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Discussion Starter · #1 ·
Can anybody tell me if a lumpy idle is normal on the Rover 45, I had the same thing on a previous Rover 400. I've tried everything on the 45 to cure it, cleaned the IACV, new plugs, checked and cleaned the plug leads, checked and cleaned all sensor connections (as best as I can). I've recently changed the throttlebody to a new 52mm from the 48mm, but it's still there, is it just me being to sensative.

Any advice appreciated.
 

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cjsale said:
Can anybody tell me if a lumpy idle is normal on the Rover 45, I had the same thing on a previous Rover 400. I've tried everything on the 45 to cure it, cleaned the IACV, new plugs, checked and cleaned the plug leads, checked and cleaned all sensor connections (as best as I can). I've recently changed the throttlebody to a new 52mm from the 48mm, but it's still there, is it just me being to sensative.

Any advice appreciated.
No it is not normal.

Can be hard to find what the problem is though. From what you have said, it looks like you have done the lot.

Do a compression test and make sure you have not got a "lazy" valve. If you get 100% compression, it is possible you have a bit of an out of tolerance engine, although I would say this is VERY unusual for a 4 pot K series.
 

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Discussion Starter · #4 ·
Thanks I'll try that next.. I should also mention that the head gasket was done just before I got the car about 1500 mls ago do you think it could be the timing, mind you it runs OK the rest of the time.

The symptom is there warm or cold and it just feels like it misses a beat every-so-often, the rev counter is steady and doesn't fluctuate, I may try putting the 48mm throttlebody back.

Chris
 

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cjsale said:
Thanks I'll try that next.. I should also mention that the head gasket was done just before I got the car about 1500 mls ago do you think it could be the timing, mind you it runs OK the rest of the time.

The symptom is there warm or cold and it just feels like it misses a beat every-so-often, the rev counter is steady and doesn't fluctuate, I may try putting the 48mm throttlebody back.

Chris
If it feels like it is missing now and again, I would check the exhaust system carefully. If this is 100% fine, I would check plugs, etc.

I had an 827 which was a fantastic piece of kit. You could stand at the exhaust and hear a totally perfect humm, with no "put" ing or anything.

I changed the plugs to NGK, as you do and started to get "put, put" every now and again. Took them back and tried Bosch Super 4's. Got the same. . . . . . Eventually went to the Rover dealer and got a set of Rover plugs. These were "Denso" (highest quality about) plugs and I put them in and it was note perfect again. . . . Some engines can be VERY fussy. The fact that yours is an offbeat miss, would suggest to me that the timing is OK.
 

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Discussion Starter · #6 ·
Thanks for that, the plugs were NGK when I got the car and I've just put a new set in, would normally swear by NGK always used them in my Metro Turbo's and Mini's and GTM. I may try a set of Rover Plugs and see what happens, talking of exhausts I do have a different rear silencer fitted it actually should be for a ZS, however Moto-Build advised that it would be OK on a 1600/45/110/ZS the pipes do have a slight mis-match, the 45 system is slightly smaller and flows into the larger bore silencer. Again thanks for the assistance.
 

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Discussion Starter · #7 ·
Brad Pitt said:
If it feels like it is missing now and again, I would check the exhaust system carefully. If this is 100% fine, I would check plugs, etc.

I had an 827 which was a fantastic piece of kit. You could stand at the exhaust and hear a totally perfect humm, with no "put" ing or anything.

I changed the plugs to NGK, as you do and started to get "put, put" every now and again. Took them back and tried Bosch Super 4's. Got the same. . . . . . Eventually went to the Rover dealer and got a set of Rover plugs. These were "Denso" (highest quality about) plugs and I put them in and it was note perfect again. . . . Some engines can be VERY fussy. The fact that yours is an offbeat miss, would suggest to me that the timing is OK.
Tried the Rover plugs they do not appear to have made any difference, I'll try the plug leads next.
 

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cjsale said:
Tried the Rover plugs they do not appear to have made any difference, I'll try the plug leads next.
Hi mate i have the same problem, a little shuddery/rumbly when idling, the odd missfire, but its not regular. If my car doesnt get written off im going to throw money at it in the form of new dizzy, rotor arms, leads and so on, will let everyone know the result.
New plugs didnt fix it for me either.
 

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Discussion Starter · #9 ·
Samuel said:
Hi mate i have the same problem, a little shuddery/rumbly when idling, the odd missfire, but its not regular. If my car doesnt get written off im going to throw money at it in the form of new dizzy, rotor arms, leads and so on, will let everyone know the result.
New plugs didnt fix it for me either.
I don't have the luxury of a distributor I'm all elecronic with coils on plugs, I'm now thinking along the lines of the coils or leads or maybe the various sensors. I had the same problem on my previous Rover 400 and mine did get written off, under bonnet fire totalled the front and drivers side.
 

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cjsale said:
I don't have the luxury of a distributor I'm all elecronic with coils on plugs, I'm now thinking along the lines of the coils or leads or maybe the various sensors. I had the same problem on my previous Rover 400 and mine did get written off, under bonnet fire totalled the front and drivers side.
Don't reckon it will be a sensor other than the oxygen sensor or curcuit, which is a possibility

Could be a dicky injector, but this is VERY unlikely IMO.

If not a compression (maybe intermittent valve seating) issue, I reckon ignition system, leads perhaps.
 

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cjsale said:
I don't have the luxury of a distributor I'm all elecronic with coils on plugs, I'm now thinking along the lines of the coils or leads or maybe the various sensors. I had the same problem on my previous Rover 400 and mine did get written off, under bonnet fire totalled the front and drivers side.
It does appear that the 400 (or probably more correctly, the 1.6k) becomes very rough at idle after a while. It really gets on my tits.
Did they change away from distributors at some point?
 

