DIY: Roadster 2.5 PEM cleaning - step by step

[Mark77a]

Although I was joking when I said "Blockage = Crap / Area" ...

There is truth in this. If the surface AREA of the filter is too small (ie ie same or similar Area to the cross section area of the air flow, then air flow will be restricted.

This may cause problems:
A) Lower amount of cooling air reaching motor and PEM !!
and
B) Higher current draw from the fan motors - which is bad for the connectors into the PEM, which are known to have marginal current capacity.

 

[Marius]

As far as I understand electric motors like this one, your statement is not correct. In case of not sufficient airflow the motor takes less current and you get an alarm dc fan problem 1146 meaning low amperage to motor. This is a kind of pre warning which tells you airflow is not sufficient, and if this is not solved eventually the PEM gets overheated. Because of bad contacts in connectors you can get reduction of amperage as well which brings the same notification 1146 active.

 

[Mark77a]

So restricted airflow is good ? ;-)

 

[hcsharp]

As far as I understand electric motors like this one, your statement is not correct. In case of not sufficient airflow the motor takes less current and you get an alarm dc fan problem 1146 meaning low amperage to motor. This is a kind of pre warning which tells you airflow is not sufficient, and if this is not solved eventually the PEM gets overheated. Because of bad contacts in connectors you can get reduction of amperage as well which brings the same notification 1146 active.

So restricted airflow is good ? ;-)

Restricted air flow is not good but @Marius is correct that the motor actually draws less current if the fans are blocked. While motors generally draw more current when they have to work harder, if a fan is moving less air then it won't be working as hard and will draw less current. This is especially noticeable with squirrel-cage fans.

 

[Mark77a]

True - However, when the fan has bits of twig and road debris in it, the current will go up
This is why I am a 'big fan' of large area filters before the air gets into the system.

 

[hallvardr]

While my PEM was out, I used the time to make filters for the fans.

Netting to stop the filters from getting into the fans

How much air they are letting through

Finished products. In theory I should be able to change the filters without removing the fans by opening 2 screws and replacing 4 zips. But It might be just as fast to just take it out.

 

[warden_clyffe]

This is my final solution. I get no error-messages at all, similar grid as hallvardr is using.

I have driven app. 800 km now with this filter, incl. light rain, high-speed an (ambitionned) curvy-roads - my PEM has never got into yellow temp-range (as before), same with motor.

Off course PEM was cleaned complete before and I renewed the IGBT- insulators...

 

[hcsharp]

This is my final solution. I get no error-messages at all, similar grid as hallvardr is using...

Nice work! Looks much more professional than the solution that I crafted.

 

[warden_clyffe]

as i have a supplier for those side-lids i'm recently working on a small series of those boxes - there's alittle change you have to do on the stabilizer-mounting, this needs a 7.5mm spacer (pics to follow), i'll make those as well either in alloy or corian

 

[Logticom]

Here is an update to this thread with my experience of cleaning the PEM.
I want to start of with thanking @m0rph and everyboy else contributing to this thread what really helped me doing a PEM clean myself.
I also had help from a car mechanic and someone with a lot of experience with pcb-boards.
My goal of this post is to share my experience with other Roadster owners and ask questions to other Roadster owners who do there own PEM cleaning and maintenance.

Insulation material
This project started out with wanting to take a look at the insulation material in the PEM. The insulation material looked pretty good in my opinion, but we could only see the sides, because we didn’t take the whole PEM apart. Material started crumbling a little bit on the sides (where you can see it, without taking it apart).

Doe anybody have an instruction how to take the PEM apart for replacing the insulation material?

PEM connecters
Taking the connecters of was no problem, but we had a problem putting the connecters back on (the 2 connecters on the right side when you are behind the car). There is only a little space to put them back on and after trying, trying and trying we put the PEM on the side so we could see better and use more force. Still didn’t work. We tried everything but we ended up removing the rubber in the female part of the connecters. After removing that rubber the connecters were easily put back on the PEM.

