Author Topic: Consistent engine missfire, no check engine light (Read 8696 times)

Voluted · « **on:** June 09, 2008, 12:03:36 PM »

Hello. My engine has been misfiring during idle and acceleration consistently throughout the RPM range. I checked the spark plugs and they all have a coating of dry black dust on them. I was hoping some one here has had a similar problem and could help me out.

So far i have tried new ignition wires, plugs, coils, and a new fuel pressure regulator and the problem persists. Also, the problem disappeared when i crimped the fuel return line with vice grips. Any ideas? And will the OBC spit out a code even when the check engine light doesn't come on?

RED IS 91 · « **Reply #1 on:** June 09, 2008, 12:56:21 PM »

If you crimped the line and it got better then the first thing I would check would be fuel pressure .At the pump you should have 42-43 psi on the supply side .

Voluted · « **Reply #2 on:** June 09, 2008, 01:46:32 PM »

The pump was just replaced last year, do you think that it could be defective?

Belteshazzar · « **Reply #3 on:** June 09, 2008, 02:17:46 PM »

crimping the fuel return line should shoot pressure to whatever the pump can manage. If only under those circumstances it keeps up then there's a chance it's bad. throw a gauge on it and see.

RED IS 91 · « **Reply #4 on:** June 09, 2008, 04:56:44 PM »

Quote from: Voluted;50863

The pump was just replaced last year, do you think that it could be defective?

Did you put an OEM pump in when you replaced it ? How about the fuel filter ?

Voluted · « **Reply #5 on:** June 09, 2008, 05:00:57 PM »

The pump and filter were both replaced new from BMW. Also, blue smoke comes from the exaust and black ash is found on the plugs which tells me the car is running rich.

Also, the O2 sensor on the car hasn't been replaced for the life of the vehicle. The car has 170,000 km on it now and it's a 91. I havn't heard of a bad O2 sensor causing this much missfire though.

RED IS 91 · « **Reply #6 on:** June 10, 2008, 08:15:42 AM »

Quote from: Voluted;50882

The pump and filter were both replaced new from BMW. Also, blue smoke comes from the exaust and black ash is found on the plugs which tells me the car is running rich.

Also, the O2 sensor on the car hasn't been replaced for the life of the vehicle. The car has 170,000 km on it now and it's a 91. I havn't heard of a bad O2 sensor causing this much missfire though.

If the 02 sensor is faulty the engine will run in default(rich) mode . You should replace it .
good luck

Cobra Jet · « **Reply #7 on:** June 11, 2008, 09:40:51 AM »

O2's should be replaced at 40,000 miles to 60,000 miles. They do not last forever. Most O2's when not functioning 100% as they should, do not always throw a CEL either.

Jimmy Lewis · « **Reply #8 on:** June 12, 2008, 12:15:53 PM »

My issue sounds similar to yours but for me it turned out to be the ignition wires. A new o2 sensor did improve my idle significantly, but then again I was only running on 3 cylinders. I hope you get it sorted out, it isn't fun driving a car that you can't run hard if you want to. Goodluck.

quinn11m20 · « **Reply #9 on:** June 13, 2008, 10:42:57 AM »

Hey check this out. Turn your ignition switch to run but do not start the car. Press the gas pedal to the floor five times within five seconds. All the way down. Your check engine light should flash once, pause (1-2 sec) once, then a series of flash flash flash. Then the cycle starts over. Example 1444 is the no faults found (no failure) code on my 91 318is. O2 is 1221. The oxygen sensor heating relay is 1264. So the check engine light will flash in a series like once, twice, six times, and then four.1264. It will pause, once, pause and repeat the code. If multiple codes are at fault , it will flash in sequence. 1264 1232 1444,Ok. I found these codes in my chiltons manual. Part # 8427 . I seriously recommend Chiltons. Everyone else says the other brand of manual. But I beg to differ. I hope this works for you. Email me the codes if you can't get a book where your at and I will tell you the fault. Cool. quinn11mc275@yahoo.com or tony.quinn1@us.army.mil . Hope to here from you.

Voluted · « **Reply #10 on:** June 14, 2008, 01:24:04 PM »

Thanks for the information. I would have never thought to look for this method to generate codes. I did some searching for the code list and found this on bimmerforums (originally from Pelican).

