Citroen Axel(Oltcit) 1.3turbo - Ms2Extra3.0 - miscellaneous

[adrian3500]

weird things happened.
I took the megasquirt in the house yesterday.
This morning when i plugged it in, the correct coolant temp was displayed instantly. Ignition on-off a few times, still the correct coolant temp. Drived the car to work, still correct temp.

The only thing i did yesterday, was to put gently the multimeter to the sides of the R4/R7.
I will keep monitoring the coolant temp.

(i will try to remove the daughterboard if problem will occure again).

[adrian3500]

so, the problem with the coolant temp got back this evening.

I don't know what to do:(

[billr]

How good at you at soldering? I would probably try adding a jumper directly from the motherboard pad to the top side of the MS3 for that input, bypassing all those connections in the stack of 40-pin sockets. I'm talking about small (28 or 30 AWG) solid wire, like used in wire-wrap. You would be trying to barely attach the jumper without really melting the solder in/on the pads thoroughly. If you have no experience using .015" solder, this operation probably shouldn't be attempted.

[adrian3500]

Well, I can go to a guy that does some repairs to OEM ecu's, probably he can solder it for me.
Just need to figure out where to solder on the motherboard

[billr]

Oops, I just noticed (again!) that you have MS2, no "stack" of sockets like the MS3, correct?

How new is the MS2? Scabbing-on a jumper may void the warranty on it.

I believe it is pin 25 of the 40-pin socket you would need to jumper for CLT. If you do try that, take great care to be well away from the pin/socket area. It will be difficult to remove the daughterboard if solder wicks in there and locks that one pin to the socket!

[adrian3500]

It's way off warranty. Already been some trace intrerrupted, that was corrected by DaveEFI.
I will try contacting Dave also, maybe he knows something.

[billr]

Oh... the MS2 has been modified/damaged and then repaired? That opens up all kinds of possibilities. Yes, let's hope Dave will join us here. Maybe pictures of the MS2 board (both sides) can give us some clues.

[adrian3500]

I uploaded some photos and shared a link a few messages away. Check for a dropbox link.

As I know, the megasquirt was bought new a few years ago, modified for a specific car, never used. I got it 2 years ago, but started using it only last year. I had some problems with it, no spark. I've sent it to Dave in England, got it fixed. Some damaged trace has been repaired, and replaced q22, q23.

I don't know anything else, but i will never make the mistake of buying anything else then brand new.

[billr]

Ah, yes, I remember that nice batch of photos now. Good photos, but rather a messy MS with all the added resistors and jumpers. A key question is whether the board has been fully repaired. I'm not blaming Dave, it is difficult to be sure a damaged board has been completely repaired; damage can be so hidden or intermittent. Do you have any idea of what the original damage (or symptoms) was?

[adrian3500]

I didn't have spark at all.
After i got the megasquirt back it worked a few months, then no spark D.
I ended up rrplwcing the whole circuit built in proto area for spark D, and also inserted a led for spark D too.

As i remember, the coolant temp was this way for a pretty long time. Don't recall if it was like even after i got it back from dave, or brfore sending it to dave. I was focused on the spark problem. First i was blaming the 1 wire sensor for the problem. Switched for 2 wire sensor, but problem was the same. Replaced the wiring.

[billr]

Did it have no spark when you bought it? I'm hoping DaveEFI remembers this unit and will join in here. Frankly, a damaged board may present all kinds of unknowns; sometimes a complete replacement is the practical way to move forward.

[adrian3500]

I noticed that there is no spark when i installed it on my car. So it probably had no spark when i bought it.
Dave is saying that he didn't ever see this kind of problem with coolant temp, on any unit...and asked me to post a message on the forum:):):)

Should i open a new topic just with this coolant temp problem?

[billr]

I would like to keep the CLT issue in this thread.

I wanted to peek at the soldering of the DB37 CLT pin, #21, but I think it is hidden behind the MAP sensor. How about lifting the MAP sensor up a bit and checking there, post a picture? Don't de-solder the MAP sensor, just remove the screws and bend the leads. While it is up, I would scab-on a dummy resistor between 21 and one of the nearby grounds (1 & 2) and see if the CLT reading is still flaky. I know you already tried a dummy resistor, but expect it was still going through that DB37. Trying a resistor connected right to the board pads would eliminate any issues with the DB37 or the mate you were using. Again, don't try for a super soldering job, just enough to ensure electrical contact; you don't need the solder around those pin tails to fully melt.

[DaveEFI]

Did it have no spark when you bought it? I'm hoping DaveEFI remembers this unit and will join in here. Frankly, a damaged board may present all kinds of unknowns; sometimes a complete replacement is the practical way to move forward.

The only damage to the PCB was where R56 had been replaced with a non standard larger item. I fitted the correct one and repaired a track.

Checked it out on my JimStim, and all sensor inputs were reacting. As were all four spark outputs.

That really was the limit of the tests I could do - short of having the actual car here.

[billr]

So, the original "no spark" problem was actually a "no sync"? How close are the CLT RC filter components to R56, any chance board damage at R56 went a little bit further into them?

[DaveEFI]

So, the original "no spark" problem was actually a "no sync"? How close are the CLT RC filter components to R56, any chance board damage at R56 went a little bit further into them?

IIRC, the damage was caused by removing the old R56 and fitting the replacement oversized one. It was very localised and had been jumpered. Indeed the VR circuit worked on my Stim. But I replaced R56 with the correct component anyway, and made a tidier repair to the PCB. All the soldering in general looked just fine - no signs of any dry joints.

[adrian3500]

Hi there!
I discovered that touching with my finger the R8 component, the correct coolant temp is beeing displayed instantly.
Got R8 out of the board, then re-soldered it.
Seems to work fine, now for 2 days. I will keep it under observation.
What's R8 doing in fact? I didn't find it in the assembly guide, it's stated only that R8 is an essential component.

[billr]

R8 is part of a noise filter for the CLT input to the CPU. It is in series with that input, so if it goes "open" the CPU has no real input for CLT.

[adrian3500]

Great.
Let's hope this problem is fixed, so I can try to tune the engine properly

[adrian3500]

Back to my usual problems...
Now it has no spark B, no spark C

Tried all the coils in test mode for spark A, and they all work fine when i connect them to spark A.
Switched coils between them, still no spark b and c.
Checked if i got 12v and ground at every coil
The LEDs are blinking for every coil output if in test mode

I assume the problem is somewhere betweet the LEDs and the outputs Spr2, Spr3.
Am i right?