was my boost.

I will be changing my n75 this coming week. It's 2 yrs old and getting sluggish. I attempted to clean it, but might have made it worse... It actually started to act up today while driving out in the country.

 

[Lug_Nut]

I used another, smaller piece of tubing. The translucent tube visible has a slightly smaller ID than OD of the 'coupling' tube. That smaller tube has an OD just slightly larger than the weep hole ID. The puck has a hole added just smaller than the translucent tube's OD. It's all press fit.

I don't doubt that there is smoke / oil mist coming out of your weep port. I don't believe that there is enough loss (guess...maybe 10 cu.in./min?) relative to the air volume passing through the engine (900 liters/min at 900 rpm) for any real measurable loss of intake pressure.

 

[honda_vtec2]

I used another, smaller piece of tubing. The translucent tube visible has a slightly smaller ID than OD of the 'coupling' tube. That smaller tube has an OD just slightly larger than the weep hole ID. The puck has a hole added just smaller than the translucent tube's OD. It's all press fit.

I don't doubt that there is smoke / oil mist coming out of your weep port. I don't believe that there is enough loss (guess...maybe 10 cu.in./min?) relative to the air volume passing through the engine (900 liters/min at 900 rpm) for any real measurable loss of intake pressure.

Thanks for the tips. I'll take a closer look at that weep hole.I've only glanced at it. I think there might be a bearing or something in there. I'm guessing i might have to attach a fitting in that weep hole.

For the N75, would it cause a bucking effect after starting up the car in the summer morning while slowly accelerating?. I have this weird symptom first thing in the morning that usually lasts for 30s-2 min. I've never had it before. I just got back into town, so i will be placing my order soon for that part.

 

[Lug_Nut]

A failing N75 would result in a surge (power-not so much power-power-not so much power) under higher load, like accelerating in 5th from 80 kph.

A more rapid 'stutter', especially at light load in the lower gears (just off idle, 2nd, 3rd) is more likely an imbalance in the injector spray pattern, or a sticky injector pintle.
At idle (and just over) the engine computer individually controls the amount of fuel delivered to each injector to smooth out the idle. A weak cylinder gets more fuel to compensate.
Once the rpm is above that control range, the fuel delivered is equal. Not that the fuel injected is by default equal, or that the spray pattern is equal. A sticky injector might not be delivering the full charge of fuel supplied and this 'weak' cylinder exhibits itself as a 'misfire' symptom.

 

[honda_vtec2]

A failing N75 would result in a surge (power-not so much power-power-not so much power) under higher load, like accelerating in 5th from 80 kph.

A more rapid 'stutter', especially at light load in the lower gears (just off idle, 2nd, 3rd) is more likely an imbalance in the injector spray pattern, or a sticky injector pintle.
At idle (and just over) the engine computer individually controls the amount of fuel delivered to each injector to smooth out the idle. A weak cylinder gets more fuel to compensate.
Once the rpm is above that control range, the fuel delivered is equal. Not that the fuel injected is by default equal, or that the spray pattern is equal. A sticky injector might not be delivering the full charge of fuel supplied and this 'weak' cylinder exhibits itself as a 'misfire' symptom.

Thanks again Mr. Lugnut. I'm going to swap out my injectors and that n75 and do some more logs/tests soon. I'm thinking i might have damaged my injector nozzles when i was cleaning/rebuilding my cyl head. I left the injectors in the head while i did that job, maybe the nozzle got slightly clogged...I was careful, but maybe some soot or sand got into a cavity...