Well to start I have a 1990 240sx and I have been having problems with the EGR (code 32) for quite some time. This is a new motor rebuild with all new vacuum lines so don't ask about the BPT vacuum line to the EGR, its new. I did the test by pressing up on the EGR and it stumbled like it should, but this didn't convince me it was clean enough. So I removed the EGR and thoroughly cleaned it with carb cleaner. I sprayed the hose out too with some black stuff coming out, but not a lot and no chunks or anything. I also ran a small wire through it. So that end should be good. I also took out the sensor on the side (measures the temperature i believe) It was covered in soot and crap so i cleaned it as much as possible. I put it all back together and no luck, CEL came back on. I checked the vaccum from the BPT hose and it feels like its pushing air at idle but turns to vaccum it seems at 2k or so RPMs. I haven't done the test on 240sx.org's faq to check the BPT, I will tomorrow. I guess that would be the next logical problem. The car was running for a while with a broken EGR control solenoid valve (had one of the vacuum tubes broken off) So I got a new one (paid too much from the nissan parts store) and put that on. Again no luck. I have a junkyard EGR just in case that is my problem, and it had no BPT to take, unfortunately. If you guys have any ideas to throw at me less than get a new BPT i'd love to hear it. I have spent too much money on this problem already. I didn't clean the metal lines either, I guess that would help too. I don't really know where to go...
On a side note it has an intake, header, and hi-flow cat with stocker exhaust. Everything is pretty much new (like 2k miles). The header is S&S 4-1 style and has the EGR, and AIV hooked up. AIV was just cleaned also. seems to be no problems. I don't think there are any major exhaust leaks and no other codes on the computer. I think the plenum is fairly clean and I would rather not take that all apart. I cleaned it before but not real thoroughly like I should have. The idle is also a little shakey at about 800 +/- 50 all the time. I tried to adjust it down a bit and it does go down but popped back up and doesn't want to stay at 750 or so like it should, with the flathead idle screw all the way in. And I did disconnect the TPS when I did this. When I hook it back up the idle goes back to 800-850.
Sorry for the long post but I thought you would like all the information up front to mill it over. Thanks for your time.
EGR/BPT problems
I dont think any thing is wrong with your EGR system including the BPT and the hoses to it.
What you dont want to hear is I think your high flow exhuast is your problem. Its not allowing enough back pressure in it to close the BPT which will allow the vaccum to reach the EGR valve.
Easy way to verify this is loan a hand vaccum pump from auto zone. on the side of the pump that pumps air instead of vaccum run a hose to the bottom of the BPT. hold your rpm just off idle and give a very small squeeze on the pump[not a full stroke]. Does the rpm drop? If so your entire EGR system operates as designed. And this proves your exhuast is your problem. If the above does not happen post back.
What you dont want to hear is I think your high flow exhuast is your problem. Its not allowing enough back pressure in it to close the BPT which will allow the vaccum to reach the EGR valve.
Easy way to verify this is loan a hand vaccum pump from auto zone. on the side of the pump that pumps air instead of vaccum run a hose to the bottom of the BPT. hold your rpm just off idle and give a very small squeeze on the pump[not a full stroke]. Does the rpm drop? If so your entire EGR system operates as designed. And this proves your exhuast is your problem. If the above does not happen post back.
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Smebbin'd'240
- Posts: 40
- Joined: Mon Mar 31, 2003 5:57 pm
Ok, sounds good. Its the stock exhaust though, and a hi-flow cat... but I could see that happening. I will do the test, and thanks for the help 
Just a thought but does everyone that has this setup (I/H/E) have a non-functioning EGR? How do you guys pass emissions, or do you bolt on the old one? Oh well, I guess I could get a stock cat if thats the case. If it does prove to be not enough back pressure will an OEM cat do the trick for more back pressure?
Just a thought but does everyone that has this setup (I/H/E) have a non-functioning EGR? How do you guys pass emissions, or do you bolt on the old one? Oh well, I guess I could get a stock cat if thats the case. If it does prove to be not enough back pressure will an OEM cat do the trick for more back pressure?
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Smebbin'd'240
- Posts: 40
- Joined: Mon Mar 31, 2003 5:57 pm
if the muffler is stock the cat is the only thing you need to worry about. Do the test on the system as mentioned previously. Make sure the system works properly if it has back pressure. While your doing that test check the BPT hose close for holes. This is the hose under the BPT, where you will be hooking up the pump.
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Magnes
- Posts: 101
- Joined: Thu Jan 30, 2003 6:58 pm
- Car: '89 240SX, done up with a chrome-plated ground wire to the engine.
Sorry to disagree but I happen to be working on a similar problem on my stock '89 240.
Everything sounds like it's working as it should, you've done your homework. The EGR code is triggered when the EGR valve doesn't open. You can open it with your finger so it is not stuck, and you have vacuum off idle as you should. The most reasonable explanation why the EGR isn't opening is that the vacuum isn't strong enough to open it, either because the vacuum is too weak or the valve is too stiff.
Makes sense no?
As far as I can tell vacuum originates from the charcoal canister (the small hose on the top). disconnect it and check that the vacuum you get from the canister is as strong as the one you feel coming off the BPT valve. I think my canister is faulty. If that checks out, compare the feel of your EGR valve to another car's. If your is stiffer that may be the problem.
