4.5 throttle linkage wear and general poor running
Discussion
Hi chaps.
My 4.5 was great last year but deteriorated and thus had a load of work done this summer including ages trying to set up the throttles. There was hessitation and midrange misfire.
The car got a lot of attention to the linkages due to unequal opening. It got 2 new coil packs, throttle pots substituted but found to be good and replaced. It has new HT leads and a new water temperature sensor. The ECU was removed and a spare 4.2 ECU tried which, oddly, seemed to cure it.
My ECU went to Powers for repair and came back with 2 new chips. Upon fitting to my car, it was instantly the worst it's ever been. The ECU may go back again but in the mean time the car is back on the 4.2 ECU however it's playing up again. When warming up now it smokes from 1 exhaust pipe at a time. It used to smoke symmetrically.
I've just used RS-AJP on it and it's back to imbalanced throttle pots. Bank 2 gets a 10% lead on Bank 1 before the latter leaves idle. When warm I ran it gradually up to 4000rpm and it remained with a 10% imbalance and banged from the exhausts a lot. Lambdas are all over the place.
I want to sort this throttle linkage nonsense first as it can't be helping. I've been waiting on ACT throttle pot bearings since the beginning of November so hopefully they'll be dispatched soon. What else is prone to wear? I don't want to mess about - I intend to blitz it.
I have an instinct telling me to replace the lambdas. Thoughts?
My 4.5 was great last year but deteriorated and thus had a load of work done this summer including ages trying to set up the throttles. There was hessitation and midrange misfire.
The car got a lot of attention to the linkages due to unequal opening. It got 2 new coil packs, throttle pots substituted but found to be good and replaced. It has new HT leads and a new water temperature sensor. The ECU was removed and a spare 4.2 ECU tried which, oddly, seemed to cure it.
My ECU went to Powers for repair and came back with 2 new chips. Upon fitting to my car, it was instantly the worst it's ever been. The ECU may go back again but in the mean time the car is back on the 4.2 ECU however it's playing up again. When warming up now it smokes from 1 exhaust pipe at a time. It used to smoke symmetrically.
I've just used RS-AJP on it and it's back to imbalanced throttle pots. Bank 2 gets a 10% lead on Bank 1 before the latter leaves idle. When warm I ran it gradually up to 4000rpm and it remained with a 10% imbalance and banged from the exhausts a lot. Lambdas are all over the place.
I want to sort this throttle linkage nonsense first as it can't be helping. I've been waiting on ACT throttle pot bearings since the beginning of November so hopefully they'll be dispatched soon. What else is prone to wear? I don't want to mess about - I intend to blitz it.
I have an instinct telling me to replace the lambdas. Thoughts?
I guess that might do it, but there has to be slop in either the linkrod balljoints, the throttle shaft bushes or both, logically?
Is there slop in the balljoints when new?
I'm wondering whether to just ditch the balljoints and get a new linkrod with rosejoints.
The whole thing just needs a good thick coat of looking at. It's almost more frustrating that a proper problem. It's like having a runny nose - useless!
Is there slop in the balljoints when new?
I'm wondering whether to just ditch the balljoints and get a new linkrod with rosejoints.
The whole thing just needs a good thick coat of looking at. It's almost more frustrating that a proper problem. It's like having a runny nose - useless!
A rose jointed linkrod seems like an increasingly good idea.
The exhausts are fine - I believe. The car blew the baffles out of the aftermarket exhaust it had on when I got it. I wasn't too upset about that - whilst it sounded great it had oversized tailpipes which were only about 5" long so you could see where they expanded in diameter from beside the car - it looked silly. That choked power right down but a s/h OE backbox was acquired, welded to some centre pipes and fitted. That looked sensible, sounded a bit naff and released a lot of power compared to the aftermarket one. Then it blew the baffles out of that one with a "wwwwumph" rather than a bang and a big lick of flame as I backed off after swerving around a Corsa which had just pulled out in front of me on a NSL A-road.
So it's on a borrowed exhaust at the moment while my bank account recovers! The manifolds were cracked at the primary joins but were welded this summer. I'll inspect around the lambda bosses but these were (haha - like that means anything) fine last time I looked. It could be a good shout though so I'll get it up in the air and do that.
I've decided to paint the airboxes and recoat the cam covers while it's all apart. I have the nicer fuel rail too so that should get cleaned up.
The exhausts are fine - I believe. The car blew the baffles out of the aftermarket exhaust it had on when I got it. I wasn't too upset about that - whilst it sounded great it had oversized tailpipes which were only about 5" long so you could see where they expanded in diameter from beside the car - it looked silly. That choked power right down but a s/h OE backbox was acquired, welded to some centre pipes and fitted. That looked sensible, sounded a bit naff and released a lot of power compared to the aftermarket one. Then it blew the baffles out of that one with a "wwwwumph" rather than a bang and a big lick of flame as I backed off after swerving around a Corsa which had just pulled out in front of me on a NSL A-road.
