Occasional Non-start

[gerlewislewis 0]

Hi guys, occasionally the pug wont start, maybe 1 in 5 starts. It has a new battery and starter and leads and plugs, and the starter is turning it over very strongly, but its not coming to life. If I try it again later in the day its fine.

 

It also has a new tachymetric relay.

 

Im guessing it could be flooding, but am not convinced, as im starting the car with no foot on the gas pedal.

 

Any obvious ports of call, or usual suspects I should check?

 

PS - even when it starts normally, I can feel its not firing on all 4 cylinders for the first 10-15 seconds, then it becomes a lot smoother - not sure if this is related to the larger lift cams - or part of the problem.

 

 

Ger

Edited April 26, 2008 by gerlewislewis

[2-Pugs 57]

I had a problem similiar to that once, it turned out to be the ignition amplifier. Try taking it off and cleaning/greasing the metal backing plate, and also making sure there is no corrosion on the pins.

Certainly worth a try

 

You could also try removing the plugs after it has not started, and see if they are wet with petrol or not. That should tell you if it's a fuel or ignition problem

Edited April 26, 2008 by 2-Pugs

[gerlewislewis 0]

good idea with removing the plugs, although even if they are wet, could it then be either flooding, or no spark?

 

I will take off and re-place the ignition amp. Does anyone have a spare I could test?

 

Ger

[DamirGTI 342]

Another vote for the ignition amp. , try with some known good spare one

 

(i've had just the same problem , and yes it was the ignition amp.)

 

Rgs !

Damir

[gerlewislewis 0]

its not starting at all this evening! bah!

 

You dont think it could be some loose electrical connection? or would your guess still be the ig-amp? (i will pick one up this week).

 

Could it be that the dizzy advance/retard is wrong, could that cause it?

 

The starter is turning over very strongly, and now and again i get the odd chug of exploding petrol, but mostly nothing.

It seems I have fuel, so my guess would be poor spark - it has new leads and plugs though.

 

Still pointing to ig-amp?

 

Cheers

 

Ger

[2-Pugs 57]

Unless your ignition timing was way out, I wouldn't have thought that would cause this problem.

 

Certainly sounds electrical related.

 

Have you tried removing a plug to see it it's wet?

 

At the same time the plug is out, you could try this. Fit the plug back into the HT lead and rest it on the block. Pull out the fuel pump fuse from the fuse box (furthest on the right). Turn the engine over and see if the plug sparks, which it should do provided it makes good contact with the block. Ideally, use a pair of insulated pliers (although I've watched someone convulse with electric shocks from the lead doing that, so I wouldn't recommend it!)

 

I don't think it'd be 'flooding' as such, because the fuel injection controls that, and even when it gets it wrong for one reason or another, it is not so badly wrong that it won't start.

Edited April 27, 2008 by 2-Pugs

[gerlewislewis 0]

no, I havent tried the wet plugs thing yet, I wil try that next.

 

If they are wet/are not wet what does it tell me?

 

I will try the plugs on the block idea too. cheers.

 

PS - there is a very short white cable (3inches) with a female connection - similar to an earth - hanging out the back of the coil, should this be connected anywhere? I cant see anywhere it should go .

 

Thanks mate

 

Ger

[Rom 0]

Wet plugs will tell you if its getting fuel. If there too wet it probably cant fire (ie flooded) Not wet means its not getting fuel. Gives you some areas to look at.

 

My Mi has startign fits, but only after i have stalled it. I have to leave it for about 10 mines before it will run. Turns over the whole time but wont run.

 

Im goign to put a bosch ignition amp on it, as im sure it has a cheap one one at the mo. They seem to be a common problem for intermitant starting / bad running

[gerlewislewis 0]

mines currently bosch.

[davemar 16]

I've had fuel-sodden plugs from the ignition system playing up, which prevented the car from starting once I'd fixed the ignition problem. If they are fuel soaked, then they aren't firing. But if they are too soaked then they can't fire and get worse. So give them a good clean and it might be OK. I recently replaced my distributor as it was giving a signal that got weaker the hotter it got, until it wouldn't fire anymore. Might be worth checking the AC voltage from the pick-up when it's cold and hot and comparing. Might also be a dodgy connection which can be a nightmare to track down. Check +12v and 0v voltages at the ignition amplifier supply contacts in case the supply wires are iffy. Might be worth buying a HT lead light, which is an inline connector for the HT leads which lights up when there's a spark. They are only a couple of quid, and useful to checking the HT is OK.

 

I though I got my ignition system working all funky-tastic a week or so ago, but when driving home the engine cut-out when queuing in traffic (it wasn't overly hot) and needed a couple of minutes before it would restart, it was fine after that. So I'm still a bit wary about mine.

