Eien

Okay, so here's the deal: my FD runs so rich you can just smell it even on idle. It won't have any noticeable smoke after few secs from cold start and idles just fine, but it runs too rich. The store I bought it from said that the original owner had changed something to make it run rich to gain power, but at the cost of fuel economy. I know it won't save me too much fuel, but I'd like to get rid of that awful smell. Or at least make it little more unnoticeable even on idle.

Am I able to change something without the help of oh-so-damn-expensive Mazda dealership, or do I just have to break my account balance to just have somebody look at the car while dinking coffee?

Car is pretty much in stock condition.

twinsinside

iTrader: (34)

Do yourself a favor and do a search on "dealership" here on the forums.

Scary stuff. I won't say ALL dealerships are this way, but the vast majority have no clue about this car. Of course they won't tell you that, they'll just make things worse and give you a huge bill.

In order for the previous owner to make the car run richer, someone would have needed to modify either the stock CPU maps, or used an aftermarket CPU like a power FC.

The first thing I would do is look at the CPU and see if it has any stickers on it from someone like Pettit/Knight sports/etc. Or maybe you got lucky and there's a Power FC in there.

If the car is almost completely stock, the cheapest thing you can probably do is buy a used stock CPU for $50-$100 and swap it out. This will make the car go back to stock injection levels.

Eien

I've heard good things about the local dealership from guys with RX-7's, so I could be confident in them. Or just drive 150ish km to a wankel specialist

But anyways, the ECU is stock. I'm not looking for any power gains (dropping back to stock would actually do backwards ) so I could go on a hunt for stock ECU on eBay or such, since local market for rotaries in general is lower than low.

Thank you for reply.

VegasG8R

My Fb has a pretty strong smell as well. It passed the smog test with flying colors.

I saw an add for "Rotary Mechanic" on Craigslist here in Las Vegas...I was wondering if I should take it by just to talk about what they know. They claim they specialize in Japanese imports including RX7s.

I'm still shell-shocked from my $400 oil changes I had to get from VW for my previously owned GTI... my '85 is my new hobby as well as my daily driver... but I don't want to pull out my AAA card anytime soon...

Eien

I still haven't tested my FD (moving to another country soon anyway, so no registration needed here anymore), but I can guess it would pass emission tests pretty fine. It's just the smell itself that I'd like to get rid of.

twinsinside

iTrader: (34)

Rotaries have a pretty strong exhaust smell.

The stock maps also run a little rich.

If you have a stock, unmodified CPU then what you were told about the previous owner making it run richer just isn't true. You have to modifiy the fuel maps to get it to run richer, and the only way you can do that is to mod the CPU or put in an aftermarket CPU.

That said there are a few things you can have replaced that are pretty simple. The first thing I would do, if you haven't, is replace your fluids (coolant, oil, tranny and differential). Replace your fuel filter and your O2 sensor.

There is one other thing that can cause a bad smell. There is a charcoal cannister that absorbs fuel vapor that vents to atmosphere. If it's saturated it won't work well, and it'll smell bad.

The other possibility is that you have an exhaust leak coming from somewhere, or a fuel leak if it smells like raw gas. The fuel leak is especially serious, and has been known to cause engine fires.

How is your boost? I ask because if you have an exhaust leak it will most likely affect your boost. Are you getting 10-8-10 pattern?

twinsinside

iTrader: (34)

$400 for an oil change? LoL are they using liquid gold to cool VW's now?

VegasG8R

That's was the 10,000 mile service... they make sure the engine is still under the hood and check to see if the wheels are still attached... total scam. I even had to take it back because the idiot didn't have the oil filter on correctly and I was leaking oil all over the place. I think the 20K checkup is close to 6 smacks... bye bye VW... (you won't be missed )

Eien

But back to my car:

All the fluids were changed like 200km ago. Still have fuel filter and O2 sensor to replace then.
It shouldn't be gas leak since there is no smell of raw gas. And if it was, then it would smell still while driving, right?

I haven't done the boost metering, since the car has just been sitting in my garage as I haven't had real time to put on it. But guess I'll be up for it this weekend.

VegasG8R

I asked the same question in another thread, a very knowledgeable member mentioned checking the seals around the rear tail lights which I'm to understand have been known to allow the smell into the cabin.

spr258

iTrader: (3)

a FD is going to smell like fuel most if not all of the time. They are tuned to run rich because if they dentinate then the motor blows. If it is real bad then that is another story.

Eien

I can't really compare it to another rotary since I have no experience in them from before, so it might be "perfectly normal" for someone who has worked with them more.

And I do prefer fuel smell over a blown engine

spr258

iTrader: (3)

My car is running rich right now. It has a puddle of fuel that accumulates when I start the car up. I let it warm up and there is a puddle.

twinsinside

iTrader: (34)

Not to hijack the thread but...

That's not normal and is very very dangerous. A fuel LEAK is not the same thing as running rich, they have nothing to do with each other.

I wouldn't drive the car like that. There are a number of RX7's that have been totaled because of engine fires relating to fuel leaks.

The FPDs especially are known to leak when they get old, there was even a recall on it I think.

One spark and your whole car is gone.

twinsinside

iTrader: (34)

Its true that the exhaust is kinda stinky, and in stock form do run a bit rich.

I personally had to pull my twins and exhaust manifold because I had an exhaust leak causing an extra smelly situation. Not horrible, but not pleasant.

One way you can check for an exhaust leak is to do a "steam clean" of your engine. Basically you suck in distilled water into the rotor chambers via the UIM nipples with vac hose while the engine is running (purpose of this is to clean carbon out of your engine). If it leaks water, it's certainly not air tight.

You should NOT smell raw gas though. If you do, you have a fuel leak, and like I just said in the last post, I would get that fixed ASAP.

spr258

iTrader: (3)

Fuel is coming out of the exhaust. I dont think its a fuel leak. Not leaking under the car but from the exhaust.

dgeesaman

iTrader: (7)

It's entirely possible that the previous owner changed some of the injectors for larger ones. This causes enriched fuel injection across the board. It's a very poor way to add power, and I would remove this "upgrade" or figure out what else is needed to make it work properly. If this is indeed what was done, you'll need a programmable ECU and tuning to properly manage the extra fuel. A wideband oxygen sensor will probably be needed too.

I would do this: remove all 4 injectors and send them to a top-line injector service shop for testing and cleaning. Make sure they can test side-feed injectors because not all of them can. Not sure how to help you find a good injector shop that's accessible to you.

The test results will do two things: tell you what injector sizes you have, and establish they are in good working condition. Injectors don't always perform as advertised.

Oh, and no dealers. Even in you accept that they will follow a manual that tells them what parts to replace, they often replace the wrong thing (engine or turbos) at horribly expensive cost.

David

dgeesaman

iTrader: (7)

You have a seriously dangerous problem. Do not start the car any more. Fuel leaks destroy cars and everything in a 50' radius. I'm serious, or else your aluminum hood may become a puddle in your driveway.

To fix the problem either tow it to a good repair shop or do it yourself. You are looking for a fuel leak. Search the forums for instructions on how to manually turn on the fuel pump and remove the UIM. You can then search for the source of the leak, often an injector or FPD. Replace what's leaking and do not skimp on this repair.

David

Jeff5808

iTrader: (7)

Could he have installed a mid pipe on the car?
Without a cat to cleanup the exhaust, wouldn't the exhuast smell bad even at idle?