misfire as the top end

[Paul V]

Went out for a spin in the tuscan today, noticed today when I held it in gear it seemed to misfire a little, also sounded like it pinked slightly. Noticed in the history file it had new leads fitted a few months back. Any idea's what could be causing it?

[longy]

i would like info also as i have the exact same problem with my tusc. just after the green light comes on it pinks or misses but then seems to want to carry on.

[Paul V]

what petrol do you run?

[nelly1]

In order of likelyness.....

1...Plugs
2...HT leads (even if relatively new - they can still be faulty / damaged / not connected properly.)
3...Coil (easy to change and relatively cheap - see here...
4...Dodgy CPS (Crank Sensor) connection or wiring too close to HT leads
5...ECU problem (or bad connection to loom - water ingress!), dodgy earth to engine block or bad connection between engine loom / ECU loom via bulkhead connector
6...Engine damage - burnt valve or timing out

HTH

Neill

Edited by nelly1 on Thursday 2nd August 22:02

[Paul V]

What plugs do Tuscan's run? Also what is the best to sealant to seal the top cover on with?

[andyvdg]

Most common cause is the vibration at high revs that causes a false overreading which makes the ECU thinks it's overfueling which causes it to cut the power. There (was) an upgrade to the throttle chip which fixes it.
I can't find the original and many-years-old thread, but here's a more recent one.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

However, it could be any of the below as well.

nelly1 said:

In order of likelyness.....

1...Plugs
2...HT leads (even if relatively new - they can still be faulty / damaged / not connected properly.)
3...Coil (easy to change and relatively cheap - see here...
4...Dodgy CPS (Crank Sensor) connection or wiring too close to HT leads
5...ECU problem (or bad connection to loom - water ingress!), dodgy earth to engine block or bad connection between engine loom / ECU loom via bulkhead connector
6...Engine damage - burnt valve or timing out

HTH

Neill

Edited by nelly1 on Thursday 2nd August 22:02

[nelly1]

Paul V said:

What plugs do Tuscan's run? Also what is the best to sealant to seal the top cover on with?

Plugs - here...
Sealant - here...
Better than messy sealant - here...

[Paul V]

Do you know what type they are? Just easier to go to my local Partco and get a set.

[stillgrinning]

When it happened to me it was due for a service and they found a old/corroded HT lead and changed the set for about £30 IIRC and it cured the problem instantly.

[Paul V]

It does have new leads which seemed to cure the problem for a while.

[nelly1]

Paul V said:

Do you know what type they are? Just easier to go to my local Partco and get a set.

See here... - NGK DCPR8E or DCPR8EIX (Iridium)

[Paul V]

interesting that I filled it with optimax and it's now not doing it, so it either didn't like the wet tunnel run on saturday night or the timing is too far advanced to run standard 95 fuel.

So the next of the many questions is can the timing be set using a straight 9 pin lead or do I need an MBE lead with the resistors in?

[nelly1]

Paul V said:

interesting that I filled it with optimax and it's now not doing it, so it either didn't like the wet tunnel run on saturday night or the timing is too far advanced to run standard 95 fuel.

So the next of the many questions is can the timing be set using a straight 9 pin lead or do I need an MBE lead with the resistors in?

Are you talking about having it remapped?
How long have you had the car? Has it done it from day one?
Is the misfire a new thing? Did it start suddenly?

If it's a recent thing, the different fuel may only be masking the symptoms rather than curing the problem.....

If it's due a service, then get it checked by someone in the know - it won't cost the earth as these things are often something simple.

[Paul V]

nelly1 said:

Paul V said:

interesting that I filled it with optimax and it's now not doing it, so it either didn't like the wet tunnel run on saturday night or the timing is too far advanced to run standard 95 fuel.

So the next of the many questions is can the timing be set using a straight 9 pin lead or do I need an MBE lead with the resistors in?

Are you talking about having it remapped?
How long have you had the car? Has it done it from day one?
Is the misfire a new thing? Did it start suddenly?

If it's a recent thing, the different fuel may only be masking the symptoms rather than curing the problem.....

If it's due a service, then get it checked by someone in the know - it won't cost the earth as these things are often something simple.

No not remapped, but the ECU sets the timing so was going to check that.
Only had the car a month or so, didn't really explore full throttle too often in the first few weeks. If it's pinking then likely to be timing if the mixture is ok.

The misfire is only at full throttle above 5.5k rpm, from the history it seems there was a problem previously which was sorted out in April, they fitted new HT leads, it was also serviced at the same time.

I will take the car in if need be but will try and find the problems firstly, if I don't discover to fault I'll let JMS have a look over it or find someone to remap it etc.

[Whitey]

misfire over 5.5K is unlikely to be the HT leads, could be numerous things, I would suggest as you have just got the car to get a quick engine service done to ensure it's correctly set up. No point pissing about when we actually have nice weather for once!