I finally got my 84 380Se running with the install of a new cap. It doesnt run very well at all! Below 2000rpm it shakes and bucks and will stall at idle. Over 2000 rpm it seems to smooth out, but doesnt seem to run strong. Here is the strange part. After 15 min of running the exhaust pipe after the cat convertor was glowing red for 2-3 feet!! BRIGHT RED! What can this be caused from? The original problem happened at highway speed and the car just died. I couldnt get it going until I replaced the cap.
Any ideas??

Gas cars are not my strong point but if the cat is red it sounds like it is getting to much fuel. I would suspect that it is running very rich.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

It's running way too rich. Check the engine timing.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

What is the long term effect of running rich - maybe not to the point of a Cat glowing red, but just too rich?

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Bernard
Dallas, TX
89' 300SEL 228K
01' E320 48k

One other thing to consider - perhaps the cat is actually clogged? Check for "normal" exhaust pressure at the tailpipe. Try partially or even completely sealing the exhaust pipe with a piece of metal or stiff cardboard. If doing so has little to no negative effect, the cat may be clogged.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Running too rich with eventually detroy the cat.

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2002 G500 74K
1998 E300 200K and rising
1995 S600 73k


"Some people spend an entire lifetime wondering
if they've made a difference. The Marines don't
have that problem."-Ronald Reagan

"Never tell people how to do things. Tell them
what to do and they will surprise you with their
ingenuity."-General George S. Patton

I think the car would start fire before the cat is destroyed! I swear the pipe was cherry red! And the smell was like as if you were welding....the buning metal smell. It was hot!
Is it possible my timing chain could of jumped? Do you think it would still run? I know the chain has been replaced once because it has a welded up drivers side valve cover. Can it be an ignition problem?
If it is a timing chain....how much work is involved?

Thanx!!!

Replace the rotor and wires, too, and check the plugs. The rotor wasn't in any better shape than the cap, after all.

If the check engine light didn't come one, the bulb is burned out.

The wires failed when you replaced the cap since they get brittle with age, and cracked, possibly breaking the conductor too, and I would bet you have a couple of them swapped around, so some cylinders aren't firing. Should be marked on the cap if you look closely. They must be in the correct order and position on the cap.

DO NOT drive it in this condition, the catalytic converter support will melt and plug the exhaust, to say nothing of setting the car on fire (no joke!). If the chain jumped, it will soon break and you will definitely be out a $4000 valve job.

Yes, it could be a timing chain jumping, in which case you need to re-set it and replace the tensioner -- although it is also probably worn out and you need a new chain anyway (they don't jump unless WAY long).

Worst case you jumped the chain and have now bent the valves, but they usually won't run that way.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

how many miles are on this car?

is it the original cat?

what is the recent history of this car's operation?

are you the original owner? if so, have you kept your records?

have you consulted them for what has been done to the car?

do you keep a log? do you monitor your miles per gallon? if so, what have been the mpg figures for the last couple thousand miles? can you contrast that with the history of the car's fuel consumption throughout its lifetime?

if so, what do you see?

Ok...here is the history of the car as I know it. It has 190k miles on it. When I bought it (just recently) it started up and ran good and strong. The only thing I noticed was a rythmatic tic that increased with engine rpm. This sound seemed to come from under the right valve cover near the back. Not loud, just a noticeable tic, tic, tic that I thought maybe a lifter or rocker noise. Anyway, I bought the car and after only 30 miles on the highway it suddenly died like you were to shut off the key. No hesitation, no sputters, just dead. I had filled up the tank just before the 30 miles as well. I cranked and cranked and tried flooring it to see if it would start, but no luck so I had it towed home. Since getting it home I have replaced the cap because it was arching out all over the place and I thought that was the problem and now I can get it running but very poorly. It will only start with your foot to the floor and crank and crank till it finally catches. It wont idle down without stalling under 800rpm. Over 2000 rpm it smooths out gradually, but still doesnt have the responsivness like it should. I guess the chain had been done prior because of the welded up drivers valve cover. Thats all I know.
If I pull number one plug Im guessing the TDC of piston should line up with 0 degrees on crank? How hard is it to reset ot change the timing chain? I am mech inclined, but need to know what kind of a project Im getting myself into!
What should I be checking first on this car?

Before you change the timing chain do the simple stuff first! Change your wires, plugs, and rotors! Their probably old and shot. It sounds like an ignition problem.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

The very first thing to check is whether or not the fuel pumps are running correctly. Should buzz for a second when you switch the key on (I think, been a long time since I had a K-jet car) and when the starter is operating. If not, replace the fuel pump relay, it's caput and you have very low fuel pressure.

Next I would replace the wires -- if the cap looked really bad, get a rotor, too. Bad rotor and wires will cause it to run very badly, lots of missing, hot cat, etc. If it was arcing all over the place, the wires are toast.

Stalling while running is usually the fuel pump relay going bad -- if it gets hot, for sure it's bad, get a new one.

From here, you need to verfiy ignition, timing (ignition and cam/crank), condition of chain (a real problem on the 380), fuel pressures, and mixture.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Well I definately dont hear a buzz when I turn on the key. Any ideas where the relay and fuse are?

My previous post may have been overlooked. Once again, I must ask: does anyone suspect a clogged or partially clogged cat? 10 years ago, My 86 VW Golf suddenly died once, as if I shut the ignition key off. I was able to start it up again; it idled poorly but would smooth out as RPMs increased. It would run but was extremely underpowered and could barely make 40 mph. I had just replaced the cap, rotor, wires, plugs, and fuel/air filters, so those parts weren't suspect. Don't ask me why, but for some reason I suspected an exhaust blockage problem and checked for exhaust outlet at the tailpipe - it seemed really weak compared to my other running car. I jacked the car up and noticed exhaust pipes from the cat forward were very hot (though not glowing red like yours). Pipes behind the cat, although warm, were much cooler. I cut the cat off and looked inside. The honeycomb-like catalyst had somehow shifted within the housing and was partially blocking the exhaust flow. It actually looked like it "shrunk" or got eroded away to a smaller size so that it was no longer snug in the housing, and it rotated. Who knows - maybe rich mixture dissolved it? I don't know... Anyway, replaced it with a straight pipe (I know - illegal) but the car ran normally again. Sold the car 6 months later due to low oil pressure.

I'm not saying this is your problem, but it sure wouldn't hurt to at least look into it.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

My educated guess is that the timing chain has jumped a tooth and it is out of time. Had a 1969 Ford car that acted as you describe. At idle it would barely run, and when it was wound up it would run smoother. Incorrect timing will also cause your exhaust to runner hotter. If it did jump a tooth, I would not only replace the timing chain, but also check all sprockets, the tensioner, and chain guides. If it did jump a tooth, then likely there is wear elsewhere that would cause this to happen. Don't forget to check the crankshaft sprocket as well. I would replace the guides anyway if you replace the chain, as they are likely wore and are cheap.

I would think that it is not the catalytic convertor, as it would likely run better at idle with the lower exhaust output and worse when wound up with the increased flow. Had another car that acted that way when the muffler plugged up. You could try unbolting the exhaust pipe at the exhaust manifold and seeing if it solves the problem.

I agree with psfred, DON'T drive it that way, as it is a fire hazard and may further damage the engine.