Did other owners also have problems with putting the connecter back on and had to remove the orange rubbers in the connecters? (see picture for the rubbers)

I am thinking about replacing the current female connecters and making an extra connecter behind the 2 connecters I am going to replace. This will make it easier and safer in the future to remove and clean the PEM.

PEM cleaning (see video)
We used an airgun to clean the PEM. Last Tesla service was about 2 years and 20.000 km ago. I dont think there really was a lot of dirt in the PEM. But I think it is wise to do a PEM clean every 2 years. Besides this, I have a snow dam installed and I think the snowdam helps with keeping dirt out.

Cleaning Motor (see video)
There was a lot of dirt in the motor. It looks like it was a long time ago the motor got cleaned. See video for all the dirt that was in there. I think I will have another look in a year or so or earlier if the motor temp goes up faster again.

Performance and temps after cleaning
After cleaning the PEM and motor I experience that it takes longer for the motor to heat up. But I think the PEM heats up faster. The temp of PEM goes up very fast to 56C when pushing the car hard. (I didn’t get it above 56C yet = last blue bar). I think that maybe now there goes more air to the motor, there is less air for the PEM? I am not sure but I will keep an eye on the temps.

Overall It feels like the car got a little bit more power / excelerating faster. But I am not sure. Maybe my brains just want me to believe so…

Videos
Cleaning PEM:

Cleaning Motor:

My experience
A PEM clean is not very difficult to do. You only need a couple of extra hands and a little bit of experience with nuts and bolts etc. The only problem I had was putting the connecters back on… My next job is to take apart and clean the rear blower.

My questions
1. Doe anybody have an instruction how to take the PEM apart for replacing the insulation material?
2. Did other owners also have problems with putting the connecters back on and had to remove the orange rubbers in the connecters? (see picture for the rubbers)

Please also respond if you have any other thoughts after reading my post
Thanks in advance.

 

[hcsharp]

Great post, thank you for this.

2. Did other owners also have problems with putting the connecters back on and had to remove the orange rubbers in the connecters?

Yes I had this problem this week! Funny thing it is not mentioned anywhere on TMC in the 8 years I have had my Roadster... until now with your post. It's also funny I have never had this problem before. Here's my theory: I sprayed DeoxIT D5 in both halves of the connectors to clean them. I think there is a solvent in DeoxIT that attacked the orange gasket and caused it to swell up. It's just a theory but I can't think of any better explanation.

I taped my connectors together because they wouldn't close all the way and latch (instead of removing the orange gasket). And now 3 days later it is a little better - one of them actually closed and latched. Perhaps the gasket has dried out and shrunk back closer to normal size?

I know my service center also cleans those connectors with DeoxIT as a preventative measure due to the known issue with the fan cable. I wonder if they have ever had this problem?

If you come up with part numbers for replacement connectors with more current capacity, please post them.

 

[Logticom]

@hcsharp Thanks for your response! I also cleaned my connecters with contact spray. The contact spray doing something to the rubbers / orange gasket is a good explantion I think. I ordered a few new connecters and will do a test on one of them to see if I have the same problem again.

I orderes connecters with the same current (I think). I will post if I find connecters with more current.

 

[warden_clyffe]

@ Logticom: When you blowcleaned the bottom you should have removed the little grey lid as well ( 4 philips-screws), this is the air-joint from PEM-outlet to the inverter - it's very often quite blocked underneath with insects / feathers / leafs etc...

 

[dhrivnak]

Rob came by four a double PEM cleaning party (party may be far too strong of a word). Anyway we got the PEMs and motors cleaned out. Far more debris in the 2.0 than the 1.5. And I most connectors are an absolute bear to work with. But we got er done!!

 

[Logticom]

@ Logticom: When you blowcleaned the bottom you should have removed the little grey lid as well ( 4 philips-screws), this is the air-joint from PEM-outlet to the inverter - it's very often quite blocked underneath with insects / feathers / leafs etc...

@warden_clyffe Thx! At the end of the video one of us says: "dit bakje kan er denk ik ook wel af" which is Dutch for "i think we can also take this lid of". One minute later the lid was of and we did some more cleaning with the airgun

 

[Carbuilder]

So if you take your car in for the annual maintenance, is this part of what they are supposed to do...remove the unit and clean it out?

