Some of you might be following my issue with an overcharging alternator Vs Voltage Regulator issues.

I have had my alternator tested on two different dates and both times it indicated it was over charging but the problem comes and goes.

After trying various troubleshooting techniques that have been suggested here on the forum, I have decided the only way to properly test the Alternator to determine if its the Alternator or Voltage regulator is to remove the Alternator and have it bench tested.

My logic behind this is simple. If the Alternator is bench tested, it takes the Voltage Regulator ( Which is built in the PCM) out of the circuit. Therefore if its a bad alternator causing my problem it will be isolated and show up during a bench test.

If the alternator tests good, then its definitely the PCM built in Voltage regulator.

I think things were a lot simpler back when we had firewall mounted voltage regulators.

Jason

 

Well, There are ways to bypass the PCM's voltage regulator.

http://www.alternatorparts.com/Dodge...tor_wiring.htm

There are reports that this keeps the check engine light lit forever after.
There are also some reports that it does not.

 

Yes, thank you, I did read about this on a couple of web sites and pages. Most I have read say the check engine light will stay on after the conversion but I am still investigating.

I also read that the problems with these PCM's going bad is that for a period of several years, there were some bad capacitors sold. Over time the capacitors fail and some even explode. The chemical inside them is caustic and can even ruin either a chip or the main board inside the PCM. This makes perfect sense to me because of a similar problems that happened with Computer Motherboards in the PC industry. Why there was never a Recall by Chrysler and other manufacturers is beyond me. I know many regular PC motherboard manufacturers like MSI stepped in and took care of this issue in the computer world.

It would be interesting to note if the newer cars produced after 04 have as many significant PCM problems and compare them to the years between 99-04.

As far as mounting an external voltage regulator to solve my issues goes, I might consider doing that just for testing purposes.

During my reading and research I discovered there is also a temp sensor in the battery tray that influences the voltage regulator based on the temp of the battery. It is supposed to help the voltage regulator tell the alternator if it should output more or less of a charge. I will be changing this also, just to be safe. I have to look for it and if I find it I will try to post a picture or link to this sensor.

My biggest concern about by passing the PCM with an external regulator is what other circuits other than the check engine light would be effected by the voltage regulator.

If anyone in the forum has used an external voltage regulator on their Dodge Ram Van 99 or newer I would appreciate their comments in regard to this.

Jason

 

Just for FYI:

Here is a thread about an external regulator conversion and the problems associated with it. Although its not a Dodge Ram Van the principal should be the same.

https://dodgeforum.com/forum/2nd-gen...onversion.html

Here is another link about ECM/PCM failure due to using inferior components.

The post is here from a repair center:

http://www.ecmtogo.com/ECMTips2.htm


The fact is, the models of ECMs and TCUs manufactured within the years of 1985-1999 utilize certain electrolytic capacitors that after a certain number of hours or mileage, begin a systematic breakdown. These capacitors eventually break their seal and leak the electrolyte which is a corrosive substance. This corrosive substance actually destroys the area of the mother board computer chip and any adjacent components will be adversely affected. So the longer one waits to repair the unit, the lesser a chance there is of reparability. Most units are repairable unless there is damage to a part that is not made available to us. Presently, their are specific components that are damaged occasionally that we can not purchase. We are the first company to specialize in this field and we have the best technicians in the business. The hardest component to acquire is the processor chips. The processor chips are imbedded chips or IC chips that contain vital information which is copy written and is likely not to be able to access. In most cases when the IC chip or chips are damaged, they will experience a heat to the imbedded chip which will damage the chip and often a heated IC will have a variance on the smooth surface of the chip from the heat. The variance may be in the form of a bubble or rise or in some cases a hole or crack is blown though. In these cases, we will likely recommend to replace the ECM. When this occurs, you will be informed of the change in the price quote and upon permission, we will attempt to acquire a replacment ECM for the additional cost. The warranty will not be affected.

 

Yesterday was pretty interesting. Pulled the battery box and removed the Temp sensor and it appears to be in spec. I might replace it anyway, but I will decide after I finished my trouble shooting process.

