Hi guys! Today I went to get my Mercury from the previous owner and drove her about 80 miles back home. No problems and loved the ride! You can see my 'new' car in the welcome-thread. When I start the engine cold or warm, the idle is extremely low and most of the time it won't stay running. You have to keep the throttle a bit on. After a little driving everything seems ok, but it still has a bit lot idle. Doesn't matter if I have the AC on or off (doesn't blow much cold either). How can I adjust the idle and how is it controlled? The Colony Park is from 1978 and has the 400ci engine (by the way, if you are used to a Grand Cherokee 5.9 or a Corvette, the 400ci is slow as hell ) Hope someone can point me in the right direction so I can try to adjust the idle a bit.
I just checked AutoZone's Vehicle Repair Info. They've got Mercury Grand Marquis listed as the closest model. You have to register (free) to see that section of the site. They seem to have offered different carburetors and EFI for the 5.8L V8, so you should check out the different carburetors. http://www.autozone.com
The idle should have been adjusted with the car in drive/park and all the accessories/lights on. Hey, we didn't do that, did we Norm!?
The 1978 Mercury wagons had a 351, 400, or 460 cid engines. None of them ever came with EFI. The 2bbl carb on his '78 Colony Park is the same as my '78 Country Squire. As for adjusting the idle, just like HandyAndy said, adjust with the car in park along with the lights, A/C, all that on. The 2150 Motorcraft series carb you have is a REALLY easy to understand carb. Don't know the maintance histroy on your wagon, but it would'nt hurt to do a proper rebuild on it. As for the 400 being slow, they are from the factory. To change that, a 4 bbl carb and intake from Edelbrock and a mild cam will wake that engine up.
Ok, an update... I have turned up the idle a little bit with the idle-adjustment-screw and now she stays running nicely. However, I have found something that isn't right; there is some kind of actuator or 'motor' that looks like it is used for higher idling when cold or when the AC is on or the transmission is in drive? I've posted some pictures beneath to show what I mean. The connecting point is bend away so the actuator doesn't do anything. Looks like it is done on purpose. When the engine is off, I can push the rod in and out of the actuator and when I start the engine it comes out to its fullest extend. I suppose that if I bend it back, the engine would rev like an idiot while in idle? How does this thing work? Why would it be bend? Can I bend it back and adjust or test its function?
That is a solenoid to kick up the idle higher when you select the a/c. It also is supposed to retract when you shut off the ignition to close the throttle plate. It is adjusted by the big nut. Once you loosen the nut it appears that the solenoid can be rotated counterclockwise to retract it thus reducing the rpm then the nut can be retightened to hold it in place. You'll have to disconnet the wire while you adjust it back. This is a dual purpose solenoid. Like I said above it's to increase rpm when a/c is selected, the rod extends. The rod retracts to close the throttle plate when you shut the engine off to eliminate dieseling. That's when the engine runs on for a bit after you shut it off. That's due to the high heat in the smog equipped engines. Once you have it set for the proper rpm with the a/c on at idle it will retract appropriately when you shut the engine off. I'm sure that it was a pain in the neck to adjust so the previous owner bent the lever over instead of simply backing off the solenoid or disconnecting it electrically. Being careful you should be able to bend that lever back where it is supposed to be and adjust the solenoid if you need it functional. It's hard to tell in the picture but it appears that the smaller bolt with the spring is the "fine" adjustment to get the setting just right when the solenoid is pretty close to being right. It appears that it adjusts the bracket that the solenoid is attached to. That wire holding the throttle lever to the carb linkage is rediculous. The proper clip for that could set you back a half dollar if you buy an expensive one. Or free if you found one in a junk yard. Just seeing your pictures makes me want to come over there but you are too far away. I just hate to see the way that carb is because it is really unecessary for it to be that way.
Those are great close-up pictures! What kind of camera and settings do you use to get that detail? Impressive.
Wow, I really like your fast and detailled explanation, tbirdsps ! The solenoid only works for a higher idle when the airco is on and to close the throttleplate with the engine off? I've read in the usermanual that the engine would idle higher when it got (too) hot; is this also done with this solenoid? I am going to look at the linkage and the adjustment of the solenoid next sunday and try to - carefully - bend it back. It seems the solenoid needs to be adjusted way back or else the RPM will be to high at first. Because the solenoid retracts en expands normally, it seems it is still working but the previous owner didn't feel like adjusting it correctly. Hope this is the case. I noticed the bloody wire holding the linkage too. Stupid solution. I really hate this kind of repairs but gladly enough this can be fixed easily. But first I want to try to fix the idle-solenoid. Wish you would be able to come over also . Or maybe I could come over to the USA. Damn, wish I lived over there. But why do you hate the way the carburator is - besides the solenoid and the wire? Do you see something I don't see? Thanks, but I'm not aware this is impressive! I'm just using an ordinary Canon Digital Ixus 60 (6MP). Just put it in Macro-modus and off you go. I like taking a lot of pictures while working on all my cars; it helps putting things back together later on. And I keep an archive with pictures which I burn on DVD for when I sell my car to the next owner. As a proof of everything that's done on the car.
Well, I'm impressed anyway. Doesn't take much to do that. Mine's a Canon too, so I'll RTFM (Read The Freakin' Manual)! Thanks.
I hate the way the carburator is because of the bent lever and the wire holding the throttle linkage. That kind of sloppy work is really not necessary. It only takes a few minutes to do things right. We have an expression for that kind of work and it is "Jury Rigging". I can understand the throttle linkage wire as an emergency fix to get home or off the road but it is so inexpensive to repair correctly that it should have been corrected. If that comes apart on the highway in traffic the car would go to idle and could cause an accident. I'm sure you'll have it fixed soon as it is so simple to do. I don't have a technical manual so I do not know why the idle would be more when hot or whether that solenoid controls that function. It's a fine car and I'm sure you will enjoy owning it for years to come.
I've replaced the sparkplugs, rotor and distributor last Sunday. They didn't really look worn. The supplied cables didn't fit; they had the 90 degree sparkplugcaps and they don't fit the 400ci. Just ordered the right ones (and return the wrong). Strange thing is that after replacing these components, the Mercury doesn't idle as smooth as before when on operating temperature. When she is cold, everything is perfect. What also remains is the higher idle when warm. I am going to a USA car specialist nearby in about two weeks to let him adjust the carb correctly (first want to replace the cables). Hmmm... come to think of it; I didn't check the gapping of the sparkplugs... Is it important? I think they were a bit closer together than the old ones. I also re-bent the rod where the solenoid touches the throttle so it is active again. Before I bent it back, I checked the functioning of the solenoid (turning on the airco) and it worked. Only thing I had to do is adjust the solenoid so it would rev up like an idiot. Does anyone know the proper procedure for adjusting the idle including setting the solenoid?
Just went through that myself. Here's what fixed it. New plugs, gapped to factory spec. The old ones were clean, and not discoloured or burred (bad spark symptom). HandyAndy lent me his carburetor while he checked mine on the bench. His carb revealed some timing and air/fuel mixture issues - the engine shuddered, idled too fast, etc. He checked the timing advance at idle, way too far ahead by about 8 degrees, after we reinstalled my carburetor. Idle mixture was too rich, idle speed was too fast. Yes, gap the plugs to factory gap, then setup the air/fuel mixture and then the normal idle. If you've got a vacuum gauge, move the distributor to get to the highest reading (18 to 23 psi) AT IDLE Speed, and turn it back by 2 psi. The gauge will tell you whether all kinds of other issues are going on or not.
