Judder under acceleration

[chrishewett]

I have just bought a 1990 SE which is in great condition.
When I bought it I was aware of a vibration which I put down to a wheel balance problem or maybe cv/driveshaft.
Now I have had a chance to drive it properly having had new tyres and wheel balance I realise I have another problem.
If the car is driven sedately there is hardly any vibration. When accelerating hard a whole car judder starts. This is worse at 3,500-4,500 revs in third when the turbo cuts in. If I then take my foot of the throttle the vibration stops.
I can't find any movement in the cv joints or any suspension bushes. The engine mountings seem ok. The car seems otherwise fine and has loads of service history. The car revs up fine in neutral.
I intend to take it to classic Le Mans in four weeks time so need it to be sorted by then.
Can anyone offer any suggestion as to what the problem may be?
Chris

[M100 TWO]

try new plugs but I expect it is the coil braking down under load there is a cheap alternative from the US rather than buying from Lotus
diff

[tweetdriver63]

Try this thread. It sounds like the same problem you're having.

http://lotuselancentral.com/forum/viewtopic.php?t=6682

Does it happen when the turbo kicks in, or when it gets up to a certain level of boost? In my car, I recently had a similar problem when accelerating hard under boost. The problem showed when the boost was way up, around 1.1 bar! A previous owner installed a MBC and a Superchip, and I was hitting the rev limiter or FCD (although the FCD is supposed to be disabled by the Supershit). Anyway, the MBC is very sensitive, and I had apparently budged the knob a little too far toward the open position, so I was over-boosting and hitting the limiter. I just had to do a few runs while making small adjustments to the MBC until I got smooth running. All is well now, and I'm maxing out at about .75 bar.

So, does your car have a MBC? I didn't know mine did until I learned that the boost is supposed to be limited to .65 bar from the factory. Then I went looking, and found it pretty well hidden in the plumbing. If you're getting boost up in the .75 bar or greater (without a mountain chip, that is), it may be part of your problem.

[Enright]

The symptoms you describe make it sound much more mechanical than electronic.

Try some slow full lock left and right turns in a car park.
If you get any knocking then it's likely to be an outer CV joint.
If not, then it's more likely to be an inner one.

What mileage has your car got on it? Can you tell if it's had the CV gaiters replaced at all? I'm thinking that one could have been done, but it may have dried out and worn before the previous owner fixed it.

[paulwatkins]

sticky wastegate.

[dapinky]

Just to be different - as everyone else has an opinion (one of which is probably a good shout!), I'll tell you what mine was...........







........A simple case of the Right-hand driveshaft not being done up tight.

By that, i mean the bit which bolts to the engine block - there is a jackshaft which goes from the differential to a bearing bolted to the back of the engine, and this connects to the driveshaft CV joint - all part of Lotus' plan to get rid of torque steer by keeping the drive-shaft lengths equal.

Anyhow, the bearing housing wasn't done up tight to the block - a couple of turns with a 14mm spanner had it sorted for zero cost.

[chrishewett]

Thanks for the input sofar.
Some interesting thoughts.
I am also getting a problem when accelerating hard sometimes the engine almost cuts out and the engine light comes on for 30 or so seconds. When it goes out power is resumed. I had suspected a sticky wastegate but had not connected the problems.
I have no noise at all from the cv joints but my mechanic tells me that there is a very small amount of play in the inner nearside cv. Almost nothing but detectable. The car has recently had a gaitor replaced but that was offside. In the past it has had a driveshaft replaced because of a severe vibration.
I can accelerate sedately to 100mph without any vibration. The problem seems to be worst when pushing it hard in third.
This is really frustrating as this is a great car and I can't wait to get it right so I can enjoy it to the full.
I also have a 111s elise and a 1971 elan +2, they are all so different but I think the se may turn out to be the best all round car once all the problems are sorted.
Chris

[Enright]

Thanks for the input sofar.
Some interesting thoughts.
I am also getting a problem when accelerating hard sometimes the engine almost cuts out and the engine light comes on for 30 or so seconds. When it goes out power is resumed. I had suspected a sticky wastegate but had not connected the problems.

Chris,
You shouldn't connect the problems. They're completely seperate.
You need to do the paperclip test which should give you a code 31. That will verify the sticky wastegate, then look up the walkthrough of the solution on the wiki.

I have no noise at all from the cv joints but my mechanic tells me that there is a very small amount of play in the inner nearside cv. Almost nothing but detectable. The car has recently had a gaitor replaced but that was offside. In the past it has had a driveshaft replaced because of a severe vibration.
I can accelerate sedately to 100mph without any vibration. The problem seems to be worst when pushing it hard in third.
This is really frustrating as this is a great car and I can't wait to get it right so I can enjoy it to the full.
I also have a 111s elise and a 1971 Elan +2, they are all so different but I think the se may turn out to be the best all round car once all the problems are sorted.
Chris

Was the driveshaft that was replaced the offside one? It sounds to me like the nearside inner CV is on it's way out.
Stick with it - it will be worth it. The Elan had the biggest development budget of any Lotus and once the problems are ironed out you're right - it's a fantastic all-rounder.

