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Discussion Starter · #1 ·
So I've been having a code 12 pop for the past year, but since its gotten cold, its becoming more frequent (like my friggin battery problem). Anyway, I notice it usually triggers a code when I come to a stop from say about 80kmh, under medium to hard braking. So basically, when the rpm's come down to an idle. I cleaned the EGR a few weeks ago, but still get the code.
Keep in mind I have a terrrible hesitation problem, but more on that later.


So I got the car warm and applied vaccum to the EGR. Im using the ol' rental vacuum pump from Canadian tire, and if I pump the hell out of it, I can raise it to rougly 5 (hg?) and I CAN get the motor to bog AND stall. But the vacuum doesn't stay at 5, it slowly comes back down to zero. I've never used a vacuum pump, I was pumpin the thing to hell, but have read it should only take a few pumps to get it to roughly 10?

The book says, does it hold vacuum...well kinda, not much of one. Does it stall the engine? if I pump the out of it...so it says to move on.
So I assume its half assed working? And should just replace it?

I did the rest of the troubleshooting, until the part about hooking up the electrical harness. Everything checked out fine, even applying postive and negative power to the connector on the firewall.


Now my hesitation problem, which I dont think is related to this (who knows) but it occurs a lot. Usually goes something like this, step on the gas, sometimes you get a bog, or bogging, the rpm's climb at a steady rate, but you can just feel the lack of power, once you get to about 2000-2100 rpm's, as if you hit the NOS, the damn thing rockets to 3000rpm and you feel the huge surge of power. Then it shifts, and the power backs off usually and becomes more steady.
You can see how this is not only a pain in the ass driving around, but in the winter, you go from slowly accelerating on ice, to spinning the tires.

Any insight to either problem would be appreciated. I just changed the pcv valve, cap, rotor and will do the plugs this weekend.

Thanks guys.
 

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One of the Oxygen Sensors is on the blink. Not bad enough to register on the ECU. You can go up to a year with this and not get any codes, I did, until it hit me while touring the Rockies, in the middle of nowhere. Get a special universal one from Canadian Tire for about $40. It was on sale twice this year for half price at CT and I informed everyone on this board. Please do a search. The part number I listed on the thread. CT does not list it on their computers and will push the $80 one instead but they have the universal one. Alternative is to check Bosch Website. Since you're getting no codes might as well go after front and rear ones. The universal ones is about half the cost of the connector equipped one.
 

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Discussion Starter · #3 ·
GREYLEGEND said:
One of the Oxygen Sensors is on the blink. Not bad enough to register on the ECU. You can go up to a year with this and not get any codes, I did, until it hit me while touring the Rockies, in the middle of nowhere. Get a special universal one from Canadian Tire for about $40. It was on sale twice this year for half price at CT and I informed everyone on this board. Please do a search. The part number I listed on the thread. CT does not list it on their computers and will push the $80 one instead but they have the universal one. Alternative is to check Bosch Website. Since you're getting no codes might as well go after front and rear ones. The universal ones is about half the cost of the connector equipped one.
Thanks Grey, I remembering reading your post and couldn't believe the price because I called and indeed, they were $80, partsource was $45. I'll pick 2 up when I return the pump.

Whats your opinion on the EGR? should it be holding more vacuum for a longer period?
 

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Unfortunately it's a pricey item and only available from the dealer. When I looked at the EGR valve it's a simple item. Just a diaphragm really. I think it's about 3 big bills ten years ago. What comes to mind is that whether the diaphragm can be patched. Take a look at where it is cracked or leaking from, see what material is used and then consider using some pliable gasket type silicone adhesive to patch it. Reinforce the patch by putting some nylon from an old bag or something over it and impregnating it with the silicone. Only use O2 sensor safe adhesives. OK.
Good luck. If it doesn't work, you still need to replace it. No loss.
 

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Discussion Starter · #8 ·
I phoned the dealer, $227 for a new one.

Where abouts is the diaphram located? From what I remember when I cleaned mine a few weeks ago, there were only 2 things that stood out.

Looking at the underside, there was a passage way in one corner and in the center was a probe like looking thing. It was a cylinder with a small cone shaped probe in the middle of it. It was black, so I cleaned it up as best as possible, using some Qtips to get to the bottom of the probe (1/4" down).

I didn't notice any diaphram, then again, I didnt try to take off the upper part of the valve that houses the electronics. Should I have done that?

I have to work tonight, but will rip it apart tomorrow, maybe get some pics up.
Thanks
 

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Discussion Starter · #10 ·
GREYLEGEND said:
Remove the EGR valve, attach a fish pump to the vacuum port and pressurize it. Now dunk it into a bowl of water. You'll see where the leak is. If the leak is on the edge, just seal it back up with some O2 sensor safe silicone.

If you don't have an aquarium pump then just blow into it.
Haha, you know if I thought my fish tank was going to be that useful, I would've hung on to it.

Thanks again grey, I'll test it in the morning.
 

