: 1985 Cadillac Fleetwood Brougham problem



cfb8595
05-29-09, 01:31 AM
I have a 1985 Cadillac FB coupe with the ht4100 engine and my problem is that it starts to vibrate pretty bad when I put it in drive. I did a tune up on the car not too long ago and the problem still continued. The "service soon" light comes on when the car warms up and I pulled these codes from the car 30 and 52 but not sure what they mean.
Any help would be greatly appreciated

carnut
05-29-09, 10:58 PM
Did you do the tune up to hopefully cure the rough idle in gear or did this start after the tuneup?

sven914
05-29-09, 11:30 PM
30 is idle speed control circuit error and 52 is ECM memory reset indicator. 52 means that power was lost to the computer (the battery was disconnected) and the stored memory was erased and it would not turn on the light.

A vibration that only occurs in a froward gear could indicate that the torque converter or driveshaft may be out of balance. If the vibration happens only after the car starts to move, then have the driveshaft balance checked.

If it happens as soon as the gear is changed, then have the idle control circuit checked. Also change any old vacuum hoses and have the routing checked because vacuum leaks can cause vibrations in certain gears.

cfb8595
05-30-09, 01:59 AM
I did the tune up hoping that the vibration would go away but it didn't cure anything.
It starts to vibrate as soon as I put it into gear and when in park the car idles up and down but not too bad, so I'm going to check the
idle control circuit and hopefully this cures my problem.
Thanks for the help

sven914
05-30-09, 11:23 AM
^Yeah, engine surge when idling is usually the primary concern with an Idle Control Circuit error.

cfb8595
05-31-09, 02:00 AM
^Yeah, engine surge when idling is usually the primary concern with an Idle Control Circuit error.
I changed the idle control thing and still no luck. I also tried to drive the car up on some ramps today to change the oxygen sensor but the car didn't have enough power or something cause it just wouldn't go up.
Any idea what that could be?

AElayyat
05-31-09, 03:02 PM
Make sure you have correctly adjusted the Idle control motor. If that is not the problem have your catylitic converter checked.

carnut
05-31-09, 04:25 PM
The idle control motor will not affect smoothness or roughness of idle only speed of idle, either too high or too low. I agree, the cat converter can plug up and restrict power. You need to do the basics, compression test first then plug wires second.

cfb8595
05-31-09, 08:36 PM
The previous owner had a new exhaust system installed back in 2005 and pretty much sat ever since until I bought the car a couple of months ago. The car has 44,xxx original documented miles. Is this a common problem for the ht4100 engines?

CaddyshackCadillac
05-31-09, 08:41 PM
any pics of this said beast?

cfb8595
05-31-09, 08:55 PM
any pics of this said beast?
After being covered with a tarp since 2005 :(
http://i40.tinypic.com/241se86.jpg

carnut
05-31-09, 11:55 PM
Most common issue is not changing the coolant every 2 years without fail and adding the sealant mentioned on the decal by the radiator. Failure to do this will cause intake gaskets to fail and coolant wiping out the cam. This car can break the rocker arm supports and cause engine roughness. Do a compression test. Pull each plug wire one at a time with insulated pliers ( engine running) from the cap to isolate which cylinder is not firing and report back. How old is the fuel filter?? wont cause rough running but will affect power.

sven914
06-01-09, 12:00 AM
After being covered with a tarp since 2005 :(
http://i40.tinypic.com/241se86.jpg

:worship: Behold, the coveted Fleetwood Brougham Coupe. Only 28,480 ever produced (just 3,000 from 1985).

I've had my eye on one for a while. Got an evil plan to loose the 4100 and drop in a race tuned 364 small block with a Powerglide; make it into a sleeper. My Uncle used to have a 65 Bel Air, which he build to stockcar racing specifications. When the car died in the Ohio salt, he pulled the engine and transmission; I just need to find time to rebuild them.

Back to your problem.

A clogged, new, exhaust pipe is not that uncommon, especially with cars that have sat for a while. Rodents build nests or hoard things in tail pipes or neighborhood kids try to steal the Cat and end up just smashing the catalyst. Even the slightest restriction can cause major problems.

One way to tell for yourself, with out any special tools, is to wrap your hand in a rag and hold it by the tailtip. You should feel a smooth flow of warm air. You could also hold a piece of paper near the tailtip and see if there is any flow (if the paper occasionally gets sucked to the pipe then one of your exhaust valves is not seating properly). If you want to spend some money, then get a vacuum gauge, hook it to manifold vacuum and increase the engine speed slightly. If the needle slowly drops to zero, then the exhaust is restricted.

Other problems that could be linked to engine roughness are plugged injectors and fouled sparkplugs. Running Gumout with Regane will clean the fuel system and make the engine run better.

http://www.carbuyersnotebook.com/wp-content/uploads/2009/05/gumout-regane.jpg

cfb8595
06-01-09, 01:48 AM
Most common issue is not changing the coolant every 2 years without fail and adding the sealant mentioned on the decal by the radiator. Failure to do this will cause intake gaskets to fail and coolant wiping out the cam. This car can break the rocker arm supports and cause engine roughness. Do a compression test. Pull each plug wire one at a time with insulated pliers ( engine running) from the cap to isolate which cylinder is not firing and report back. How old is the fuel filter?? wont cause rough running but will affect power.
The fuel filter was replaced when I did a tune up,
Im gonna have to try that compression test and Hopefully all the cylinders are good.
Thanks

cfb8595
06-01-09, 02:00 AM
:worship: Behold, the coveted Fleetwood Brougham Coupe. Only 28,480 ever produced (just 3,000 from 1985).

