HT4100 4.1, 4.5, 4.9 Discussion, 1994 Cadillac Deville High Idle in Cadillac Engine Technical Discussion; Originally Posted by Sevillian273
P/S cooler?? I didnt know there was one. Ill have to check that out tomorrow..... I ...
Automobile(s): 1984 coupe deville 4.1 67,000original/1991 sedan deville 4.9
Re: 1994 Cadillac Deville High Idle
Originally Posted by Sevillian273
P/S cooler?? I didnt know there was one. Ill have to check that out tomorrow..... I was really surprised to find that there was a factory oil cooler on my Seville. Gotta love Cadillac!
i was under there tryin to find out why my power steering lines were rubbing my serpentine belt , saw a little tiny cooler tucked up unger the passenger floorboard.....traced it back, damned power steering lines going to it...LOL
Honestly I dont know. But if I had to find it, I'd follow the lines coming from the power steering pump. Or, follow the rod coming out of the firewall for the steering wheel. The sensor is probably a threaded fitting-like thing with a connector on it. Thats the best I could tell ya without pulling the car out and taking a look.
It was directly on the steering box on my '89 Bonneville. Easy to see with the 3800V6, it is on the firewall low mounted. Should be the same on a Caddy. At any rate it's on the steering box, it's to give a little throttle at full lock to prevent stalling. Looks like a small O2 sensor, just 2 wires coming from it as I recall. About the only sensor I didn't replace on that POS
FINALLY!! I located the SOB!! it's in a rough place to get to from under the car. An to my suprise!!! It's unplugged. I had some work done on my mounts, sway bar end links, and also the tie rod ends a couple of weeks ago. Ever since I got the car back the power steering code has been in the computer. I searched high and low for the damn thing in visible places. You get under the car and look near the rear manifold and it's perched on top of the power steering lines. I plugged it back up, cleared all codes in the system. Will run the car about 50 miles tomorrow to and from work to see if it returns and if it's still giving me the idle issues.
Yeah, all the damn headaches though! it's running a bit better now. The gas pedal still moves off an on though. I'm going to check for fuses and replace the cruise control box on it soon. They are around 100.00 remanufactured.. At a junkyard I'd say under 30-35 bucks! It's the only other thing I could think of that could cause the pedal to accel up and down on it's own. I'll have the car put on the computer afterwards to see if there is anything screwed up in there. First and last cadillac I will EVER own.. lol I think I'll stick to older cars for the simple fact that all of these *later model cars* have too much shit on them
You dont need to 'put the car on a computer'. That 'computer' is already in the car. You can pull all the codes from the car itself. Check the sticky at the top of the forum front page about extracting and deciphering codes.
As for the gas pedal, disconnect the hose going into the cruise control diaphragm and cap off the hose with a screw or something. Then see if the gas pedal still moves on its own. If it still does, then it is the ISC motor.
Here is a picture, the arrow points to the cc diaphragm. The hose is on the back of it.
OK, first thing is first, I believe you changed the Idle Speed Control motor (someone called it the A/C idle solenoid). This controls the idle speed. This car has NO idle air control motor. That is a different setup entirely.
If the gas pedal is moving without the cruise engaged, it cannot be the cruise control. The servo is not energized. Try pulling the vacuum hose off of the cruise servo or disconnecting the electrical connector and drive it--that way it absolutely cannot work.
However,that's probably not your issue. There are two possible causes in my mind: 1) improperly set throttle position sensor, or 2) worn distributor gear caused by the leaking head gasket issue a while back. To check #1, enter diagnostics (hold "Off" and the red warmer button for 4 seconds) and observe ECM parameter P.0.1 at fully warm idle in drive. It should read approximately 1.0. If it is reading less than 0.5 you'll need to adjust the TPS. If it reads more than 2, you'll also need to adjust. If you need to do so, let me know and I'll instruct you on what to do. Do you notice the car idling high or low at all when you're driving at speeds above 10 mph? It will always idle at around 550rpms in drive at a full stop irrespective of the TPS setting, but the TPS setting affects idle speed above about 5mph.
The worn distributor gear will also cause a similar problem. If it's chewed up, there will be play between the camshaft drive gear and the distributor gear at idle. This will cause erratic timing. Since the ECM senses the timing when setting the idle, the idle speed will be erratic. You can check this by putting the car in fixed timing mode and checking the timing with a light. If the mark dances around a lot, there's a good chance the gear is worn and will need to be replaced.
The TPS wasn't throwing any codes but I think somewhere inside of it there's a spring that stops the throttle plates from staying wide open with no gas applied to the accelerator. It wasn't the servo, I pulled all lines, clogged the vaccum and disconnected it and it still had the issue. The TPS on there was no good, I purchased a replacement today for 32 bucks and installed it and it's back idling the correct way. Before at idle the throttle plates would be about 1/4th of the way open actually. It went down now and the idling calmed. I'll put it on the highway tomorrow for the *real test* to see if the pedal would still move up and down at 60MPH on it's own like it did once before...
The TPS doesnt have a spring inside of it, That spring is on the opposite side of the throttle body where the cables attach. The TPS is kind of like a 'volume' knob on a radio, your foot on the pedal raises and lowers it and the ECM reads the 'volume' and decides how much fuel to inject. Im surprised that it ran good after you replaced it because it has to be calibrated with a volt meter. You cant just stick it on there, it has to be set at a certain voltage or 'volume' when the throttle blades are at their minimum open angle(minimum air). There's very little margin of error there so maybe you just got lucky.
The movement that the ISC motor imposes on the throttle blades is minimal, I didnt think one could even feel that with their foot. At least I couldnt feel it when my first ISC went bonkers. Not to mention, I dont beleive the ISC motor can even reach the throttle lever when you are driving at 60 mph. I dont know what the cut-off point is but im sure its not that high. Have you driven the car at highway speeds with the cruise control disabled yet?
Yeah... I have It's as if there was no different from it before. I had cruise engaged doing 65 down the freeway and the pedal was still moving up and down. So I knew there was nothing wrong with the cruise for the most part. I had no codes for it either. Since then I had PO61,62,65 for the cruise because it's disabled. The car idle with or without it made no difference what so ever. On highway or off.
The TPS I purchased was a bit different from the one I took off of the car from what I could tell. The one on the car had around 1/2 inch adjustable slides where the torque bolts go through. this one had no wiggle room. I don't know if it came *calibrated* already. It was an off brand name manufacture.. it seems to be working fine though.
Edit: I had actually had to calibrate the ISC bolt that sticks all the way out to get the plates to *nearly* close. With the ISC at the level it was before It kept the plates open around 1/4th of the way open. I have noooo idea how the electronics in a cars computer corespond. Before changing the TPS I had adjusted the ISC down so that the plates were near closing and it wouldn't idle for anything while started. So I opened it back to the same level, once I put the new TPS on and adjusted the ISC which was FULLY extended leaving the plates open down and it idled correctly.