What could this be? (starter runs, but engine wont start)

[Tahrey1043]

I already have my suspicion on this but I need second, third etc opinions.

The 1.0 I sold my uncle has decided to quit. It ran fine when I drove it up and the first couple days his company was using it, but now it's "dead" to use his description. The starter will run and run, but the engine doesn't catch.

Symptoms are similar to what happened just before I sold it to him, when an ECU pin was bent, but I thought I fixed it. Obviously it may have snapped since from fatigue or something (hence I'm looking for a spare ECU to test with), causing same problem - insofar as I can tell, the pin in question is responsible for the injector trigger signal, so the motor runs, the spark plugs fire, but no fuel goes through.

It'll be a definate diagnosis if I do what i did before and squirt some meths (or petrol in a squirty bottle) down the throttle body and have it briefly run, but until I can get up to Manc with the appropriate kit, what else could it be?

I need to sort this ASAP as its family, an essentially needed working vehicle, and he gave me a good rate..... argh!

Cheers,
Tah

[roger-d]

I already have my suspicion on this but I need second, third etc opinions.

The 1.0 I sold my uncle has decided to quit. It ran fine when I drove it up and the first couple days his company was using it, but now it's "dead" to use his description. The starter will run and run, but the engine doesn't catch.

Symptoms are similar to what happened just before I sold it to him, when an ECU pin was bent, but I thought I fixed it. Obviously it may have snapped since from fatigue or something (hence I'm looking for a spare ECU to test with), causing same problem - insofar as I can tell, the pin in question is responsible for the injector trigger signal, so the motor runs, the spark plugs fire, but no fuel goes through.

It'll be a definate diagnosis if I do what i did before and squirt some meths (or petrol in a squirty bottle) down the throttle body and have it briefly run, but until I can get up to Manc with the appropriate kit, what else could it be?

I need to sort this ASAP as its family, an essentially needed working vehicle, and he gave me a good rate..... argh!

Cheers,
Tah

It sounds very similar to a problem I had. The hall sender unit on the dizzy is the key ignition sender and it triggers all other functions. Check for sparks at the plugs. If there is no fuel from the injector and no spark at the plugs it is almost certain that the Hall sender has packed up (unless as you suggest the pin on the ECU has broken). This is a common fault. Fit a new dizzy cost about £68 worked for me.

[Tahrey1043]

Yeah I was fearing it was the hall sensor - he's already progressed to changing the spark plugs and things (damnit, unc, i already told you it was only one or two things, the plugs were practically fresh off the shelf! )... only a matter of time before he starts ripping the dizzy apart if I don't nip it in the bud.

Be just sodding typical if the sensor's packed up though... however I was thinking it was going to be about ninety quid just for that, so an entire dizzy for under £70 isn't bad (and thankfully it's easy to swap out, if i remember right.... just, do i still have my timing light?) --- was that a new one, or a scrapper?

[hardhitter]

You can just buy a new hall sender from a bosch parts dealer. Not too difficult to change either, just a bit fiddly.

[Tahrey1043]

hm, sounds alright then, but how much?

....and how much would a garage rape you for doing it? Uncle's got tired of waiting for my work pressure to ease (WAS going to go up today... but now he's told me it's been towed, i'm gonna get some more writing done instead) and took it to a pro's already.

Gah! Well at least I got to talk to him and reccomend he tells them to check the ECU out first.

(just when i was going to ask if there was any definate way of checking the sensor was bust, e.g. with a multimeter, and how to swap it too)

[danutzBUN]

Near your digifant there are two relays. One for petrol pump, and one for ignition. I had a similar problem and I had to change the relays. (both of them).

[DelG40]

An entire new dizzy won't cost you under £70. It will cost you closer to the price of £160.

Maybe £70 for an expensive second hand one.

Hall senders are about £40 odd.

When you put another dizzy on, if you do at all, you might be lucky not having to need timing light etc. Just turn the altenator till the notch sits in the window, so it's sitting at TDC, take a mental note of roughly how the dizzy is positioned, the rotor arm should also be facing piston 1 (worth mentioning too, get a new cap and arm while you're there. Only cost you a tenner for the both together). Cap off, rotor arm off, two bolts for dizzy, pull off, new dizzy on, push new rotor arm on the same way the old one came off and then cap. Give it a start, see how it runs for you. Might need to adjust the dizzy back and forth a little for timing/idle.

[Tahrey1043]

argh.......!