I've had my eye on one for a while. Got an evil plan to loose the 4100 and drop in a race tuned 364 small block with a Power-glide; make it into a sleeper. My Uncle used to have a 65 Bel Air, which he build to stock car racing specifications. When the car died in the Ohio salt, he pulled the engine and transmission; I just need to find time to rebuild them.

Back to your problem.

A clogged, new, exhaust pipe is not that uncommon, especially with cars that have sat for a while. Rodents build nests or hoard things in tail pipes or neighborhood kids try to steal the Cat and end up just smashing the catalyst. Even the slightest restriction can cause major problems.

One way to tell for yourself, with out any special tools, is to wrap your hand in a rag and hold it by the tailtip. You should feel a smooth flow of warm air. You could also hold a piece of paper near the tailtip and see if there is any flow (if the paper occasionally gets sucked to the pipe then one of your exhaust valves is not seating properly). If you want to spend some money, then get a vacuum gauge, hook it to manifold vacuum and increase the engine speed slightly. If the needle slowly drops to zero, then the exhaust is restricted.

Other problems that could be linked to engine roughness are plugged injectors and fouled sparkplugs. Running Gumout with Regane will clean the fuel system and make the engine run better.

http://www.carbuyersnotebook.com/wp-content/uploads/2009/05/gumout-regane.jpg
I replaced all the spark plugs,dist. cap/rotor but one thing I didn't do was the wires but tomorrow after work I'm gonna swap them out and well see if that helps. Also I did try that fuel cleaner on my 95 Cadillac FB and did notice that the engine idles a lot better now.
Thanks for looking out fellas

cfb8595
06-02-09, 11:32 PM
I had a chance to change the spark plug wires but didn't notice a change.
It now throws codes 27,30,52 when I do diagnostic test. :(

sven914
06-03-09, 02:11 PM
27= Open Throttle Switch Circuit
30= Idle Seed Control Circuit
52= ECM Memory Reset indicator

An open throttle switch error was set because when you throttled up the engine, the nose switch on the IDLE SPEED CONTROL MOTOR, that keeps the engine idling, did not detect the throttle linkage touching the nose switch on the ISC motor.

cfb8595
06-03-09, 10:42 PM
27= Open Throttle Switch Circuit
30= Idle Seed Control Circuit
52= ECM Memory Reset indicator

An open throttle switch error was set because when you throttled up the engine, the nose switch on the IDLE SPEED CONTROL MOTOR, that keeps the engine idling, did not detect the throttle linkage touching the nose switch on the ISC motor.

I cleared the codes today and now I only get code 30,52
What about if the gas tank is diryt? would it have anything to do with the idle and vibration problem?

carnut
06-03-09, 11:28 PM
Very frustrating to try to help when someone's bound and determined to throw parts at a car. Did you run the compression test? what were the readings? The ISC will not cause a rough idle. An open throttle switch circuit could possibly because the TPS tells the ECM what amount of fuel to deliver. I would hope that all these tune up parts are not on an engine with an internal problem??

cfb8595
06-07-09, 04:34 PM
I think your right, it might just be an internal problem the reason I say that is cause when I accelerate the car there's some loud poping noices coming from the trottle body.

carnut
06-07-09, 04:38 PM
Popping thru the throttle body usually is a sign of a flat camshaft. Pull off the driver side valve cover, then start the car. Usually the affected rocker arms will barely move in relation to non worn cam lobes.

cfb8595
06-08-09, 11:19 PM
Since now I know that the car has internal problems, is the 4100 worth getting rebuilt? or what can I use in place of the 4100?

sven914
06-09-09, 12:35 AM
I pretty sure that an Olds 307 will bolt in without any changes to the rest of the drivetrain. The 307 will give you a good power increase over the 4100 and it is a very dependable and durable engine. If you are seeking substantially more power, then a 350 would be better, but it think you would have to replace your transmission with a TH700R4 or TH400. The 400 doesn't have overdrive.

cfb8595
06-09-09, 08:50 AM
So if I put a 307, I don't have to change the alternator,starter..... And will fit right in?
My work car has an lt1, so that's enough power for me. I'm just trying to get the car running right
and get it painted.

sven914
06-09-09, 04:34 PM
Just looking at the part numbers, I would say they're not interchangeable. To be sure I would go to Auto Zone (not Advance, those people are dicks) and talk to one of the counter dudes.

cfb8595
06-09-09, 09:37 PM
I went to a place here in Dallas were they sell remanufactured engines to get a price check and to see if they were familiar with the 4100 to 307 swap but they were no help. They didn't know much about caddy's. Also isn't $1350.00 kind of steep for a 307 or is that about right?

JTL1043
06-11-09, 04:54 PM
Ha did you do a complete Tune up one of the Best Problems I had with ht4100 was not Getting the Orfis Tubes Cleaned.here where they are take air cleaned off and what looks like a carb. open the butterfly and you will see two tubes brass about 1/8 inch dia these get pluge with Gunk from gas fumes use pipe cleanner if lucky or wire and gunk cleaner they go into the intake so don,t drop wire into intake. after you get the tubes open Start engine and idle up and use the rest of the gunk cleaner to clean throle body and injectors check facum lines wile your their and I think your 85 will be on the road agan

sven914
06-12-09, 12:57 AM
Also isn't $1350.00 kind of steep for a 307 or is that about right?

Know anyone in Ohio? (http://akroncanton.craigslist.org/pts/1194148055.html)