XR8 running very rough

[BillC]

Missus took the XR8 out last Saturday and gave me a call at home saying the car is shaking. When I got there I started the car and it looked and sounded like it was running on 5 or 6 cylinders. Its done 92,000 and I had just bought NGK iridium plugs so I put them in and it made no difference. I took it to a mate of mine who used to be a Ford mechanic and he pulled some of the leads out and it looked like No. 7 lead made no difference so he suggested it could either be the HT leads or the coil pack. I then went and bought new HT leads and guess what ? Still no difference. I then went and bought a coil pack and again no difference. Any ideas ? I have reached my limit as to what to try next.

[james22]

uh-oh, I don't like the sound of that. Maybe a broken valve spring on No 7. Fairly common on them too...

[xr8ute]

I would be doing a compression test on each cylinder, paying particular attention to cylinder 7.

Its pretty quick and easy to do. Compression testers are like $20 from Supercrap if you dont already have one...

[BillC]

I have it booked into Ultratune tomorrow. So if its the valve spring hopefully they will be able to tell me. Finding a good mechanic in Townsville has proven very difficult. I am hoping Ultratune are OK. Each time I took it to the Ford dealer for the warenty service I kept getting it back with problems they introduced. I have a bit of mechanical knowledge so I do most of the mechanical work myself but I have my limits. Valve springs sounds like one of them.

[b2tf]

been here done this, doesnt have a Unichip does it :hihi:

Its pretty easy to check if its a valve spring or not, I have done it and I am not by any means any good with mechanics.

[BillC]

No unichip. What are your thoughts of driving a car when its running so rough and not knowing why. I have to drive it about 30 K to get to Ultratune. I would hate to think I am doing it more harm.

[b2tf]

Originally Posted by BillC

No unichip. What are your thoughts of driving a car when its running so rough and not knowing why. I have to drive it about 30 K to get to Ultratune. I would hate to think I am doing it more harm.

if it were me (having been in this situation before), id check it. i had to make a decision as mine was in my driveway when it spat the dummy, and i had to get it to the mechs on the other side of town. If it is a valve spring and it jams on the way, you could be up for major dollars in repair work.

There is a thread where I asked all the questions about how to check the valve springs myself, it took me a while but I learnt a lot along the way. I'll find it for you, and Id strongly suggest you do. Best case is you will find they are fine, worst case is you will find the problem.

[b2tf]

http://www.fordforums.com.au/showthread.php?t=79540

[BillC]

Thanks, I'll have a look this afternoon. I don't have any rattle in mine at any revs though. But my symptoms don't sound much different to the thread. In the thread it didn't say it ended up being the valve spring. Is that what it was?

[b2tf]

Originally Posted by BillC

Thanks, I'll have a look this afternoon. I don't have any rattle in mine at any revs though. But my symptoms don't sound much different to the thread. In the thread it didn't say it ended up being the valve spring. Is that what it was?

nope, in mine it was the unichip

[bodes-sh]

i remember someone mentioning in a thread similar to this that it could also be the injector, i'd also check for power at the no7 injector, if it has power, put some cleaner thru and see what happens, if not, you'll need to replace it

[GT290]

is this a common thing just for the 260 or does it happen on the 290 also. Does the 290 have a stronger valve set?

[b2tf]

Originally Posted by GT290

is this a common thing just for the 260 or does it happen on the 290 also. Does the 290 have a stronger valve set?

er, we're talking about AU's?

[BillC]

Ultra tune has been right through the car today. They found that unplugging the HT lead from No 7 and No 4 plugs make no difference to the car when its running. They found that the plugs were not wet on either plugs when they removed them. He checked both injectors and they were fine. He has now come to the conclusion that its more than likely the computer and has suggested sending it South to be tested ($90) if its faulty it will cost $270 to repair. He has said he will only charge me $80 for the diagnostics and the cost of the repair if its the computer. Sounds reasonable to me. I just hope it gets fixed.

[NeishaXR8_347]

Originally Posted by BillC

Ultra tune has been right through the car today. They found that unplugging the HT lead from No 7 and No 4 plugs make no difference to the car when its running. They found that the plugs were not wet on either plugs when they removed them. He checked both injectors and they were fine. He has now come to the conclusion that its more than likely the computer and has suggested sending it South to be tested ($90) if its faulty it will cost $270 to repair. He has said he will only charge me $80 for the diagnostics and the cost of the repair if its the computer. Sounds reasonable to me. I just hope it gets fixed.

But has he done a compression test? The comp test should have been done while the plugs were pulled out. I doubt its the computer but try and disconnect it for an hr or so and see if it improves.

Shaun

[xr8ute]

Originally Posted by NeishaXR8_347

But has he done a compression test?

I was thinking the same thing....would be weird if they skipped this (?)

[BillC]

Because its on no 4 and 7 its unlikely to be anything to do with valve springs etc. 4 and 7 are on opposite sides of the engine. Its an electrical problem. The spark plugs on both pots were dry and advice given to the mechanic was that the injectors are probably not getting a signal (or strong enough signal) to operate

[BillC]

Just an update. Seems that the computer checked out OK. Just to re-cap. Car running on 6 of the 8 cylinders. Replaced spark plugs, HT leads, coil pack. Still no improvement. Took it to Ultra Tune in Townsville. They checked spark plugs, HT leads, Coil pack, compression on all cylinders, injectors and came to the conclusion that it was probably the computer. Sent computer South to get checked and all was fine. I asked the mechanic if it could be one of the sensors and he said they all checked out fine. Any suggestions ?

[xr8ute]

Originally Posted by BillC

Any suggestions ?

Find a better mechanic.

[Umineko]

I have a Brother in Townsville who's a Ford trained mechanic, I'll call him tomorrow and see if he'd be prepared to look at it for you if you want, I'll PM you if he's ok with it. If it's a go I'll give you with his phone number and you can get in touch.

[hatch]

I had rough running on my ef. It could of been many things. In the end it was one lead not plugged onto the spark plug properly.I had put in new plugs and was careful in reconnecting the leads and the car ran great for about two weeks. And then it started to run rough. I bought new leads but when I was replacing them I noticed one lead had carbon or a black look where the others were clean. I now know to make sure those leads are on properly. They're a tight fit so I lubed the rubber and they slipped on easier. Good luck!

[nitroman]

I have found on xr8's the connectors going into either ends of the coils get corroded and dirty causing a misfire. They are a 3 pin connector and from memory it's the middle one that gets dirty. Remove each pin one by one (by pushing them out of the connector block with a little screwdriver) then clean the inside of the connector with contact cleaner and scrape with a tiny screwdriver/knife. Check that the coils and coil mounting bracket are tight (in case of a poor earth connection)Try this before you spend more money.

[Free347]

Take it to Doig Automotive - 4/25 Keane Street in Currajong (4775 2917). Graham (Doig) is very good and knows his Fords.

[5 FTR 5]

the problem i had sounded like yours ,plugs,leads they even changed my computor saying it was faulty.Ended up being on mine the heat sheilds on the plug leads was causing the spark to earth to the heads.
When they where removed the problem went away.

[Umineko]

My brother is too flat out to look at it but as Free347 said Doig knows his Fords, doubt you'll find better up that way