(£160? That says to me "get a scrapper off ebay, swap the dizzies, then sell the frame for a fiver more than you paid")

reminds me, i need to phone up and see what happened after i told the mechanic what the craic was... seems he'd tried everything else but not looked at the ECU, because, yknow, you wouldn't

Relays sound like a good one to try too...

[Gareth_GT_Hatch]

2nd hand SPI dizzy shouldnt cost more than about £25. I bet 86cs got a box full of em!

[Tahrey1043]

probably more like a skip

[roger-d]

I dont know where others buy their parts but check out this site.
http://www.gsfcarparts.com

They supplied mine for £68.00

Roger-d

[Tahrey1043]

sorry, i am a mong, i forgot GSF!!!!!!!!

was that the relay or the ecu you mean

[roger-d]

sorry, i am a mong, i forgot GSF!!!!!!!!

was that the relay or the ecu you mean

Sorry, they supply all parts for VW's I was talking about a new Dizzy.

[PGWLE]

My polo did/does the same until I relised it had an imboliser fitted.... Which is the biggest pile of s**t ever known to man, forgot the make, I think the make wants to forget they ever made it, as there no reference to it anywhere!

[Tahrey1043]

haha, i'm going to go all Derren Brown (no, not be an even more enormous arse, but become psychic) and go ....mmmmmmmmmmhhh. hhhhhnnnnnmm..... it's a ....... MOSS

i've never figured out the full origin of the Moss alarm that i found the sounder and control box for under my bonnet (and signal light & some wiring in the cabin)... disconnected, and it would appear, the connections somewhat ripped in a state of extreme peed-offness. but i bet it was dealer-fit.... jammed on after only a couple years, and nothing short of disconnecting the battery - or mashing the alarm - would stop it. possibly it had an immob as well.

ANYWAY ....... all fixed now. I don't know if I've put the full story on here (think it was Por... ahem, Club Polo). So, why not....:

After weeks of faffing, got to go up and look at it. Even then, it changed unexpectedly from Sat to Sun.

The extremely helpful and sadly recently GT-bereft Rik Austin supplied me with a bonzer AAU computer for a nice price; GSF, a relay which I will be taking back totally unused at the weekend; and halfords, from a while ago, a spare earth strap.

Got to the place, Polish mechanic geezer pointed out everything he'd checked and tried fettling (pretty much everything, at least everything you'd find on a fiat 126, even had the airbox off to play with the plugs and sensors, changed the dizzy cap etc)...... and some small earth wires with ugly looking melted insulation... at least one looking like it pointed towards the ECU. Plus the alternator earth that he thought looked dodgy.

Indeed, it would happily turn over (on jump leads), but do absolutely nothing else. I broke out the multimeter and started messing about with the power leads on the injector as i reckoned that was at fault. But there was a steady 10V AC coming down the cable at certain times (reckon that represents 100% of usable injector duty cycle vs 12V). Unexpectedly it caught and ran for a few seconds during this.

Then noticed fuel tank was empty. As in utterly, completely, no movement on the dial empty. The kind of emptiness i've never previously witnessed, that comes of running past the usable reserve and then leaving it sit a week for the dregs to evaporate. Put a full 5L jerry can in and carried on playing. Some funny noises, caught, revved up, sprayed gunk everywhere from the breather. A little play after that ended in a massive jet of fuel out of the injector, blasting off the throttle butterfly and going all over.

So, looks like the earth strap has screwed the ECU, which has locked into ultimate throttle mode.

New earth strap + ECU = Car catches and idles ok. Smiles
Then when i rev it briefly (still without airbox), another jet of gunk. Quickly kill power and investigate.
It's not coolant as my fingers dont burn when i touch it, the paint isnt bubbling, and it smells more of paint stripper than pancakes.
Guess that big jet of fuel wasn't the first. The oil channels are packed with petrol and the breather's shooting off some of the excess.

Whip off to halfords (IN DIFFERENT CAR!), get a new filter and bottle of oil. Open drain plug and decant the far-too-fast flowing stuff into the empty fuel can (nearly get knocked backwards). Can't get rid of filter; forgot to get handwipes at the same time, cant get a grip and dont want to ruin half decent coat/shirt (already topless). Settle for refilling oil and letting it be.

Whizz it round the car park a couple times; go to get cleanups; find the disagreeable git who was watching me go through this trial (and i shouted across to, i'm just going to get something to clean all this up with...) has locked the place up when i return and let the guard dogs out. Sod.

If it breaks down again, though, Uncle's on his own apart from me giving remote advice (and some web addresses!). I don't think there's anything else now that I can be held responsible for OR easily fix.