New guy with some questions

[Grandma_quis]

Hey yall. Finally registered on here because a certain field doesnt properly show on the mobile version but here i am. Ive owned an 89 vic and now own an 85 marq and have a couple questions you 5.0 gurus can answer with your eyes closed...

1. Car runs lean as hell. Bought the marq from an old boy that drove it upto new york (live in FL). Spark plugs show me it runs very lean (white soot)...whats most likely my issue? No check engine light to come on but i wouldn't want to start throwing money at it.

2. Small issue (maybe related to my past question?) Car sometimes misfires and stutters wide open at the top of the rev range. Champion spark plugs #25 would make it lose all power after about half way up to the top of the rev range and would make the engine run awful up there. Replaced with motorcraft and now its mostly happy but there's a time when it will still struggle to find full power at wot (only at top of rev range)...fuel pump going? Crap in the spark plugs again? Maybe YOU know

3. I saw the air pump/ac removal thread and it seems pretty soild but does that apply to my crappy cfi style motor? I dont believe a year was in the thread.

4. Another small forum question. I want to do the cfi to mpi switch and again have seem the threads but am a little ignorant to doing that much work. I live with my grandpa and he's very competent with cars but wont touch fuel injection because its "too advanced for him" if someone can give me a baby talk down on how to go about this id appreciate it.

And thats pretty much it i think. Im happy to finally be in a place that is purely box knowledge


http://imgur.com/a/tx8ZN (:

[DerekTheGreat]

I had an '85 with CFI. See what kind of fuel pressure you're getting. Not sure what the spec is but probably at least 15psi if it's anything like the TBI GM stuff I have. Could be the issue as you say it misfires and stutters on the top of the RPM band, sounds like it's not getting enough fuel. Replace the fuel filter too, probably original. '85 was the only year to have CFI & EEC-IV but you wont ever see a check engine light with it because it wasn't there. You can still hook a scanner up to it to see if there are any stored codes, the plug will be under the hood on the driver's side next to the coolant overflow bottle. Other issues with these are the choke pull-off mechanism and EGR passages tend to plug up & the thing wont idle.

[sly]

+1 Change the fuel filter if it hasn't been changed recently.

Also, if the timing gears have not been replaced, replace them. You have a plastic cam gear if it's original.

[gadget73]

EFi cars do tend to run what most people would say is lean. The plugs should be white or extremely light brown if things are normal.

Odd running problems with CFI are often timing chain and vacuum line related. Might also be bad oxygen sensor. Not personally a fan of Cham-peen plugs but YMMV of course. I'm more of a Motorshaft plug kinda guy.

Smog removal is pretty much identical on all years. The pipe is shaped slightly different but thats about it.

The CFI to SEFI swap you'd want to ask Pantera77 about. He's probably the most recent conversion and can likely tell you the particulars.