Good luck.
Everything sounds like it's working as it should, you've done your homework. The EGR code is triggered when the EGR valve doesn't open. You can open it with your finger so it is not stuck, and you have vacuum off idle as you should. The most reasonable explanation why the EGR isn't opening is that the vacuum isn't strong enough to open it, either because the vacuum is too weak or the valve is too stiff.
Makes sense no?
As far as I can tell vacuum originates from the charcoal canister (the small hose on the top). disconnect it and check that the vacuum you get from the canister is as strong as the one you feel coming off the BPT valve. I think my canister is faulty. If that checks out, compare the feel of your EGR valve to another car's. If your is stiffer that may be the problem.
Good luck.
Magnes wrote:Sorry to disagree but I happen to be working on a similar problem on my stock '89 240.
As far as I can tell vacuum originates from the charcoal canister (the small hose on the top). disconnect it and check that the vacuum you get from the canister is as strong as the one you feel coming off the BPT valve. I think my canister is faulty. If that checks out, compare the feel of your EGR valve to another car's. If your is stiffer that may be the problem.
Good luck.
OK super tech. Keep working on it I think your on to something...he he he...snicker snicker.:rolleyes
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Magnes
- Posts: 101
- Joined: Thu Jan 30, 2003 6:58 pm
- Car: '89 240SX, done up with a chrome-plated ground wire to the engine.
You mean I'm wrong? Great! It wasn't maing any sense anyways.NISTECH wrote:OK super tech. Keep working on it I think your on to something...he he he...snicker snicker.:rolleyes
In any case there is no signal vacuum coming from any of the 3 vacuum hoses attached to the EGR solenoid. The canister was my best guess as to the source of vacuum, and it certainly failed the test as outlined in the service manual, so it was doubly suspect.
So where is the signal vacuum supposed to originate from, and is there anything wrong with my evap canister? (the service manual has been wrong before).
Magnes wrote:Sorry to disagree but I happen to be working on a similar problem on my stock '89 240.
Everything sounds like it's working as it should, you've done your homework. The EGR code is triggered when the EGR valve doesn't open. You can open it with your finger so it is not stuck, and you have vacuum off idle as you should. The most reasonable explanation why the EGR isn't opening is that the vacuum isn't strong enough to open it, either because the vacuum is too weak or the valve is too stiff.
Makes sense no?
As far as I can tell vacuum originates from the charcoal canister (the small hose on the top). disconnect it and check that the vacuum you get from the canister is as strong as the one you feel coming off the BPT valve. I think my canister is faulty. If that checks out, compare the feel of your EGR valve to another car's. If your is stiffer that may be the problem.
Good luck.
well i do have a small vacuum (barely enough to feel it) going to my EGR valve but when i rev the motor the diaphram moves up.
And no, the canister is not the source of the vacuum, if u look at the vacuum hose diagram (which is a sticker on your hood) the hose that connects to your solinoid valve (the connection from the drivers side) is from the throttle body. which makes sense because there is no vacuum at idle but one when it revs. so that canister hose is also a vacuum line (check the vacuum hose diagram in the FSM).
hehe i once thought that vacuum did come from the canister (cuz i had no idea how this vacuum thing was set up) but that diagram on the hood really helps out in trying to find hoses and whats connect to what. The FSM's hose diagram does not help at all in finding out what goes to where.
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Magnes
- Posts: 101
- Joined: Thu Jan 30, 2003 6:58 pm
- Car: '89 240SX, done up with a chrome-plated ground wire to the engine.
Ah that makes sense now, thanks.
I saw the vacuum line to the intake, but I thought vacuum only came from the plenum. This was my mistake. My EGR still isn't operating right, but I'll figure it out eventually.
Any luck with your problem? Do you have to get your car emissions tested in your area? If not, the inoperative EGR shouldn't be a huge concern.
I saw the vacuum line to the intake, but I thought vacuum only came from the plenum. This was my mistake. My EGR still isn't operating right, but I'll figure it out eventually.
Any luck with your problem? Do you have to get your car emissions tested in your area? If not, the inoperative EGR shouldn't be a huge concern.
well check to make sure that all rubber hoses are not burned/cracked/ or slit. (its a pain and some u cant check unless u dismantle your intake manifold (like the one to the intake) but hopefully those are not a problem.
But as for smog, I have failed twice now! just cuz my CEL light was on (but my emissions passed lower then the avg car!). But the first time i took it in, the little hose under the BPT valve was burned and i replaced it for the second try but the light still came on.
Nistech just posted on my other thread ( http://www.nissaninfiniticlub....02788 ) and he says its my partially clogged EGR tube (whiich connects to the exhaust manifold). So im gunna do that hopefully tommorow (maybe ill finish by tommorow!).
But as for smog, I have failed twice now! just cuz my CEL light was on (but my emissions passed lower then the avg car!). But the first time i took it in, the little hose under the BPT valve was burned and i replaced it for the second try but the light still came on.
Nistech just posted on my other thread ( http://www.nissaninfiniticlub....02788 ) and he says its my partially clogged EGR tube (whiich connects to the exhaust manifold). So im gunna do that hopefully tommorow (maybe ill finish by tommorow!).