[chrishewett]

I have just done a paperclip test and sure enough - code 31.
It looks like I will have to get a new n/s driveshaft. Any ideas as to the best source? And what sort of job is it?
I am off to Le Mans tonight so it will have to wait until next week.
Thanks for the help. What a great forum.
Chris

[Enright]

I think you can buy the driveshafts complete in the Lotus Parts Sale, but I'm afraid I don't have a link to it. And as I recall, they're still not cheap.
The alternative is to get one from a breaker (there are a couple on eBay at the moment), and to just replace the outer CV joint and boots.
Inner CV failures are pretty rare, so the risk should be low.
SW Lotus have outer CV joints in stock - I picked up 2 for £30 or 35 (can't remember which) at Donington, and the CV boots are standard MkII Cavalier stuff available from any decent motor factors.

As for the job itself, I just did the o/s last weekend. The n/s is slightly trickier - you lose your gearbox oil and refilling it is a pain because you have to remove the speedo drive and do it through there.

I would also recommend replacing the front wheel bearing at the same time. It's a Cavalier one and there is a part number in the cross-reference thread if you do a quick search. You can get them for about £15 but you need to have a garage press out the old one and press in the new one.

Other than that it's no harder than any similar aged Vauxhall:
Loosen wheel nuts.
Chock wheels and jack up car to gain access to centre nut (32mm socket needed).
Tap a screwdriver in to lever out the peining of the centre nut so that you can get it off.
Put wheel back on and lower car.
Remove centre nut.
Remove caliper and disk.
Remove track rod end ball-joint nut and split joint.
Remove upper and lower ball joint nuts and split ball joints.
Remove hub assembly.
Remove driveshaft but NOT by pulling on it - lever it out from the inner CV end.

Note that most of the "remove"s of the nuts above will involve a lot of straining and swearing. The ball joints are wickedly tight and difficult to split.

You should try to download the manuals - it walks you through the process properly.

[DeeAitch]

IIRC the wheel bearing is also rumoured to be Astra circa early '90's - the bearing itself is used on lots of things but you need the GM kit to get two new circlips. I'll be finding out for sure soon as my offside is grumbling
Best use a new nut on the driveshaft as well.
Might be worth checking the jack shaft bearing while you are at it.

Neil, how difficult was it to get the O/S driveshaft off the Jack shaft? That square section clip looks to be a pain round ones are hard enough!

[Enright]

Dave,

It was fine. I used a crowbar in there simply because the end was the right size to fit in, but all I had to do was to twist it and the two parts separated quite easily. Then as soon as the gap was wide enough I used the end of a 1/2" drive 10" extension bar from my socket set, and they popped apart with no trouble. Ah, there's nothing like using the right tools for the job.
And that was nothing like using the right tools for the job!

[tweetdriver63]

Here's the link to the parts sale. The parts list is a link at the bottom right of the screen. To the left of that is the link to the order form.

http://www.grouplotus.com/cars/lotus_parts.html

You'll find this there:

A100R6006S Inboard Drive Shaft Assy RH Elan 1989 on 282.43 89.50 19
A100R6007S Inboard Drive Shaft Assy LH Elan 1989 on 282.43 89.50 2

[Enright]

Nice one Tweet.

Good price too - I only remembered the £282 from before, but £89.50 is pretty reasonable. Mind you it only says inboard assembly so you may still need to buy the CV joint to go on it.

Oh, I forgot 2 nuts more nuts that have to be undone in my instructions above - you have to remove the rod that bolts the anti-roll-bar and the bottom of the yoke to the lower wishbone.

[dapinky]

I got to mine really really easily without having to split any balljoints .........









If you get the engine and gearbox out first, it's a breeze


....I'll get me coat...

[Enright]

Um, you got a pair of yoke spreaders then, or just funky ultra-slimline CV joints?!?

[dapinky]

I got to mine really really easily without having to split any balljoints .........

I removedmine really really easily without having to split any balljoints .........

[DeeAitch]

Not 100% sure but that sales list looks to be 2007's
For sure there are no CO pots left

Also shown is the RH drive shaft - that is the full shaft assy - @£127.50

[GeoffSmith]

Not 100% sure but that sales list looks to be 2007's

They're re-cataloguing after moving from Avonmouth to Hethel...... allegedly.

[GeoffSmith]

60th Anniversary list:
Elan C100R0001F L/H DRIVESHAFT 86 367.40 93.61
Elan C100R0002F R/H DRIVESHAFT 49 356.69 93.61