Punto (Mk2/2b) MES two problems - related?

[boguing]

Started with a suspected fuel relay problem on an Punto 1.2 8v. That was my 'phone diagnosis so headed up to the daughter's place, plugged in the K lead, MES immediately confirmed a relay fault. Couldn't get a relay locally so left it and got one sent to her. It still wouldn't start. Went up again, forgot the MES lead and after a lot of messing, re-gapping plugs etc, and after a lot of cranking it started. Drove it round the block to get some life into the battery, red engine light on, but I gathered from here that it would reset itself after a while. That it did, and for a couple of weeks has been fine, but the red eng light came on again briefly last weekend.

I tried to hook up MES, but it kept insisting that I needed the three wire lead. Gave up, she had to go home. She came down again this weekend, car's been fine, no red light, but thought I should have another go at finding out what caused the light last week. Once again, insists on three wire. I've played with all the settings on the usb settings, com port and then in mes itself used the tests etc. Still no connect. Then tried deleting previous cars and bingo, connects - but drops out a couple of seconds later. I've tried it in the similar engined Panda just now, no problem, connects perfectly.

But guess what, now the Punto won't start. Spins, no firing.

I'm thinking the problem's on the car end of the cable, but I find it hard to believe that trying to connect has changed anything so that it won't start. Baffled, because that's the only thing I can think of.

Edit. It did start, reluctantly. Since initially posting :-

Disconnected the ecu plugs and gave them a shot of cleaner. Disconnected the battery, shorted the neg cable to the positive. Hooked up jump leads to a running car to give a bit of a boost. Left it charging for 20 mins and it started - rough to begin with, loads of smoke, but that's to be expected with a load of unburned fuel in there. Not sure that any of that helped, or if it did, which part.

After making sure it would restart I then tried mes again with the engine running, still no dice. Connects and drops out after about a second.

At this point I'm suspecting the ecu?

 

[bugsymike]

Maybe totally unrelated but I had a fuel pump relay issue on a daughters Fiat Grande Punto 1.3 Multijet some years ago.
By removing the fuel pump relay I could power up the pump at the relay connection using a fused powered test probe, I traced the wire all the way back to the ECU on the o/s inner wing and the wire had corroded through about a cm from the ECU.
Personally I would be very reluctant to condemn the ECU as unless water has got in they are generally not the issue.
Another point I use a "breakout" box to plug the OBD port to as it can tell if the two lives and two earths required at OBD port are working as that can be an issue.

 

[boguing]

Maybe totally unrelated but I had a fuel pump relay issue on a daughters Fiat Grande Punto 1.3 Multijet some years ago.
By removing the fuel pump relay I could power up the pump at the relay connection using a fused powered test probe, I traced the wire all the way back to the ECU on the o/s inner wing and the wire had corroded through about a cm from the ECU.
Personally I would be very reluctant to condemn the ECU as unless water has got in they are generally not the issue.
Another point I use a "breakout" box to plug the OBD port to as it can tell if the two lives and two earths required at OBD port are working as that can be an issue.

Thanks, both are interesting points.

I'd be kind of surprised if it was the wire because so far it's only a starting problem (twice). If the wire were dodgy I'd expect it to run badly in between times - although it certainly makes perfect sense as a cause. I'm not sure if it's the same on your daughter's car but the ignition system on ours is also supplied by that relay. On this one a brief interruption in fuel could go unnoticed, a lack of sparks less so. I do know the wire goes to pin 6 on the ecu LHS socket, so could test for resistance while wiggling along the harness.

I like the idea of a dodgy power connection at the port. If I knew the pin numbers it would make life easy, but can certainly test for two 12s maybe the two earths too. I'll call Gendan (supplied the mes kit) tomorrow and see if they've any ideas? Seemingly loads have had the disconnection problem if I Google but nobody has ever come back and said they'd fixed it.

 

[bugsymike]

Thanks, both are interesting points.

I'd be kind of surprised if it was the wire because so far it's only a starting problem (twice). If the wire were dodgy I'd expect it to run badly in between times - although it certainly makes perfect sense as a cause. I'm not sure if it's the same on your daughter's car but the ignition system on ours is also supplied by that relay. On this one a brief interruption in fuel could go unnoticed, a lack of sparks less so. I do know the wire goes to pin 6 on the ecu LHS socket, so could test for resistance while wiggling along the harness.