So it's on a borrowed exhaust at the moment while my bank account recovers! The manifolds were cracked at the primary joins but were welded this summer. I'll inspect around the lambda bosses but these were (haha - like that means anything) fine last time I looked. It could be a good shout though so I'll get it up in the air and do that.
I've decided to paint the airboxes and recoat the cam covers while it's all apart. I have the nicer fuel rail too so that should get cleaned up.
I haven't had a chance to drive it again, but with an assistant to push the accelerator pedal, it became immediately apparent that most of that throttle imbalance was due to the link rod which had lengthened itself. A 6mm spanner sorted that pronto and it's now much better balanced according to the app diagnostics.
I'm keen to drive it and see if that mid-range misfire is still there. If it is, then I'm stuck. Otherwise, my ECU isn't as fixed as one would hope.
I'm keen to drive it and see if that mid-range misfire is still there. If it is, then I'm stuck. Otherwise, my ECU isn't as fixed as one would hope.
ukkid35 said:
jackwibble said:
You could give Joolz a bell at Kits and Classics he's usually happy to offer a bit of phone advice first 5 minutes free then get your gold card out! (Just kidding Joo)
And get one of Joolz throttle return springs too while you're at it. A massive improvement on the standard spring. Check that neither of the individual springs have broken as well.
Today is the first time I've driven the car since last post. The ACT throttle pot bearings are now fitted, and running static in the garage everything seems in order on RS-AJP. The first drive this morning wasn't an intelligent decision, as the roads were sheet ice. I crawled 4 miles to the nearest village, spun around in a carpark 
and crawled home again.
This afternoon the ice had melted. Still cold and wet so I can only try 4th and 5th gear really - but push the loud pedal a long way and it still stutters and slobbers and generally goes nowhere fast. I've emailed Joolz. Hopefully he'll get back to me.
and crawled home again.This afternoon the ice had melted. Still cold and wet so I can only try 4th and 5th gear really - but push the loud pedal a long way and it still stutters and slobbers and generally goes nowhere fast. I've emailed Joolz. Hopefully he'll get back to me.
Hi Aide.
My phone automatically updated to V1.6 the other day I think? I read through the "what's new" bit in Playstore but admit I didn't notice the datalogging. That could be insightful.
Rob I have some rose joints here but haven't done anything with them yet. I bodged around the slop by shortening the link rod a smidge. The balljoints aren't great, but the springs hold it snug and it's working well in that respect.
My phone automatically updated to V1.6 the other day I think? I read through the "what's new" bit in Playstore but admit I didn't notice the datalogging. That could be insightful.
Rob I have some rose joints here but haven't done anything with them yet. I bodged around the slop by shortening the link rod a smidge. The balljoints aren't great, but the springs hold it snug and it's working well in that respect.
Thanks for the input everyone.
Sadly Joolz's website suggests he won't actually do the fixing thereof but hopefully he can offer some insightful steer:
http://www.kitsandclassics.co.uk/servicing/
I used Aide's latest datalogging feature this morning and came back with this. I reproduced the problem - particularly on the stretch back home towards the end of the log and a few times on the way out too. Negative adaptives mean it's running lean, right? It came back with the AFRa fault code lit up red which it's never done running up the RPM unloaded in the garage. I suppose that's good - there is evidence of some sort now.
The adaptives are miles out but both negative.
It had a new fuel pressure regulator in summer. Imbalance-only issues as well as air leaks tend to manifest themselves worst at idle in my experience of other engines. Mine idles beautifully and if just driving round town you'd never know there was anything wrong with it. It's only when you put your foot down that it falls on its face. Should I try a new fuel pump?
Sadly Joolz's website suggests he won't actually do the fixing thereof but hopefully he can offer some insightful steer:
http://www.kitsandclassics.co.uk/servicing/
I used Aide's latest datalogging feature this morning and came back with this. I reproduced the problem - particularly on the stretch back home towards the end of the log and a few times on the way out too. Negative adaptives mean it's running lean, right? It came back with the AFRa fault code lit up red which it's never done running up the RPM unloaded in the garage. I suppose that's good - there is evidence of some sort now.
The adaptives are miles out but both negative.
It had a new fuel pressure regulator in summer. Imbalance-only issues as well as air leaks tend to manifest themselves worst at idle in my experience of other engines. Mine idles beautifully and if just driving round town you'd never know there was anything wrong with it. It's only when you put your foot down that it falls on its face. Should I try a new fuel pump?
The thing is that Barry has spent ages chasing this problem round in circles all summer. It's psychological in some way but I'll resent the car less if I can severely punish it by stripping it apart. It needs to learn where its bread is buttered.
It runs *so* badly at wider throttle openings and it's such a drastic change that this simply cannot be slightly-off throttle set up. Throttle imbalance tends towards irrelevant the wider they're opened as the percentage difference in airflow reduces the higher the flow rates. My car runs fine until a certain throttle opening then it all just goes to pot.
I could chase this round in circles again, but the only thing that wasn't swapped was the fuel pump last time.
It runs *so* badly at wider throttle openings and it's such a drastic change that this simply cannot be slightly-off throttle set up. Throttle imbalance tends towards irrelevant the wider they're opened as the percentage difference in airflow reduces the higher the flow rates. My car runs fine until a certain throttle opening then it all just goes to pot.
