Vandergriff84 Posted April 30, 2014 Share Posted April 30, 2014 Ok, So my car seems to run fine and all the parameters on data scan and my wideband seem right to me but the car has this horrific exhaust smell that gives me a headache after about five minutes of driving it or just running it in the drive way. I have replaced all of the exhaust gaskets but there is still fumes coming into the cab with the windows down. The only thing that I can guess being how bad the fumes are is that the car is running really rich. My question is, is it possible for the motor to run so rich it causes horrific fumes to escape the engine compartment? Like I said there are all new gaskets and I am still getting fumes coming into cab while driving or sitting. For example the fumes make me dizzy and wreck my sinuses in a matter of minutes. I would appreciate any advice as to where to start. Motor is stock, I have a freddy intake and greddy BOV. Quote Link to comment Share on other sites More sharing options...
5thgenluder Posted April 30, 2014 Share Posted April 30, 2014 Did you get many fumes in the cabin with the stock motor? Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 30, 2014 Share Posted April 30, 2014 (edited) You're kind of rambling all over with the driving, and the sitting in the driveway and fumes in the engine bay escaping and fumes coming in through open windows. Creating a vision of a car sitting in a cloud of noxious fumes. To your specific question about a rich mixture overpowering gaskets and metal to "escape" versus a lean mixture - no, all gases behave the same. Although, if you've modified your PCV system, blowby could be escaping in to the engine bay. If you can get all gases to exit via the hole at the end of the exhaust system, you should be bale to keep them out of the cabin by sealing the perimeter of the big vinyl covered panel on the inside of the back hatch. Several people around various forums have described this. Don't worry about all of the small holes on the outside, just focus on sealing the edges of the trim panel on the inside. Stick-on weatherstrip works well. The cloud of fumes while running in the driveway should be handleable by idle tuning (obviously). Idle tune is typically a whole different world from driving tune, both ignition timing and air-fuel ratio. Edited April 30, 2014 by NewZed Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 30, 2014 Author Share Posted April 30, 2014 I never had the car running with the stock motor. It was blown when I bought the car which is why I went ahead with the RB swap. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 30, 2014 Author Share Posted April 30, 2014 As far as I know the PCV setup is the same as stock RB25 even though I switched to the freddy intake. Can you further explain this blow by scenario? Don't forget that this is not a problem with fumes entering with the windows up it is mostly with the windows down. I do have to keep the air vent closed as well to keep the fumes from coming in through the cowl. For a while I only noticed it after running the car under boost and now it is certainly worse under boost but it's there all the time now. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 30, 2014 Author Share Posted April 30, 2014 I forgot to mention that I have the 3" exhaust and down pipe from McKinney Motorsports. I still have the stock 2.5" elbow/dump pipe coming off the turbo as I have not found a 3" to replace it with yet. Quote Link to comment Share on other sites More sharing options...
5thgenluder Posted April 30, 2014 Share Posted April 30, 2014 This is very strange. I have the exact same setup. Rb25, Freddy, greddy bov, McKinney exhaust. I also never drove my car in its stock form and I also have the exact same smell. I always assumed it was because of poor seals in the car. But it's crazy that you have the same thing. Oh and I'm tuned with a haltech platinum pro plug in. Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 30, 2014 Share Posted April 30, 2014 Sounds like garden variety exhaust system leaks. Lots of flanges and gaskets to leak from on a turbo engine. Quote Link to comment Share on other sites More sharing options...