I like the idea of a dodgy power connection at the port. If I knew the pin numbers it would make life easy, but can certainly test for two 12s maybe the two earths too. I'll call Gendan (supplied the mes kit) tomorrow and see if they've any ideas? Seemingly loads have had the disconnection problem if I Google but nobody has ever come back and said they'd fixed it.

On daughters, we bought it as a non runner, basically that relay controlled the fuel pump in the tank and also the starter circuit, the problem was the previous owners "garage " had towed it so violently trying to start it , they caused the valve timing to slip on the "free wheeling" crank pulley!
Re the port connections , if you zoom in enough on my photo you can read them.

 

[boguing]

if you zoom in enough on my photo you can read them.

So you can! I can see four 12s - any idea what the (15) and (30) suffixes refer to?

 

[bugsymike]

So you can! I can see four 12s - any idea what the (15) and (30) suffixes refer to?

If you mean the switches at bottom , that is for when it is powered up.
If you need more information:-
www.godiag.co.uk//wholesale/godiag-gt100-break-out-box-ecu-connector.html?gad_source=1&gclid=EAIaIQobChMI2c7K-trrhAMVJggGAB3NtwHbEAQYASABEgLaw_D_BwE

 

[boguing]

Right, spoke to the very helpful Grant at Gendane and got connected with the red OBD cable.

It still had the fuel relay fault, so cleared it, ran the engine and it's back logged again. Since the relay is fine it almost must be the wire from relay to ecu plug. A job for a drier day.

And it seems that the problems aren't linked. Good.

I'll now revive the earlier thread.

 

[The Panda Nut]

Started with a suspected fuel relay problem on an Punto 1.2 8v. That was my 'phone diagnosis so headed up to the daughter's place, plugged in the K lead, MES immediately confirmed a relay fault. Couldn't get a relay locally so left it and got one sent to her. It still wouldn't start. Went up again, forgot the MES lead and after a lot of messing, re-gapping plugs etc, and after a lot of cranking it started. Drove it round the block to get some life into the battery, red engine light on, but I gathered from here that it would reset itself after a while. That it did, and for a couple of weeks has been fine, but the red eng light came on again briefly last weekend.

I tried to hook up MES, but it kept insisting that I needed the three wire lead. Gave up, she had to go home. She came down again this weekend, car's been fine, no red light, but thought I should have another go at finding out what caused the light last week. Once again, insists on three wire. I've played with all the settings on the usb settings, com port and then in mes itself used the tests etc. Still no connect. Then tried deleting previous cars and bingo, connects - but drops out a couple of seconds later. I've tried it in the similar engined Panda just now, no problem, connects perfectly.

But guess what, now the Punto won't start. Spins, no firing.

I'm thinking the problem's on the car end of the cable, but I find it hard to believe that trying to connect has changed anything so that it won't start. Baffled, because that's the only thing I can think of.

Edit. It did start, reluctantly. Since initially posting :-

Disconnected the ecu plugs and gave them a shot of cleaner. Disconnected the battery, shorted the neg cable to the positive. Hooked up jump leads to a running car to give a bit of a boost. Left it charging for 20 mins and it started - rough to begin with, loads of smoke, but that's to be expected with a load of unburned fuel in there. Not sure that any of that helped, or if it did, which part.

After making sure it would restart I then tried mes again with the engine running, still no dice. Connects and drops out after about a second.

At this point I'm suspecting the ecu?

Hot wire the pump direct to battery. DONT CAUSE SPARKS THOUGH. see if it will fire with a bit of forced pumping / check the pump actually works.

 

[boguing]

As I wrote on the other thread.

Fixed.

On the underside of the engine compartment fuse/relay box there are about five connectors. I disconnected them all, sprayed each plug and socket with contact cleaner and then put them in/took them out four or five times to dislodge anything the contact cleaner was releasing. I did the same with the two on the back of the engine ECU. I also took off the main 12v supply to the fuses and cleaned it, but it was bright and shiny and unlikely to have been a problem.

Checked for faults with MES and fuel pump relay and water temp sender were logged as failed. Cleared them, started the car and checked again. All fine. Previously the fault came back without even running the engine. It now starts like it used to, almost before you turn the key!