Some Funky Issuses after engine swap.

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Krafty

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Hey guys, Have some questions for some of you more Efi experienced persons. 1989 F150 302 efi 4x4 aod auto. I swapped my oil spewing 302 for an engine out of a 1990( I was told) f150 2wd 302 efi. swap went alright got everything hooked up the way its supposed to. drove it for a while an noticed it ran alright most of the time but anything over 1/2 throttle and it just bogs and refuses to rev any higher. sounds like throttle position sensor( haven't changed it yet).

also thought it could be the cat so i cut it out with no change.

But here is where it gets weird, right as soon as I put it in and got it running my oil pressure and temperature gauges refused to work, I even swapped in my sensors from my 89 engine which all worked fine before, and no change those 2 gauges are completely dead. Plumbed in a mechanical oil pressure gauge and I have great pressure.

so which leads me to my question. does anyone know of any wiring differences between the motors 89 and 90(?) being as i'm having multiple sensor issues , the connectors on the wiring harness are colour coated and i'm not colour blind and are hooked up right as far as I know.

now that I think of it its kinda acting like it did after the last motor blew except for not spewing oil and my gauges worked before. I attributed my power loss to the piston rings that got fried but could it just be that my ECM is on its last legs?

this thing is driving me nuts, I've had it just over a year and I'm getting tired of having something I have to fix every couple weeks.

 
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Seabronc

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Do you have a ground strap from the back of the intake manifold to the fire wall?

Did you use anything on the threads of the sensors? If so, clean it off,the threads are designed to seal and are the ground path for the two instruments.

Good luck,

:)>-

 
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Krafty

Krafty

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I didn't use anything on the threads of the oil pressure sensor but I did use teflon on the temperature sensor, neither of them are working regardless.

yes the ground strap was reconnected when the new motor went in.

I was looking at the parts listing for the ecm's and it appears 89 and 90 had different Id numbers and 90 had a bunch of other ecm options based on type of auto trans emissions requirements, would be worth tying to get the ecm out of the truck it came out of? its 3 hours away. or eventually dropping the 120 dollars on a remaned ecm .

and icing on the cake after cutting out the cat, I found out my heater core is leaking. ***

 

BLADE262US

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When I put a 91 motor in my 89 I had simmilar problems the motor harness is pinned out different you have to move the pins around . Best thing I can advise is to get very familiar with the electrical prints for both yrs make lots of notes on color codes and location in the plug of the wires in question . I think the chiltons manual has better wiring diagrams than the Haynes ? I have complete prints from ford garage so I just laid them side by side and compared . Im pretty sure on mine the coil was feeding through the oil pressure sensor and I had to get a new sensor after I got the wires correct because it had burned it up .

 
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Krafty

Krafty

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hahah sounds like im lucky that my engine is even running at all. does anyone know of a decent online source for the diagrams I need to set everything staight or scan and email me ones I can print out? my email is [email protected] thanks,

if its going to be a big mess would it be worth trying to pull the complete wiring harness off my old engine so I can just plug it in? like how hard is it to switch the pins in the connectors?

 

AdamDude04

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Just wondering.. you said "Oil spilling 302".. by any chance you check the valve covers for oil leaks? My 302 did the same thing two years ago. So bad when I was driving down the highway, it looked like the coulds in the sky came down behind my truck, turned blue, and ofcourse smelled like oil. It was pouring out onto my exhaust.. Sense then I tighten them up every 6 months as for some reason they seem to come a little loose.. Also replaced the valve cover gaskets with rubber vs the crappy cork.

 
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Krafty

Krafty

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no its wasn't the valve covers, what my old motor was doing was loosing oil through my exhaust pipes, when you reved the engine in one spot for a couple of minutes you would have a hot oil slick on the ground coming from the tail pipe. the only smoke came out of the exhaust tail pipe on the highway.

 

Elmo

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I would use the harness from your original engine being that it is pinned for the ecm that you have. Also you may want to go the three hours and get the harness and ecm form the truck that you got the engine from, to have as spares.

 

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