Misfire Elan 1990 Turbo

[DaKa]

My Elan 1990 turbo misfires under full throttle.
It is particularly noticeable when the car has not long warmed up.
The car is little used 1500 mile p.a. and has a current mileage of 34,000.
Will changing the HT leads / plugs improve things, or, am I best putting this money towards a rolling road diagnostic check?
The car's history suggests it has had the BBR turbo conversion applied - but I don't really know what this means and whether it alters how best I should seek to resolve the problem.
The Turbo Boost gauge doesn't hit the top 1.0 level that it used to - it tends to border between 0.5 and 0.75.
I used to feed it 4 star for the higher octane levels but as it no longer sells anywhere I now use "super" unleaded - however, my misfire started before this change.
P.S. Does anyone have an opinion as to whether a modern dump valve is worth fitting? if so, which valve is recommended?
Thanks

[johnbenk]

Hi

The best Dump valve for the Lotus Elan is the Piston type available from Demon Tweeks at www.demon -tweeks.co.uk. £90..47 you need also fitting kit

Can not offer advice on misfire, it a question of finding what causes it?

Plugs best bet, timing, fuel filter sensor etc. You need to run a "snapshot"
on a diagnostic program to find fault, best bet electrical rather than mechanical.

Dump valve good idea to stop load on Turbo but noise can be a problem
you can get a re-circulation type if you do not want the noise when you change gear .
Cheers,

Jbenk.

[stevo]

daka, sounds like you have one or two faults, does the check engine light (cel) come on when the missfire happens?

[John_W]

Daka,
To eliminate the misfire I suggest starting by changing the plugs for a new set properly gapped at 31 thou. If the misfire is still there then look to the leads then coils.
John

[delta]

The best Dump valve for the Lotus Elan is the Piston type available from Demon Tweeks at www.demon -tweeks.co.uk. £90..47

Not to sure about that.
You WILL need a type, which can be ajusted to allow higher boost.
This one is a ajustble re-circulating pistontype in aloy. Have one myself and it works perfectly.

[Enright]

That looks rather interesting - where did you get it from for $38, what model is it, and do you have any pics of it installed?

[delta]

It's from http://www.bestuning.com It's a Taiwan site also selling on Ebay. Quality is good, delivery fast without problems and payment via PayPal.

Sorry, price not right.
It is.: Buy Now rate $30 + $8 shipping + $2 insurance. Total shipped ~$40. to US and Europe (Denmark)

The latest model almost identical.: Blow Off Valve S. Same price. Delivery to Denmark was within 5 days. It was marked as "Gift" so there was no importduty or tax added.

Below a pic. of the new type, which I have installed on the "Bling-Mobile"

[Enright]

Hmm, any chance of checking that link, or do you have their eBay ID? I'm getting a "bandwidth exceeded" error message, and can't find a seller with that name in Taiwan on eBay.

Also re the routing of the pipework - where does the small pipe from the dump-valve go?

[ESM]

Drifted off topic a bit...

Could be the plugs its worth changing them since its a cheap, easy fix. If that doesn't work check if the sparks are weak on 1&4 or 2&3, if they are then a coil is probably on the way out. Failing that check the timing too.

[Doug]

agree with all the above

also you know I am here to say that it could be a sign of emminent CAS failure even without a check engine light. ESM and myself have had these problems, with no light, but cured with a new CAS. If there's a CEL and the code is correct then it may already be a full blown CAS problem. With the BBR in place you may still get good boost but less than usual when the CEL is on.

[delta]

Hmm, any chance of checking that link, or do you have their eBay ID? I'm getting a "bandwidth exceeded" error message, and can't find a seller with that name in Taiwan on eBay.

Also re the routing of the pipework - where does the small pipe from the dump-valve go?

Site is back-up again, but he's not at Ebay for the moment. Don't buy direct from he's website. Wait untill he go's on Ebay, as buy now prices are much lower. Hes Ebay name is "bestuning".

The small pipe is cut into the pipe going to the boost transducer on the LH side of the engine.

[DaKa]

What is a CAS problem?
I am thinking of fitting a Bailey Dump Valve after the mis-fire is cured. Not as cheap as the ones mentioned but I'm happy if this is okay/recommended also?

[M100 TWO]

DaKa the Bailey DV26 is a twin piston design, and it is quieter in use as it will not flutter on small movements of the throttle,also this twin piston design can be put into the re-circulating body if you wish

www.dumpvalve.com

[DaKa]

I found a local firm "BENCHSOUND" Stanford-le-Hope, Essex who, although not a Lotus specialist, turned out to be better than I could have expected.
They tuned the car at a very reasonable price including new plugs. They also fitted new Magnecor HT Leads that I had supplied together with a Bailey Dump Valve at NO extra cost.
What a service.

BENCHSOUND have a rolling road tuning service and Mario (who is the top dog there) did a great job, he even replaced tired and worn pipes/clips as and when he found them - again at no extra cost.

The end result is that the car is running better than ever and I can't wait for dry conditions to give it a proper blast.

Thanks for the feedback on the original reported problem.

I would encourage anyone who is hesitating leaving their pride and joy with a unknown garage NOT to hesitate to use Benchsound, Stanford-le-Hope.