Hello,
I did an engine swap and put a brand new improved-flow cat on my 3rd gen. Since then, Its had a sulfer smell coming out of it on and off... mostly on. I'm thinking its a bad wire somewhere. Not sure where to start looking, though. I'm also thinking its a bad cat.

Any ideas?

 

a strong rotten egg or sulphur smell is usually always indicative of a bad catalytic converter get it changed out as soon as you can.

 

Exactly what kind of cat...design, brand, did you put on?

 

Sulfer...I'm thinking it's prob the cat.

Either that or Satan has inhabited your FD

 

By federal law converters have a long warranty on them. So, in most cases, they should swap you a knew one with no charge.

The exception, of course, is if your engine isn't running right or you're using the converter for an unapproved application. To be honest with you, a brand new cat shouldn't fail so soon. Something is wrong somplace. Are you using some cat that has no business being on a FD? Is your engine so out of it that you burned up the cat?

If they give you a free one in exchange, without fixing the problem, the same thing is going to happen all over again. When you come back for your second free cat in a row they're likely to be less accomodating. I'd try to figure out the problem before putting the second one on.

 

honestly, I got the cat from Tri-Point. All the invoice says is TPE-51143 High Flow Main Converter. I brought the car in to get the purple ecu piggy back dialed in a bit and they hosed all but the first preset. I brought the car in again because the sulfer smell didn't go away with time; as if this was a 'new cat smell' that would go away after awhile.

Also, it was backfiring and would stall from a super-low idle; under 800. What I have recently figured out is that Idle goes up to around 900 if I turn on something, like the parking lights. This leads me to believe that something in the exhaust system isn't pulling an electrical load... just a weird hunch. The air pump does pump air (I was told that could be a source of the smell).

I brought it back in and, over a month and $400 later, I get it back with the stock ecu wired, no troubleshooting done on the exhaust and it was still stalling. It doesn't backfire as much. They told me they would have to start going through the wiring harness (after having it for a month... I'm convinced it just sat there most of the time) and, if they find a broken wire, they will insist on replacing the entire harness; not just patching up what they find.

Now, if I had the cash, I'd probably blow it on a whole new harness; those days are over. So, I paid the bill and never called again. If I could find a shop that still enjoyed working on these things, maybe I'd try that. I've even thought of bringing it to midas to see what opinion they give.

I plan on putting the stock cat back on some day and see if the smell goes away. Tri-point didn't bother with that.

 

First, i want to know if ur vehicle is running rich? Running rich can kill the cat easily. Another thing is, that rotten smell means that ur cat is actually working. Second, idle has nothing to do with the rotten smell from what I know of. When you turn on a load, the ecu will automatically fast idle the car(kick the idle higher) so it does not stall. So, right now, you need to isolate each problem by figuring out whats causing what? I would first think of, "What have I recent done to the car that made the car to stall?" "When I did the engine swap, have I missed something out?" "Is my car running rich that's causing the cat to smell like sulfur?"
You see where I am heading at? Like start with the easy stuff, and work you way on. Fix 1 problem first, before trying to complicate yourself with another problem. Seriously, if it's the harness that causing your car to act this way, there will most likely be ALOT more problems. Because remember, all your other wires are connected to the same harness, and a harness just doesnt go bad itself; there must be a reason to it.

Hopefully this helps a bit on breaking down how to diagnosis your own vehicle, good luck on the fix.

 

Oh another question is the swap the same model engine or something else? Also, try to figure out what can cause the car to be running rich. e.g Leaky injectors, plugged intake, anything that restricts ur air flow or a restricted fuel return line can cause the car to run rich, which can lead to : backfiring, rotten egg (sulfuric smell) and a poor idle. OR a leaking spot after the mass air flow sensor and before the O2 sensor can cause a false reading in return the ECU tries to compensate for.

What i meant is, your car is actually running really lean, and the ECU is trying really hard (richen ur vehicle) to compensate for the lean (exhaust leak or something in that nature) in return of a sulfuric smell.

Sorry for the long tedious paragraphs of explanation, I hope this helps =)
-Eric

 

Gordie-

Like AzEKnightz says, running rich is the first thing that comes to mind. What's causing that? Could be a number of things. (I don't even want to get into wiring. Glad I don't have to face that.)

Anyway, I'd suggest several things.

First of all, there are good rotary engine specialists in SoCal. Go to the West Coast section and explore their shop list ( I think they have one - haven't looked)
Or post asking for a recommendation. I think one way or the other, you're going to have to see somebody about your problem. TriPoint sure didn't come through for you. But that's a whole other matter.

If you've got a stock cat and it's still good, don't put it on your car while this problem exists. You may need it if your new cat is fried and they won't give you a free replacement.
(Really, TriPoint should be doing a make good on this. You should have received a warranty with your cat. It's the law. If they give you static about it tell them you're filing a complaint with the EPA and the California Air Resources Board. They can be fined for this sort of stuff. The govt. takes it very seriously.)

