1989 Ford F-150 Engine swap now poor performance

  • 1989 FORD F-150
  • 6 CYL
  • 2WD
  • 180,000 MILES
Swapped a 4.9 Liter from a 1989 F250 with 4 speed manual tranny into a 1989 F150 that had a 4.9 liter and still has a 5 speed manual tranny.

Engine is dumping a lot of fuel, running rough and turning new plugs charcoal black. Tailpipe puts out black and white smoke.

Engine ran good in the F250. We tried chaning the EEC from the 250. Engine would turn over but no fire in plugs so we still have the 150 EEC.

We changed the EGR and fuel pressure regulator with no change in performance.

I am suspicious of a plug coming out of the fuel injector wiring harness that came on F250 engine but does not seem to exist on the old 150 engine. All plugs are in the injectors.

The original F150 engine had a suplimentary air tube running parallel above the fuel rail. No such air tube on the 250 engine. The f150 also had a cooling air tube along the fuel rail. No such tube on the 250 engine.
Do you
have the same problem?
Wednesday, September 2nd, 2009 AT 3:18 PM

1 Reply

OK so if I understand you right you pulled one engine out of one truck and put it into the other complete? Now that don't work because there is a difference in emissions so it won't run right. You can swap the long block part of everthing no problem. Meaning you need to use the intake and such from the F-150 so the computer can do what it was programmed to do.
Was this
Thursday, September 3rd, 2009 AT 10:00 AM

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