Running like a bag of nails?
Discussion
Right where do I start, my car (94 Chimaera 4.0) running has gone down hill rapidly this last week, to start with theres a clonking noise on startup from the back end 
which is there during stop-start driving aswell, I've had a quick look underneath but don't really know what I'm looking at, then theres the idling, or lack of, every so often the revs die at idle causing the car to stall at lights or junctions, and when its moving at times it sounds like it's running on 7 cylinders, it also seems to be chucking out a lot of soot, anyone got any ideas other than drive to dealer asap and hand them large sums of cash 
Could dodgy petrol be the cause as I have recently changed brands, I've now changed back just in case but it was still rough this morning
which is there during stop-start driving aswell, I've had a quick look underneath but don't really know what I'm looking at, then theres the idling, or lack of, every so often the revs die at idle causing the car to stall at lights or junctions, and when its moving at times it sounds like it's running on 7 cylinders, it also seems to be chucking out a lot of soot, anyone got any ideas other than drive to dealer asap and hand them large sums of cash Could dodgy petrol be the cause as I have recently changed brands, I've now changed back just in case but it was still rough this morning
try cleaning your stepper motor first to see if that helps your idle problems and your clunk sounds like a worn UJ on the drive shafts or prop shaft, check to see if your rubber UJ boots arent split, if they are then the lubricating grease will escape and leave the UJ's dry which leads to premature failure,either way you need to check this out sooner than later.
heliox
heliox
Depends if clunking is whislt moving or standing still, if the clunking is on start up aswell as moving off, it can't be the UJ's, more likely the exhaust knocking against something, may be especially true is the engine is missing and shaking in the car more than normal.
It may be something as simple as the plugs or plug leads, first check all are fitted on ok, and none are loose or suffering from damp. The shrouds over the plugs can fail and cause a misfire, a dealer should be able to diagnose quickly.
It may be something as simple as the plugs or plug leads, first check all are fitted on ok, and none are loose or suffering from damp. The shrouds over the plugs can fail and cause a misfire, a dealer should be able to diagnose quickly.
Sound like its running way too rich, fuel injection problem possibly? injector jammed open is a possibility, get the car to a specialist, if the knocking is when static and from the back of the car, probably only the exhaust as the engine is moving more than normal due to uneven running.
The knocking is evident when stationary, had a look at the exhaust on Saturday and it all seemed fine, but the engine wasn't running, keep the suggestions coming at this rate I'm going to have to get a Saturday job to pay for it, only problem is it's a daily driver, trying to book it in somewhere asap
2 Sheds idea on the exhaust was a good one, I forgot that the exhaust knocks on the chassis if its adjusted too high on the rear hanger,try lowering the rear a touch..
If you have checked the exhaust and all is fine then look at the drive shafts next.
heliox
>> Edited by heliox on Monday 22 July 10:14
If you have checked the exhaust and all is fine then look at the drive shafts next.
heliox
>> Edited by heliox on Monday 22 July 10:14
sorry to hear about the trouble. I've just been through similar problems, and from that experience I'd say that plugs, leads and distributor rotor arm are the bits that are pretty easy to check. If they all seem okay, you'll really need a fault code reader for the ECU before you can go much further. Given that there are loads of things that can go wrong with the fuel injection system, at that stage it'll probably be worth getting someone with experience and the right equipment to look at the car. From what you've said about sooty exhaust, I'd be worried that your cats may be being damaged by unburnt fuel.
Well I leave it in carpark all day, don't touch a thing and it runs fine on the drive home, guess it doesn't like Monday mornings, it's still running rich though, one of the banging noises was indeed the exhaust hitting one of the petrol tank bolts, thats now adjusted, and we'll see what it's like in the morning? 
It was fine this morning, strange thing is the rough running coincides with switching TO Optimax, now I'm back on Esso Unleaded it seems fine 
Cleaned the stepper motor, checked dizzy/rotor arm, checked plugs, still a bit sooty though, see if it's the same after this tank of unleaded?
Cleaned the stepper motor, checked dizzy/rotor arm, checked plugs, still a bit sooty though, see if it's the same after this tank of unleaded?
