lemon1986

I've fixed my 96 LS400 ECU because it caused me problems and produced bluish white smoke while running as if the engine burns oil. Returned it to the shop and told me if the problem persist after fixing the ecu, then it's useless to fix it again because the main chip gone bad because of the bad capacitors.

Is this true or a myth?

LScowboyLS

It is absolutely untrue, and please don't patronize places like this with your business!

and if someone who knows what they are doing were talking to you at that place, they would understand that the main chip is not even on the same board with the electrolytic capacitors!

PS - here is a bit of trivia for you, after examining ECU's repaired by 26 different rebuilders, including all of the one's on ebay, craigslist and several other places, I have seen NONE using the correct rare type of capacitors that work right in the LS400.

So the problem with you car may possible be, that this place that fixed your ECU used the wrong type of capacitors, in fact, that is highly likely!

you can read about how to do it right and see a list of the correct capacitors here

also, if you can give use some clear hi-res photos of your repaired ECU, Yamae or I can inspect the capacitor type used and identify whether the correct ones were used!

timmy0tool

iTrader: (7)

in addition, your car burning oil might not be oil at all but power steering fluid which is a very common problem.

the air control valve (ACV) in the power steering pump tends to fail and leak introducing PS fluid into the intake tract where it is burned. here is the fix:
https://www.clublexus.com/forums/ls4...ystem-diy.html

sshhlexus

The title of this thread caught my attention. I now have 2 ECU, bought a second as a spare. The first one has been repaired, supposedly, with the caps from 'Digi-Key' I sent them as per the list on the first thread. But was done by one of 'those companies'.

Some of the original symptoms are cropping up again. I'm at a point now where I can easily disassemble and re-assemble the dash/glove-box area. But this is where my minimal soldering experience comes in. I need to get proper soldering equipment. I have 2 irons, one with an unknown wattage and a 45W one. Some 50/50 lead/tin solder, nothing else. I think the caps have to be worked on in place, that is, the board cannot be disassembled from the aluminum book frame.

I have read the posts on the original thread about, practicing on PC boards, protecting from electrostatics. Using a pin and heat to ream the hole for the new cap.

What are some good tools to have and where to get them for this specific job:
Rosin
Fine solder tips
Vice. I don't think it is useful in this case, as I think you have to do them in place.
Magnifying glass, with a holder and light.
De-soldering tool or de-soldering wick, which is better? Any other good tools.

Since I have 2 ECUs, is it better to fix the original or the 2nd one? I shall soon have a look the original repaired one. Also I have an extra set of caps from Digi-Key.


Thanks.

LScowboyLS

it's Digi-Key, not Digi-Com, and you definitely want to get it down to a science before tackling this, by practicing on computer motherboards until you have it down cold.

I have a list of recommended tools and supplies for doing this job in post #1 of my famous ECU capacitor repair post, so you might want to have a look there first.

as far as which one to repair, take photos of the insides and post - there could be many reasons to take one over the other to repair, such as one has extensive corrosive leak damage, or the one that the company fixed, they did not use the correct capacitors after all, even though you sent them!

sshhlexus

Original ECU repaired by Circuit Board Medics, they seemed to have replaced the caps, But there are hot wire fixes on the underside of the board as seen in the photo covered with a hard blob of glue. Pic 1.


The extra board that I have has some liquid and dirt to one side. Underneath the top right cap. corrosion on some tips of the IC chip near it. Also dirt around the other side of the same IC chip. Pic 2.


Let me know if both are finished or any are salvageable. Thanks.

LScowboyLS

OMG - I have never seen a screwup like that slop with two wires added before, and I have seen 100's of repaired ECU's! - oh my! - that is in no way acceptable and whatever you paid to have your board butchered needs to be refunded, I want to use that pic in the "hall of shame" in the main ECU thread!

as far as the other ECU, I need higher quality pics, but I do not really see anything to get in a twist over, you have some corrosive leakage, but it may well be salvageable.

please shoot some pics of the capacitor side of the board with the silly wires added, I want to see the damage and what caps they used

Let these pics be a warning to folks, please be very careful about who you entrust to repair your ECU!

timmy0tool

iTrader: (7)

they must have had the schematics of the ECU to do a bypass repair like that!

LScowboyLS

they do not have the schematics of the ECU, no one does, outside of Nippon Denso! - ask Yamae, these schematics are secrets more closely guarded than nuclear missile launch codes! - lol

sshhlexus

The 1st original board after repair drove okay, no problems except for rare drive idle die-off, and mis-fires. You could feel the mis-fires.

The 2nd board after being tested once drove okay, idle okay, but would shift back and fourth in higher gears.

I'll take more pics of the botched up board tomorrow. It seems upon inspection, that they used the Digi-Key caps I sent them. the cap replacement work seems to be okay. I even have some pics of the actual caps I sent them.

This is a close up pic of the spare board with the leakage.

MattLS400

he's right....this really is a sloppy job...

sshhlexus

I actually have 3 soldering irons, I have one with a blade tip used for wood finish work, 25W. I was able to shovel the glue on either ends and expose the green wires.

I may be able to clip the wires, and try the board. All else looks good I verified the caps with the duplicate set I have and the caps and work that was done look okay.

What do think me of trying the board out with the green wires clipped.?

I don't have access to a good camera right now, maybe later.

Thanks.

sshhlexus

Clipped the green wires that were installed by 'Circuit Board Goofballs' and drove the car locally 45-50 mph max, speed zone. All was okay. Re-plugged the negative, and let the ignition run a bit, before turning on. It ran on cold idle for the whole trip. Going to try again tomorrow.

I kind of though it was a logical thing to try to experiment with. How would the goofs know what part of the board to hot wire anyway, since Nippon-Denso keeps the schematics a secret. So other than the slop, I'm pretty sure the got the cap install right.

I'll remove the board again since it is just plugged in, to reexamine the cap connections and surrounding and do a cleaning and pic, if I get a chance. On both boards any corrosive crud does not get removed by simple cleaning. Any ideas on how to clean, maybe a light sanding and vacuum. And then the simple cleaning, mentioned in the 'original main ECU problem' thread.

Thanks Cowboy & Timmy

LScowboyLS

do NOT sand on your ECU circuit board - you can take some of the special rosin mentioned in mine & Yamae's ECU capacitors thread (a particular part number from Radio Shack or CAIG) and try applying it for 24 hours and then removing with q-tips and 91% rubbing alcohol

sshhlexus

Today the entire blob came off cleanly by prying gently with a pointed tool. I had severed both ends yesterday. Added some Radio Shack rosin/flux (p/n 64-022) with q-tip, to the other side (one spot) not where any glue residue might be. Going to let the rosin sit for 24 hrs and try to get pics.

Question: Is there any danger to the ECU from magnetic fields? Some of the tools I was using were unknowingly magnetic. Also while I was moving things around I may have placed the ECU near, 10" away from a large speaker coil.

Thanks.