1989 bmw 325i no Injector pulse

10

Asked by Oct 04, 2013 at 10:00 PM about the 1989 BMW 3 Series 325i

Question type: Maintenance & Repair

Car will run good all day on ether but will not start without .Obcc gives fault code 1252 - Fuel Injector #2 (single or group). Crank sensor was replaced, main relay seems ok, feul presure good, just no pulse going to the injectors. Any ideas ? I'm at a lose, mechanic couldn't figure it out either..

7 Answers

87,155

Recheck all of the ECM powers and grounds, remember that the injectors are triggered by a negative pulse, so one side is battery voltage and the other side is the trigger signal negative pulse, so usually if you loose the injector pulse then it is most likely the computer but make sure you have all of the necessary power and ground pathways, a service manual with wiring diagrams will really help with this.

10

all the grounds have been checked, they are good. Mechanic said he checked the computer it seems to be ok, only thing I can think is maybe the chip blew, I don't think he pulled the computer.

87,155

He needs to check for the injector pulse at the ECM, if it is there and not at the injectors then a wiring problem needs to be sorted out, if it is not at the ECM then the problem is in the ECM.

10

can you tell me the procedure for checking injector pulse at the ECM?

1 out of 1 people think this is helpful.
87,155

You need to find the injector driver wires coming out of the ECM, a wiring diagram should help with the color and location, once you locate the wires then using a low draw test light, led is preferable or a "noid light" this will prevent and injector driver damage due to high current draw, tap into the driver wire with one end of the light and put the other on a positive power source, crank the engine, the light should flash rapidly, if it doesn't then the usually the ECM needs replaced or rebuilt. If it does then you need to trace out the wiring until you find the broken circuits. Of course all of this is assuming that all of the power and ground pathways and sensors have been check and found to be good.

10

thanks for the info I'll besure to check

10

I found another ECM, confirmed good, and installed it .. still nothing. Any other ideas?

Your Answer

Add photo

Related Questions

  • bmw 320d 6 answers

    hi i have a bwm 3 series ..havent long bought it ...its started to lose power then when i reacted my location was off a cylinder black smoke from exhausted leaving black make on the ground ...when u...

    2002 BMW 3 Series 320d

    -

    Maintenance & Repair

  • DSC and Amber break lights 3 answers

    Driving along and the front right brake will pulse and then the two lights come on DSC and the amber brake light.took to BMW dealer could not find any thing wrong.Lights are gone after restart vehi...

    2001 BMW Z3 2.5i Convertible

    -

    Maintenance & Repair

  • fuel injector pulse signal 1 answer

    got a '91 tuned port.had sat for 7 years.replaced the fuel pump and filter,ign.module and ecm.cranks and dies.fuel pressure and spark are fine but injector pulse fades away.checked all ecm power and g...

    1991 Chevrolet Corvette Convertible

    -

    Maintenance & Repair

  • Won't pulse injector 3 answers

    1989 Ford Ranger XLT Standard Cab LB

    -

    Maintenance & Repair

  • There is no pulse in the injectors 1 answer

    1995 Buick Riviera Supercharged Coupe

    -

    Maintenance & Repair

3 Series

Looking for a Used 3 Series in your area?

CarGurus has 35,975 nationwide 3 Series listings starting at $1,233.

ZIP:

Search BMW 3 Series Questions

BMW 3 Series Experts

#1 Tom Demyan
Tom Demyan
Reputation 4,300
#2 Robert Charlson
Robert Charlson
Reputation 1,460
#3 Michael Branan
Michael Branan
Reputation 1,160
View All

Related Models For Sale

Used BMW 5 Series
542 Great Deals out of 14,240 listings starting at $495
Used BMW M3
59 Great Deals out of 1,907 listings starting at $4,988
Used Ford Mustang
321 Great Deals out of 43,893 listings starting at $2,000
Used Honda Accord
723 Great Deals out of 78,726 listings starting at $899
Used BMW 6 Series
96 Great Deals out of 3,192 listings starting at $4,895
Used BMW 7 Series
161 Great Deals out of 5,736 listings starting at $3,995
Used Chevrolet Camaro
215 Great Deals out of 36,462 listings starting at $1,250

Used Cars For Sale

2017 BMW 3 Series For Sale
17 Great Deals out of 8,164 listings starting at $27,877
2016 BMW 3 Series For Sale
201 Great Deals out of 4,279 listings starting at $22,000
2015 BMW 3 Series For Sale
22 Great Deals out of 817 listings starting at $15,995
2014 BMW 3 Series For Sale
206 Great Deals out of 3,581 listings starting at $11,980
2013 BMW 3 Series For Sale
197 Great Deals out of 4,098 listings starting at $10,900