Engine 850: B5234TR/2.3/20v/T5R: Sooty Plugs, judder at low revs

[AndysR]

Petrol will be a good way of cleaning the gunk that collects inside the intercooler. But I am not sold on this idea as a way of detecting a boost leak. Would it not be better to try and adapt the system to sort of seal it then use a vacumn cleaner and try and see by vacumning the intercooler if it is leaking? Or maybe sealing up the intercooler making something up which seals to the intercooler then using a foot pump try and pump the intercooler full of air and see if it looses significant pressure. Probably both silly idea's but aside from removing the ic and taking it to someone that re-cores radiators for a leak test I am not sure what the safest way to test it yourself would be.

[Georgey dee]

good idea,, I'm gonna go to Bradford Radiators and see how they do it. I really really don't want to take the aircon/coolant and IC off to search for a leak but i'm sure i've got a leak.

[AndysR]

Originally Posted by Georgey dee

good idea,, I'm gonna go to Bradford Radiators and see how they do it. I really really don't want to take the aircon/coolant and IC off to search for a leak but i'm sure i've got a leak.

Ah that sounds like good thinking! although if you do have a leak you will need to remove all the gubbings to get to it anyway.

[Georgey dee]

Just an update,

Things changed----

All IC big pipes
All Turbo Vacume pipes
HT Leads
Plugs
BCS
Rotor Arm
Dizzy Cap
Air Filter
Auto Box Fluid
Whole PCV system

Things fiddled with
IC Leak checked = Was solid
Re-gapped plugs to 6mm
Bought a new set of plugs to put back to standard
Fuel pressure checked


Result= STILL JUDDERS

So after a chat with Marco and Don at his pad in London yesterday and some serious head scratching from me I'm gonna change to ignition coil next.

The reason for this is = the boost stays solid put it's like a switch is tripped at 4000rpm, it's wierd!!! It must be an ignition fault and the only thing I haven't changed for genuine Volvo on the ignition system is the coil.

It comes on monday, I'll keep you posted.

[Jod T5]

Originally Posted by Georgey dee

Just an update,

Things changed----

All IC big pipes
All Turbo Vacume pipes
HT Leads
Plugs
BCS
Rotor Arm
Dizzy Cap
Air Filter
Auto Box Fluid
Whole PCV system

Things fiddled with
IC Leak checked = Was solid
Re-gapped plugs to 6mm
Bought a new set of plugs to put back to standard
Fuel pressure checked


Result= STILL JUDDERS

So after a chat with Marco and Don at his pad in London yesterday and some serious head scratching from me I'm gonna change to ignition coil next.

The reason for this is = the boost stays solid put it's like a switch is tripped at 4000rpm, it's wierd!!! It must be an ignition fault and the only thing I haven't changed for genuine Volvo on the ignition system is the coil.

It comes on monday, I'll keep you posted.

Sounds like the same issue, boost leak, Pnut had after his MTE map, IIRC he changed everything he could and found a MBC helped out alot....Map, Actuator?? im not sure how he sorted it but im sure he will be along...
cheers
jod

[Georgey dee]

I have a MBC if it comes to that. I had the judder before the Re-map so I know that's OK. I'll just keep changing bits till I get it LOL. Who ever buys this car after me will be getting a new car!!!!

The reason I'm changing the ignition coil is the same theory as the shorten gap, weak spark. And it's only a transformer and it may have got weak after 11 years.

We'll see.

[Georgey dee]

Just an update.

Changed the Ignition coil and fuel pump relay and still no change.

I'm starting to wonder that the Vibration I can feel may be because of the poly engine mount and the step at 4000rpm is ment to be there, a trate of the ECU perhaps.

I need to go out in another auto R with a poly bush to see if it's the same feeling.

Hopefully one will come to the track day at Marham then I can finally put this to rest.

PS, it seems to be temp related but this could be because of the poly material being stiffer at low temps.

[dooby]

Hiya Georgey,

I'd love to bring my auto 850R to Marham but I was too slow to get in your initial 10 places :-( Watching carefully in case you manage to free up any more :-)

However I can state that my 850R does not have a noticeable step at 4k RPM. I do have a polybush top mount but am running a RICA304 map as opposed to your MTE map.

I don't know whether the MTE map would be meant to be different in this respect but I doubt it...

HTH, Pete

[Georgey dee]

I'm 99.99% sure it's nothing to do with the map as it did it before the re-map. I'll keep looking and I'll try for some more places for Marham.

Cheers

George

[Paul240480]

Hello, just seen this thread & I'm talking as a novice! Has your engine got a MAF sensor? If yes unplug the electric connector. if it then runs smoothly you have detected an air leak!
Main prob' is to find & cure it!
Good luck