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1995 Deville
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38 Posts
Discussion Starter #1
Greetings folks,

while I am new to this forum in regards to posting(this is my first post) I have been a lurker for a few months as I started to consider buying an older Cadillac. I recently bought a 1995 Deville with the 4.9l V8 with 112,000+ miles on it for $1000. It is in good condition for being 20 years old and with the exception of it being a bit dirty on the inside(I will have it detailed soon enough) and a small tear in the back seat on the the portion of of the seat that is hidden when the rear arm rest is up the interior is pretty good( as I don't see actually using the rear arm rest, it will continue to hide the tear)

I have had to replace the front brakes and rotors and both driver and passenger side front door latches(to fix a bad door open sensor(kept killing the battery because it was telling the computer/RAP module that the door was still closed and leaving the radio to stay on) and also to fix a dead lock actuator which was both not working and also binding the rod that unlocked the door via key) but that only cost me $80 for the brake parts and the latches and about 4 hours of my time so all is good on that front.

The other issue the car has is that it it slightly stumbles/bucks when you drive away from a stop(i.e. stop sign) normally(i.e. not flooring it) and while it does not cause the car to violently shake(like the dash is about to fall off) this stumbling/bucking is prominently felt.

If I accelerate briskly(I.e floor it) the bucking/stumbling is gone also if the car is already moving slightly(i.e on a hill or dip that allows the car to move on its on(or at least creep forward) on its own without touching the gas pedal after letting off the brake) then the stumbling/bucking is also gone.

I was thinking misfire but then the check engine light came on with a code of P041(which is no Cam signal) So I got to thinking that the bucking/stumbling issue I get when I drive away from the stop was caused by a bad cam sensor(aka the hall effect sensor that is under the rotor. But then I noticed that during the time I drive it to work or other places, the check engine light will come on, then go off then stay on for a few minutes or hour and then turn off for a few minutes. I have never seen this in a car before. Usually the check engine light stays on until the car is shut off or a code reader is connected and used to turn off the check engine light. I have never seen one do the things I saw the CEL in the Deville do, so that got me thinking that perhaps it might be wiring issues and not the actual sensor?

Is the off and on of the check engine light during driving normal for a failing hall effect sensor in these engines or a sign of something else?

I have a new AC DElco hall effect sensor arriving to me by the end of the week and plan on replacing it this weekend along with new plugs, wires, coil,rotor and dist. cap

Also when replacing it I read in this forum, that you don't need to remove the dist. to get the sensor off, you simply use as offset 1/4 wrench. How long does this actually take to remove doing this? I went out and bought a couple of Sears Craftsman offset 1/4 ratchet wrenches. One will be kept in original condition to use on 1/4 bolts. The other wrench will be cut down so as to be used to remove the sensor(the wrenches were on sale for $5 each this past week). Anybody use a ratchet wrench?

Thanks in advance for your help
 

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1991 Cadillac Sedan deVille
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591 Posts
It takes about a couple of minutes to replace it that way, but is tricky. Before you attempt to remove it make sure the rotor blade is nowhere near the sensor as that will make the R&R more complicated (you don't want to break the sensor). If the blade is close to the hall-effect switch and won't give you enough clearance just crank the engine slightly to move it out of the way. You already purchased the new sensor, but since you're suspecting a wiring issue (very likely given your description) inspect the wires and clean the contacts if needed. Also, right behind the wiring harness there's a plastic piece on the distributor base - remove it (slides up) and it'll make it easier for your camshaft sensor R&R.

Hopefully this and the tuneup you're about to do solves your drivability issue. Good luck!
 

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1995 Deville
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38 Posts
Discussion Starter #3
Hello

Thanks for your reply. I am trying to get all my "ducks in a row" when I replace the sensor as i have read and seen the brittle condition of the under dist cap wires. The 2 4.9l cars in the junk yard both had connectors that were cracked and exposing the terminal connectors. If mine are like that then I plan to carefully add some electrical tape(3m super 33) in order to protect the terminal connectors from touching each other.

