rc_cola_j Posted January 1, 2016 Share Posted January 1, 2016 Does anyone know a good way to clean an EGR valve without removing it? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 2, 2016 Share Posted January 2, 2016 Not really. The only port you'd be able to get to without removing the connection to the manifold (which I'm assuming is seized if you want to try cleaning w/o removing) is the one inside the intake, and IIRC you can only find that one by braille with the throttle body off. Besides, if there are chunks of carbon in the valve, it's probably best to avoid dropping them down the intake. Link to comment Share on other sites More sharing options...
rc_cola_j Posted January 2, 2016 Author Share Posted January 2, 2016 Sigh. Guess I have another project to add to my list. It seems like the EGR would be a be a time consuming thing to remove. Eh? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 2, 2016 Share Posted January 2, 2016 Really depends on how bad the exhaust inlet fitting is. If that's seized, you're gonna have a hell of a time. If not, there really isn't much else holding it down, just a couple bolts to the intake and some vac lines. The one on my '93 was really easy thanks to some PO or mechanic who'd smeared gobs of antiseize on the connection to the pipe going down to the manifold. The one on my '95 was rusted solid, and either stripped when I tried to undo it or was already stripped and the last guy had just sort of jammed it back into place for me to find. That one was bad enough that I had to replace the valve and cut 3/8" or so off the end of the coupler sleeve bit to get down to threads with any hope of grabbing the new (salvage) valve. If yours fights you, try it hot, try penetrating oil, try sacrificing a goat... 1 Link to comment Share on other sites More sharing options...
rc_cola_j Posted January 2, 2016 Author Share Posted January 2, 2016 I'm getting sad. I can't get to it for a little while......can probably live with a rough idle until then, or just disconnect it. In the mean time I'll put some penetrating oil on the threads and such Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
rc_cola_j Posted January 3, 2016 Author Share Posted January 3, 2016 So I'm doing a lot of reading online......how do I properly diagnose my EGR issue? What's going on is that once the engine warms up it begins to 'lope' at idle......as though it has a small vacuum leak. If I disconnect and plug the vacuum lines between the EGR valve and the EGR Backpressure Transducer. It runs fine. How do I tell if it is the EGR valve itself sticking open or if it is the EGR BPT? Or is it an Aspect of the EGR? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 6, 2016 Share Posted January 6, 2016 Interesting that the BPT seems to be acting up. I remember the one on my '95 had a short rubber hose at the bottom (where exhaust pressure joins up) that was dry-rotted and had a big hole in the back. It looked fine until I removed the valve and could see the back. I would start by checking that. IIRC the service manual has procedures to test the valves manually, most likely in the EF&EC section. the EGR Backpressure Transducer ... so that's what BPT stands for. Thanks for clearing that up! Link to comment Share on other sites More sharing options...
rc_cola_j Posted January 6, 2016 Author Share Posted January 6, 2016 Interesting that the BPT seems to be acting up. I remember the one on my '95 had a short rubber hose at the bottom (where exhaust pressure joins up) that was dry-rotted and had a big hole in the back. It looked fine until I removed the valve and could see the back. I would start by checking that. IIRC the service manual has procedures to test the valves manually, most likely in the EF&EC section. ... so that's what BPT stands for. Thanks for clearing that up! I don't actually know what component of the EGR system is the issue. I just know disconnecting the Vacuum line between the BPT and EGR valve eliminates the rough idle problem. I'm trying to understand the EGR system and have been doing some reading. I came across and article (http://www.aces.edu/~parmega/efi/egr.txt)......in it it says that there are a few different types of systems based on how the BPT works Question.....which type would apply to the R50 Pathfinders? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
rc_cola_j Posted January 6, 2016 Author Share Posted January 6, 2016 Is it a negative back pressure or Positive type? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 7, 2016 Share Posted January 7, 2016 I honestly have no idea. I would start with the service manual rather than a more generic list that looks to be geared more towards GM products anyway. Pre-round dash WD21s didn't have a BPT valve. This was added (and apparently carried over to the R50) to shut the main EGR valve when exhaust backpressure rose (basically turning off the EGR when the engine is loaded). That doesn't sound like it would change idle, but for some reason it did when you unhooked it. Having looked at the manual again, I would be more inclined to suspect the EGRC solenoid valve (which lets the computer shut down the EGR at idle or high revs), but that doesn't explain why unhooking the BPT would change anything. Then again, I'm looking at the '95 manual, and Nissan may well have changed the operation of the 3.3's EGR. Again, download the appropriate year of the service manual, find the EF&EC section, and look up how the EGR is supposed to work. Somewhere in there you should find descriptions of the parts, their location, and how they're hooked together. If you're running the original vac lines, probably best to replace those, they do dry out over time and new line is cheap. Poke around, take stuff apart, try to rule things out, eventually you'll either stumble onto the issue (like I did with the rotted hose) or rule everything else out. Link to comment Share on other sites More sharing options...
