Sluggish acceleration 1985 Colony Park

I just retired my 2000 Hyundai Elantra wagon and bought the car I've been waiting for: a mid-80s Mercury Colony Park with all the bells and whistles. I have two kids, a third on the way, and have made it clear to my wife that I will never own a minivan. This one has the 302 and the previous owner admitted the car seemed unusually slow--the local Firestone service center couldn't find anything wrong and suggested a fuel system cleaning in their printout.

Where do you suggest I start my diagnosis? The previous owner said he thought it needed new fuel injectors but I don't want to take a shot in the dark or pour money into repairs I don't need. It starts fine and idles well and revs well in neutral, but is a tired dog trying to pass or climb a slight rise on the interstate. I don't think it could hold 65 if I encountered any real hill. The exhaust doesn't smoke and when I popped the breather off the valve cover there was no excessive blowby. Truth be told it acts a lot like my Hyundai when the catalytic converter plugged up.

Any suggestions?

 

As I was reading your post I was thinking that the exhaust might be partially plugged. When was the last time it had a full tune up? Does the transmission seem to be slipping at all? Are you getting a check engine light? I believe by '85 they had switched to multipoint fuel injection from the CFI correct? How many miles are on the car?

 

If it is in fact fuel injected you might consider a product called BG44K if it's available in your area. I have sold this product for 24 years now and found it is often a "simple cure" if there is one. Kevin has some other good suggestions and questions here, I just thought I would throw in my 2 cents worth as well. A simple way to test the cat on an older car like this is to pull the oxygen sensor and take it around the block, it's noisy but usually can show you if it's a blocked exhaust or cat.

 

Since you really don't quite know what to look first than I guess a good starting point would be to hook up a vacuum gauge. I find using a vacuum gauge is a lost art but it certainly can get you heading down the right road pretty quickly. It's a great tool that anyone can use and should be in everyone's tool box. Scenario #14 in the below link will even tell you if the exhaust is blocked.

http://www.secondchancegarage.com/public/186.cfm

 

I believe it has the CFI--it looks like a carburetor tucked under the air cleaner but it is fuel injected. The car has just 107k original miles. The previous owner replaced the plugs, plug wires, and distributor cap, and ran a bottle of cleaner through the gas tank. The transmission does not slip. The check engine light flickers at low idle--usually when you first put it in drive or first come to a stop. I assumed that was probably from low oil pressure.
Shwag, thanks for the tips--I'm going to have a look this weekend. Everyone seems to think the car should have dual exhaust to make the most of this engine anyway, so I'll probably have that installed even if the old exhaust isn't plugged.

 

Re: Hullinger

Excellent! I have a set of vacuum gauges for balancing the carbs on old motorcycles. I never thought to use it for diagnosis.

 

After you have driven after dark look at the catalitic converter. On my 2004 Dodge truck they were cherry red and both were plugged.

 

The red check engine light is more like, a replace engine light. Has no relation to the EEC. Its only for overheating and low oil pressure. First thing I would do, rent a compression tester and do a compression test on the engine. Then you can go from there. Its also possible that the cats are plugged or, you have a weak fuel pump. However, the compression test will send you in the right direction.

 

Yes that is the CFI. Not the greatest in the world, but it is serviceable. A lot of people swap over to a carb once they start having issues.

In addition to the other suggestions I would also get a real oil pressure gauge hooked up to the engine. It's not a good sign that the Change Engine light is coming on, but hopefully it is just a bad sensor or connection.

Dual exhaust was a factory option so it should be easy to piece a system together with off the shelf parts unless you want to have a shop fab up a custom system for you.

 

I pulled one spark plug to check the compression and got 130+ after a couple cranks. I found a vacuum hose coming off the manifold and followed the instructions for reading the vacuum gauge. Everything checked out fine--steady in the green at idle, drops then quickly builds back when you rev and goes higher as the engine winds back down. No sign of the exaust pressure building when revving.