I read a post here on this forum that the poster mentioned that the plastic connector cracked and one of the terminal connectors worked its way loose and caused the PO41 code and he fixed it by simply reconnecting it(I am hoping for this scenario as the sensor would still be good and I could put the new one away to use later(less work) )

Thanks again for your help
 

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1992 Fleetwood S&S Hearse, 1993 Buick Roadmaster
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567 Posts
I'm having symptoms that sound identical to yours, except I don't have a check engine light on. Please keep us updated on your efforts and your results. If you can take any pictures of the wire connectors or any work you'd do, I'd personally love to see them.
 

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1991 Cadillac Sedan deVille
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591 Posts
I just thought of a suggestion. While you're in there, disconnect the distributor harness (6 terminal, 5 wire connector) and check all the wires from the distributor to the harness for continuity, and for shorting to ground. Also, make sure the grounds in the distributor are clean and tight. I can imagine they would have some corrosion build up - disconnect them, wire brush them and tighten them down. Hopefully your issue is indeed in the wiring!
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
When I had that code it was the sensor. It drove fine but once it was well warmed up it would stall and wouldn't restart until it was cooled down for a while. For a while before that it was also pinging at times, probably from the failing switch causing timing problems.
 

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1992 Fleetwood S&S Hearse, 1993 Buick Roadmaster
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567 Posts
I took mine apart last night, and one of the connectors was loose. Took the insulator apart and hooked the wires up individually. I still have a problem. So I ask a question to those more knowledgeable than me - should I take it apart and wrap the wire connectors? Could I have electricity jumping that large of a distance, causing them to interfere with each other? It's a few mm's max, so I guess it's possible.
 

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1992 DeVille, 2013 ATS 3.6
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2,366 Posts
Wouldn't surprise me. I mean dist cap contacts arc and look at how far apart they are
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
It needs to touch or be close enough to look like they could be make it 'jump'.
 

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1995 Deville
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38 Posts
Discussion Starter #10
Hello again folks,

Sorry for the delay in responding as I just now(today) got around to finishing up everything. As I had several non car things to do and have another car(99 Firebird) to use if I needed to get around and had not put the Deville back together.

I did this in 3 stages this weekend. On Friday afternoon I took care the hall effect sensor. It was a much easier job then I had envisioned. My thought to cut down a cheapy Craftsman 1/4 ratchet wrench failed as those are tough wrenches and it broke my hacksaw blade. It would not work at its size so I ended up using a small regular wrench going quarter turns. the wiring was intact and I ended up only breaking the little clip that keeps the connector from coming loose from the sensor(which is not really needed as those connectors hold onto that sensor tightly. With my issue it seems that the sensor was bad as it looks like it has a bit of rust on the metal prong that faces the little circiut board. I am not sure how that was caused as the rest of the sensor and the dist. internals looked clean and shiny.

I also replaced the Ign. Control Module. I put it back together and it ran without the check wallet light coming back on.

Saturday morning I replaced the dist. cap(I was going to replace it when I was changing out the hall effect sensor but the auto parts store had given me the wrong cap and I did not check it till I got it home) I remarked all the wires with markers to make sure they went back on the cap and removed the old cap. The night before I took the new cap, new coil, new metal ground strap(this dist cap came with a new one) and a coil cap/cover I got from the pick pull junk yard near me and built up the new cap so I did not have to switch anything over to install it. I also replaced the PCV valve.

Car started up and ran better but still had a slight hesitation.

Sunday(today) was the pain in the back end day with this car but it also was a day in which I was even more impressed with the car I went to replace the plugs and wires and discovered that the plugs and wires look to be the original ones that came on the car. The wires are have the cylinder number on them(which is a factory thing) and the plugs have 902 on the plugs (the replacement plugs have 41-902 on the plugs) so these plugs and wires are over 20 years old and have 112,000+ miles on them and yet the car still starts on the first crank and other then the hesitation when pulling away from a stop it runs very well driving.

Finding that out was the highlight of my day changing the plugs. I lost a lot of blood and sweat but all in all with the exception of plugs 1, 3 and 8, it was not really that bad. Plugs 1 and 3 required me to unbolt the top two bolts from the power steering pump in order to get the plug wires out and then in which I could not get lined up to put the bolts back in without a lot of swearing and pulling with a pry bar(not to self: next time just loosen the bolts a few turns). Plug 8 had that god awful harness and sensor in the way.