toughroad Posted January 7, 2016 Share Posted January 7, 2016 Do you guys use any chemical that could safety clean the EGR and the housing it self? Link to comment Share on other sites More sharing options...
rc_cola_j Posted January 7, 2016 Author Share Posted January 7, 2016 I honestly have no idea. I would start with the service manual rather than a more generic list that looks to be geared more towards GM products anyway. Pre-round dash WD21s didn't have a BPT valve. This was added (and apparently carried over to the R50) to shut the main EGR valve when exhaust backpressure rose (basically turning off the EGR when the engine is loaded). That doesn't sound like it would change idle, but for some reason it did when you unhooked it. Having looked at the manual again, I would be more inclined to suspect the EGRC solenoid valve (which lets the computer shut down the EGR at idle or high revs), but that doesn't explain why unhooking the BPT would change anything. Then again, I'm looking at the '95 manual, and Nissan may well have changed the operation of the 3.3's EGR. Again, download the appropriate year of the service manual, find the EF&EC section, and look up how the EGR is supposed to work. Somewhere in there you should find descriptions of the parts, their location, and how they're hooked together. If you're running the original vac lines, probably best to replace those, they do dry out over time and new line is cheap. Poke around, take stuff apart, try to rule things out, eventually you'll either stumble onto the issue (like I did with the rotted hose) or rule everything else out. You and I are thinking along the same lines. I was planning on replacing the lines this weekend........I did look at them today....the vacuum line on the manifold side of the BPT valve seems to have a restrictor in it, sot of looks and feels like a little ball bearing, but it has a tiny hole in it....it is passing a vacuum signal. Q..is this normal? Could this be a mistake that a mechanic made on previous work? Also....there is a metal line running from the EGR back to the bottom of the BPT valve. Is it worth a try to take this off and spray some seafoam inside both the EGR and the BPT valve? Do you guys use any chemical that could safety clean the EGR and the housing it self? Seafoam? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 7, 2016 Share Posted January 7, 2016 The valves themselves pass exhaust gas, so I don't imagine they're full of plastic parts that are picky about solvents, assuming you're not spraying into the vac fittings. Carb cleaner would probably be my first choice. Again, I'd be more worried about the solvent I dumped in draining into the intake manifold, especially if I suspected that the valve was sticking open. As for cleaning the outside, I'd just take a wire brush to it. I don't think my '95 had one of those little beads in the line. Seems like a difficult thing to install by mistake, so I would guess at it being some sort of damper or something. Check the service manual! You might also check the vacuum routing diagram on the underside of the hood to see if it shows anything there. Link to comment Share on other sites More sharing options...
toughroad Posted January 8, 2016 Share Posted January 8, 2016 You and I are thinking along the same lines. I was planning on replacing the lines this weekend........I did look at them today....the vacuum line on the manifold side of the BPT valve seems to have a restrictor in it, sot of looks and feels like a little ball bearing, but it has a tiny hole in it....it is passing a vacuum signal. Q..is this normal? Could this be a mistake that a mechanic made on previous work? Also....there is a metal line running from the EGR back to the bottom of the BPT valve. Is it worth a try to take this off and spray some seafoam inside both the EGR and the BPT valve? Seafoam? Sent from my iPhone using Tapatalk Beside seafoam do you use any other products? Link to comment Share on other sites More sharing options...
rc_cola_j Posted January 9, 2016 Author Share Posted January 9, 2016 Carb cleaner on occasion or a degreaser available at local auto parts Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
rc_cola_j Posted January 9, 2016 Author Share Posted January 9, 2016 I'm pretty new at this too, so I am not up on all the different products available. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
toughroad Posted January 11, 2016 Share Posted January 11, 2016 Carb cleaner on occasion or a degreaser available at local auto parts Sent from my iPhone using Tapatalk Thanks man really appreciate it! Link to comment Share on other sites More sharing options...
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