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John Mc
John Mc, Ford Technician
Category: Ford
Satisfied Customers: 6240
Experience:  19 years Ford Lincoln Mercury experience
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1989 ford: cylinder..Changed MAP sensor, coil, engine..injector

Customer Question

got a 1989 ford pickup with a 6 cylinder. It started with an eratic idle, but now has moved on so you can feel the "miss" at highway speeds too. Changed MAP sensor, coil, Engine computer..... Checked the plugs because it feels like an injector not working right, but the plugs are all the same, good color by tip, but alot of black carbon inside by the insulator.... Any clues?
Submitted: 5 years ago.
Category: Ford
Expert:  John Mc replied 5 years ago.

John Mc :

Hi, I am John Mc, a Ford dealer tech. I hope I can help you quickly and accurately. One moment while I work on your problem.

Customer:

ok

John Mc :

Sounds like it may be running rich and loading up on you. I would suggest you check the fuel pressure. On your model it should not be higher then 60 psi. If so you have a bad fuel pressure regulator. If it is normal 50-60 psi, then you may be looking into a tune up issue such as plugs, wires, cap and rotor. If you still have problems after a tune up all that would be left is a bad distributor and ignition module. These can act real strange and in these cases you repair them by process of elimination. I really doubt you have an injector issue. If that was the case your problem would be only at idle or a dead skip. Since it also acts up at high speed and all plugs have black on them I would lean towards the high fuel pressure or the distributor.

Customer:

disconect the MAP it actually runs better, idle is alot higher tho... has new tune up on it.

Customer:

actually if you disconect any vacum line it seems to run better.

John Mc :

Make sure the map sensor hose is not cracked or blocked up. If ok check into the fuel pressure. You could have an issue with too much fuel pressure but when the map is disconnected it may lean out the injectors. Same with removing a vacuum line. Also you need to check the voltage coming out of the oxygen sensor. If voltage is staying at 0.01 and not going up and down it would be telling the computer that it is running lean so it richens up the mixture. Good possibility here also!

Customer:

ok, i will do some cking, tnks

John Mc :

You're welcome!

John Mc :

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John Mc


 


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Customer: replied 5 years ago.
Nope, it was a leak in a fuel line. Got a diff prob maybe u can help on? 1998 E350, sat a couple years and I. Put an engine in. Can't get power to fuel system. Changed pump, checked shut off, got power at relay but the relay not getting activated. Had ecm flashed, still nothing...
Expert:  John Mc replied 5 years ago.

Is the ecm turning on? Does your check engine light turn on with the key on?