: 1991 caddy brougham idles rough and stalls



fjennings
07-27-09, 02:52 PM
Maybe someone can point me in the right direction. I have 91 caddy brougham and she idles rough and at lights she will stall on me. What could the cause be? Could it be that the fuel filter needs to be changed? Any help is appreciated.

jey
07-27-09, 03:07 PM
I would start by checking all the vaccuum hoses.

sven914
07-27-09, 07:10 PM
I've had problems with vacuum, and it is hell finding the leaks. To see if you have one, open the hood and start the engine, and listen to the engine idle for a hissing sound. If you hear one and can get the engine to idle on it's own, get up close to the engine and try to find the general area where the sound is coming from.

If you are not afraid to spend a little ca$h, then I would have the vacuum lines "smoked," which is where a garage uses a smoke machine to pump pressurized smoke (heated baby oil) into the vacuum lines to find leaks. Smoking the vacuum lines can find anything from bad hoses to a ruptured oil pan gasket. I would expect a dealership to have a smoke machine, because the have to repair EVAP leaks on a warranty basis.

fjennings
07-28-09, 10:59 AM
Thanks! I am going to start there first and work my around to the known culprits.

fjennings
07-28-09, 01:05 PM
I have another question does anyone know the location of the throttle position sensor on 5.7L V8 FI engine?

VortecCaddy
07-28-09, 01:33 PM
TPS is located on the passenger side of the throttle body. In regards to the stalling, you may also want to check the EGR valve. Is your SES light on? Tried pulling any codes?

fjennings
07-29-09, 11:43 PM
When I first turn the car on the SES light is not on. Once I have driven for about 20 minutes the light does pop on. I did find a leak in one of the vaccum hoses today. How do you pull the codes from the ECM?

csbuckn
07-29-09, 11:59 PM
Have you done any work on the distributer. My SES comes on after driving also and reads Ignition signal and lean exhaust. Maybe something to do with timing.

sven914
07-30-09, 01:47 AM
How do you pull the codes from the ECM?

You use a paper clip to jump the terminals of the ALDL connector, which is under the center of the dash. You put the paper clip into the last two holes (going toward the passenger side) on the top row of the connector. Turn the ignition to the run position, but DO NOT start the engine, and the check engine light should begin to flash a two digit code. The first code will be 12 and will be presented as 1flash/pause/2flashes. Each code will flash 3 times.

Follow this link for a complete list of codes. (http://www.extreme-check-engine-light-codes.com/GM%20OBD1%20Decoder.htm)

fjennings
07-30-09, 12:09 PM
Thanks guys I will check out those codes when I get a chance. I have alot to check out. If I didn't love the car so much I would part it out.!:banghead:

brougham
07-30-09, 11:44 PM
You get the codes by pressing the off and warmer buttons on the heater controls. Look around for the posts that say how to do it. You have to be careful with whatever list of codes you use because some of them mean different things depending on the year of the car.

sven914
07-31-09, 02:37 AM
You get the codes by pressing the off and warmer buttons on the heater controls. Look around for the posts that say how to do it. You have to be careful with whatever list of codes you use because some of them mean different things depending on the year of the car.

Just for my own clarification, can the cars with the 5.7 (LO5) and the 305 engines be diagnosed through the ALDL, without a scanner, or is the diagnostics solely on the CC head? I know that the Old's engined Cadillacs could only be diagnosed through the ALDL and I was under the impression that the 91-92 models were the same.

fjennings
08-04-09, 01:13 AM
Thanks guys for all the help. As a starting point I repaired one of the vaccum hoses that plug into the throttle body. There was a lot of air coming out of that tiny hole. Since I had more than enough hose and the hose was in decent shape I cut off the part with the hole and placed back on the throttle body. No SES light and no more rough idle or stalling. I couldn't believe it was something that simple. Go figure!

brougham
08-07-09, 01:48 AM
Just for my own clarification, can the cars with the 5.7 (LO5) and the 305 engines be diagnosed through the ALDL, without a scanner, or is the diagnostics solely on the CC head? I know that the Old's engined Cadillacs could only be diagnosed through the ALDL and I was under the impression that the 91-92 models were the same.

I don't know. It doesn't say anything about it in the manuals.

sven914
08-07-09, 02:06 AM
I don't know. It doesn't say anything about it in the manuals.

Well you've got a Chevy TBI motor, and I assume you've pulled DTC's through the Climate Head, so why don't you try it my and see if it works?

I can't really see them changing the diagnostic wiring on the 91 and 92, just because it got a TBI engine. But the 93, with the same engine can only be diagnosed through the climate control. But, the 93 was completely redesigned so redueing the wiring is logical. But they would have had to redone the wiring to accommodate the change from carburetor to throttle body (unless the same computer that does feedback carburetor can also do TBI).

csbuckn
08-07-09, 02:29 AM
90/91 does have the aldl

brougham
08-09-09, 01:39 AM
Well you've got a Chevy TBI motor, and I assume you've pulled DTC's through the Climate Head, so why don't you try it my and see if it works?

I can't really see them changing the diagnostic wiring on the 91 and 92, just because it got a TBI engine. But the 93, with the same engine can only be diagnosed through the climate control. But, the 93 was completely redesigned so redueing the wiring is logical. But they would have had to redone the wiring to accommodate the change from carburetor to throttle body (unless the same computer that does feedback carburetor can also do TBI).

Well its the computer that does the diagnostic stuff and that's different for the different engines so there's no reason to think it would work the same way. The 1993 wasn't completely redesigned. Only the way it looks was. Everything else is the same as 1991 and 1992.