Leaking caps, ECU ruined?

9guy9 · 12-17-2005

I just aquired a 91 Eclipse GSX. The car hardley runs. It idle surges between 100-2000RPM's. When driving the stock boost gauge shows full boost at anything over about 20% throttle., causing the car to run extreamly rich and load up. I did a compression test and it has 125-140 in all 4. Next I checked the ECU for leaking caps.

Well, they're leaking, my question is; Have they leaked for too long? The board is blackened around the caps. I already ordered the caps to replace them, but I'm worried the board might be shot. I tried getting a couple pics, sorry for the lack of quality. My $150 cammera shows its shortcomings on the closeups.

tim · 12-18-2005

Anyone?

**scheides** · 12-18-2005

Chances are, if the car still runs, it will be fine once you replace them. Idle surge could be attributed to several other things, boosting out of control could be either an unhooked wastegate actuator or a cracked hose, and the richness could be either the car running normally (stock 1g's run pretty rich) or more likely a boost leak. This could also be the cause of your idle surge too, actually. Start by checking every hose you can see, then check them again.

...when you're done with that, do a boost leak test, and then check them again. Now start checking your coolant hoses if you replaced any vacum lines, they could be cracked too.

9guy9 · 12-18-2005

Saying the car still runs is being very generous

I managed to drive the car across town to my house, about 6 miles. Over about 3000RPM's the car stutters and has no power.
I did a quick boost leak test. The car dosn't have a aftermarket boost gauge on it, so it was somewhat difficult to tell how much it held. However it didn't appear to be leaking enogh to cause it to run as it is. I have already ordered the new caps. I figured they were only about $4 shipped so I will try them first.

**scheides** · 12-19-2005

I would do a full boost leak test with a pressure gauge right in front of you so you know how much pressure your system is holding. If you have a bad enough leak, you may not even hear it leaking, as the system will not build boost at all. You can make a proper boost leak tester for about $20. I say make one, borrow one, or buy one!

acidrumz · 12-21-2005

boost leak test. it can direct you to where the culprit is leaking at. around 2psi is enough.

best thing to do about your ecu is replace your caps and carefully clean your board where the effective area is at. there you can tell what condition your board is in.

gluck.

9guy9 · 12-21-2005

I just threw a ECU out of tim's newly aquired 92 laser in my Eclipse tonight. The car is now driveable. It idles decent, and drives good under partial boost. There must still be some good sized leaks however, under full boost the car whistles and hits fuel cut.

So if let go long enough leaking caps can make a car undrivable. Now hopfully putting new caps in my ECU will fix it, and the board is not ruined. Tomarrow I am going to take the car to work. There I can do a boost leak test, and try to track down the leaks.

LightningGSX · 12-22-2005

Make sure you clean up the board good and remove the coating in areas you will be soldering/desoldering with acetone.Looks like the surface mount cap (circled in pic) is trashed as well, you can replace it with a non surface mount 0.1 uF ceramic cap.Make sure you clean the board again when you're finished soldering, flux(from the solder) is corrosive.