My '85 MGM, "Maisa"

[Arquemann]

Here is the thread I should've done the second day on this forum.
Her name is Maisa, and she's a bit stubborn and temperamental. As some of you are already aware of



I paid about 5000€, since I've thrown in about 2000€ more, and it's still not okay.
Bought in June 2019, from the second owner (old lady falling victim to dementia), she had the car from '91. Florida car, imported to Finland in '01 or '02.
Original FL plate D66 LZG, VIN 2MEBP95F2FX635235. (If you yanks have some free car history sites available, I want to know as much as possible about it's history, since I have none).

-1985 Mercury Grand Marquis LS
-5.0 Central Fuel Injection (for now...)
-Faded white paint, porn red interior, slightly sunburnt, otherwise mint
-Automatic Temperature Control (which actually works really well!)
-Cruise Control that worked exactly twice
-Power antenna, locks, windows and seats
-Currently sitting at ~103000 miles, those 3k from me last year.

When I got the car, it was maybe too original...
-Original plug wires
-Original timing chain
-Original engine sensors except for O2

Overall the car is in pretty nice condition, except for the engine issues and faded paint, no clunks, rattles or squeaks, barely any rust.
Driver door is misaligned so wind makes a lot of noise. And a dozen of other minor things, more coming later.

The car could be quite easily registered as a "museum/historical vehicle", but that means keeping it in factory-like condition.
I'm not really into that kinda stuff, I'm thinking lowered, some classic chrome wheels, meaner attitude and a nice rumbling V8. A bit of a hot rod / street rod. Currently it's too much of a grandpa's church-mobile.
I don't want a garage queen, I want to cruise, drive it alot, enjoy it and not worry about little things.

All in good time, number one priority is to get the engine running good and smooth.

[Arquemann]

For recap and archiving reasons:

Misfire at idle and lower rpms, cruising and deceling. Causes jerkiness when cruising up to about 50 MPH. Smooth as butter when properly accelerating.

Also:
-EGR acted really stupid until CFI unit rebuild, now it doesnt get any vacuum
-Fast idle is broken
-Smog pump system probably works correctly
-Snorkel hot air flap is dead

Parts changed last summer:
-Probably every single engine sensor
-Fuel filter, injectors, pressure regulator
-Plugs, wires, entire distributor, TFI module & it's connector
-CFI unit rebuilt
-ECM
-Double roller timing set
-Alternator & used voltage regulator (reg failed, not alt)
-PCV
-Oil & filter
-Metal TV bushing



Onto today, 27th of March, 2020:
-Out of storage
-Fresh tank of gas
-Still misfires
-I think I overfilled the tank and it pissed some on the driveway, at a slight downhill
-No KOEO codes (systems pass), couldn't get KOER codes even with instructions
-Getting on the throttle seems a bit sluggish

[gadget73]

ever done a compression test on this thing to verify its actually got 8 healthy cylinders?

When you say CFI unit rebuild, what did that entail?

[Arquemann]

ever done a compression test on this thing to verify its actually got 8 healthy cylinders?

When you say CFI unit rebuild, what did that entail?

I've done a compression test, a bit wonky how I did it but I got pretty even numbers. Redoing it with a proper screw-on tester definitely wouldn't hurt.

I'm guessing the CFI "rebuild kit" included new seals and such, probably got cleaned to. (This was done by the shop)
I wonder if the top part has a gasket like carbs do, and it happened to go upsidedown so it'll block the egr vacuum passage.
Car doesn't really feel any different from before - after the shop visit.

Tomorrow I'm thinking on checking the engine harness grounds and probably start opening up the wiring after that.

[gadget73]

no internal gaskets. Only thing in there are the injectors and O rings. No vacuum passages either. Supply for the EGR comes off the manifold. I think the 85 uses two valves to make the EGR work, one is the control solenoid and the other is the vent. Supply should go to the control, then out to both the vent and the valve. Control opens it, vent lets it shut. Either way, so long as the egr valve remains closed it shouldn't cause any real running issues.

