Hello all -- here's my problem: The exhaust on my 245 smells bad, like when you first start up any car, except it smells bad from the beginning, and after the car has warmed up. Also, the fuel economy is terrible; I used to get 320 miles from a tank, now it's down to about 200. Smells worse after I've been "getting on it" a bit to keep up with Chicago traffic.

I suspect a (rich) fuel problem. The car has two new fuel pumps, and I just had the injectors overhauled (the ECU had thrown a "fuel injector" code and the generic "compensating for lean/rich mixture at idle" code).

Fuel pressure regulator? I removed the vacuum return line to the manifold and didn't see or smell any fuel. Other tests?

O2 sensor? The ECU didn't throw that code, but could it still be bad?

Cat?

Any other fuel injection sensors to test?

Car has only 146,000 miles on it and runs like a scalded puppy. No discernable black smoke or oil consumption, dipstick smells like oil, no white or blue smoke either. But when I'm sitting at a light for a minute or two, the stank gets pretty bad...I've had to turn off the engine and open the windows on some single-digit days in Chicago to avoid stinking myself out.

Thanks!
HP

Now I'm suspecious of the ECU.

Greetings --

I replaced the cat...it was definitely clogged. The car now starts and runs fine, but I now have a new ECU code 1-1-3, "Fault in fuel injector(s)." That's the only code, and I also checked the ignition codes, nothing there.

I followed the Bentley diagnostic process, spraying water onto the injector seat on the intake manifold. No discernable change in RPM. I also disconnected the harnesses, one at a time, from the injectors. The RPM decreased initially for each injector. I also listened to each injector with a screwdriver and they all are clicking along just fine.

I suspect either the O2 sensor or the fuel pressure regulator. I removed the vacuum line from the FPR and noticed a change in RPM, no gas smell. I have not read the O2 sensor voltage yet, but that's next (I don't have a good enough voltmeter...not enough ohms.) Any other thoughts? Thanks -- Paul

Thanks for the continuing information. Here's the latest:

The car would not start yesterday morning. It initially fired, but sounded like it was running on two or three cylinders -- very rough. I tried to get it to "clear" by revving it a bit, to no avail. It then shut down and would not refire. It is now partially blocking my driveway, and I had to go out of town for a few days. I will return on Thursday next and will dive into it.

To 240nut, you sound authoritative and convinced that it's the cat. I'll surely check that, but what is it that makes you so confident about it?

The temp sensor/cold start system is another good candidate. I'll add that to the list.

Thanks again, guys. Keep it coming. -- Paul

One more thing. The weather turned cold overnight before it wouldn't start. I had driven the car several miles the previous day, when the temperature was in the 40s. Overnight it dropped to the mid 20s.

You have a clogged catalytic converter. It needs to be replaced.

It worries me that you can smell it from the driver seat. If what you can smell is getting in the car, then CO (which you can't smell) will get in to you as well.

Is your rear door sealing well? Any exhaust leaks upstream? Check especially the downpipe from the manifold to the cat. That one is double-wall so leaks may be hard to detect.

With regard to your mileage, I would add the possibility of a leak in one of your freshly-rebuilt injectors to the other suggestions.

Another possibility is the engine coolant temp. sensor. The ECT signals the ECU, and when cold, the ECU responds with a richer mixture for warmup and smooth acceleration. If the ECT goes bad it could be signalling "cold engine" all the time.

There are a number of archived posts with good info on this subject and ECT sensor testing methods.
--
Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD; hobbycar 77 MGB, and a few old motorcycles)

My 240 was doing this and it turned out to be a bad o2 sensor. With help from this site I discovered that I could wire in a two wire o2 sensor and it would work. The third wire is to pre-heat the sensor. I bought a new Bosch sensor for $17.00 at Autozone and borrowed their o2 sensor removal tool for free. Make sure that you have the exhuast system warmed up before trying to remove it. You could buy the cheap one if you want just to test it out before you splurge for the $100.00+ for the other one. I have been using this set-up for over a year with no problems. My computer would give me different codes everytime I cleared it, so I wasn't sure if it was the o2 sensor or not either.
Good luck.

Not stinky like a rotten egg, is it? If yes - that should be the catalytic converter.
--
'Be blessed in your quest'' 89 764 (110K), '94 940T (180K)

Thanks guys...

Not stinky like a rotten egg, so I hadn't really considered the cat, but I guess that could be it too. I'll see if I can test that.

I had suspected the o2 sensor from the start...just seems to make sense with the bad fuel economy, but I thought I'd try to rule out the injectors and other stuff first. I guess I can test it, and I'll surf around the board to get the info on the 2-wire sensor. Thanks guys -- any more info is appreciated as well.

Hello:

A failed fuel pressure regulator can cause an O2 sensor to read bad (staying pegged near one voltage or oscillating by only a small amount), but the O2 is easy to check with a voltmeter-- you should see swings from about 0.15V to about 0.9V about once a second with the car warmed up-- read it at the firewall by pulling back the rubber bullet cover at the connection. No nead to unplug it.

Have you looked in the fuel pressure regulator vacuum line to see if it is dripping with gas? That is a classic failure sign which will cause your symptoms. They will fail without leaking there, though-- I have had them fail and be dry in the vaccum line.

The sensor you want is a 3 wire-- the universal is probably fine, but there are two heater wires (not polarity sensitive) and one signal line-- usually a different color.

Good luck!

--
Herb Goltz, Aurora, Ontario, Canada '92 245 w/124K mi, '92 945T w/200K mi

Thank you, Herb. I'll get into the Bentley manual and test the O2 sensor at the firewall as you recommend. I'd also appreciate any advice on testing the pressure regulator. I've removed the vacuum line and sniffed it, but I did not notice any gas smell or obvious liquid. Is there any particular test condition that would make this failure more obvious (ignition on, engine running or similar)? I'm pretty sure it's got to be the FPR or the O2.