TimZ Posted April 30, 2014 Share Posted April 30, 2014 If you can get all gases to exit via the hole at the end of the exhaust system, you should be bale to keep them out of the cabin by sealing the perimeter of the big vinyl covered panel on the inside of the back hatch. Several people around various forums have described this. Don't worry about all of the small holes on the outside, just focus on sealing the edges of the trim panel on the inside. Stick-on weatherstrip works well. Check the seals around the taillights, too - these are also well known to allow exhaust fumes to enter. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 30, 2014 Author Share Posted April 30, 2014 Sorry if I didn't make it clear what the problem is. The fumes are not coming into the cab with the windows up just when they are down. The problem is that the fumes are super strong and are present now with the car on the road and at idle. I have now ruled it unbearable even just for a few minutes as it destroys my sinuses for the next couple of days. So sorry for asking about leaks since as you can tell this is more of a tuning issue than a leak as a leak would just be a small irritant. Is there away to adjust the A/F mix on the stock ECU? Quote Link to comment Share on other sites More sharing options...
CasperIV Posted April 30, 2014 Share Posted April 30, 2014 (edited) This sounds very strange. If the exhaust is getting into your car through the windows while moving it must be horrific standing next to the front of the car at idle. Personally, the description makes me think you are getting a massive leak under the hood/front and it's being drawn into the car by the air passing by the windows causing a pressure differential, but that is pure speculation. Have you put the car on stands and checked for leaks? Is the turbo boosting properly? Have you removed breathers/emissions parts without properly rerouting or blocking them off? As far as I know, the stock ECU will already be trying to correct AFR if everything is stock. The sensors (such as O2) will be sending it the information it needs to adjust within the allowed map. Do you have all the sensors wired up and do you have a wideband you can use to test? Edited April 30, 2014 by CasperIV Quote Link to comment Share on other sites More sharing options...
5thgenluder Posted April 30, 2014 Share Posted April 30, 2014 (edited) From what I've read that may be common. Most guys say that windows up is fine and when u put the windows down it creates a vacuum that pulls all the fumes thru any of the seams or leaks. I originally thought the same thing about the tuning issue but even with my fully tuned ecu and optimal a/f ratio at idle and throttle I still get the smell. I'm going to use a method of making a cardboard template for the window that will seal a shop vac in it. Then put a smoke or fog machine near the exhaust turn on the shop vac and check where you see the smoke coming in the car. Seal that area and move on to the next. But I'm excited to see if these guys have any more theories of what may be causing the smell. Edited April 30, 2014 by 5thgenluder Quote Link to comment Share on other sites More sharing options...
CasperIV Posted April 30, 2014 Share Posted April 30, 2014 From what I've read that may be common. Most guys say that windows up is fine and when u put the windows down it creates a vacuum that pulls all the fumes thru any of the seams or leaks. I originally thought the same thing about the tuning issue but even with my fully tuned ecu and optimal a/f ratio at idle and throttle I still get the smell. I'm going to use a method of making a cardboard template for the window that will seal a shop vac in it. Then put a smoke or fog machine near the exhaust turn on the shop vac and check where you see the smoke coming in the car. Seal that area and move on to the next. But I'm excited to see if these guys have any more theories of what may be causing the smell. That's a really good idea. That would be a great way to try to find the leaks if you can generate enough draw with the vacuum. It's odd that a stock car wouldn't have the issue unless the exhaust exit is in a radically different place though. Quote Link to comment Share on other sites More sharing options...
NewZed Posted May 1, 2014 Share Posted May 1, 2014 The exhaust fumes in the cabin problem is written about all over the internet. Still seems like you might have two problems, or more. The exhaust on my stock L28 smells so sweet sometimes I lean down and take a sniff just to know that things are stilled tuned right. I enjoy when a breeze of exhaust blows in through the window. It was only close to horrific quite a while ago when my FPR went bad causing a super-rich condition. My engine is catalytic converter-free so the smell is unprocessed. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted May 1, 2014 Author Share Posted May 1, 2014 As far as fumes getting into the cab I think for now I am going to say that that's a minor issue and the major issue at hand is the ungodly strength of the exhaust fumes that are present. I have been noticing for the past few weeks how bad my garage smells and I just thought that was the gas going bad from the lack of turn over. I have known about the fumes getting into the cab for a few months and at first i tried to fix the problem by putting new gaskets on everything thinking that aslong as they are blowing out the back I would be fine for now. But there is something wrong with these fumes whether it mixture or what have you I do not know. I ran the car in the garage With the garage door open for 3 or 4 minutes last night just so I could see what data scan would show and immediately my sinuses started to freakout. I just got home and walked by the car a few minutes ago and felt like I was going to be sick from the smell in the garage. I am clueless as to what would make the car smell this bad. I know that there are some types of grease and transmission fluids that make me gag but I don't think that is the problem here. Quote Link to comment Share on other sites More sharing options...
