Injectors problems?

[s1.5f]

Happy New Year everyone. Just thought I'd do the traditional thing and post on a new owners problem... Symptoms are; juddering/shaking at low revs with rich smelling emissions and a constant misfire throughout the rev-range which is loads worse when throttle is only feathered at say 1500 - 2000 revs (at higher revs pefomance fine but the car sounds like my old aircooled VW a sort of cyclical 'thrumming' noise). I have tried:

Removed throttle pot - whole car feels more responsive, the misfire is still there but juddering loads better. when I reconnect the revs shoot up to 1500 at idle
Two tank loads of RedX injector cleaner
Higher octane fuel - better performance but no overall change
Retarded ECU timing for 95RON UL - no change
Sprayed loads of carb cleaner into air intakes
Removed plugs - all were perfect browny colour except no. 5 which was very black and sooty, renewed plug for same (NGK BCP6ES) but symptoms same. Tested ignition system with flash tester and all OK. Magnecor leads and coil, motocraft dis cap/rotor.

As I'm getting a very rich mixture on only one cylinder my current thinking is either the injector is stuck open mechanically/electrically or the plug has a weak enough spark to cause the fouling??? If you agree can I test and how easy are the injectors to source and fit?

>>> Edited by s1.5f on Sunday 4th January 18:21

[Rozza!!!]

I can't confirm what you are suggesting, but it does sound logical. Sorry I can't help.

Roy.

[mikee boy]

If you suspect a weak spark on that cylinder, check the contact in the dist cap, and change the plug lead and plug with another cylinder you know is working. That way you'll eliminate the ignition side from the problem. If the No5 is still fouled then it points to the injector being faulty, if not then the other cylinder you did the swap with should be fouled and then it is the ignition system. CORRECT FUEL MIX + SPARK + COMPRESSION = BANG!


ps. I always find a quick call to a decent Ford garage may give you an insight to a problem you hadn't thought of.

[M@H]

Could be a dodgy coil.. just a thought..
Cheers,
Matt.

[Hood38]

Sounds identical to the problem I just fixed. My S2 was doing all the things you mention until eventually it wouldn't start. It took a look in the dark one evening and could see a whopping spark from the LT side of the coil to the HT lead. Pushed it back in, sprayed with WD40 and all seems OK. Car has never run this well before so the problem must have been there for ages.

[greenv8s]

I had the V8S injectors cleaned a few months ago, apparently the spray pattern was pretty bad and this has become a common problem in recent years. Theory was that it was something to do with changes in petrol composition, but whatever the cause it's definitely a problem that is becoming more common.

[s1.5f]

Hood38 said:

Sounds identical to the problem I just fixed. My S2 was doing all the things you mention until eventually it wouldn't start. It took a look in the dark one evening and could see a whopping spark from the LT side of the coil to the HT lead. Pushed it back in, sprayed with WD40 and all seems OK. Car has never run this well before so the problem must have been there for ages.

Must admit I haven't checked in the dark but I used a flashtester on each plug lead and the results were all good, I'll give anything a go though and am thinking of replacing the entire system (minus coil)

greenv8s said:

I had the V8S injectors cleaned a few months ago, apparently the spray pattern was pretty bad and this has become a common problem in recent years. Theory was that it was something to do with changes in petrol composition, but whatever the cause it's definitely a problem that is becoming more common.

Peter

Where did you get them cleaned and was this preferable to replacing?

[greenv8s]

s1.5f said:

Peter Where did you get them cleaned and was this preferable to replacing?

Tower View took them off and sent them away to be cleaned for me while they were doing other things on the car. Much much cheaper than replacing them.

[s1.5f]

Hood38 said:

It took a look in the dark one evening and could see a whopping spark from the LT side of the coil to the HT lead.

Peter, Thank You I don't believe it thought I'd have a look tonight 'just in case' and I've got a s*dding disco going on under the bonnet too ! However I tried cleaning, pushing and all but spark stubbornly refuses to disappear albeit at much lower strength. I'll try a new coil and lead tomorrow, but would this cause a single plug to run weak or have I numerous problems...

[s1.5f]

OK, spent the weekend spending loads of time and money to no avail, replaced complete ignition system dizzy, rotor, leads, coil, plugs, sussys. Slightly better juddering but still the misfire, I have been quoted £170 approx (+ vat) to strip and clean the injectors... before I pay I wanted to check if anyone has got any ideas on other causes for the single sooty plug? I've spoken to Gadgit and the valve clearances were set recently so not that. Plenum camber blockage, is it possible for something to block the airflow into this single cylinder? (need to get a Granada haynes manual I think!)

[Roy_S2]

I can't see it being an airflow blockage. Is the sooty plug dry or wet? Have you had compression tested?

Roy.

[gadgit]

Good news Simon,

I've got a Granada manual and its now yours for free!
I'll send it on.
If you know for certain which injector it is, replace that one with either a new one or one from a breakers.

Take out the plug for that cylinder and check the spark on the plug! If thats ok its the injector. Check the conector is on ok and the conector is clean.

To do this pop of the plenum chamber, all is then revieled in front of you. you will see all the injectors from what I remember. Remove the throttle cable and release the pressure on the fuel rail ( little tyre pressure looking thing) take the fuel rail off and then you can get to the scumbags that are hopfully causing the problem. The book says if they are faulty they must be replaced as no spares are available. Buy a new set of injector seals as well for the job. Easy! Well I would say that!

I'll see if I have some seals, I think they came with the Head set, I'll have a look round tonight.

Gadgit.

[s1.5f]

Cheers Pat, not the plugs or leads as it's now had 3 fitted and each one 'soots' up (dry) after about 200 miles. I do remeber having a problem on my BMW bike which had stood for a couple of years and the petrol had evaporated from the injectors leaving a horrible sticky mess behind which I was able to blast through with carb cleaner! I'll definately check the connection, is it safe to put a multimeter across them and any idea on the expected readings?

I did think of a compression test but as the plug is completely dry black hoped this wasn't an issue?

[andyf007]

If it's black and dry, then I would go along with an injector problem, a mis-fire would be wet, rings gone would be oily. I would start by checking the connector to the injector first, make sure it's clean and there's no moisture in it. If that's OK, then either have the injectors cleaned or replaced. Personally I would take it out and try a blast through with the carb cleaner myself then fill it with neat STP injector cleaner and stand it upright in a small container of the stuff (2cm deep) overnight, but then I don't like spending money.

You could get one from a scrappy too.

Andy