I called the wife and kids and took them for a cruise. Everything started out fine then as the car warmed up it started to stumble. After 30 minutes it was stumbling and missing so bad it was all I could do to keep up with traffic. I filled the gas tank a couple miles from home but did not notice any improvement. Still smooth at idle, but terrible under any throttle. Go figure, when I bought it two days ago it ran great (albeit lacking in power)and I had no trouble during the 30+ mile trip home.

BTW I live in San Antonio and I just noticed that the guys in the classifieds section just spotted the add:
http://www.stationwagonforums.com/forums/showthread.php?t=29909

Right now I'm thinking I'll add some STP in the oil to buy time on the low oil pressure issue (check engine comes on at idle when hot), and try running sea foam or BG44K cleaner in the gas.

 

Was the car sitting without being used for a long period of time prior to your purchase? Wondering if you have old/bad gas or sediments in the tank. It would make sense that the sediments would settle down and the car would run properly under initial start up. After warming up and driving a bit, that stuff could get stirred up and may be blocking somewhere along way, starving the engine of fuel.

 

Going through the obvious one-by-one things....

Air- Really shouldn't be any means of being warm causing restricted airflow. Too much air coming-in from the correct place won't cause problems. If the stumble is only off-idle and a stuttering I'd wonder about the EGR. It could be acting as a vacuum leak. I see the EGR is the typical 'door handle' looking unit, and if I recall they are very easy to access. I'd try pulling it to see if it is carboned-up. I'd even put your vacuum gauge to it. I would try pulling the vacuum line, plugging it, and then go for a test drive with the EGR not hooked-up. I'd also make sure your PCV is clean/rattling. There is also a vacuum control valve. It's a $5 part that may be worth swapping out.

Fuel - It's always possible you have a fuel pump that is weak and after it runs for a bit it starts to lean out. I'd assume Firestone would have checked this though, both cold and at temp. Fuel pressure regulator should be cooled by the fuel so I wouldn't suspect it was the problem. Also can't see the injectors being the issue unless they are leaking and letting fuel seep into the cylinder early and causing a misfire on a hot/not yet ignited spark plug.

Sounds stupid, but make sure it has the correct/correct type of fuel filler cap..... Some are vented, some are not, and it can make a different.

Spark - There is always a possibly the ignition module is getting interference when hot. Some of them are notorious for doing just that. Many local parts stores can test them. Plugs could always be carboned-up or even the wrong ones. If there have been intake and/or exhaust changes they could now stand to be changed to a colder plug, but guessing that is not likely.

Always possibility of battery/juice issues. Just take a look at your cables and such to make sure everything is clean and connected correctly. The alternator might be having issues after running for a bit/up to temp, but not most likely. Same with battery. If you have a meter I'd check voltage running hot, cold, and even at the battery when not running, but I'd pursue the other things first.

And I'm fresh out of ideas.....

 

Just to clear things up, did you just pull 1 spark plug or all 8?

My dad had a 87 H.0 5.0 T-Bird that was coming up to 300k miles and with the exception of no over heating or engine lite coming on it had similar if not identical problems you describe (where did the power go?). In our case it was the #7 cylinder all ways fouling the plug for the last 20-30k miles. The car never ran like it was missing, but ran rough and lack of power every 3-4k miles, swap that one plug and off it went. We never cared about the why's and or fixing the problem as it's time was done and heading for a trade in.

I find this forum (I'm not a member) is real handy when it comes to trouble shooting with no BS answers on just about every Ford engine........

http://www.f150forum.com/

I did find some reference on the site backing up a bad cylinder and or the coil pack being the problem on 80's EFI 351/302's but "oops", I closed those pages.

Good luck, and don't give up. far to nice a wagon you have

 

thats why its a slug !!
I also have one...it takes about 2 minutes to hit 4000 RPM
.... those carbs are junk !! almost as bad as the 'slider' carbs

 

Quote:
Originally Posted by motokeb
I believe it has the CFI--it looks like a carburetor tucked under the air cleaner but it is fuel injected. The car has just 107k original miles.

Very interesting to know......................... if I ever find a Colony again?