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code 41, alternator junk?

4K views 15 replies 5 participants last post by  BeeZnutZ1979 
#1 ·
After spilling a small amount of what I guess was brown Freon oil onto the top of the alternator now I have a check engine light on for a code 41, also have a code 21 but I guess that's for an o2 sensor, the alternator appears to be a recently remanufactured unit but I'm guessing this thing is toasted, cars been running in the 13-14 volts range prior to this and now its stuck around 11.5, any suggestions or should I just pick up a new unit at the parts store? and should I get a 90 amp one or the 120 amp one or doesn't it matter? thanks Brandon.
 
#4 ·
thanks NAJ, I know how to run a voltmeter just didn't know what to do with it as far as diagnosis goes besides checking voltage, this will help me figure it out, where is this information from? also if it turns out to be the alternator do you know if I should get a 120 amp or a 90 amp and if it turns out to be the ecu I think I'll just swap it out for a calibrated ecu. hopefully it's just a broke wire or fusable link, thanks Brandon
 
#5 ·
Info is from the Factory Service Manual 1990 Charging and Speed Control Diagnostics.
Most FSM's are available used on eBay but considering that you need...
1)Engine/Chassis/Body
2)Electrical/Fuel/Emissions
3)Wiring Diagrams
4)Powertrain Diagnostics
5)Body Control Diagnostics
6)Charging and Speed Control
7)SRS Systems

You can try to find all of those manuals at a decent price or buy a one year subscription to Alldata.DIY for $30.00 which will give you all of that info and more.
At the end of the one year you can renew the subscription for $17.00.
I have had all of the FSM's for my car since 1990(there was a card in the glove box to get them from Chrysler) but I have Alldata for my Daughters 2005 Saturn Vue and my Sisters 98 Acura CL 3.0.
My Son has Alldata for their 2003 Grand Caravan and his 1994 Plymouth Sundance.

https://www.alldatadiy.com/

The 90 Daytona came with both a 90 amp and a 120 amp alternator, neither the FSM or the Chrysler Parts Catalog specifies which cars came with what.
The alternators are the same other than the amperage output, they are both Denso's with 4 groove pulleys.
The alternator output is only going to be what the controller allows so if you are planning on adding anything that may increase electrical load then go for the 120.
 
#6 ·
I randomly get a check engine light and code 41,but charging voltage is always around 14 VDC. The check engine light will only come on during initial cold start for the day, and even if I shut car off right away and re-start, it won't come back on, but code 41 is stored. About once a month I will get the check engine light.

As far as which alternator you should get, personally Id say get the 120 regardless. You can't have too much amp for an alternator as it will only output what the electrical load demands. It's better to have one that can put out more than you will ever need and leave you room to add more electrical load in future.
 
#7 ·
I randomly get a check engine light and code 41,but charging voltage is always around 14 VDC. The check engine light will only come on during initial cold start for the day, and even if I shut car off right away and re-start, it won't come back on, but code 41 is stored. About once a month I will get the check engine light.
If this is an ND alternator your issue is worn brushes which are replaceable.
Common problem, mine started at about 100,000 miles and did exactly what your car is doing and then one day the CEL came on a stayed on.
Remove the tin cover on the rear of the alternator and examine the brush holder and you will see that the brushes are worn and barely making contact with the commutator.
You can buy the brush holder on eBay for about $10.00.
I now keep a spare at home.

 
#9 ·
NAJ is it correct to do this testing with the key in the on position? I tried it first with the car running and got numbers that were all over the place, then I tried it with the key in the on position, and if that's correct by the schematic I need to replace the ecu, I had correct battery voltage at both DB and DG and the same voltage on the number 20 pin connector on the ecu harness with the key on, at one point with the car running today I recorded voltage readings of 18-19 volts at the battery for a short period of time and then it dropped down to 11-12 volts, not the news I wanted to hear but do you recommend I get another stock ecu or would this be a good time to send it off to fwdperformance and get a calibrated ecu? I know im not ready for increased boost yet but do they go through the ecu and make sure they function properly? If I get one from a scrap yard there is a possibility it will have issues as well, also now the car will barely move under its own power and when you rev it up it sounds like its sucking air realy bad which it has never done, thanks Brandon.
 
#12 ·
1)NAJ is it correct to do this testing with the key in the on position? I tried it first with the car running and got numbers that were all over the place, then I tried it with the key in the on position, and if that's correct by the schematic I need to replace the ecu, I had correct battery voltage at both DB and DG and the same voltage on the number 20 pin connector on the ecu harness with the key on, at one point with the car running today I recorded voltage readings of 18-19 volts at the battery for a short period of time and then it dropped down to 11-12 volts.

2)Also now the car will barely move under its own power and when you rev it up it sounds like its sucking air really bad which it has never done
1)Key On Engine Off.
I also agree, have the alternator tested before replacing the ECM.

2)Sounds like this problem should take precedence over #1.
Vacuum Leak, Cam Timing or Exhaust Restriction
 
#13 ·
Took the alternator to the local carquest and unit tested bad, replaced the bad 90 amp unit with a remanufactured 120 amp model, after I got the alternator installed the car is back to charging at the appropriate level, I'm thinking the cam timing must be off on the car by the way it's running, also very possibly has a vacuum leak as all the original vacuum connectors are dry rotted. took the car for a 20 minute cruise around and seems to have a miss in upper rpm ranges and quite abit of hesitation, when I got home I put the timing light on it and unplugged the coolant temp sensor and was unable to see a timing mark through the slot in the tranny, should I take the airbox off to get a more vertical position with the timing light? anyways, next step is going over the timing and redoing the vacuum lines, Thanks Brandon
 
#14 ·
Glad to hear the charging system issue has been corrected. :thumb:

Before verifying ignition timing is correct be sure cam timing is correct.

If the original plastic vacuum harness is still on the vehicle and dry rotted it is probably time to install a vacuum block with thick walled rubber hose or poly tubing.

CHECKING CAM AND IGNITION TIMING.
http://www.turbododge.com/forums/f4/f14/359212-cam-timing-belt-tension-84-95-a.html

INSTALLING A VACUUM BLOCK
http://www.turbododge.com/forums/f4/f14/363281-installing-vacuum-blocks-84-93-turbo.html

 
#15 ·
Sounds like some good insurance Dr. Johnny, any more info, part numbers of pics about that install? also about the vacuum lines anyone know what sizes are used? I got to return my core alternator and was going to pick up some new lines and try to replace them until I can get a vacuum block ordered, unless someone knows anything that can be had at a local parts/hardware store that would suffice, thanks Brandon.
 
#16 ·
So I dug into the timing belt on this old Daytona and found that the intermediate shaft was one tooth off, after further inspection I found a rip in the timing belt about half way across in one section, slapped a new belt on it and set the timing to 12* and the car is purring like a kitten.
 
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