I'd also try running a code for the car. This takes a bit of doing and interpretation.
Search the Forum to find info on how to run a code. This may point you in the direction of the problem.

Bottom line is that it's unlikely a new cat really is the source of your problem. Something made your converter go bad. A good rotary engine mechanic may be able to spot the problem in relatively short order.

Good luck. Let us know how things turn out.

 

Just out of curiosity how is the car running? For example fuel millage, power, and etc.

 

Your cat is fine most likely. Ever smell a car with no cat? Does it smell like sulfur? No. A stock cat with a working air pump can help to eliminate excess sulfur in the exhaust but the sulfur smell does not originate from your engine or its tune (no matter how lousy it sounds like it is..)

Have you tried using a different gas station? Seriously. If the fuel was refined from oil found with heavy sulfur deposits this happens. Not all of the sulfur gets removed during refinement. Fill up somewhere else.

 

I have a Ford Focus that, when started first time in the morning, gives off a strong sulfur smell. After the car and the cat warm up a bit, the smell disappears. It has done this since new.

Therefore, I'm guessing that the smell you have is a combination of the FD's normal rich mixture, and a cat that is not entirely warmed up or does not have an operating air pump attached, or is in some other way, marginally efficient.

BTW, I am still using my original main cat on my FD, and it doesn't do that.

 

This has been happening on my FD recently with the added condensation of winter. Once the car is warmed up there is no problems, just smells a bit of start up.

 

Hi guys, thanks for all the feedback. Sorry I've been 'out', but I've dealing with an entirely different hassle.

Here is a quick answer list:
I get gas wherever I need it. Don't thinks its the petrol source. Also, I have a Celica that I fuel at the same local station; no sulfer smell.

The smell is randomly apparent, hot or cold doesn't seem to matter.

The air pump is working and seems to be on most of the time.

When I mentioned the harness, I don't mean the whole thing, I mean that there probably wires that are on their last strands, etc, not the entire thing. For example, the O2 sensor's wire is in such condition, right near the connector.

I do notice that the car seems to be drinking gas much more. I have an air/fuel ratio meter around here somewhere; I could try that. Aside from that, the purple piggy-back is out of the loop, the car runs strong with cold boost peaking at 13-15. The car typically has great pull overall. But, that gas needle drops pretty fast, even if though I keep the RPMs around 3k most of the time. I don't smell any fuel smells (like from a leaking hose or something).

I did a couple off-the-cuff tests yesterday because when I stopped after some driving, the sulfer smell was gone. Notice, these are largely stupid tests:
I pulled the wire from the O2 sensor and noted no change in the car's running at idle. I did this because the sensor's wire can be pulled from the connector in the engine compartment and I thought it might have an intermittent connection problem. I pulled the hose from the air pump to see if its blowing... Don't know the CFM, but its not a hair dryer. At one point, the sulfer smell returned. I tried revving the car to around 4500 for awhile and noticed that the smell went away, after returning to idle.

So, with your hunches that running rich will incur the smell, and that the problem is definately intermittent, I'm thinking that there might be a faulty wire thats involved with the fuel mix.

What is frustrating is that Tri-point didn't resolve this issue after having the car for an entire month (where is mostly sat, I'm convinced). So, I've decided to try to figure this out on my spare time (not that I have alot of that).

I'll have to start looking into what sensors feed info to the ecu regarding fuel-mix. As I said before, the idle is always low. Its more like 500rpm most of the time. Which is why it would stall occasionally when I would come to a stop.

It has a cold air box with new filters. perhaps the airflow sensor is bad.

Thanks for your input, its great!

 

If you don't mind can you tell me what they charge you for? Just out of curiosity how old are they plugs and ignition wires? I recently had the same problem as the one you described and was caused by some old plug wires. There was no indication that my wires were bad and my car just passed smog not too long ago. The only reason the wires was replace was due to the fact that they are 5 years old. After i replace the wires i gain 10% on fuel mileage, increase in power, improved idle quality and best of all the sulfur smell was gone. I hope this helps.

 

It sounds like your car is running too rich from a problem with your O2 sensor, especially considering that your idle is low and the car sometimes stalls. The sulfur smell is caused by the cat not being able to handle all the hydrocarbons (fuel) being thrown at it, and the partially converted gases include a form of sulfur.

The fuel source won't have anything to do with it.
That's because once you get above a certain rpm, the car isn't running too rich and it's able to burn off the excess fuel.
The air pump is on until about 3500 rpm, where it shuts off.
It definitely sounds like you're running too rich at lower rpms. Your O2 sensor is either probably going bad or the wiring connection is corrupted, judging by the rest of your post.
It definitely sounds like the wiring to the O2 sensor is bad, or the O2 sensor itself is going south. Pulling the wire probably won't result in an immediate change in idle speed, because the ECU may be sensing a problem with it already. Have you tried "pulling the codes" from the ECU?
At idle or under no load, it's not required to pump too much air.
The FD doesn't have an airflow sensor. It uses a MAP (manifold air pressure) system to determine fueling requirements, not MAF (mass air flow).

