Mi16 Intermittent Fault

[Veero 1]

Right had loads of shenanigans with my Mi lately. Rebuilt the loom and missed soldering a single connection which resulted in a spluttery death (after 5 days of perfect operation) and non-starting and a tow home by the AA. After replacing the cap, arm, leads and coil it still wasn't playing ball so in pulling the wiring out of the dash reconnected the dodgy connection meaning it ran fine. Eventually found and soldered the joint so thought all was fixed. All good.

 

Went to drive up to Coventry yesterday, got on the M5. As I left the slip road the rev counter dropped to 0 and lost all power, by the time I coasted onto the hard shoulder it was idling perfectly at 1k. Pulled away and 5 minutes later the same thing. I tried restarting but it was lumpy and wouldn't stay idling without constant throttle. Called the AA but by the time they arrived it started fine and we couldn't replicate the fault. AA man followed and sure enough it happened again. This time it restarted instantly and again it wouldn't replicate the fault even revving it for 4-5 minutes to simulate driving. So gave up and he followed me to a Doug's place nearby who kindly lent me his car for the day and of course it was fine all the way there. AA bloke suggested it could be the crank sensor breaking down when hot, maybe the ignition amp. Meanwhile Doug took my 205 around for a thrash and couldn't get it to repeat. Drove it gently, couldn't get it to repeat. I drove it back to mine last night and again all fine.

 

Today I took the dash cowling off and started waggling wires with it running. Sure enough revs dropped to zero and it cut out. So much wiggling later and it restarts still none the wiser. At one point it wouldn't start. So I changed the ignition module over (and touched absolutely nothing else) to a spare and it started straight away. Thinking that was it I switched it back and it again started. Much more waggling and it won't cut out so I have absolutely no idea what is wrong.

 

Even when it has cut out there is switched live to the coil so it's not the lack of volts causing the issues.

 

Patience is wearing thin, hopefully I will be getting another car shortly so won't have to rely on the 205 but I am absolutely determined to get this running right.

 

Any advice or suggestions greatly appreciated.

 

Cheers

Veero

Edited October 12, 2009 by Veero

[Veero 1]

Slight update. Ran it on the drive for ages this afternoon with no fault, went for a drive. 5 minutes of pootling through town got onto the bypass and started to gently accelerate away and it died again. Changed the ignition amp over and it started straight away, so maybe it's just that. I am now unsure which one was fitted yesterday when it did the same thing.

[gav_mi16 0]

I had a similar problem, the engine would splutter and cut out if I accelerated at anything other than granny pace when the engine was warm and it and would not restart for 10-15 minutes.

 

Mine problem turned out to be worn out ignition leads, one in particular was quite bad. When I changed them then the problem went.

 

Might be worth a try if you have a spare set knocking about.

[Adnic69 0]

Ignition amp is at fault I would say.

Take it off, give it and all contacts a clean. Check the earths and asseble with some heat paste. If it's still doing it then try a new ignition amp.

[Veero 1]

Yeah it's got a brand new set of leads on, also a set of plugs which I forgot to mention.

 

I am going to order a new igntion amp tomorrow and see if that sorts it, at least a brand new one would rule it out, no idea how old or (ab)used my 2 amps are here. Last new one didn't come with heat paste, will that thermal compound for PC processors do the job?

 

Just before it cut out I was sure I could hear some rapid but quiet clicking from under the dash, but much quieter than the relays click on starting.

 

Anyhow I tihnk now my starter is on the blink as with a fully charged battery it struggles to even turn over, bump starts fine though. Pesky car, it really hates me for some reason.

[yorkshirekowboy 19 1 Cars]

Yeah it's got a brand new set of leads on, also a set of plugs which I forgot to mention.

 

I am going to order a new igntion amp tomorrow and see if that sorts it, at least a brand new one would rule it out, no idea how old or (ab)used my 2 amps are here. Last new one didn't come with heat paste, will that thermal compound for PC processors do the job?

 

Just before it cut out I was sure I could hear some rapid but quiet clicking from under the dash, but much quieter than the relays click on starting.