I also pulled the Alternator and then took it to one Auto parts stores in my area to be checked. Even though the two guys working in the store claimed they knew and were comfortable running their computerized Alternator testing machine, it appeared to me they were both pretty clueless. They ran the test but the alternator tested bad. My problem was that since it appeared that neither one of the workers was competent, I decided to have it tested again at three other stores that were open that day. All of the other three including one from the first chain tested the alternator as good. Problem was they could only see volts and not amps. While volts tested good, I new that I needed to know amps as well.

Today I decided before ruling out the Alternator and settling on the PCM as the problem, I will take the Alternator to the local electric shop where the guy actually specializes in rebuilding alternators, starters, and trouble shooting electrical problems in vehicles. I asked him to test my alternator for volts and amps and he said he needed about 45mins. I also mentioned to him that I had it tested yesterday at the local auto parts store but I did not really trust the results and they could not tell me output amps. He said that the auto parts stores were really not able to test my alternator properly and he would test it.

I told him I felt my issue was between the Alternator and voltage regulator in my PCM. I did mention that the PCM was flagging the IAC bad code even though I had just replaced it. He said he doubted it was my PCM but would tell me after he tested my alternator.

I got a call about 45 mins later as promised. I was told that my alternator appeared to be the original that was on the Van and it appeared to be tired and possibly have intermittent problems.

Since this fit with the issues I had been experiencing, I told him to go ahead and rebuilt the alternator. He charges $125 for that service and it includes testing it again after I put it back on the Van and its included in the price. I think that is a pretty good deal since the parts stores are charging more and he will also check it once on the vehicle.

I was told it would be ready by tomorrow for pickup. If this does not work, at least I will have someone else trouble shooting just in case the PCM is bad. I have my fingers crossed.

Jason

 

Good diagnostics.

Having your Alternator professionally rebuilt locally for 130$ is way better than spending 120 for an overseas Reman'd one of questionable quality available at the autoparts stores.

Hope it works for you, and it is not the PCM.

 

Picked up the alternator today and put everything back together. Van started up but would not stay running. So after a couple of tries I kept it running by slightly depressing the gas pedal. After letting the engine get warm, the van kept running by itself. I figure it took it a few mins to clear or re-learn the codes. All the warning lets were gone so I sat there and let it idle for a few mins and watched for any issues. All of a sudden the lights got brighter again and the check gauges light came on so I believe I diagnosed it right the first time and the Voltage Regulator in the PCM is bad so the PCM needs to be rebuilt or replaced.

Since the electric shop said he includes his trouble shooting with the price of rebuilding the alternator for the $125 he charged, I am going to take it to him and see if he confirms what I have concluded.

As far as my alternator rebuild is concerned. I do not feel like I wasted money doing that. My alternator was the original and has not been rebuilt or replaced since 1999 so it was probably time.

Next update will be posted after the electric shops diagnoses.

Jason

 

Well the electric shop is still diagnosing the Van. Since I put on the alternator he rebuild and drove it down there he has had it two days and says he pulled the schematic and is testing every single wire that come to the PCM to make sure it is receiving the proper single it should.

I am glad this trouble shooting he is doing was included in the price of rebuilding the alternator.

I am waiting to see if he finds something else, but I really think he is going to find its the Voltage Regulator in the PCM.

Time will tell.

Jason

 

Ok the electric shop guy calls me up today about 4:45 and tells me so far he cannot find anything but now thinks it's the PCM. LOL I think that is what I told him to begin with. Thank God this did not cost me money.

Anyway then he asks me if I can leave it until monday. I told him to just plug in the three molex plugs to the PCM and then leave it locked up outside. He did not want me to drive it the 14 miles home with the alternator plugged in because he was concerned that I might burn up something. I told him to just plug everything back in and I would pick up the van. If some of these guys would just listen to their customers and not assume they are the only ones that know anything, I think they might be more successful.

Monday I am going to send my PCM for rebuild. I should have it back in a few days.

Thanks for reading,

Jason

 

Depends on the mechanic and the customer. As an electrician I all too often get calls for things not working that I have to troubleshoot. I will listen to everything the customer tells me as far as symptoms go, then I start with the troubleshooting because that's MY job. After that point if a customer tells me what the problem is or how to solve it, I always reply with, "if you know what the problem is, then why am I here?" They usually get the hint and leave me alone. Shortly thereafter I find the problem, fix it, and off I go.