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*Sniff* Uh oh! What's that smell?!? Help!!

8149 Views 67 Replies 20 Participants Last post by  savvasKE35

Ok, I posted this over at Supraforums a while ago...but the MK2 section over there isn't receiving much attention I thought I'd post it here since this is where the party's at! ;)

The Problem: For a while now there has been a weird smell emitting from my car. I've come to the conclusion that whatever this smell is, it seems to be coming from the exhaust. When I drive with the windows down I smell it...when the car is idling in the garage I smell it even more!

The car has recently had a new exhaust's been examined by my mechanic and found to have absolutely no leaks...the smell was there with the old exhaust as well. So it's definitely not an exhaust problem, but the smell is coming from there regardless.

The car never had a Catalytic Converter (They weren't needed at the time here in Aus). So we can rule out that being the cause of the smell. This leaves me with little else to work with...I have no idea what could be causing this's definitely not normal...after the car has warmed up the smell becomes unbearable.

If the car is burning too much fuel (running rich?), would I get this bad smell? That's all I can think of...I have no idea... :?

Hopefully you guys can help me solve this puzzle... :cry:
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There's a lot of different smells you can get - burning rich generally produces a gasoline/carbon type smell running lean can give a hot or burnt type odour, if you have a BHG you'd get a sweeter smell. Is your car blowing smoke - blue smoke and strong smell is burning oil, black smoke is running rich, white smoke is often antifreeze.
Does it smell anytime the engine is running or only once you start driving it? You could have a leak of some sort in the engine bay and whatever it is, is flying back and hitting the muffler or tail pipe somewhere. That can create awful smells and keeps you looking in the wrong place for the fix.

Can you tell us a bit more about what it smells like? That might help diagnose the issue a bit easier.

You can smell it while you drive, with the windows blows right into the car, but you can smell it when you stand outside the car while it idles as it's not just when I's worse when you stand outside while it's a strong smell it's hard to say what the smell is like, it's just very gassy and you can't take much of it before it starts to get to you. The car doesn't blow smoke...but when I look inside the muffler, it's quite black in there...what does that mean? It's burning something right?
this may be a shot in the dark, but could it just be the smell of a new exhaust system? Those of us who've installed headers or new mufflers/cats know the smell. It seems to be almost like burning metal and a touch of oil to it.
Does the smell come out right when you start the vehicle, or is it only noticeable after you've warmed up the vehicle???
You mentioned that you could smell this odor before you replaced the exhaust system, and also after your new exhaust system was installed. Does the odor smell like raw gasoline from a possible fuel leak?
I'm positive it's not the smell of a new exhaust because the smell was there with the old exhaust as well...that's part of the reason why I changed the old exhaust because I thought the smell was an indication that it was on it's way out...but when the new exhaust was installed (around a year ago), the smell was still there...this is why I'm certain it's not the exhaust itself...I think it's engine related and it's coming out of the exhaust. But, I must also tell you that the exhaust was changed from where the cat would be,'s still got the old exhaust manifold...

I can only really notice the smell once the car is warmed soon as I start the car, the smell isn't there...but after about 4 - 5 minutes or so, then I can start to smell it...once the car is fully warmed up the smell is unbearable. :(

This problem is driving me insane...what do you think it could be?
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It kind of smells a bit like gasoline I's hard to's not a pleasant smell.

I must also point out that I don't think I'm getting the mileage I should be getting...I usually get around 180 - 190 miles off a full tank. That's not very good right? I'm not sure if it's related or not but I thought I'd point it out just in case...
How does your car run? Good, fair, poor? You mentioned that the inside of the tailpipe is black. That's a good indication that something is causing your fuel mixture to be on the rich side. How long has it been since you did a complete tune-up on the engine and cleaned the fuel injectors? An engine that is in poor tune can cause exhaust odor to increase since some amount of raw fuel can be mixed with burn't fuel, especially if the injectors aren't operating up to par.
How about the gasoline in Australia. Have any recent changes been made to the gasoline formulation in Aus. such as the addition of Methanol??
What year is your MKII? Is your check engine light coming On? I also have a suspicion that you may have a bad 02 (oxygen) sensor that may be causing your air/fuel mixture to be running a bit rich most of, if not all of the time.
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Hmm, It hasn't had a tune up in ages. I do all the regular maintenance stuff myself but I haven't taken it to a mechanic for a 'tune-up' in years. I've never got the injectors cleaned...but I've added the liquid injector cleaner through my fuel a couple of times in the past...that was over a year ago though...not sure if that stuff actually cleans the injectors or not...