 

Anyhow I tihnk now my starter is on the blink as with a fully charged battery it struggles to even turn over, bump starts fine though. Pesky car, it really hates me for some reason.

 

 

pc processor thermal paste is fine, i used it on my mi amp its running fine. you tried the earth points on car etc? sounds like an earth issue to me?

Edited October 12, 2009 by surferkid205

[sub205 5]

pc processor thermal paste is fine, i used it on my mi amp its running fine. you tried the earth points on car etc? sounds like an earth issue to me?

 

i had a similar problem with my 8v...

 

first it started to stop sometimes for about 1sec, just like a hard braking. turned out to be a rotten cable somewhere in the loom (bridged it but never found the true location of the fault.)

 

second one was like yours ... turned out to be a broke cable to the AFM. i fixed it by connecting a second connector directly to the corresponding pins of the ecu-connector and using this cable instead of the original one.

[GLPoomobile 958]

Tris, I really do feel your pain. Persevere though, and get to the bottom of this, otherwise you'll never have faith in it and may give up on the car like I did with mine for the last year. At least you have AA cover though, so you can go for a fault finding drive safe in the knowledge that if you get stuck you can get recovered.

 

I can see this from 2 sides. On the one hand, it sounds exactly like my problem. Mine seemed to have a pattern of cutting once warmed up, but then I discounted that as it mostly did it when driving, and hardly ever when left idling and revved whilst stationary. I was also left confused by the seemingly random nature, as sometimes it would start again after 30 seconds, sometimes after a few minutes, sometimes not at all, and once after swapping a relay. I guess I struck it lucky the other night when everything just seemed to come together and make sense - I knew I had no voltage to the relays, but I knew I had no voltage to the coil either, and both rely on the switched live, so it just took enough waggling of the plugs under the dash to restore that connection and it worked. From then on I isolated that area and played about until I found exactly what was breaking the connection.

 

Buy you say you still have voltage at the coil, so don't think it is the switched live. So on the other hand, perhaps your loom is a red herring. You are assuming there is a problem with the wiring because it is a significant change to a previously working setup. I thought the same with mine. But it's entirely possible you've got another component failing, which is just coincidence. Unfortunately that might make hunting the problem a bit more difficult, time consuming and costly. But there's only so many things you can swap, and you will get there.

 

Couple of questions from me though:

 

1 - When it cuts out, how does it feel? Does it go instantly, as if someone has just switched the ignition off? Does the tacho needle drop dead? Or does it feel more like it's struggling and then dies gradually? Does the tacho drop naturally like the engine is slowing?

 

2 - What voltage do you see at the coil with engine off and ign on, and with engine running?

 

I wold say it's worth spending a bit more time playing with the plugs though. You've made it cut out by wiggling them, so spend a bit more time playing with certain wires and moving them about. If there is a duff connection, you'll soon start to repeat the problem until you find the sweet spot. With mine, I could move my switch live to the mm perfect position and get the engine to cut dead, but then move it back again in time for all systems to come back on and the engine pick up again before it had stalled completely. That's when I knew I was on the money

Edited October 13, 2009 by GLPoomobile

[TT205 42]

I had something similar 3 years ago. The engine would be absolutely spot on sometimes for days at a time, the it would suddenly lose power and then cut out. After 10-20 minutes it would restart as if nothing was ever wrong - but by then, whatever you had most recently wiggled was assumed to be the culprit therefore I ended up with lots of new ignition parts but the problem remained

 

Turned out eventually to be the Dizzy - never had a problem after swapping it for another

[jackherer 543]

Have you tried another crank sensor? I've had them fail intermittently several times in various peugeots and citroens. The only way to properly test one is with an oscilloscope which is very tricky if its intermittent so replacement with a known good one is easiest.

[skeggyrik 3]

I had a similar problem with mine not long after I first bought it.

It was short from the loom to the inlet manifold. Hidden from view i might add.

 

I would never have spotted it unless I was working outside my flat in the dark under a street light.

So the advice I have is to do the wiggling of the loom you did before but do it in the dark and keep your eyes peeled for a spark whe it starts mis behaving.

 

HTH

 

Good luck