Alas rough running, odd smell, code 44

[Ellie]

Why is it that whenever you need to get under the hood to fix that pesky problem, it rains, lots!?

What's the news, Dean?

[DeanG]

I've been unable to do a lick of work on anything fun. I'm swamped! Work, eat, sleep.

[Ellie]

Still swamped or has the sun shone on your Elan?

The link below goes to the O2 sensor thread - see page 2 for a graph of the sensor output which may provide some data for you.

O2 sensor thread on LEC

[DeanG]

Unfortunately I have not had a chance to even look at the poor old M100. I did get to spend about an hour working on the Seven last week although I broke the part that had taken two months to from order to arrival.

[DeanG]

I had a chance to charge up the car and try and determine what was wrong.

Hard starting and rough running. If I pull the ignition wires for either cylinder 1 or 3 the car tries to die. Pulling ignition wires for 2 or 4 makes no difference.

I swapped out the ignition base plate with an old one in my possession and reused the newer coils. Same results.

Any ideas?

This problem has kept me from driving the car for several months. Now the weather is good and its time to start driving!

[Enright]

Try using both sets of 2 & 4 coils. You could have a dud pack on each base - I did.

[GeoffSmith]

Dean,

It may be the injectors as 1&3 are common as are 2&4 - see the Wiki. I would suspect you are not getting continuity in the 2&4 injectors.

Geoff

[DeanG]

I am getting spark at all cylinders, so I will start troubleshooting the injectors tomorrow.

[Ellie]

This one has been baffling me as I've had trouble reconciling your code 44 which after the O2 sensor problem I had, suggested that code 44 meant Oxygen Sensor Lean (not reading full O2 level).

Having replaced my O2 sensor & everything having gone back to 11/10 I reflected on my Elan's performance over the years and recall a steady decline in performance, misfiring etc as the sensor deteriorated, some years ago.

Why I bring all this up again is that I recall a defining event that I'm sure actually caused the sensor's demise - this was the collapse of the catalytic converter (in the 1st stage of exhaust downpipe after the turbo). I had little power, hard starting, no turbo boost and an odd smell (exhaust gases not altered by the cat. converter).

Now I'm not sure how to test the catalytic converter - others here may - I'd suggest having a check of this item as your symptoms seem to match mine at that time.

Good luck.

[GeoffSmith]

I think that a lean exhaust (code 44) could be caused by an injector problem as only half the fuel being injected. If it was the ignition side, I would expect to see rich exhaust (code 45).

[DeanG]

A recap of the horror.

My 49 state 1991 M100 is running on two cylinders #’s 1 & 3.

I was having an intermittent problem for over a year where the car would run rough and loose power for an instant to a few seconds then clear itself. This became worse shortly after returning from LOG 27 (after covering over 5,000 miles). The last long ride (150 miles or so) the problem became constant and displayed a code 44 displayed. After clearing the codes by disconnecting the battery it hasn’t come back however I have only driven around the block and have been running the car in the garage.

I pull plug wires 1 or 3 and the car tries to die. If I pull the plug wires for 2 & 4 there is no difference. I get spark at all 4 plugs. The coil packs are only a few years old and I have changed out the ignition module with my “spare”. I see no difference. The iridium plugs have varying amount of soot on them.

Based on responses to my posts I started looking at the fuel injection. Here are my readings. Sometimes it took several attempts to get the digital VOM to settle on a reading.

All the injectors have a resistance of 2 ohms.

Checking each of the two female pins on the electrical connector against chassis ground show 81K ohms for one and 5 K ohms for the other.

Checking the voltage of each of the two female pins on the electrical connector against chassis ground I get 0.04 volts with the ignition off and 11.4 volts with the ignition on. A test light shows steady (no blinking that I can detect) when I put it between the hot pin and ground.

I can start the car and hold I high idle (I’m guessing 1500 – 2000 rpm as I have been doing this by myself) I have pulled the connectors off each injector. When I pull the connector on injectors 1 or 3 the car dies almost immediately. When I pull the connector for plug 4 I find no difference; but when I pull #2 the engine seems to run more smoothly. This seems very odd.

Does anyone have suggestions for further tests?

[GeoffSmith]

Swap an injector over to see if it is the injectors or drive.

[ESM]

Unplug the oxygen sensor. This will force the ECU to run open loop and, if the oxygen sensor if bad, should improve running a lot. If it makes no difference don't keep it unplugged for too long (15 minutes say). They are damaged if run unpowered for too long. I have got away with running mine unpowered for hours but I did it before I knew there was a risk.

Use ElanScan to get CTS and MAT readings when the engine is stone cold and not running (the best time is first thing in the morning). The temperatures should be within a couple of degrees and close to ambient.

When checking stuff remember you will be getting extra symptoms caused by the car running at the wrong mixture and sooting everything up.

The Op temp - temp parameter is simply the difference between the nominal operating temperature (around 82°C) and the current CTS reading.

[DeanG]

Battery has been going dead. I need to get it checked.

This run was from a stone cold engine. Ambient temperature 24 deg C (ahh spring in tidewater Virginia so the stones are not that cold). After the engine had run for a few seconds I started pulling injector wires (one at a time) then ignition wires (one at a time).

[DeanG]

I forgot to mention that I had disconnected the O2 sensor on the turbo housing.