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Samuel said:
It does appear that the 400 (or probably more correctly, the 1.6k) becomes very rough at idle after a while. It really gets on my tits.
Did they change away from distributors at some point?
When it went to 45 IIRC. VVC was always dizzyless, "wasted spark".
 

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Brad Pitt said:
When it went to 45 IIRC. VVC was always dizzyless, "wasted spark".
Right well its not encouraging news as i was hoping that a dizzy change would sort it (it still might) but obviously this fellows problem is not caused by it.
 

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Discussion Starter · #14 ·
Hi again, as I stated originally I had this problem with my previous 400, unfortunatly it was burnt out before I sorted (hope it wasn't related) see pics here
http://gallery.mg-rover.org/showgallery.php/cat/500/ppuser/20294

After changing the plugs to the Rover ones last night I didn't think it had made any difference, however after driving it today I think it may have cured the problem, or at least made it less pronounced. I'll give it a few days and report back, problem is I've been changing various other items like the throttlebody and disconnecting various sensors etc.., .

On my 400 I once had the tickover alter itself to 2000 revs, I touched the thermostat sensor and it dropped back to normal, after cleaning it the problem never came back for the rest of its short life !

A mechanic friend also mentioned that some cars run very weak at idle and this could possibly cause the problem.

Does anybody know if the change to distibutorless ignition had anything to do with the 400's damp start problems (No distributor no problem).

Sorry to go on a bit Chris:run!:
 

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cjsale said:
Hi again, as I stated originally I had this problem with my previous 400, unfortunatly it was burnt out before I sorted (hope it wasn't related) see pics here
http://gallery.mg-rover.org/showgallery.php/cat/500/ppuser/20294

After changing the plugs to the Rover ones last night I didn't think it had made any difference, however after driving it today I think it may have cured the problem, or at least made it less pronounced. I'll give it a few days and report back, problem is I've been changing various other items like the throttlebody and disconnecting various sensors etc.., .

On my 400 I once had the tickover alter itself to 2000 revs, I touched the thermostat sensor and it dropped back to normal, after cleaning it the problem never came back for the rest of its short life !

A mechanic friend also mentioned that some cars run very weak at idle and this could possibly cause the problem.

Does anybody know if the change to distibutorless ignition had anything to do with the 400's damp start problems (No distributor no problem).

Sorry to go on a bit Chris:run!:
Should not have any damp start problems. If you have, there is an issue somewhere - damp getting into something. What are the exact symptoms?

The 2000 RPM idle was probably a sticking throttle body (it is plastic and warps).

Does not surprise me with the plugs. Some engines can be VERY sensitive to things like this.

It would not be a sensor issue I would not have thought, if it is an offbeat miss.
 

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Discussion Starter · #16 ·
Brad Pitt said:
Should not have any damp start problems. If you have, there is an issue somewhere - damp getting into something. What are the exact symptoms?

The 2000 RPM idle was probably a sticking throttle body (it is plastic and warps).

Does not surprise me with the plugs. Some engines can be VERY sensitive to things like this.

It would not be a sensor issue I would not have thought, if it is an offbeat miss.
It's all water under the bridge with the Rover 400 problems but the symptoms were, if there had been any damp or heavy rain the previous night the car just would not start the following morning without drying everything off, I had already replaced the entire ignition system apart from the coil. Twice the car started no problem in the morning and then cut out after driving round the corner, once in the middle of a main road. The cure was to spray silicone spray into the dizzy, outside it and on the leads and coil and wipe the excess off, never had the problem again. Once I even had it stop while I was driving it after going through a puddle, I could only think that water may have got on the coil. I got so paranoid I hated going out in the wet !!

Three other people I know had had the same problems and two mechanic friends also new of the problem, one suggested the silicone.

Chris
 

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Discussion Starter · #17 ·
Brad Pitt said:
Should not have any damp start problems. If you have, there is an issue somewhere - damp getting into something. What are the exact symptoms?

The 2000 RPM idle was probably a sticking throttle body (it is plastic and warps).

Does not surprise me with the plugs. Some engines can be VERY sensitive to things like this.

It would not be a sensor issue I would not have thought, if it is an offbeat miss.
I'm not sure if i've confused you a bit, my present problem is on a Rover 45, the dampstart and same problem previously were on a 400. I don't have any dampstart problems with the 45 (touch wood). Thanks for the advice and help much appreciated.
 

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ive got a 2000"w" reg rover 45 1.6 and mine does the same.On tickover it misses a beat every few seconds.One of the lads in work has a 400 and his does the same.
 

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Discussion Starter · #19 ·
manny said:
ive got a 2000"w" reg rover 45 1.6 and mine does the same.On tickover it misses a beat every few seconds.One of the lads in work has a 400 and his does the same.
MMM as I thought I'm deff. thinking along the lines that it is normal and not abnormal, especially as I had the same problem on the 400. Seems as though all we can do is lessen the problem. The new plugs do seem to have made a difference though Part No. R NLP100290 £21.23 set of 4 from Rover Parts Dealer. Thanks Manny

Chris
 

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My R25 1.6, '03 model does exactly the same and i found it to be sensitive to different air filters. Using a Fram type seems to be best and when new it really cut down on my lumpy idle. I just tried a new Champion at the last service interval, its terrible and seems to be getting worse each week.
I might try to do a bit more investigation over the weekend to see if this really is the area to be looking at for a cure to this annoying problem.
Nigel
 
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