1989 Sword w/ 3.8L "C" engine give OBD1 code 41 for camshift position sensor...

I just finished w/several other issues...EGR valve...cleaning the throttle body area, rewiring the EGR, IAC...etc along with plugs & wire-set...O2 sensor...MAP sensor...

so the last issue is the CPS...

I am getting 'engine knock' as some describe it since doing these engine system changes, cleaning & repairs. I got a few replacement CPS @the bone yard but not change in the 'engine knock'....so I am going to check the port & electrical circuit to it as well.

Anyone have any experience with these issues....?

I haven't yet removed the 'knock sensor' or inspected it...just found it (I think)...to the left of the CPS & under the power steering pump...I'll have to 'explore around that area while checking the electrical circuit & port of the the CPS...

Your thoughts & experience would be appreciated...

 

A code 41 is related to the cam sensor signal. As you already know it is located under the water pump area.
Something to keep in mind, where the older engines used a remotely mounted ESC (electronic spark control) the "C" engine has the ESC located in the Mem-Cal chip in the ECM. Check that it fully installed in place.
A few quick questions that might help, Did you check for voltage available to the EGR Valve? There is a 15 amp fuse that supplies the EGR Valve solenoids. If the EGR system isn't working you could get some spark knock there. A quick way to check would be to have the engine idling and ground each solenoid of the EGR valve and you should see some difference in engine speed. Actually when you ground the solenoid with the largest hole the engine may even stall.
If you tap on the engine lift hook or the side of the block you should see a reduction in timing if you have a light to see that. That's one way to check the knock sensor. Let us know how you make out.

 

Thanks a lot for your insight & suggestions.... I didn't have any idea about your suggestions...only a few from Haynes' manual.

Ok...double checked the VIN...yes it's the 'C' 3800 engine (no twin port) so were talking about the proper OBD1 codes (41) for my 1989 'sword'...

The Haynes manual mentions something about checking to ensure that the 'magnet' is still attached to the camshaft as well port connector & circuit to the ECM.

After re-checking the Haynes' OBD1 codes...I see the mention of the Mem-Cal chip or ECM problem....so how would you advise to check this out...?

The EGR valve was replaced w/a bone-yard since the original 'appeared to have been faulty'...some time ago...BUT I have not done any multimeter analysis...I am a little weak on that topic...How would I check the voltage to each solenoid...?

Prior to the plugs & spark wire set change...I have two OBD1 codes..41 & 13...w/out the 'knock sounds'...

After the plugs & wire set change...I still had the two OBD1 codes but w/the 'new' engine 'knock'...then I changed the Oxygen sensor...Power picked up nicely but the engine 'knock' was still there.

I replace the CPS w/a bone-yard version but the OBD1 code (41) & engine 'knock' are still there...the idle is now rather ruff...

I'll try to figure out your suggestion but I don't know what to check in the
ECM...? I hope (don't think) that the the camshaft magnet has dropped out of position or the original CPS is defective...I think it's in the circuit (wire or port) OR as you mention...w/the ECM

I'll check Haynes' for any assistance in the 'works' of the ECM...

Thanks again for your sincere help...I'm very grateful...

 

chip....Now I really think that is the issue....

I just missed that on the OBD1 codes & went for the CPS mentioned code...

Rather than continue to trouble shoot the CPS...I'll head to the bone-yard tomorrow for replacement PCM Prom's (Mem-Cal's)...I'll be very careful w/matching the same serial numbers (GM model, year, engine)...

I'll also check the fuse box for the EGR as Hanky mentioned...thanks again...

More later

 

Thanks for the update. Will check back later.

 

Hello Hanky:

It's been a while but I found many bone yard ECM's & recorded the serial numbers & lots...OK I used one as a test...everything worked fine as a starter...but didn't make any changes in the OBD1 code 41...

Bottom line...I'm still getting an engine knock...about half the volume prior to giving a update to oil filter, fluids & commercial engine solutions...!

I was asked about checking the oil engine PSI....which I'll do soon.

It appears to have the engine knock while @ idle (seems to idle nicely) but will immediately disappears when applying accelerator peddle pressure. The accelerator power is better w/new plugs, wires, O2 sensor...carbon cleaning of throttle body (intake & EGR areas).

I just don't think it's the cam or knock sensor but that's what my Haynes repair manual has printed.... I somewhat dread the idea of pulling the H20 pump & etc. to check the cam sensor magnet....

Before that...I'll check the oil PSI & cylinder PSI as well...

 

Hi...did you ever get this resolved? I have a similar issue with a Reatta 3800 C...but knocks only when hot on mild acceleration...sometimes..sometimes not....and with a 15 minute rest can disappear, but not always. I changed the EGR because I thought the large valve was never opening (not clean around the edges like the smaller ones), but after a long tollway ride realized that the problem is still there. The chip idea in the ECM is intriguing.

 

Yes, I did find out the main issue(s)....
I replace the CPS twice...no change....

After many more checks w/oil pressure, filters changed
and examined... it appears that the bearing were now out
of tolerance....!!!

I could have pulled the engine and done the rebuild but w/the milage
and age of the body....I didn't want to put the "time" and limited $Parts
for an/a near equity swap...

The old Sword's body just wasn't going to support many more years of
service...(undercoating rust....)...

So I when Iron/steel prices were high...I salvaged the Sword for $300.
That's about what is would have cost me to do the rebuild...less my time...

Hope this helps...

 

I originally suspected the front rod or front main bearing as the car sat for 3 years and apparently was started without just spinning it first to get the oil pressure up. ..the front of that engine gets the oil last as you may know...and I recently noticed the oil pressure falling a bit when it gets hot. I might put in an original size set of #1 front rod bearings since the oil level switch is not working either and both can be done by pulling the pan and see if it make a difference and will be able to inspect the front race at that time also. ....it is the intermittance of the knock that keeps me looking for other reasons...a sensor or a chip.

Sorry you lost the Sword.

Thanks.