The car runs great...the power is all there and there is absolutely nothing else wrong. Aside from the bad smell a tad rough idle and what I believe to be poor mileage, it's perfect...

Not sure if there has been any changes to Aussie fuel, but I doubt it...The engine check light has never come on...not once. The car is a 1983 with the 5M-E engine.
You can check the output (feedback) signal of your 02 sensor by connecting a voltmeter to the 4-terminal service connector located behind the AFM on the passengers side strut tower. Terminals VF and E1. Page FI-59 in the 83 TSRM. My guess is that you may indeed have a bad 02 sensor. That would explain the rough idle and smell of a rich mixture. The ECU can detect when the 02 sensor is outputting a lean signal for a longer than normal time period and cause a code 21 to be stored and turn On the check engine light. OTOH, the ECU doesn't detect when the 02 sensor outputs a rich signal for a longer than normal time period, thus no check engine light even though the sensor is not operating properly.
Sounds like it's running rich to me.
Is that the grey square box that is bolted to the strut tower and has wires coming out the bottom of it?

What reading should I be getting on the volt meter to say whether it's bad or good? I don't have the service manual sorry. :(

If the car is running rich, what do I need to do to correct it?
Nights... I have the same problem.....and I'd be willing to bet if you feel like shooting over to the states and smelling my car...its the same.

I really don't know what it could be.......But I'm going to replace the O2 sensor just to see.
A vacum leak can cause the system to run rich, along with a million other things. A temp sensor could cause it also. Also, incorrect ignition timing.

On my '84, the leak that caused those symptoms was the vacum line that ran between the rear of the throttle body to the cam cover. Luckily regular hose from the auto parts store could be adapted.

You might also check all the accordion rubber hoses and the plastic thingy on the intake that runs over the top of the engine. You will need to pull it off and check all around for cracks.
What about dirty injectors or bad fuel filter? Would that cause it to run rich? I fully inpected most of my hoses last week...they seemed fine. The only things that I think need to be changed because they haven't been changed in years are the Air Filter and Fuel Filter. Other than that everything else is good. The injectors might need a thorough clean...but somehow I doubt they are the cause of this annoying smell.

I heard someone say that the 5M-E engines don't have an O2 Sensor...can anyone confirm this?

If I can't solve the problem through this forum, I'll just take the car to a different mechanic either tomorrow or on Monday...The car is using up way too much fuel and this smell is frustrating...I have to get it repaired...argh! :mad:
I really don't know which MKII's have an 02 sensor and which ones don't. The fact that your car doesn't have a catalytic converter from the factory could also mean that it doesn't have an 02 sensor. Dirty or clogged injectors would cause more of a lean condition in your case if your car indeed does not have an 02 sensor. The feedback signal fom the 02 sensor would normally tell the ECU to widen the injector pulse and richen up the fuel mixture if one or more injectors are badly clogged, but that won't happen if the EFI system doesn't have an 02 sensor. You might try checking your fuel pressure regulator and see if it is working properly. A ruptured diaphragm in the FPR could allow extra fuel to be drawn into the intake manifold through the vacuum hose connection. Try disconnecting and plugging the vacuum hose on the FPR and see if that makes a difference while you're driving. The rough idle may also improve some with the hose disconnected but the idle mixture will be a little rich with the FPR valve closed.
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Hey Dave!

Where abouts is the Fuel Pressure Regulator located?
NiGHTS said:
I heard someone say that the 5M-E engines don't have an O2 Sensor...can anyone confirm this?
I can confirm NiGHTS that the Aust. Spec Supras are not fitted with the 02 Sensor because in 1983-1985 we still had leaded petrol still avaliable then the introduction of unleaded petrol in mid to late 1986 which most car (made after 85) was fitted specifically for the running unleaded petrol.

Oh ok, thank you ZZT231. :)

That rules out a faulty O2 sensor then...I don't know what could be causing this problem now. I still think it's fuel related though...but I'm out of idea's...D'oh! :(
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