Hey guys. Have had my sel for about a year now put about 5 k miles on it. Love the car but recently it has been running poorly.

Up until a few weeks ago she cranked and fired right up. Now when cold she cranks 5-10 seconds before firing. Changed out plugs for Bosch platnums did not help. Old plugs looked ok possibly fouled but I had a rich condition last year which was corrected.

So what did I do? Ok I ran some marvel through the gas tank ( before changing plugs) now she's running like she's missing. Did the marvel eat up seals ? Or free up gunk that's now in the system? ( or just coincidental)
I only kick the car around town daily. She is prob not happy with that,

Below are the symptoms,

Cold start- long cranking fires up stumbles sounds like misfiring (bad)
Warm running- smells rich still stumbles a little less
Idle-500-600rpm
Idle smoother (not perfect) in neutral, in gear feels like she wants to stall.
Driving speed- seems ok but I'm not taking it far don't want to breakdown
Damn thing smells rich but not "fat" in fact I leaned it out last year through the mixture screw.


Now I have above average mechanical skills but this car is built like a Rolex so can someone help diagnose ? Which vac accessories/sensors should I check first? Would a cap and rotor and wires be the next logical? Simple things first.

This problem came on suddenly and progressively worse that's why I'm not thinking cap rotor wires.

Last question,,,since it rarely gets over 35-40 mph should I take it out on the highway and drive it like I stole it? Blow it out?

 

First you said it feels like it's missing.Is it? Perhaps changing the plugs introduced a loose connection. At the distributor,at the plug connection,or the wires themselves.Hopefully only one wire,if that is what it is.
Now it seems to run ok while traveling at speed.
That could be because the problem is in the secondary air bypass.
That means, the car does not rely on extra air being fed into the intake at speed.The throttle plate being opened manually with your foot.
At idle the throttle plate circular sealing surface may not be fully closing.
Possibly a vacuum leak at this point.They also develop carbon around the sealing surface. If you suspect that is the case.Clean it off with a lint free rag and some carb cleaner. Don't spray directly into it. The surface facing you is the sealing area.With the car running is the plate closed completely? If yes, go on to the next step.It is ok to have the air filter housing off.
If all that checks out o.k.I would pull off the intake control valve off the top of the engine. It's in front of the air filter housing.Between the housing and the distributor.About 4in long and round,with a 2pin electrical con.Engine not running at this point.
Spray up inside of the opening a few times and check the condition of the cleaner as it runs out. [use rubber gloves]
Is it really black?If yes, keep cleaning it until there is no sign of carbon.
Install the valve back on the engine.Plug in the electrical con.
Button up everything.Run the engine.
Sometimes cleaning it this way is enough.If the car has just started acting up,it may be enough.
Some people run the car a long period before acting on it.
You may have to soak it over night.If you have the time to be without the car a day.This would be my route of endeavor.
Hope this helps.....

 

Thanks for the advise. I checked the cap and rotor and they look shot. That would def produce a miss. I will replace and see how that goes..


Any tips on changing the timing chain? I have seen a few people "cheat" by feeding the new chain linked to the old one. Is this best route?

Car is at 101k no clue if the chain has been done.

 

Cap rotor and wires did the trick. Wires were chaffed thought the insulation. Runs like new. Now on to the timing chain.

 

Hi, I have an 85 SEL of which I changed the timing chain with no problem, or special tools. I used vise-grips to hold the chain form falling in the case, pulled the plugs to make it easier to rotate the crank, had the ratchet/socket in place, connected the new chain to the old, and kept tension on the chain while turning the crank. Worked fine . Just take your time and keep the tension on the chain.