 

[Rolf68]

So if you take your car in for the annual maintenance, is this part of what they are supposed to do...remove the unit and clean it out?

Absolutely

 

[Rotarypower]

Performance and temps after cleaning
After cleaning the PEM and motor I experience that it takes longer for the motor to heat up. But I think the PEM heats up faster. The temp of PEM goes up very fast to 56C when pushing the car hard. (I didn’t get it above 56C yet = last blue bar). I think that maybe now there goes more air to the motor, there is less air for the PEM? I am not sure but I will keep an eye on the temps.

@Logticom yes I have the same issue. After doing a very thorough cleaning of the PEM last year, my PEM runs even hotter. I am perplexed as to what is going on. I bought a borescope and scoped the PEM hose all the way from the blower to PEM inlet with no apparent holes or tears. I’ve confirmed the hose is properly connected. I don’t know what is going on. Yesterday evening here in North Carolina I took my wife to the grocery store, top off, early evening. Outside temp in low to mid-90’s F (32-35 C), no hard acceleration, low speed residential neighborhood drive, and PEM was running so hot around 51 C, this is not right. The blower is running. Just doesn’t seem to cool. I have no errors coming up but have not pulled the logs. I guess that would be the next thing. Could it be the blower? Maybe one of the blower driver circuits is shot so I’m not getting the combined output to drive the motor? But wouldn’t I get error codes if that was the case? I though there was a current sensor on each circuit? Not sure. Any ideas from the greater community would be welcome!

 

[gregd]

@Logticom yes I have the same issue. After doing a very thorough cleaning of the PEM last year, my PEM runs even hotter. I am perplexed as to what is going on. I bought a borescope and scoped the PEM hose all the way from the blower to PEM inlet with no apparent holes or tears. I’ve confirmed the hose is properly connected. I don’t know what is going on. Yesterday evening here in North Carolina I took my wife to the grocery store, top off, early evening. Outside temp in low to mid-90’s F (32-35 C), no hard acceleration, low speed residential neighborhood drive, and PEM was running so hot around 51 C, this is not right. The blower is running. Just doesn’t seem to cool. I have no errors coming up but have not pulled the logs. I guess that would be the next thing. Could it be the blower? Maybe one of the blower driver circuits is shot so I’m not getting the combined output to drive the motor? But wouldn’t I get error codes if that was the case? I though there was a current sensor on each circuit? Not sure. Any ideas from the greater community would be welcome!

I was getting 114x errors some years ago after a 1,000 ft freeway climb, and getting off at my exit. The usual cleaning didn't fix it, but among the things the SC tried was using some foam weatherstripping material around where the air "plumbing" connects to the PEM. Even though properly secured, there was enough air leaking around the joint that it affected the cooling.

 

[Logticom]

@Logticom yes I have the same issue. After doing a very thorough cleaning of the PEM last year, my PEM runs even hotter. I am perplexed as to what is going on. I bought a borescope and scoped the PEM hose all the way from the blower to PEM inlet with no apparent holes or tears. I’ve confirmed the hose is properly connected. I don’t know what is going on. Yesterday evening here in North Carolina I took my wife to the grocery store, top off, early evening. Outside temp in low to mid-90’s F (32-35 C), no hard acceleration, low speed residential neighborhood drive, and PEM was running so hot around 51 C, this is not right. The blower is running. Just doesn’t seem to cool. I have no errors coming up but have not pulled the logs. I guess that would be the next thing. Could it be the blower? Maybe one of the blower driver circuits is shot so I’m not getting the combined output to drive the motor? But wouldn’t I get error codes if that was the case? I though there was a current sensor on each circuit? Not sure. Any ideas from the greater community would be welcome!

@Rotarypower Thanks for info. Your PEM seems to get hotter than mine. I have also been thinking about looking at the PEM blower a little bit more. And I will take a look at the "hose" at the same time as well. I will post if I find something that helps.