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Ask Juan Crespo Your Own Question
Juan Crespo
Juan Crespo, Tech Trainer
Category: Car
Satisfied Customers: 1526
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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I have a 1998 old nintey eight no power to fuel pump and

Customer Question

i have a 1998 old nintey eight no power to fuel pump and even if i give it power the pump will run but wont start
Submitted: 1 year ago.
Category: Car
Customer: replied 1 year ago.
i have spark i have no power at any time to the fuel pump but i am starting to think ecm
Expert:  Juan Crespo replied 1 year ago.

Hi there. Welcome to our site.

I can probably help you, but I'll need a bit more information before we can start:

Are there any codes?

Is there injector pulse?

Customer: replied 1 year ago.
no the battery was dead when i started messing with it
Customer: replied 1 year ago.
i dont own niod light tester but i can tell you that if i power the fuel pump i will get fuel to the fuel rail but it still wont start
Customer: replied 1 year ago.
i just tried to pull codes again and i have no response from ecm
Customer: replied 1 year ago.
this is taking a bit longer to get a response then they made it sound originally i guess send me your reply when you have time since i already paid for this conversation i am going to try to find more info another way thanks
Expert:  Juan Crespo replied 1 year ago.

OK. Make sure the battery has a full charge before you try to pull codes. Then check both ECM fuses; 20A fuse under the hood and 10A fuse in the dash. Also check the data link connector terminal 16 for voltage and terminal 4 for ground. Also, I strongly recommend you get yourself a Noid light (under $20 at most auto parts stores) to check for injector pulse.

Please let me know what you find.

Customer: replied 1 year ago.
all fusses are good and i have power and ground at the connector
Customer: replied 1 year ago.
from what i can see all power to the injectors and fuel pump comes straight out of the ecm
Expert:  Juan Crespo replied 1 year ago.

No. The ECM doesn't provide power to either the fuel pump or the injectors. It provides ground to the control side of the fuel pump relay to energize it; then grounds each injector in sequence based on signals it gets from the cam and crank sensors.

If the battery is fully charged and fuses and connector values are OK, and you still can't communicate with the ECM, then it is probably bad.