Cadillac Owners Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Hi y'all, new to the forum and new to vintage Cadillac ownership. Needless to say, the first day has been a ride. I picked up a beautiful 93 deville with 83,000 miles. It ran great on the test drive, and the next day on the ride home after signing the paperwork the car started to act extremely strange. First, when you really gave it some throttle, it would stumble and almost die completely until you let up a bit then it ran smooth. A few more miles down the road, it had the same stumbling and sputtering and dying at part throttle when climbing hills. Finally about 10 miles from home it just shut off on the interstate, which was scary enough. I got it to restart and got it off the road and then let it sit for a bit and limped it the rest of the way home at 5mph, all the faster it would creep in gear, if you gave it gas it would die. I got it home and it was surging like a vacuum leak, I sprayed ether all around the vacuum hoses I could see with the intake off and noted no rpm change, but if I sprayed the area near the distributor it would seem to stumble, but not sure if it was just coincidental because it was having trouble idling. I checked the brake booster by plugging off it's line and no change in the performance of the car, and the fuel pressure regulator didn't have gas in it. All the other lines vacuum lines looked in surprisingly good shape for being 25+ years old. I gave up at this point, no use burning myself trying to work on a hot engine. After the car had cooled, I took it for a ride again and it seemed to run ok. Not great, but didn't stumble and die like it did. The only codes I had were from unhooking the battery and a ISC code which went away after it started idling normal again and not missing. This car is all original it seems, and the only other thing of significance was that the seller filled it up with gas at a small gas station, which I assume he filled it up with 87, but the car was only down a gallon or two when I test drove it so he didn't add that much. To top the night off, the car blew a brake line by the ABS module after the second test beat, so it got towed to my mechanic to look at. I'm just putting out a post to see where we should start to make the car run right. The seller is willing to help me with the repair bill, he offered to take the car back and give me my money back, but this car is clean and finding one in this shape in PA is high near impossible so we decided to see if it can get fixed before it comes to that.
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,494 Posts
THIS is one of the biggest problems with a "low mileage" - 27 year old car -
EVERYTHING - except gas and oil - might still be original -

it takes 3 things for an engine to run properly -
AIR -
FUEL -
SPARK -

I'd start by pulling and inspecting the spark plugs -
the firing/wear pattern CAN tell you a LOT - if you know HOW to read them -

fuel pressure and fuel delivery is critical -
pressure at the fuel rail must be between 39 and 45psi -

faulty fuel injectors were a well known problem -
measure the resistance of EACH injector - they should be almost IDENTICAL -

if the ignition parts are original - they are WAY overdue for replacements -
cap - rotor - wires -

the ignition module was also a "weak point" in the system -
and diagnosing one is nearly impossible - IF there is any question - just replace it -

----------------------

after you get it running properly -
ANY of the fluids that has NOT been changed within the last year or two NEEDS to be replaced -

flush the cooling system -

power bleed the brakes to replace ALL of the brake fluid -

power bleed the power steering fluid -

DRAIN and FILL the trans fluid -
DO NOT FLUSH THE TRANS -

I recommend replacing the serpentine belt unless it is brand new -

I recommend replacing each and every heater hose and radiator hose -
pop ANY of these and you're STUCK on the side of the road -

CAREFULLY inspect the rubber brake lines for ANY sign of cracking -
blowing a brake line can be THRILLING -

also inspect the steel brake lines - PARTICULARLY at the plastic mounts -

lastly - be sure to replace the winter air in the tires with summer air -









OK - so - I'm kidding about the air in the tires -
 

·
Registered
96 FWB
Joined
·
564 Posts
Sounds like a potentially nice score, and you really lucked out with that seller. The only thing I can possibly include to above in your climb up the diagnostic tree is whether you got the car up to full temp during that great test drive. If not, then look into specifically heat-related resistance issues.

And it's critical with suspension design of those old cars to fill the tires with air containing at least 78% nitrogen.
 

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,969 Posts
Sounds a lot like fuel pressure to me.
 

·
Registered
2001 eldorado,2008 DTS,2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
Joined
·
1,771 Posts
This has all the hallmarks of a clogged fuel filter.
 

·
Registered
70 Deville 78 Seville 92 Deville 03 Deville
Joined
·
764 Posts
How much gas is in the tank? Sometimes they don't run with less than a half tank due to bad baffles in the tank.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #9
Hi yall, got the car home and a fuel filter and cap/rotor fixed it up. Car runs good, has a slight miss at idle but the mechanic said he thinks it's due to poor gas, as when he did the filter he said it did't smell like gas whatever was in there. I know for sure the car got up to temp, we drove about 10 miles and it was a fairly hot day. Thanks for all the advice, and I found a notebook with a lot of service records, and the car has a lot of newer parts.
 

·
Registered
96 FWB
Joined
·
564 Posts
Yes, just a little something for the "pure nitrogen fill" purists. Every bit as good as the fuel line magnetic molecule aligner.

Mr. -31, glad you found the fix. Did you happen to keep the filter? I've replaced many, but never think at the time to slice it open for visuals.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #11
Yes, just a little something for the "pure nitrogen fill" purists. Every bit as good as the fuel line magnetic molecule aligner.

Mr. -31, glad you found the fix. Did you happen to keep the filter? I've replaced many, but never think at the time to slice it open for visuals.
I didn’t happen to keep it, but from what the mechanic told me it was pretty clogged. I think some sediment from sitting got stirred up when the seller topped off the car for me. i have to get the brakes re-bled because after hiding the pedal down for a little bit it goes soft, and you really have to push it to the floor to get it to stay put. If I pump the brakes they come on strong. I think the ABS needs bled but I don’t think my mechanic has the tool to do it
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,494 Posts
I didn’t happen to keep it, but from what the mechanic told me it was pretty clogged. I think some sediment from sitting got stirred up when the seller topped off the car for me. i have to get the brakes re-bled because after hiding the pedal down for a little bit it goes soft, and you really have to push it to the floor to get it to stay put. If I pump the brakes they come on strong. I think the ABS needs bled but I don’t think my mechanic has the tool to do it
====================
i have to get the brakes re-bled because after hiding the pedal down for a little bit it goes soft,
and you really have to push it to the floor to get it to stay put

a "SOFT" - but constant - brake pedal is typical of air in the system -

a "SINKING" pedal - that CAN be pumped up - is a failing master cylinder -
the brake fluid is internally leaking past the "O" rings on the piston -

DO NOT MESS WITH IT -
the next time you hit the brakes - the pedal MIGHT go all the way to the floor -
and NOT pump up - meaning - NO BRAKES -
 
1 - 12 of 12 Posts
Top