Quote

Pelican Technical Article:
BMW On Board Diagnostics
Jared Fenton

Did you know that your BMW 3 Series has an internal diagnostic program built into the computer? Not many people know about this. On the BMW 3 Series, there is a way that you can diagnose common engine problems without having to purchase a code tool or take it to the dealer to have it scanned. This is one of those neat little features of the Service Indicator Computer; the series of lights directly under the tachometer and speedometer that remind you to change the oil and perform service. In this tech article, I will provide you with the procedure for checking the fault codes and what the codes mean. This guide will help you to diagnose any possible problems with your car.

This article is written for both the BMW E30 and E36 3 Series cars (up to 95) and should work on both models where a Service Indicator Computer is used. I will go over the small differences between the early and late cars, as they differ slightly. Keep in mind that this procedure will not work on early cars with Motronic 1.1.

Now on the E30 models, get in the car and put the key in the ignition and turn it to the second turn or "ON" position, but do not start the car. Now, press the accelerator pedal all the way to the floor, then let it release all the way back. Now repeat the depress/release cycle 4 more times fairly quickly, but not too fast. It may take some time to get this timing down correct. It should only take you a few seconds to do this. What this does is activate the wide-open throttle switch and the idle switch 5 times. This then sends a signal to the Motronic ECU to send fault codes to the Service Indicator Light.

On the E36 models, the procedure works the same way, but the timing at which you press/release the gas pedal is faster than on the E30. Just keep at it, and you will eventually get the correct speed.

Watch the "Check Engine" light. It should blink once, and then start blinking a series of four numbers. For instance, say this is a sequence you see�. the light blinks once, then twice, then four times and lastly four times. If you read it correctly this means that the SI light is reading out the code 1244 (faulty camshaft sensor) The codes appear as a series of flashes for each digit. The flashes indicating one digit are about one second apart, the next digit will appear after a couple seconds interval. If there are no faults in the car, the computer will flash out the number 1444.

Here is the list of codes and what they indicate.

1211 DME Control Unit
1215 Air Mass Sensor
1216 Throttle Potentiometer
1218 Output Stage, Group 1
1219 Output Stage, Group 2
1221 Oxygen Sensor 1
1212 Oxygen Sensor 2
1222 Lambda Control 1
1213 Lambda Control 2
1223 Coolant Temperature Sensor
1224 Intake Air Temperature Sensor
1225 Knock Sensor 1
1226 Knock Sensor 2
1227 Knock Sensor 3
1228 Knock Sensor 4
1231 Battery Voltage/DME Main Relay
1232 Throttle Idle Switch
1233 Throttle Wide Open Throttle Switch
1234 Speedometer A Signal
1237 A/C Compressor Cut Off
1242 A/C Compressor
1243 Crankshaft Pulse Sensor
1244 Camshaft Sensor
1245 Intervention AEGS
1247 Ignition Secondary Monitor
1251 Fuel Injector 1 (or group 1)
1252 Fuel Injector 2 (or group 2)
1253 Fuel Injector 3
1254 Fuel Injector 4
1255 Fuel Injector 5
1256 Fuel Injector 6
1257 Fuel Injector 7
1258 Fuel Injector 8
1261 Fuel Pump Relay Control
1262 Idle Speed Actuator
1263 Purge Valve
1264 EGO Heater
1265 Fault Lamp (check engine light)
1266 VANOS
1267 Air Pump Relay Control
1271 Ignition Coil 1
1272 Ignition Coil 2
1273 Ignition Coil 3
1274 Ignition Coil 4
1275 Ignition Coil 5
1276 Ignition Coil 6
1277 Ignition Coil 7
1278 Ignition Coil 8
1281 Control Unit Memory Supply
1282 Fault Code Memory
1283 Fuel Injector Output Stage
1286 Knock Control Test Pulse
1444 No Fault Codes

When i get off work i'll see what pops up. Thanks again for the info.

Voluted · « **Reply #11 on:** June 14, 2008, 06:19:34 PM »

Im getting 1222 Lambda Control 1, which is the oxygen sensor relay. Have to wait till monday to buy a new one

. Hope thats the problem!

EN318isPDX · « **Reply #12 on:** June 14, 2008, 06:46:17 PM »

have you checked your fuel pressure?

vanghis109 · « **Reply #13 on:** June 15, 2008, 12:31:52 AM »

i get 1444 but my car is misfiring like crazy could it be my fuel filter??

quinn11m20 · « **Reply #14 on:** June 15, 2008, 11:09:53 AM »

Voluted That is outstanding. Glad you found that info. For Vanghis109 could be a bad lead, or solenoid. If you can test those for continuity with a multimeter. If you know that your fuel filter hasn't been changed in over a year, I would try that too.
Hope to hear from you later.