 

If you really feel that the O2 is the culprit of the problem you can just skip all the guess work and perform a voltage drop test on the O2 harness and replace the o2 if the harness test good. Although a bad O2 will cause a rich running condition i feel that there is a chance that you have more then one problem that cause your rich running condition. If you have a spark tester you should also check the spark output of your ignition coils. I had worked on cars with failed ignition coil or coils and they will not always cause a misfire. I found this to be especially true on rotary engines. Good luck!

 

+1, I agree.

What you are smelling is sulphur dioxide (SO2); it is a by-product of the reaction in the cat. This will usually result from high levels of sulpher in the fuel. This was a big problem when cats were first introduced in '74; subsequent fuels were cleaned up to help reduce SO2 emmissions as not only does it smell, but it is also a contributer to acid rain (if you remember that).

Additionally,

I will add that the reaction to create SO2 is temperture dependent and may be affected by engine/AFR conditions that affect the operating temp of the cat. Not all cats use the same cataylitic materials and processes, so there may also be some variations among different types of designs with some more likely to produce this effect. And It may also be more noticable in the presence of heavy condensate.

 

+1 for ignition coils. When the smell is not present, is your downpipe glowing red hot indicating that the excess fuel is being burnt in the exhaust system?

 

Hi Guys, finally got back at this (I've been on a major job hunt lately). Thanks for all of your feedback. Per your suggestions, I'm going to replace the plugwires and plugs, since I don't think they've ever been done. I'll replace the o2 sensor as well.

I'll try to figure out where the o2 sensor wire winds up. I'm kinda hoping it goes to either the terminal on the passenger wheel well or to the ecu; that would make replacing the line much easier. Really, the one I have is hanging by a thread. I might just patch that area and see if it helps.

As far as the coil paks go, sounds like an expensive proposal. Unfortunately, I have an old jacobs electronics computer spark-booster, but don't know how I would replace the coil paks with a single unit setup. The jacobs really delivers the spark, though.

I'm on a budget, here. Maybe I can have a local place test the coils.

Thanks!

 

http://www.toolfetch.com/Category/Au...s/LIS50850.htm You can use this to test the spark output. It should at least out put 3.5 kv (which is marked on the tester). I had pretty good luck with this tool but can't really recall having any success with on a rotary engine. As far as the o2 sensor wire you can either patch the wire or just run a new wire straight to the pcm. Good luck!

 

Someone threw stinkbombs in your exhaust ^_^

 

I would not recommend replacing the O2 sensor without doing a functional test on it. Is there anyway you can have a Oscilloscope and verify the O2 sensor with creating a lean (air leak in the system) and a rich problem (use propane injected into intake air housing) and see a reaction of Lean to Rich voltage varying from .1 (lean) to .9 (rich) for the propane enrichment. And the process for the O2 to react from Lean to Rich should be less than 100ms. This would qualify your O2 being good.

Any parameters outside the 100ms indicating your O2 sensor is lazy, and which resulting replacement. Otherwise, if you just shotgun whatever every body says to replace, you will need to have a fat pocket with loads of cash in there.

Not saying everyone here is a shotgunner, but keep in mind. Our vehicles are already expensive enough, and if a technician tells you to replace something, and it didnt fix the problem, wouldnt that gets you angry?

So let i said earlier, eliminate your problems, isolate them, and fix them 1 by 1.

My suggestions:
1) just deal with the smell first
2) Try to figure out if the vehicle is actually running Rich or running Lean
3) Either running rich or lean will cause fuel consumption to increase (people who are smog techs should know this by air fuel ratio)
4) if you figured out that the vehicle is running rich or lean, try to do tests on the 7 to verify the richness/leaniness (tail pipe emission tests .etc)
5) when you're at this point, you probably have a pretty darn good idea what's the problem.
6) by knowing the problem, you will now hunt it down and find the root cause of it. DONT STOP HERE, most people tend to thing (Oh the O2 is bad, replace it)... Dont do that, try and find out WHY is the O2 bad? Contaminations? Maybe Carb cleaner sprayed on it accidentally? Whatever the case is.

Hopefully this long statement of mine will help you clarify things and make it much easier and more clear to diagnose your vehicle instead of just buying whatever people tells you to do. This method can be used on any diagnosis.

As a tech, I would:
1) Verify complaint
2) duplicate complaint
3) isolate the problem
4) fix the problem
5) verify problem fixed
6) road test to make sure everything should be running the way it should

Thanks for the reading =)
AzEKnightz

 

AzEKnightz you seem pretty knowledgeable and i totally agree with your method for repairs but those equipments mentioned above are pretty expensive. Do you have an alternative method of testing these suspicious parts?

 

you mean (manifold *absolute* pressure)