DaX

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A common problem with Beats is that the six electrolytic capacitors on the ECU's PCB wear out over time. This is a natural aging process that is accelerated by heat soak from the engine through the firewall. If you don't catch them in time, they swell and burst, releasing their highly corrosive electrolyte onto the PCB and causing lots of problems. There are all sorts of gadgets to help prolong the life of them - from thermal insulation blankets to put between the ECU and firewall (which I will eventually do) to wiring harness extensions so you can relocate the ECU away from the firewall.

I finally got around to pulling my ECU and main relay to check them. The main relay has the same issues as those on Civics - cracked solder joints. My main relay is perfectly fine, but two of the capacitors in my ECU have leaked the corrosive electrolyte onto the PCB and corroded some of the surrounding resistors and diodes. As I understand it, the capacitors work mostly with the fuel control circuit, and are the cause of poor efficiency and poor performance.

I'm going to clean up the board and replace all affected components. The current capacitors are rated at 85*C and I'm going to be replacing them with 105*C or even 125*C capacitors if I can find them.

Electrolytic capacitors break down like this after a period of about 10 years. It's better to catch and replace them before they leak. I don't know if Civic ECU's are affected like the Beat ECU's, but I figure this tech may get people looking.

My P36 ECU's PCB (It is chipped, but I don't know what program it's running)


One leaking capacitor. You can see the electrolyte on the board, and how it has affected the neighboring resistors (they will be replaced).


An overhead shot of the first leaky one. You can also see that the diode at the right has been affected - I'm going to replace it as well.


The other one that has leaked.

DaX

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105*C is the highest temperature rating that they make the capacitors that I could use. I picked up a set today from my electronics supplier along with the two corroded resistors.

I have decided to not replace the Zener diode yet but instead reflow the solder joints - first because the corrosion isn't that bad and second because I don't know what power rating the diode is without removing it (the labeling is on the bottom).

DaX

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I finished last night. After removal of the components, I used a q-tip with rubbing alcohol to clean the board up. New components soldered right in and the car fired right up. Now to see if there is an improvement in performance and FE.

SlowHX

So is this a problem on Civic virgin ECU's as well? Anything a stock DD should be worried about?

DaX

iTrader: (1)

I'm not really sure - I'm just posting this as general knowledge. If the Civic ECUs have electrolytic capacitors, it is possible this could happen as this is a natural aging process. I believe that heat plays a large role here though, and Civic ECUs are located away from the firewall. I'd be inclined to check my Civic's ECU, but I haven't heard anything about them having problems.

Relic1

as our cars get older and older these type of problems will start popping up.
As far as I know, there are very rare occasions of a problem with the Civic/Teg ECUs where one electrolytic dies that results in the fuel pump not priming.

DaX

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<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">as our cars get older and older these type of problems will start popping up.
As far as I know, there are very rare occasions of a problem with the Civic/Teg ECUs where one electrolytic dies that results in the fuel pump not priming.</TD></TR></TABLE>

Is that due to a electrolytic capacitor and not cracked solder joints in the main relay? The Beat also has this similar main relay issue.

The capacitors in the Beat ECU contribute to the fuel circuit, and cause fueling issues when they go bad.

Relic1

it's the result of a bad cap, replace it and it's fine again.
the main relay fix I consider manditory like the timing belt and water pump. lol