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Stalled...again...getting closer I think


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Well the 93 STS N* stalled on me again today, but I think I may be getting closer to the source of the problem. I WOT'ed onto the highway this morning (carbon cleaning;) and got off the highway after around 10 kms. Once I exited, stopped at a light, it started hesitating, and died at idle. I got home, opened up the hood and started playing around with the coil wires and sparkplug wires. What I noticed was, on the left hand side of the coils (standing in front of the car), there are two wire clips. One multi wire clip, and another infront of it with 2 or three wires (same on each side of the coil packs). While running, I disconnected the multi wire clip and it died. I started it again, this time disconnected the 2 0r 3 wire clip, and it still ran?! What are thos wires for? When I disconnected the right side's 3 wire clip, it died.

Anyways, I started taking the insulation of the 3 wire clip on the left side of the coil packs, and to my suprise, only 2 wires where in there. The third was just a black spacer, with nothing coming through the other end.

Can someone please tell me exaclty what these series of wires do?



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If you plan to do much of your own work, I would strongly urge you to get a set of Factory Service Manuals (not Chilton or Haynes). The factory manuals are a 2-volume set totaling about 4" thick. They cover diagnosis and repair of every conceivable problem with your Cadillac's powertrain, electronics, and body.

They can be found on E-bay and other sources (I got mine from factoryautomanuals.com). They generally run around $75 for the set (sometimes more, sometimes less). They are loaded with illustrations and step-by-step procedures. They make interesting reading even if you don't do your own work - it just helps you to understand the car's systems better. They are well worth the money!


Happiness is owning a Cadillac with no codes.

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The short one on the right side goes to the cam shaft position sensors. The long one on the right side goes to the crank shaft position sensors. The short one on the left side is ground, ignition/battery & PCM. The long one on the left side goes to the PCM.

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There are a lot of wires you could unplug while the car is running to make it die. Just because you can unplug this wire and the car stalls means nothing about the real cause of your stalling unless the plug is bad or the wires are in bad condition.

If it dies at idle speed there could be a host of problems:

stuck open egr valve

bad idle speed controller

stuck torque converter

fuel pressure regulator

ignition module

and on and on..

Best have someone check for diagnostic codes, or have someone knowledgable along for a test drive when it stalls.

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I figured out that wire was connected to the camshaft position sensor, and is irrelevant to disconnect, since it works in unison with 2 other crankshaft position sensors (redundancy incase 1 fails, so that idea is out).

The only code I ever get is P095, stall detected. I took the car into the dealership, and they say everything is fine (of course it didn't stall while they had it). I am getting horrible gas mileage also, about 11mpg (highway & city average).

Maydog, you mentioned a stuck torque converter, would this cause a rough stall? My car just shuts off, sometimes I don't even know that it has stalled until the light turns green.

The TPS, EGR, ISC have all been replaced. New plugs, wires checked out fine, fuel pressure is between 35 and 43psi. I don't know what else to do.

I wish I could at least get a code for this problem, but no such luck.

Any ideas?

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Slim...Its sounds like your fuel is possibly going. I had similar problems when my pump went out. The car died while decelerating, but it started up perfectly...No other incidents for 2 weeks. Then it stalled again, at idle. It shook and stuttered and finally died. I did get it started (had a moment of hesitation) and was able to drive home. I drove it for another week and then it stalled, and didn't start. Luckily I was near my house when it died. Pushed it into my garage, turned on the ignition and listened for the fuel pump hum....no hum. I replaced the pump myself....saved a ton of money and had some fun..(was my first time working on a car). Really not that complicated. Also I got P095's after every stall. I noticed you checked the fuel pressure. And Im wondering if the fuel pump, in an early stage of failure, is still able to provide adequate pressure to the fuel rail. Thus giving you a "false" reading. I would probably say its the fuel pressure regulator or the fuel pump. Also...leave the dash board display set to "battery volts". I noticed that right before I would stall the battery volts would drop waaaayyyy down (like 11.9) possibly as a result of the pump wires drawing to much current...good luck


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Ok, I'm learning more and more here :blink:

I've run some diagnostics on the car via the PCM Overrides and also found out that P095 creates a PCM Snapshot automatically. Here are the numbers from the snapshot

PD01 (ED01) TPS (Throttle Position Sensor) in degrees - 3.3

PD02 (ED02) Manifold Absolute Pressure Sensor in Kilo Pascals (kPa) - 92

PD03 (ED03) Barometric Pressure in kPa - 101

PD04 (ED04) Engine Coolant Temperature (ECT) sensor in degrees Celsius - 103

PD05 (ED05) Intake Air Temperature (IAT) sensor in degrees Celsius - 39

PD07 (ED07) EGR Pintle Position - 42

PD08 (ED08) Spark Advance in degrees Before Top Dead Center (BTDC) - 7

PD09 (ED09) Ignition Ground Voltage - 2.437

PD10 (ED10) Fuel Pump Feedback Voltage (battery voltage) - Not Shown

PD11 (ED11) Engine Speed in revolutions per minute (rpm) - 0

PD12 (ED12) Vehicle Speed in miles per hour (mph) - 0

PD13 (ED13) Pintle Position - 0

Can someone please decipher these numbers?

Also, in the service manual I ran a diagnostic for the code P095, and it's saying if my snapshot parameter for PD02 is less then or equal to 95Kpa, to refer to a section on Hesitation , sag and stumble. I am doing this now.

Another diagnostic I ran was the Exhaust Gas Recirculation System Check. In this test you shut the engine off when the coolant is greater then 90 degrees celsius, override the EGR to 0 ( in PCM overrides), then note the EGR pintle position (PCM Data PD07). In my case it was 41. If less then 103, it says to override the EGR to 99, then check PD07 again. In my case it was 214. At this point you turn the engine on, note the rear bank block learn value (PD39), in my case 118, then slowly start increasing the EGR override to 30% while making sure the engine keeps running. At EGR of 30, I checked my PD39 again after 60 seconds, and it was at 98. You subtract the two values, and if you have a difference of greater then 10, the EGR system has no fault. A difference of 10 or less means there is a fault in the EGR system.

So next steps and any help?



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