4.5 throttle linkage wear and general poor running

4.5 throttle linkage wear and general poor running

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jamieduff1981

Original Poster:

8,022 posts

139 months

Monday 1st December 2014
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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?

ukkid35

6,138 posts

172 months

Monday 1st December 2014
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jamieduff1981 said:
I have an instinct telling me to replace the lambdas. Thoughts?
Really sorry you're have such a hard time, especially since you contribute so much. I am very cheap (as you probably recall) so my instinct would be to swap the lambdas first rather than replace, to see how that effects the smoking.

My throttle assemblies are also very worn, in addition the angle of the arms means they do not act symmetrically (and flats on the shafts means this can't easily be adjusted). I can either have the pots equal when closed or equal when open.

I don't have any solutions I'm afraid, but I suggest you start with the cheap stuff.

FarmyardPants

4,099 posts

217 months

Monday 1st December 2014
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If bank 2 gets a head start on bank 1 then doesn't the link bar need shortening?
Assuming bank 2 is the the even bank/drivers side which is directly attached to the cable.

jamieduff1981

Original Poster:

8,022 posts

139 months

Monday 1st December 2014
quotequote all
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!

ukkid35

6,138 posts

172 months

Monday 1st December 2014
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I have a rose jointed linkrod in steel, rather the original aluminium rod. I reckon this is a flaw because as the engine heats up the block/heads expand, but the linkrod doesn't so much, effectively shortening the link and skewing the throttles.

Vee8ight

734 posts

138 months

Monday 1st December 2014
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What condition is Your exhaust in? The reason why I ask is, I recently set all my throttles and my 4.2 was bang on, running sweet, idling lovely, 25mpg! It then started to idle funny, stalling, 16mpg, sometimes only steam (smoke) out of one tailpipe. I'd had the rear exhaust off for some work and it's had been really tight to remove and refit from the intermediate pipes (now replaced with v-band clamps) What I've discover is that I had cracked the manifold on port 1, and more importantly cracked the joint on the collector near the lambda sensor, thus giving the ecu dodgy feedback and making the idle / mpg all rubbish.

Worth a look and feel for gases escaping, to eliminate.


Daz

jamieduff1981

Original Poster:

8,022 posts

139 months

Tuesday 2nd December 2014
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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.

jamieduff1981

Original Poster:

8,022 posts

139 months

Thursday 4th December 2014
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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.

jackwibble

664 posts

158 months

Thursday 4th December 2014
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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)

ukkid35

6,138 posts

172 months

Friday 5th December 2014
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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.

jamieduff1981

Original Poster:

8,022 posts

139 months

Friday 5th December 2014
quotequote all
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.
Thanks chaps. I'll give him a tinkle. I want him to map my car anyway, especially that I now have a Whirlwind kit fitted although I need to give Barry at TVR Ecosse his exhaust back and get a new one of my own first - so ringing Joolz to introduce myself properly can't hurt smile

jackwibble

664 posts

158 months

Friday 5th December 2014
quotequote all
jamieduff1981 said:
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.
Thanks chaps. I'll give him a tinkle. I want him to map my car anyway, especially that I now have a Whirlwind kit fitted although I need to give Barry at TVR Ecosse his exhaust back and get a new one of my own first - so ringing Joolz to introduce myself properly can't hurt smile
Joolz is the god of AJP8 mapping and a top bloke if you need accommodation when you come down with the car drop me a pm I'm only 50mins from Chesvagas.

jamieduff1981

Original Poster:

8,022 posts

139 months

Saturday 3rd January 2015
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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 biggrin 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.

aide

2,276 posts

163 months

Saturday 3rd January 2015
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jamieduff1981 said:
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 biggrin 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 Jamie

To help you track down the cause of your problem you could get the latest version of RS-AJP (v1.6). It has a time-series data logging feature that stores all sensor data (ecu, gps and gyro) in the rs-ajp dir.

Hope you get it sorted

Aide

robsco

7,822 posts

175 months

Saturday 3rd January 2015
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Jamie, have you made any inroads into the throttle link rod? I wonder whether Peter could make us some up... He will be able to tell us that of course, but I was chuffed to bits with the dash he sent me and if we could get a group buy going, it might be something to look into.

jamieduff1981

Original Poster:

8,022 posts

139 months

Saturday 3rd January 2015
quotequote all
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.

robsco

7,822 posts

175 months

Saturday 3rd January 2015
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Ok, just an idea that popped into my head this evening. I almost can't remember how mine drives. hehe

pmessling

2,284 posts

202 months

Sunday 4th January 2015
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If people want anything made up by me just pm me and I can do individuals no problem.


pmessling

2,284 posts

202 months

Sunday 4th January 2015
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Paul was just reading through and I remember making a rod for you which was indeed steel. However I have changed it to aluminium now. I have the same as you having the steel one haven't gotten round to replacing mine with alu yet.

Jamie have you balanced the throttles with an air flow meter? Or checked the heat barrier o rings. I would be tempted to start from scratch. I found changing the o rings and tightening the bits holding it all down made mine better. Perhaps a mistake from the last person who worked on it not tightening them correctly.

Supateg

724 posts

141 months

Sunday 4th January 2015
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pmessling said:
Paul was just reading through and I remember making a rod for you which was indeed steel. However I have changed it to aluminium now. I have the same as you having the steel one haven't gotten round to replacing mine with alu yet.

Jamie have you balanced the throttles with an air flow meter? Or checked the heat barrier o rings. I would be tempted to start from scratch. I found changing the o rings and tightening the bits holding it all down made mine better. Perhaps a mistake from the last person who worked on it not tightening them correctly.
As it turns out Aluminium is the best material to use, something that expands more would suit; but there's not many options out there.

I've been racking the grey matter hoping to offer sound advice.
You've come so far and changed many components resulting in the saying 'a needle in a haystack' now.

I think it's best to let Jules look at it with the data logging feature of the fantastic RS-AJP App. It's now turned into a fault finding procedure ie ruling out Fuel, Mechanical, Electrical etc.

If you need help with Logistics I'm in Doncaster 45 mins from Jules.

-Craig