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Discussion Starter · #12 ·
So here were my findings,

After taking it off the engine and actually studying it, I understand how it works and where the diaphram is. Everything looked great, no rips or tears, just diry as hell because my Distributor O Ring is leading (changing as we speak)

So I put it a bowl of water, just past where the diaphram is and started blowing.
I got 1 bubble. Tried it again, no bubbles. I could suck in, and make the diaphram stay at the top, then quickly put my tongue on the hose to keep the vacuum, but it would still slowly come down.

If I removed it from the water and put it back in, I could once again, get 1 bubble, and sometimes none.

So I filled it up even higher, right up to were the plastic of the electronics meets up with the metal. And boy, she was leaking like a siv from every corner. Bubbles streaming out. So I need to know how I can remove the plastic piece so I can put some gasket sealer between the two.

But is this even possible? I took the spring off the unit, should the plastic part just come off? Maybe its stuck because of the oil and crud?


Anyone, Grey, do you know if this is a possible fix? I don't want to rip off the plastic piece and crack something or screw up the electronics (maybe I already have with all the water).

Anyway, Im gona go fool around with it, if anyone has any ideas, let me know.

Thanks
 

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Discussion Starter · #13 ·
Well, I couldn't remove the plastic peice that holds the selenoid. So I applied some silicon around the corners and on the diaphram where the single bubble was coming from.
I reinstalled it because I need the car, but left the electrical and vacuum lines un hooked, so hopefully it will dry within the next day or so. I noticed that it held a vacuum longer after I applied the silicon, so its getting better.

When I got the car warmed up, it through a code 12, which is a good sign, at least the computers are working correctly.

Also installed the Distributor O-ring, new plugs, and adjusted the kick down cable, running really nice now.

I'll keep the EGR fix updated when I find out how it holds up.
 

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The plastic piece on the top is actually just a variable resistor. Kind of like a slide volume control. The plunger/ valve gets pulled up and down and it then varies the resistance. The solenoid is actually in the "black box" by the firewall. The ECU pulses the solenoid till enough vacuum is generated that lifts the EGR valve. When it senses the valve has lifted enough ( via the slide resistor) it backs off the solenoid pulsing. If it wants more lift it pulses the solenoid more. So if you have a very slight leak, the EGR will still work. Notice that the ECU does NOT sense the actual flow of exhaust gases. It assumes the flow will be there.

If you say to yourself what the heck, if I don't fix it then I'll have to replace it then, just really "seal" the sucker up and really load on the silicone. Just make sure you don't seal up the disconnect. Can't see what can go wrong.

Whenever you mess with the EGR, always reset the ECU. It recalibrates itself to sense lift.
 

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Discussion Starter · #16 ·
Very informative :bowdown: , I also was trying to figure out what part of the EGR valve 'sensed' the flow, but it makes sense,it just assumes there is always a flow.

This is essentially what I have, a slight leak, and only causes it to throw a code once in a while, although its more frequent now.

Does the EGR system have any effect on fuel consumption or fuel management?
What part are are you taking about when you say the 'disconnect'?

What I don't understand is this, the car bogs because there is too much lift in the sensor, allowing too much exhaust back into the combustion chamber correct?
The time it takes from when I apply vaccum to the EGR and the time it takes for the diaphram to slowly lose vacuum and close is pretty much the same time it takes me to go from 1,000 rpm to 2,000 where the surge of power is.

So if I seal it up like you said, I still want it to be able to move right? Because if it doesn't move, the resistor will keep saying its closed and the selenoid is going to try to open it, thus throwing a code?

I have to stop thinking about it, just making myself more confused hehe.

On a side note, the new plugs seem to work very well (or the lack of the EGR valve) Car is running very strong. I also noticed that the old plugs were all gapped at .40 instead of .44...wondering if that would've had much of an effect?

Thanks again Grey :D
 

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Don't seal the whole thing, I meant seal the leaks!!!!! Keep the diaphragm moving!!!!

What I haven't figured out yet is whether the EGR is better for the engine or not. A working EGR is GOOD for the environment though. So on that basis I'd recommend you try and keep it going. If the EGR doesn't work, the engine falls back to another another mapping that keeps it going. What some guys have done is make a plate in the shape of the gasket that blocks the return flow even if the valve is open. Better performance is claimed but worse pollution. ( We Canadians care very much for the environment). The EGR circuit doesn't kick in until the car has gone to "closed loop" ( That's when all the sensors kick in and it starts getting feedback from O2, EGR lift etc) before that it is "open loop" where there is no feedback but is operating on assumed conditions from basic sensor readings such as the engine and air temperature sensor.

If your EGR is kaput, it's probably running open loop with rich fuel mixtures and is not even taking feedback from your O2 sensor. Your mileage is going to tank. It's also not good for your cat.
 

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Discussion Starter · #19 ·
GREYLEGEND said:
Don't seal the whole thing, I meant seal the leaks!!!!! Keep the diaphragm moving!!!!
Hahah...ok thats what I did. I'll plug it back in today. I hope the silicon actually set and just didnt' freeze....its getting cold out here in Western Canada!
 
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