AU II Slow/bad acceleration with shuddering -why ?

[dc33]

Hi all,

Whilst driving home from work the other night, the engine suddenly started to "shudder" when I accelerated to speed up (as you do when you need to get in front of a truck - without flooring it). As it happened last Friday night, I spent the whole of Saturday troubleshooting what I thought was obvious like:

* replacing fuel filter
* replacing HT leads and plugs
* Nulon fuel system clean into fuel system, however this has not solved the problem.

The last thing to go (I think) is the injectors.... ?

I have searched the forums here for similar troubles but have not found a similar entry, so I hope someone can help.

As far as the car is concerned, it starts and idles like it should, but when I try to accelerate quicker than normal (mid range or more I guess you could call it) the engine shudders with no response and I may as well be driving a mule drawn cart!!! HOWEVER... if I accelerate "moderately" the engine seems to respond ok'ish.

Would this be due to the injector(s) being dirty (suddenly due to bad petrol) or something else ?

Any pointers would be appreciated.

[bodes-sh]

few things to try, clean the throttle body, check/replace the fuel pump, check/replace the coil pack, give that a try and see how it goes

[Brisbane ghia]

could be a vacuum leak, or maybe water in your fuel?

[ratter]

2nd vote for coils, a vacuum leak would show up at idle not under acceleration

[dc33]

OK.. silly q'n...Is there an easy way to confirm the serviceability of a coil pack or not? where exactly is it in the engine bay ? Do I need to replace it in order to prove the point or is there a quick test ?

[ratter]

measure the resistance between the coil posts, the coil pack is under the inlet manifold, just follow the leads, it is at the end of the leads, you would have to pull the leads off it when you replaced them.

[dc33]

OK I see, no worries there, but if there is something wrong with the coil, is there a certain resistance value I should be looking for ? (min or max ?)
Thanks

[ratter]

Not sure of the specs at the momment, but you measure the posts on each opposite side of the coil (imagine the coil pack is 3 seperate coils), each of the 3 coils should give very similar readings, if 1 of them is different, it is stuffed

[FGII-XR6]

are you sure it's the engine with the shuddering it could be a tranny problem if the engine shudders it would more likely be something major mechanically i could be worng of course but something to consider

[dc33]

Its the engine alright. I have done a few tests and it isnt the way it was before. I am wondering whether a batch of bad fuel could cause all this, and IF SO.... will it go away once new fuel (good stuff) s put though the system ?

[FGII-XR6]

if you think it's fuel get as much out as u can and tip a bottle of metho in before you refill it the metho lets any residual water ( the most common contaminant) mix with the petrol and pass through in small quantities reducing dramas

[dc33]

Will give it a bas I s'pose... Any idea of the safe level of metho is before I go any further? ... like 1/2 a tank = 500 ml metho etc.?

[JC]

If you are going to chuck metho in, you won't need much. 100mls would be heaps. I wouldn't put the metho in, but it's your car.

Also check your inlet manifold bolts, and while you're at it, exhaust manifold bolts as well. I doubt it's them, but worth eliminating as a potential cause.

[FGII-XR6]

Originally Posted by JC

If you are going to chuck metho in, you won't need much. 100mls would be heaps. I wouldn't put the metho in, but it's your car.

Also check your inlet manifold bolts, and while you're at it, exhaust manifold bolts as well. I doubt it's them, but worth eliminating as a potential cause.

a full bottle to a full tank will do no harm on straight petrol not ethanol blend (this is only a mix of 68 to 1 and they do 10% ethanol blends) and dissipate any water you have in your tank mechanics have been doing this for years but bear in mind it won't remove other contaminants, but water is the most common contaminant anyhow

[peterban]

Could be fuel pump starting to give up the ghost.
It might not be able to deliver enough fuel when you really need it.

[dc33]

Well, it seems like it ain't the fuel as no spluttering happens when on a cruise (steady) speed. I reckons that it may be a sensor issue but yet to find out. Bought me'self a DIY manual today and see that it could be this or that (as always) and I am yet to figure it out.

The car still runs ok as long as I don't ask too much, but if i'm gonna drive a 6cl car, then I don't want it to feel like a 4.

Does anyone know if the throttle position sensor may have anything to do with it maybe ?
Cheers

[dc33]

Problem fixed by local mechanic - non Ford

[JC]

Originally Posted by dc33

Problem fixed by local mechanic - non Ford

And???? What was it? Dodgy lead?

[dc33]

Hi JC,

I knew someone would ask. Good to see someone is paying attention

I replaced leads/plugs and fuel filter without luck....... so,

After I rang my closest Ford repairer who shall remain unnamed due to lack of willingness to troubleshoot the issue over the phone and insisted that I take the car in for a diagnostics check blah blah, I decided to pop into the local garage. Spoke to the mechanic there and before I could finish my story he bluntly said it was a blocked injector; if not a few. He offered to do the job of cleaning the injectors on a rig and reverse flow them etc, for $260. As I wasn't keen on spending money just to find that this would not fix the problem, I asked "what if it doesn't fix the problem"? He laughed and said, "mate, if it doesn't fix the problem - you owe me nothing as I will foot the bill - that's how confident I am !!"

So there you go people.... speak to the local garage mechanic first.

Just out of interest for someone who may need to know, Ford sells the injectors for a mere price per unit at $120 + GST ($792 total) plus labour (price unknown), but then again I would do this myself.

I asked my local Repco branch and they quoted me $240 for the set of six - mind you these are reco units and they are also require your old ones back (exchange price).... Bit of a difference would you not agree?



Cheers,

[theshermans]

Hi DC33,

I just got back from a holiday drive with my Territory (2004 Ghia RWD, 85,000kms) and it demonstrated the EXACT same behaviour. Runs fine at all speeds but if you are doing 100km/h and need to accelerate to 110km/h it shudders badly.

I am grateful I found this thread as you seem to have done a lot of trouble shooting - thanks for posting - it really helps.

My questions:
1 - Is the problem still fixed?
2 - Any chance you are Sydney based and can point me to the mechanic that did the work (I have a feeling that if I call up my usual guys they will doubt this diagnosis and want to charge me a fortune to figure it out for themselves. They will also likely simply want to replace the injectors which as you point out, it much more expensive).
3 - Any other advice would be much appreciated.

Cheers
Kevin

[rag top]

DC33 hasn't been on here for a while -Last Activity: 20-11-10 01:57 PM

[theshermans]

Ah - thanks for that.
Anyone else know of any good mechanics in the Sydney eastern suburbs area that would take care of this for me at the price DC33 mentioned - around $270?

My guess is that most would simply rather replace injectors than try to clean them... so could be a bit costly...

Cheers
Kevin

[4ford]

You may want to try the Mobile Injector Service guys, they will come to your door and will clean or replace as required, usually in my experience at a reasonable price.

Try the web or your local 'book, you may be surprised!

Cheers,
4ford