[KimSingapore]

Hi I have a 1998 STS with about 48K miles. It has been in Singapore it's entire life as it was previously the Embassy vehicle for the Ambassador. It runs great at speed but when stopped at a light and occassionally slowing down for a turn it stalls. This is with and without the Air Con on. It is not every time but happens more often than it doesn't happen. The probelm is there is no Cadillac dealer in Singapore so the mechanics are struggling with this problem. I just had the 4 coils changed, new wires installed and oil/air filters changed (all parts I brought back from the US on my last business trip- but the local mechs did the work). They tell me there are no codes and they first indicated they thought it was an A/C problem but now they think maybe a fuel pump. Don't want to rebuild the whole engine one part at a time. Anyone have experience with this problem and have a fix or where I can point the mechanics?? Thanks

 

[thu]

I had the same problem in my 93 Deville. When I replaced the gas tank along with the fuel pump, the problem disappeared.
When I slowed quickly (e.g for a stop sign) or turned corners when less than six gallons in the tank, it would stall, too. There were a host of other fuel-related problems that were solved when I replaced the whole stinkin' tank and fuel pump as one unit.

 

[KimSingapore]

Thanks, so it looks like a fuel pump will be my first try at a solution. Just FYI I had almost a full tank of gas when it stalled so amount of fuel doens't seem to be a problem---yet.

Any suggestions on a good mail order parts store??

 

[91TexasSeville]

Thanks, so it looks like a fuel pump will be my first try at a solution. Just FYI I had almost a full tank of gas when it stalled so amount of fuel doens't seem to be a problem---yet.

Any suggestions on a good mail order parts store??

Please do not rush out and buy parts until without a doubt in your mind, that they (it) will solve the problem.

Suggest to your mechanic to test the fuel pressure first, by putting a gauge on the fuel rail and driving the car for a few miles.

The mechanic should learn in short time if the fuel pressure is adequate during normal driving conditions.

 

[thu]

91TexasSeville has an excellent point. Ask your mechanic if he can verify that fuel pressure at the rail is insufficient when this happens.

Note that when I had a similar problem, my fuel pressure tests showed the rail had 40+ PSI when idling and would drop off significantly and get very erratic (pressure gauge indicator jumped all over the place) when the problem occurred.

I suspected the FPR. I had that replaced to no avail. That's when I swapped out the tank from a local junkyard.

 

[WarrenJ]

This doesn't address stalling at traffic lights, but your mention of stalling while turning brought to mind the power steering pressure switch. Perhaps it's something you might want to look into?

Its purpose is to tell the PCM to "bump" the idle speed control motor up a notch when you are making a sharp turn at low speed, so as to compensate for increased load on the engine while the pump is generating more pressure for the turn.

This photo is from my '95 manual, but I'm guessing yours is the same.

http://i7.photobucket.com/albums/y299/WBucket/PSteerSwitch.jpg (163KB)

Regards,
Warren

 

[WarrenJ]

It's really not possible to properly maintain a Cadillac without the Factory Service Manual (FSM). Have you considered getting a set?

The two volume OEM FSM is available stateside for about $135. Other aftermarket manuals should be avoided.

You can find the OEM manuals here:

http://www.helminc.com .

I don't know what shipping charges might apply, but they may be scary.

Regards,
Warren

 

[Intheknow]

I'll bet the shipping charges for the manual are insignificant compared to the overseas shipping charge of an un-needed fuel tank.

 

[WarrenJ]

Understood :d :d :d

 

[JimD]

Hi I have a 1998 STS with about 48K miles. It has been in Singapore it's entire life as it was previously the Embassy vehicle for the Ambassador. It runs great at speed but when stopped at a light and occassionally slowing down for a turn it stalls. This is with and without the Air Con on. It is not every time but happens more often than it doesn't happen. The probelm is there is no Cadillac dealer in Singapore so the mechanics are struggling with this problem. I just had the 4 coils changed, new wires installed and oil/air filters changed (all parts I brought back from the US on my last business trip- but the local mechs did the work). They tell me there are no codes and they first indicated they thought it was an A/C problem but now they think maybe a fuel pump. Don't want to rebuild the whole engine one part at a time. Anyone have experience with this problem and have a fix or where I can point the mechanics?? Thanks

I have experienced random stalling, but not as extensive as you are describing. Removing and reinstalling the connectors (as a cleaning-the-contacts procedure) on the crankshaft position sensors stopped my stalling condition. And have your tech put a wrench on the sensor attachment bolt while he is in there cleaning the connector contacts.
The same procedure could be applied to the timing signal connectors on the ignition module. Salt water air environment can promote corrosion growth.
Running strong at speed would indicate zero problems with the fuel delivery system. But check the fuel pressure regulator for evidence of a ruptured diaphram by pulling the vacuum hose and looking/sniffing for evidence of fuel.
I do not know if any of the U.S. based internet parts houses can or will ship overseas. But I have been happy with the domestic performance of
http://www.gmpartsdirect.com/
Good luck to you....

 

[KimSingapore]

Thanks everybody...I'll pass on the ideas to the garage and look into making sure they have the correct manuals. Appreciate all the help, K

 

[peteski]

Hmm..
nobody so far sugested to pull out the codes yet? Shoudln't that be always the first step in troubleshooting?

I think there is a sticky thread on the Northstar engine forum which explains how to do this on a OBDII car (like yours).

the codes might tell us what the problem is.

Peteski

 

[WarrenJ]

They tell me there are no codes and . . . .

 

[peteski]

Loks like I've missed that part...

Peteski

 

[KimSingapore]

The last few posts got me thinking, so I went to the tech forum and figured out how to pull codes myself. and I don't know what the techs at the garage were looking at but I found two codes -- one in the AMP section U1064 and one in the PCM section P1599 HISTORY.

I thought I read somewhere that there are codes just for the last time you drive and also history codes.

So on the way home last night the car stalled twice and I got the U1064 and P1599 HISTORY codes. Didn't stall on the way to work and only had the P1599 HISTORY code this morning.

Can that help anyone diagnose the problem???
Thanks

 

[JimD]

How about an inexpensive shot in the dark?

Get under the rear seat cushion and disconnect the battery negative terminal cable. Inspect the battery connections and cable ends for corrosion.

With the battery negative cable still disconnected, inspect the battery/starter/alternator terminal junction under the red cover at the rear of the fuse/relay box under the hood. You are looking for signs of corrosion again.

Clear your codes and test drive it. You will lose your GALLONS USED and AVERAGE MPG data when the battery is disconnected.

These computers-on-wheels are sensitive to battery voltage. Do you know if your battery has been replaced?

 

[KimSingapore]

Inexpensive sounds good to me and sounds easy enough to do.

I don't know if the battery has been replaced, but can find out. I'll do the checking of the connectors when I get the car home today. thanks

 

[sunkneedaz]

i also have the same troubles you are having w/your cadillac...I have been w/out a car for 3wks now!!! Thought they had the problem fixed when they put in a new computer.... guess what ..it is still stalling :rant2: ... good luck on your car.... let me know if you have the problem fixed ...and what you did to get it working again....:bonkers: