Really strange ignition problem....

[jacko 0]

Afternoon guys,

 

Ive got a pretty strange problem with my valver, every now and then it will decide that its had enough and start miss-firing, backfiring and just refusing to rev.

 

Today is the 4th time it has done it. Twice just before xmas, the AA came out, cleaned out the dizzy cap and it was fine until it happened again. The last time it happened was when i took her to get MOT'd, the Mechanic went to reverse it out of the MOT bay and it was doing exactly the same as it was today. The garage mechanics are pretty good mates so they spend about an hour checking every thing over. in the end it worked fine and they didnt do any thing to it other than look at everything.

 

I have just ordered a new dizzy cap hoping this will fix the problem but i wont know until it happens again in another 2 months time!!

 

Has anybody had anything like this happen to their valver and if you have what caused/fixed it?

 

thanks in advance

 

Pete

Edited September 3, 2011 by jacko

[boost monkey 0]

Never had it happen, but Ignition module perhaps? I hate diagnosing wiring issues cos they don't get fixed with the lash of a hammer :/

 

Might also be a fuel delivery or dirty fuel problem. Does it ever hesitate like you've just put your foot on the brakes?

[jacko 0]

Thanks for your reply, Yeah it feels just like that when it hesitates but as soon as i take my foot off the throttle it will idle fine again

[easypops 8]

5th injector overfuelling?

[jacko 0]

How would I check the 5th injector?

All the injectors are original as far as the service history goes and have done 185k miles lol so they are next on my loooooong list of things to do

 

Cheers!

[easypops 8]

Just spotted you have an abf engine, if its like the 9a(i know they are similar) then the 5th injector(cold start) is in front of the block. Follow the fuel lines and its the one not on the engine.........on my 9A it was faulty so just unplugged it(electrical connection) with no adverse effects(4+ years)

[jacko 0]

Ha brilliant!!

Yeah the ABF lump is pretty much the same but i kept all the original 9A injection system so the injector is there.

I will see how the car behaves on the way home and if it starts having the same problem i will unplug it and see if it helps.

 

I really do hope it is something simple!!!

 

Thanks again!

[dannyboy 0]

Dizzy retaining bolts loose? had it on my old gti valver caused the same prob and slapped myself for forgetting to tighten them up

[jacko 0]

Hello again!

 

After a week or so driving the raddo about with a new dizzy cap and the 5th injector unplugged it is still doing the same thing and it is really starting to get on my nerves!

I have noticed that when the engine starts lagging the rev counter needle is bouncing all over the place! Its got a new coil on there, new spark plugs but im thinking would the HT leads cause this really intermitant fault? I also had a random thought that could the ECU or dizzy itself be playing up? is there any thing thing i have missed?

 

any thoughts?

 

Thanks again

Pete

[easypops 8]

My old valver(2.0 16v 9A) had a bad idle/bad running problem for ages...........i found the fault more by luck than anything else...........2 of the 3 wires that plugged into the throttle potentiometer were broken, not visible though as the plastic sheathing was still intact, but once i had stripped the wires and rejoined them , no more bad behaviour.

Start by looking for any air leaks around the throttle body, 2 small vaccum pipes on the underside of the rubber boot at the TB need to be on(in case one or both are loose), then check the isv and related pipework, then check all the wiring for the isv and the throttle potentiometer. Also look at the fuel metering flap thingy(sits on top of the airbox)

 

Good Luck :)

[davidwort 0]

my bet is on the hall sender breaking down, replacement dizzy needed or change hall sender in your current one (need to press out pin on dizzy shaft)

[jacko 0]

I took the car to my mates garage middle of last summer after i had compleated the engine change and he found i had cocked up all the vacuum hoses and managed to break 2 of the 3 wires that connected to the throttle body switch. so they are both sorted by a professinal mechanic unlike my attempts!

I also had a really bad idle problem for a while where the revs would just bounce all the time, i checked, cleaned everything until i discovered the little rubber grommet on the idle screw had totally perished. changed that and its been perfect apart from this intermitant fault.

 

I think a new dizzy is about £60ish so it might be worth getting 1 as its probably pretty worn out!

 

Thanks again

[aide 0]

yeh as above, hall sender on way out.

[jacko 0]

The problem continues... :(

 

I got a new dizzy and fitted it yesterday but i still have the same intermintant fault, any more ideas what could be causing it?

 

ive been trying to work it out, could it be anything to do with the ECU?

There seems to be a fair bit of un-burnt fuel getting into the exhaust when the problem occours

[jacko 0]

I have taken a quick video of the rev counter dancing this morning on the way to work. Can anybody please help me?

I use the car as a daily for work and its just starting to get on my nerves now as when i need the power to pull away i have nothing apart from back-firing

 

 

click to view video...

 

thanks in advance

Pete

[easypops 8]

Mine used to do a similar thing..............Throttle Potentiometer

 

http://the-corrado.net/showthread.php?28407-bad-idle-2.0-16v-SORTED-!!!!&highlight=potentiometer

[jacko 0]

The idle is fine tho :( and it revs up fine some times. Its a really intermitant fault. When the needle starts dancing around the car will not rev without the exhaust popping like there is un-burnt fuel getting in there.

 

Im constantly looking at the rev counter expecting it to happen when im sat at a junction just when i dont want it to happen. when it does im buggered, ive been left stranded in the middle of roundabouts a few times while im trying to get the revs up high enough to let me pull away without it cutting out

[easypops 8]

Mine did it at idle and also while on the move, very similar to yours, bit of a distant memory though. If it was me i'd be waiting for it to happen and get under the bonnet and unplug the tp, the isv, the flap thingy on the airbox and see if there is any noticable change. Then check all hoses for air leaks etc

[jacko 0]

well... it all went wrong this evening on the way home form work. The car ran perfectly for the first 5 miles of the journey home and then all of a sudden it wouldnt rev at all, like it was about to cut out if i put my foot on the throttle. so i rolled to a stop and somehow managed to break down outside my girlfriends brothers house so went inside put the tv and kettle on and called up the AA.

 

He showed up within about 20 mins and it turned out to be the same guy i have had a few times in the past! he scratched his head for about 20 mins and couldnt work it out so he towed me to my mates garage and thankfully he was still there. he had 1 quick look at it and asked if i had checked if the speed sensor which i havent, i dont know where it is! He is going to have a go tomorrow and let me know and hopefully its something simple and doesnt cost much

[deliripper 10]

I had a similar problem on my G60. That video gives me the creeps. It turned out to be the power relay for my ecu. The book referred to it as the Digifant control unit Relay.

Best of luck

[farrantino 0]

has your tb got the two micro-switches on it ??

[jacko 0]

believe it or not i havent had this problem since i posted this back in april, but jus the other day it did it again! still have no idea what it is and the garage have said they cant do anything about it as its sooo intermitant.

 

there is only 1 switch on my tb and that was recently re-wired. ive got a funny feeling it might be my ignition switch, as the radio hasnt been turning on sometimes but if u wiggle the key it works.

a trip to euros me thinks!

[jacko 0]

OK, so its started doing it again :( more often this time tho. Every morning for the last week, when the car is started from cold the rev needle starts bouncing and the engine starts being very unresposive. normally to get rid of it i just blip the throttle a couple of times and it stops but today... it didnt, all the way to work it was spitting flames and being very slow. Does anybody have any ideas? i got another video of the rev needle dancing again, ill upload it later today and post it here, its pretty freaky!!

 

Thanks guys

 

---------- Post added at 09:17 AM ---------- Previous post was at 09:06 AM ----------

 

Here it is....

http://www.youtube.com/watch?v=AifH7f8MtbE

[pumbaa 0]

If its still running 9a injection it could be the injectors. As they reach the end of their life they tend to get stuck open, dripping fuel into the cylinder overnight which would explain the startup backfiring and massive hesitation when pulling off at roundabouts etc.

 

All my Rado stuff is back at my folks and im not on the forum much these days (the C is in storatge until i can afford to insure her again, my premium went up by £1000 this month and my situation hasn't changed at all! The insurance company said it was because of the insurance premium rises and my area is now 'high risk') but if i head that way i have a few spare (old) injectors that are working i can send you for a tenner. No idea when im heading that way though. sorry buddy.

[jacko 0]

yeah it is still running the orginal injection system and as far as im aware the injectors are what came with the car 20 years ago and 190k miles too, probably wayyy past their best lol. i'll deffo take those injectors off you for a tenner, cant be any worse than what ive got!

 

as for the backfiring and hesitation it does it anytime and i would of thought it would of cleared out the system by the time i got to work 10 miles later and it was still popping and hesitating, it has to be the HT leads as thats the only part of the ignition system i havent changed yet lol

 

fingers crossed they are at home waiting for me