If the engine has been adjusted to run on unleaded 95 octane it may be that the optimax is causing the plugs to soot up and hence misfire ( especially when cold).
The rover engine mgnt system does not adjust timing, it's set statically ( the old way) via twisting the distributor so it may be your car was adjusted to run on 95 octane rather than the 97/98 superplus/optimax level. Most modern engines have knock sensors which allow the timing to be altered by the EMS to tune the timing based on the quality of the fuel.
The rover engine mgnt system does not adjust timing, it's set statically ( the old way) via twisting the distributor so it may be your car was adjusted to run on 95 octane rather than the 97/98 superplus/optimax level. Most modern engines have knock sensors which allow the timing to be altered by the EMS to tune the timing based on the quality of the fuel.
On Optimax it was costing £5 a day and it's only a 15 mile trip 
Did you ever resolve the uneven running problem? I just took over a 450 with about half a tankful of whatever fuel that came with the car. Not wishing to test the accuracy of the fuel guage on the long run home (!) I filled up with Optimax. Probably around one-third was old plus two-thirds Optimax. Then, after about 20 miles I noticed a gradual change in the deep base section and it sounded like one or two of the players got up and left. Now I'm left with a car that sounds/feels like its timing is all shot to pieces. (still grinning though!). It's not just when cold starting - I did around 70 stop start miles through London today (temp never got above 85 - thanks Otter!). The missfire was still evident at the end of a 20 mile blast down the A3 on the way home.
SMB posted that there's no facility for the timing to adjust on the rover v8 and this engine may have been set for less Octane than Optimax.
So should I pay to have the electrics diagnosed and reset to run with Optimax or go back to a standard super unleaded? I reckon on doing about 6-7 thou a year. Or should I soldier on and use up this tankful of Optimax then go back to a cooking brand of super. Decisions, decisions!
Anyone got a view on whether I'm doing any damage (to the cats?) by running the Optimax through without changing the timing?
What's the long term benefit of changing to Optimax with the associated incremental cost of timing reset and premium priced fuel?
Maybe there's a coincidental failure somewhere (coil/HT/plug leads insulation failing in the heat?) that may be obscuring things....but I think the fuel thing is guilty until proven innocent.
Thanks in advance for any thoughts
Hutch
SMB posted that there's no facility for the timing to adjust on the rover v8 and this engine may have been set for less Octane than Optimax.
So should I pay to have the electrics diagnosed and reset to run with Optimax or go back to a standard super unleaded? I reckon on doing about 6-7 thou a year. Or should I soldier on and use up this tankful of Optimax then go back to a cooking brand of super. Decisions, decisions!
Anyone got a view on whether I'm doing any damage (to the cats?) by running the Optimax through without changing the timing?
What's the long term benefit of changing to Optimax with the associated incremental cost of timing reset and premium priced fuel?
Maybe there's a coincidental failure somewhere (coil/HT/plug leads insulation failing in the heat?) that may be obscuring things....but I think the fuel thing is guilty until proven innocent.
Thanks in advance for any thoughts
Hutch
I can't believe the 1 octane differene between Optimax and normal Super makes the difference you're describing. More likely a dodgy supply or something needs a quick cleanout on your car. Maybe you should run it on 95 octane for a few tanks and see what happens.
Usually dealers retard the timing to prevent pre-ignition (pinking) on 95 octane (normal) unleaded, so IF yours has been retarded, it will need advancing a little - only get someone who knows what they're doing to play with this though, you could lunch something by advancing too far.
Usually dealers retard the timing to prevent pre-ignition (pinking) on 95 octane (normal) unleaded, so IF yours has been retarded, it will need advancing a little - only get someone who knows what they're doing to play with this though, you could lunch something by advancing too far.
I had a long chat with a very well informed member of the technical team at Millersoils recently regarding fuel additives and Shell Optimax,he said fuel additives (octane boosters lead replacement etc)can 'go off' seperate in the tank if left unused,this apparently happens to Optimax.So if the filling station is out in the sticks with a low turnover and fuel sits in the tanks awhile it's possible get a bad tank full.He suggested(where possible) buying Optimax from a busy garage with an high fuel turn over.
Gassing Station | Chimaera | Top of Page | What's New | My Stuff