TimZ Posted May 1, 2014 Share Posted May 1, 2014 As far as fumes getting into the cab I think for now I am going to say that that's a minor issue and the major issue at hand is the ungodly strength of the exhaust fumes that are present. I have been noticing for the past few weeks how bad my garage smells and I just thought that was the gas going bad from the lack of turn over. I have known about the fumes getting into the cab for a few months and at first i tried to fix the problem by putting new gaskets on everything thinking that aslong as they are blowing out the back I would be fine for now. But there is something wrong with these fumes whether it mixture or what have you I do not know. I ran the car in the garage With the garage door open for 3 or 4 minutes last night just so I could see what data scan would show and immediately my sinuses started to freakout. I just got home and walked by the car a few minutes ago and felt like I was going to be sick from the smell in the garage. I am clueless as to what would make the car smell this bad. I know that there are some types of grease and transmission fluids that make me gag but I don't think that is the problem here. The exhaust fumes from the seals in the rear that both Xnke and I mentioned specifically happen when the windows are down. The air doesn't flow like you would think - as somebody already mentioned the Bernoulli effect from air passing over the window opening causes a vacuum in the cabin and exhaust is sucked into the cabin through the leaking taillight or hatch seals. This is a very well known issue. 1 Quote Link to comment Share on other sites More sharing options...
5thgenluder Posted May 1, 2014 Share Posted May 1, 2014 I think vandergriff is saying he wants to forget the exhaust fumes while driving issue and concentrate on the bad smelling exhaust. I'll start with a few questions. How do you have your crank case vented? I know u said you had a Freddy intake. If you have no way to tune your a/f is off. You should at least get an afc or something along those lines. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted May 1, 2014 Author Share Posted May 1, 2014 I am starting to get the picture of the fumes entering through the back which makes sense as there are all new seals on the exhaust. I will probably take a look at this once I get the fumes sorted out. I don't recall having this problem with the 78 280z I had in the early 2000s. As far as the venting goes I tried to run everything as it was on the stock setup. PCV hose goes from the Freddy intake to the PCV check valve on intake valve cover and then there is the pipe that connects the intake cover to the exhaust cover that Ts off and goes to the intake pipe just before the turbo. I have the stock Throttle body connected with a 1/2" adapter plate that I made for clearance. I have the Greddy BOV just in front of the TB and is circulated back to the intake pipe just before the turbo. I don't really understand how the Freddy intake could make such a difference in the way that it runs but at the same time it is the only major change from the stock setup. What would be a reasonable FC for the money since I don't really care to make ton of power? I know that Nistune is not that expensive in comparison to AEM and what have you but I haven't found anyone here that is running it on their car yet. Quote Link to comment Share on other sites More sharing options...
CasperIV Posted May 2, 2014 Share Posted May 2, 2014 Is that a piece of PVC pipe functioning as a re-circulation line? Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted May 2, 2014 Author Share Posted May 2, 2014 Its actually Aluminum, it has a Teflon coating on the outside of it. It was leftover from the compressed air lines I ran in my shop. I am planning to relocate the BOV to the other side of the intercooler to clean things up a bit. Some one gave me the BOV with a bunch of piping and that was the only place that it would work so I went with it. There is one piece of PVC under the throttle body for the idle air control. I couldn't find any metal piping that size at the time. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.