I did however wind up damaging the air conditioner box. It was already cracking but while changing the rear plugs I wound knocking huge chunks of plastic off so it now shows the yellow foam. I will probably use that aluminum ducting tape as a fix. Pulling an engine to replace it with a NOS cover is a no go.

Thanks again for the help and assistance in this post
 

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70 Deville 77 Fleet 78 Seville 92 Deville 03 Deville
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3,310 Posts
That's a big bummer about the heater box. My Park Ave did that and it lets in hot air in the summer and cold air in the winter. It really cuts down on the enjoyment in extreme weather. I hope your climate is somewhat moderate. I didn't have any luck getting any kind of tape to stick to it. I was thinking about using some Baer Bond like they use on stock cars but I retired it instead. My 92 Deville had the original plug wires until it got hit and runned at 192k miles and it was still running as smooth as silk.
 

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94 Cadillac Sedan Deville 4.9 V8
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2 Posts
I have that same code cane up on my 94 Cadillac Deville 4.9 V8 I replace the whole thing piece by piece. Me and my mechanic replace the distributor and the connectors to the Hall Effect Sensor and the Ignition Module got so bad they broke off and now I don't know and forgot where the wires go to my Hall Effect Sensor. I looked a every where on the net and I can't find a good diagram. I don't wanna take a wild guess and just plug it in to see if it runs..I been on this for days. Does any have a diagram wiring for the Hall Effect Sensor?
 

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1992 DeVille, 2013 ATS 3.6
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2,366 Posts
Twiin317 said:
I have that same code cane up on my 94 Cadillac Deville 4.9 V8 I replace the whole thing piece by piece. Me and my mechanic replace the distributor and the connectors to the Hall Effect Sensor and the Ignition Module got so bad they broke off and now I don't know and forgot where the wires go to my Hall Effect Sensor. I looked a every where on the net and I can't find a good diagram. I don't wanna take a wild guess and just plug it in to see if it runs..I been on this for days. Does any have a diagram wiring for the Hall Effect Sensor?
Photo credit to cadillac edd:



From a 91-93 4.9. Don't remember edds specific year
 

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1995 Deville
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38 Posts
Discussion Starter #14
Ah yes, I remember this thread. Replacing that part was a real bear. The pic that dchavezo posted should also be the same as the 94-95 4.9l. My connector got a brittle and broke apart and I ended up just getting rid of the remains of the connector and wrapping a piece of 3M Super 33 electrical tape(the stuff used for cold and hot environments) around each wire terminal and then plugging it in to the sensor.

Buy the GM sensor as I found the aftermarket one from advance auto had the tangs that the connector mounts on, to close together.
 

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94 Deville
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2 Posts
I am also getting the P041 code now, is the Hall Effect Switch the same as the cam sensor? I replaced the ICM and Distributor pickup coil 3 years ago.
 

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2003 Deville Base
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5,312 Posts
I am also getting the P041 code now, is the Hall Effect Switch the same as the cam sensor? I replaced the ICM and Distributor pickup coil 3 years ago.
you realize that this thread is over three years old and the OP hasn't logged in since December of 2015?
 

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1991 Cadillac Sedan DeVille, 1993 Cadillac Sedan DeVille Special Edition
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260 Posts
you realize that this thread is over three years old and the OP hasn't logged in since December of 2015?
He replaced the pickup coil and ICM 3 years ago, the thread is 3 years old... Could be OP after he forgot his password!
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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He replaced the pickup coil and ICM 3 years ago, the thread is 3 years old... Could be OP after he forgot his password!
Different members from different parts of the country. MrRol had his site view preferences set to "View oldest posts/threads first" so he saw the old stuff before any later updates.

MrRol, Yes, the "switch" is a Hall effect trigger. A bump or tang or teeth on the distributor shaft induces a signal each time it passes the magnet/coil on the sensor.
 

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94 Deville
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Thanks for the information. I am not the original op, and have had this car for over 15 years, and never really had any problems with it. I do frequent this site for simple answers, so I don't always login. I ordered a new ICM and Hall effect sensor and it will be here on Monday, so hopefully it solves my problem. Thanks again.
 
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