Check engine light

[Jrs3800]

Chris I think you need to check and see if that Cam is walking in and out... if the cam is walking out the interrupter can impact the cam sensor

[1oldman]

Jrs3800 wrote:
Chris I think you need to check and see if that Cam is walking in and out... if the cam is walking out the interrupter can impact the cam sensor
-----------------------------------------------------------------------------------------------
What would cause the cam to walk ( wear & ?? ) and how would you check to see if the cam was walking? - BC

[Chris D.]

if the camshaft is walking, there's nothing more I can you do it other than a complete rebuild..

can't really do anything other than spacing the sensor out a few mm's..

so with a code 41, I replaced everything involved with a code 41..
unless I got a bad outer can sensor

[Jrs3800]

There is a Button on the cam with a spring, you can call it the cam thrust spring/washer... I believe in 89 the button would wear the timing cover and allow the cam to walk a little.. If the cam walks then the interrupter can walk out and impact the cam sensor... iirc in 1990 they went to a Button that had a bearing in it, this allowed the cam and spring to move or spin and not wear out the timing cover thrust surface... for 1991 the Vin C was nothing more than an L27 Block with LN3 heads, this was also the first year for the block to have a cam thrust plate attached to the block and cam to keep the cam from walking at all...

I can't say for sure this is your problem but it may likely be the case..

[Chris D.]

Here's what I did today..

Removed the new Autozone camshaft position sensor, replaced it with the original one..
I saw no contact marks on the camshaft sensor.. (used a little grease on the magnet)

no change..

then I left the sensor unplugged, fired it up..

no change..

The new camshaft interrupter magnet is still intact and exactly where it needs to be..

ran codes, when I jumped the pins, this time I noticed the fan came on, I don't remember it doing that before.. relevant?

Codes still 12 and 41 still present..
Cleared codes with battery disconnect.

p.s. The old interrupter had hardly ANY magnetism left in it.. very very weak..
I read on a random forum from a search for "Buick code 41" and a few places mentioned
the possibility of it being a faulty wire from/to the ECM harness possibly?..

heres what it said..

Check For
Poor connection or a damaged harness - Inspect ECM harness connectors for backed out terminal "BC5,"
improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.
Intermittent test - If connections and harness check OK, monitor a digital voltmeter connected from ECM terminal "BC5" to ground while
moving related connectors and wiring harness. If the failure is induced, the voltage reading will change. This may help to isolate the location of the malfunction.

BC5?

Has anyone had this issue? could this be the cause?

Thanks guys..

[Jrs3800]

Ok, you are on a good track..

Yes it is possible to have a bad wire to the ICM or the ECM.. iirc all of the pulses from the cam and crank sensors are routed through the ICM..

[Chris D.]

In my experiences, I seem to always have more than one thing happen to any engine at the exact same time..
and 9 times out of 10, its usually something super simple or dumb.. lol

[myfirstbonnie]

Ok, you are on a good track..

Yes it is possible to have a bad wire to the ICM or the ECM.. iirc all of the pulses from the cam and crank sensors are routed through the ICM..

Yes, they go to the ICM first. Your memory isn't that bad yet, Don.

[1oldman]

[[Check For
Poor connection or a damaged harness - Inspect ECM harness connectors for backed out terminal "BC5,"
improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.
Intermittent test - If connections and harness check OK, monitor a digital voltmeter connected from ECM terminal "BC5" to ground while
moving related connectors and wiring harness. If the failure is induced, the voltage reading will change. This may help to isolate the location of the malfunction.]]

Chris, I think some of the fancier scan code readers can read that signal going into the PCM(?), but I don't know if it's possible on your car. Maybe Jrs3800, willwren, 00Beast or someone more knowledgeable could tell you. If I remember right, the fancier code scanners can read that signal on my '92. If it can and you can find one to use, it will save you a lot of work. - BC

[Chris D.]

[[Check For
Poor connection or a damaged harness - Inspect ECM harness connectors for backed out terminal "BC5,"
improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.
Intermittent test - If connections and harness check OK, monitor a digital voltmeter connected from ECM terminal "BC5" to ground while
moving related connectors and wiring harness. If the failure is induced, the voltage reading will change. This may help to isolate the location of the malfunction.]]

Chris, I think some of the fancier scan code readers can read that signal going into the PCM(?), but I don't know if it's possible on your car. Maybe Jrs3800, willwren, 00Beast or someone more knowledgeable could tell you. If I remember right, the fancier code scanners can read that signal on my '92. If it can and you can find one to use, it will save you a lot of work. - BC

Where is BC5 located? Is this on the icm?

[myfirstbonnie]

Thr first thing to check would be the wiring harness from the CPS and cam sensor that goes to the ICM connector. This is the harness that runs down the front of the engine behind the waterpump to radiator hose.

[Chris D.]

Is it normal for the car to even run with the cam sensor unplugged?

[Jrs3800]

Yes the car will run with the cam sensor unplugged.. Might not run very good but it will run... The cam sensor is strictly for the ECM to see #1 TDC... The ECM then makes the SFI calculations...

For everyone... I know all the Books say MFI .... All 3800 engine made are all SFI regardless of what the Book says...

So the Cam sensor is used so that the engine can run in true SFI mode.. If the cam sensor / circuirt is having issues the engine will still run but injector timing will be off causing a drop in MPG's and performance..

[Chris D.]

update....

ICM/coil issues?

video..

http://www.youtube.com/watch?v=n1pebrphSoY

I'm going to grab a newer delco ICM soon and do the upgrade/swap..

[Chris D.]

Yes the car will run with the cam sensor unplugged.. Might not run very good but it will run... The cam sensor is strictly for the ECM to see #1 TDC... The ECM then makes the SFI calculations...

For everyone... I know all the Books say MFI .... All 3800 engine made are all SFI regardless of what the Book says...

So the Cam sensor is used so that the engine can run in true SFI mode.. If the cam sensor / circuirt is having issues the engine will still run but injector timing will be off causing a drop in MPG's and performance..

I'm not exactly sure what SFI/MFI means.. sounds familiar, but I'm not quite there with it lol

[Jrs3800]

That sounds like some of your problem... More than most of the time it is cheaper to update to the Delco Type 2 system then it is to replace the coil pack..

[Chris D.]

after some searching on here with no luck, whats a year range/models for the good Delco setup?

found a 97 LeSabre that had a crapped out transmission being parted out..

[Jrs3800]

http://www.pontiacbonnevilleclub.com/fo ... =44&t=1684

[00Beast]

The ICM and coils from the LeSabre should work, but you'll need the older bracket, from what I can tell. If you can find a supercharged car with blue tabs on the bottom of the coils (any S2 S/C), they have the best spark of any 3800 coil.

[Chris D.]

The ICM and coils from the LeSabre should work, but you'll need the older bracket, from what I can tell. If you can find a supercharged car with blue tabs on the bottom of the coils (any S2 S/C), they have the best spark of any 3800 coil.

Dont I already have the old bracket?

S2?

Is it likely the icm is causing the code 41?