I could chase this round in circles again, but the only thing that wasn't swapped was the fuel pump last time.
It hasn't had the injectors tested.
It's had new plugs, new leads, both new coils, new coolant temp. sensor, both lambdas substituted with known good ones, and both throttle pots substituted for known good ones. It has a new fuel pressure regulator also. It must have been re-set up from scratch around half a dozen times at summer chasing this issue around. TBH I don't see any benefit in repeating the exercise again without something materially having changed.
It's got to be more fundamental - like head gasket failure or something like that.
It's had new plugs, new leads, both new coils, new coolant temp. sensor, both lambdas substituted with known good ones, and both throttle pots substituted for known good ones. It has a new fuel pressure regulator also. It must have been re-set up from scratch around half a dozen times at summer chasing this issue around. TBH I don't see any benefit in repeating the exercise again without something materially having changed.
It's got to be more fundamental - like head gasket failure or something like that.
It's not RPM related. It's high throttle positions. All torque disappears and the engine just splutters. The torque then comes and goes in very short surges. It struggles to accelerate at all unless the throttles are backed off.
At light loads it runs as sweet as a nut.
Been discussing just getting rid this evening. I've had it 2 years. Year 1 was ok. Year 2 was crap. My wife won't drive it any more and I don't want to forego the things I want to do with my precious free time taking another car to bits.
At light loads it runs as sweet as a nut.
Been discussing just getting rid this evening. I've had it 2 years. Year 1 was ok. Year 2 was crap. My wife won't drive it any more and I don't want to forego the things I want to do with my precious free time taking another car to bits.
Hi Matt,
I spoke with Joolz this morning who has counselled me to go straight to the HT side of the ignition system. My car has become steadily worse since mid 2013 where it would do this once in a blue moon until now where it does it every time. It has a set of Magnecors on which were bought in 2013 but they were hard to push on. Joolz has suggested starting with the leads and take it from there - so there would appear to be a parallel with your problem as you say.
Access is a PITA on these to get the leads on so it's not impossible it's that. I'll check that first although getting another set of leads (non-Magnecor) isn't the end of the world.
I spoke with Joolz this morning who has counselled me to go straight to the HT side of the ignition system. My car has become steadily worse since mid 2013 where it would do this once in a blue moon until now where it does it every time. It has a set of Magnecors on which were bought in 2013 but they were hard to push on. Joolz has suggested starting with the leads and take it from there - so there would appear to be a parallel with your problem as you say.
Access is a PITA on these to get the leads on so it's not impossible it's that. I'll check that first although getting another set of leads (non-Magnecor) isn't the end of the world.
I'm getting somewhere...
The Racetech HT leads arrived today. I removed the airboxes and inlet hoses, and noticed that I had a manifold crack on Odd/Driver Side bank. Hmm thinks I. It looks accessible from above but I thought I'd remove the manifold and get someone else to weld it.
I unplugged the lambda and they had been accidently crossed banks when plugged in to the loom. Easy to do - it's fiddly. That can't have been helping with a leaky manifold and the lambda adjusting the other bank to compensate.
I changed my mind about removing the manifold and just MIG welded the crack myself. I haven't reassembled the car yet but with the manifold and lambdas sorted and non-Magnecor HT leads I reckon it'll run miles better!
If not, I'll be crying!
The Racetech HT leads arrived today. I removed the airboxes and inlet hoses, and noticed that I had a manifold crack on Odd/Driver Side bank. Hmm thinks I. It looks accessible from above but I thought I'd remove the manifold and get someone else to weld it.
I unplugged the lambda and they had been accidently crossed banks when plugged in to the loom. Easy to do - it's fiddly. That can't have been helping with a leaky manifold and the lambda adjusting the other bank to compensate.
I changed my mind about removing the manifold and just MIG welded the crack myself. I haven't reassembled the car yet but with the manifold and lambdas sorted and non-Magnecor HT leads I reckon it'll run miles better!
If not, I'll be crying!
Can't think why? The throttle set up is about getting the airflow equal on the way in at minimal load where it runs well, to get the throttle pots doing the same thing at the same time and to set the idle screw.
It'll need the adaptives cleared again, but I can't see how dud HT leads and crossed lambdas would affect the butterflies and potentiometers?
It'll need the adaptives cleared again, but I can't see how dud HT leads and crossed lambdas would affect the butterflies and potentiometers?
Joolz is the Cerb a wasted spark set up? It runs, so it's either wasted spark or I've just f*cked up the lead numbering when I first fitted them. I did them one at a time. The print on the cable is not important but the coil pack and LT plug into coil pack is.
Which coil goes with which bank?
Which coil goes with which bank?
Ta muchly. I didn't touch the car this weekend. I'm positive all the leads from one bank go to a single coil though, and vice versa. I suspect this is just a previous lead numbering mistake on my part though. Nevertheless, I'll sort it out. Unfortunately it means the lambdas were ok so I've unplugged the buggers for nothing. Doh!
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