I've actually got a 1984 diag manual in the mail, should mostly apply to your 85. When it shows up I'll see if i can offer some more specific troubleshooting info from it.

[87gtVIC]

She is a looker eve with faded paint. Hope you get things sorted out this season.

[Arquemann]

no internal gaskets. Only thing in there are the injectors and O rings. No vacuum passages either. Supply for the EGR comes off the manifold. I think the 85 uses two valves to make the EGR work, one is the control solenoid and the other is the vent. Supply should go to the control, then out to both the vent and the valve. Control opens it, vent lets it shut. Either way, so long as the egr valve remains closed it shouldn't cause any real running issues.

Here's how my EGR is currently:

(images are old, before the shop visit aka stuff is old and dirty)

The line I'm holding with my finger goes to the EGR Valve, line marked with red goes from underside of the CFI unit's top plate -thing to the EGR solenoids.
I haven't had any reason to believe this is incorrect, but it is?

I haven't taken apart the CFI unit myself, is is just the the fuel passages and the injector wiring connectors?
EVTM would be super handy to have, the credit card sized smudgy sticker on the core support isnt exactly useful.
It seems that I can't trust the wiring and vacuum routing, even though the car is very much untouched otherwise.


Today I'll get to checking the grounds.

[gadget73]

I believe thats right, 2 solenoids connected to the EGR line would be control and vent.

yep, just fuel and wiring connections in there. Its not like a carb, no small passages for fuel or any of that. Supply line in, the round thing in the back is the regulator, it sends any excess pressure back to the tank through the return line.

[Arquemann]

G120 ground looks like this. The uninsulated wire goes to the aluminium shielding covering some of the wires from the TFI connector.
Kind of a dead end there since its a ground.

I removed some of the sheathing and tape from the main wiring bunches and everything under seems clean and original-looking, nothing really looks damaged or chafed in any way.
Main battery to block ground seems fine, I can't see the ground on the RH cyl head at all due to the air tube.

There's so much to test and try, I'm seriously running out of skill. Because of my lack of knowledge, my patience is running thin and I hate that.

I snapped a pic of the vacuum routing sticker, so I can see better


Also I got the new trunk seal in, wiped away probably 35 years of dirt, the new seal is a snug fit and I got the ends butted pretty tight. I put the seam above the taillight so it doesnt get splashes. Now I actually have to press a bit for trunk to shut, its just perfect.

I was going to fix the small leak from behind the RH taillight, but rain scared me away and it's going to be around freezing to around Thu, so I won't even try sealing it.

[Arquemann]

I believe thats right, 2 solenoids connected to the EGR line would be control and vent.

So it's the EGR vent line. Upon further inspection, it's just a hole to the top of the CFI unit.
I'm fucking dumb.

[87GrandMarq]

Aren’t those for the thermactor system?


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[Arquemann]

Aren’t those for the thermactor system?

Thermactor solenoids, TAB & TAD are on the RH inner fender:

Under the 2 connectors in picture

Solenoids on the valve cover are the heat flap control, EGR solenoids and throttle kicker.

Pic courtesy of matth825 (would you mind copying the whole book for me? )

[gadget73]

thermactor ones are over on the fender.

might be worth pulling and cleaning the grounds anyway. Won't hurt it any to be hit with a wire brush and get a wipe of spark plug grease to keep it from corroding. The ground to the engine is probably more important though. I think on a CFI car it bolts to the back of the head. Thats the sensor ground and things get dumb if that is bad.

those manuals can be found for not much money on ebay. Shipping would probably cost more than the book.

[87GrandMarq]

Well then disregard, its been a while since I had a cfi car.


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[Arquemann]

Yeah, I can find 1 EVTM on ebay, 10 bucks and about 40 for shipping lol

Now to figure out how I can get at the ground on the back of the cylinder head, a bajillion tubes in the way and mostly the rigid air tube right in front.