[leitoo 0]

Another vote for the ign amp... mine started playing up just like yours, it wouldn't start every once in a while until finally it just stopped working... I tried some "non-oem replacements" which didn't work and finally settled for the original bosch one... All was well!

[gerlewislewis 0]

a small update:

 

I have bought an ignition amp from Nigel_B so when that comes I will try it, also I took out a spark plug and tried to start the car to see if it would spark, but the car just started on three cylinders! - Thats the trouble with intermitent faults - they dont occur when u need them too!!!

 

I will post more once Ive fitted the amp.

 

Ger

[Miles 331 1 Cars]

It's more down to the ECU not liking the engnie mod's, It really should be running a decent ECU and it will run sweat as then and you'll get more HP from her too, I know when I;ve worked on it the starting can be a mare and you have the Fuel, Spark etc but it won;t have any of it.

[gerlewislewis 0]

oh

 

So how come having fuel and spark means it starts perfectly 80% of the time, but not at all the other 20% of the time? are you sure this isnt just an electrical gremlin?

 

What sorta money am I looking at for an ECU that will do the job? - What one should I be looking for.

 

Ger

Edited April 29, 2008 by gerlewislewis

[Miles 331 1 Cars]

I think the main issue is if it doesn't start straight away it will foul the plug's, I'd be surprized if it was the amp as they normally play up when warm and the Rev counter starts jumping around but when the car's running it run's fairly well.

A aftermarket ECU, Loom, Install and Mapping would be around £1400.00 or you could use the Volcane Motronic as I think this can get re-maped by old Graham would know if that is possible

[welshpug 1,657]

Graham did say it's mappable, pretty sure his has been mapped too, not had any starting troubles since fitting the system onto mine but it is standard.

 

its Motronic MP3.1 if you want to search for more on it Ger.

[gerlewislewis 0]

the plug I took out last night was black all over. Would this stop the spark jumping?

 

where did you get your ecu form welshpug? expensive?

[Miles 331 1 Cars]

Not at all,but it would be a factor on the starting, but even with new plug's it did the same which is why I've talked about fitting a good ECU,

The motronic ones are cheap, from £25.00 if you can find them or there's the 405 GTX/SRi etc which is basically the same

[gerlewislewis 0]

is that plug and play? if so I will get one asap (any one got one for sale?!)

[Rob_the_Sparky 9]

I don't know what your engine spec is but my experience would also point to ignition amp. Some fail with a in sensitive input, as the hall effect sensors in the dizzy output is related to engine speed they can cause intermittant starting problems but are absolutley fine once the engine starts (or when the AA man tests it, grrrrr).

 

If this is the case then it will initially be VERY intermittant, so a cow to find out for sure what is causing it. When it dies you will also loose both spark and fuel as the igntion amp supplies the timing signal for the ECU (at least if you are still using Jetronic that is).

[gerlewislewis 0]

well, im awaiting delivery of my ignition amp from a forum member, so will try that when it arrives.

 

'annoyingly'? its starting fine at the moment! I took the plugs out just now and they are all black and sooty - which means running rich apparently. I cleaned them off. Would retarding the dizzy help to run it a little leaner? - this may be a different issue altogether?

 

ha!

 

Ger

[Rob_the_Sparky 9]

Different issue, a few possibilities and probably a seperate discussion/thread.

 

On the ignition amp: mine would normally start eventually when it did fail to go so I just ignored it. Eventually (6+ month) it gave up altogether while at work (~30 miles from home) and the AA had to drag me home. They tested the ignition amp and gave it a clean bill of health, took me a lot of time and work to eventually find it was the ignition amp afterall!

[gerlewislewis 0]

well ive just fitted a second hand one from an mi16 (so no guarantees even this new one works) and it started ok just now. But I guess Im gonna have to wait and see if the problem happens again. Next time it does happen I will check for a spark and for fuel, which might at least help me diagnose it.

 

Ger

[sutol 0]

. Would retarding the dizzy help to run it a little leaner? - this may be a different issue altogether?

 

ha!

 

Ger

I wouldn't retard it.

 

You will overheat the exhaust valves and it will run on when you switch off , from the little I know about electrickery on engines it could be one of the temp sensor thingys duff or a blocked air filter. But dont quote me

[feb 47]

This sounds like an electrical problem (from my limited knowledge-past experiences). Have you checked the connections/cables around the tachy relay? I wouldn't change the car's timing. You can try giving Skip Brown Cars a call (01829 720492) or get it booked for a RR session-checkup sooner rather than later to make sure the car is running as it is supposed to be. I used to take it for a tune at SBC once a year but it hasn't been on a RR for more than 1.5 yrs now IIRC.

Edited May 3, 2008 by feb