1

I was fixing the throttle cable on my 1985 Ford f150 and in the process of doing that I unplugged my MAF and removed the air intake pipe. After fixing the cable and putting the air intake back on my car wouldn't start. It would crank and crank but would never get sparking, whereas just before this repair it started just fine.

I was doing some debugging figured it was the MAF so I unplugged and it started right up, it ran super rich but at least it started.

I'm wondering why did unplugging MAF and removing the pipe cause this to happen.

Should I get a new MAF?

Improve this question
2
  • '85 Ford F-150 came with 4.9L 300cid L6, 5.0L 302cid V8, and 5.8L 351cid V8. All using carburetors. Carburetors don't use mass air flow (MAF) sensors. Maf sensors are mainly used in EFI engines, measuring airflow volume. Are you running a modified engine or mistakenly identified a part on the carb or intake air tube?
    – F Dryer
    Commented Aug 23, 2022 at 15:26
  • @FDryer Mine is a 5.0 v8 EFI.
    – Sam Orozco
    Commented Aug 23, 2022 at 15:47

1 Answer 1

Reset to default
1

I can't comment specifically on the F-150 but most vehicles can default to a "limp home" mode when one or more sensors have failed. In this mode, the engine uses a predetermined set of parameters that should allow the engine to start and run, but with limited power, excessive emissions and bad fuel economy. It's intended to get you home or to a service facility rather than leaving you stranded by the side of the road.

If you test the connector and wiring for the MAF sensor pin-by-pin and wire-by-wire and find that all are good, then it's likely that your MAF sensor is broken and should be replaced.

Improve this answer
2
  • I don't know what the issue was but I did end up getting it start with the MAF plugged in. My issue now is the throttle cable is a little too short, so it's opening the disc in the throttle body a little big and basically just revs to 4,000 RPM when idle.
    – Sam Orozco
    Commented Aug 24, 2022 at 16:53
  • @SamOrozco So the initial goal -- to repair the throttle cable -- still needs work. But at least now you know all about "limp home mode"!
    – MTA
    Commented Aug 24, 2022 at 19:56

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .