TopCat

Guys,

The other day I was driving down the motor way cruising at 90mph, and I experianced a lumpy, rough, judder, feel when trying to maintain the above speed. my 0-100 when accelerating hard is quick / the norm only when I try to cruise it than starts the problem as mentioned and I don't want to force through this as it gets worse.

The dealer had taken the car out with a select monitor no faults and the engine is fine?? what the hell can it be? the dealer is not sure either. They want the car for the whole day. No way jose!

My car is a MY97 Catalunya, with the following.

had 45k miles service and cam belt change.
oil ( SHELL HELIX)
K&N Panel filter
SS downpipe
Forge piston DV
Magnex centre pipe & Back Box (No cats)
run on Sul
PE boost G (car reaches max 18psi in 4th & 5th(
Superchip bleed Valve(turned off) not needed already hitting 18psi without it.

I do have plans to change to Unichip very soon, don't get me wrong the car does go very well 260 bhp on PE r/r runing on UL which I have been told to change to SUL and was running much better, also at the time of the R/R I did not have the SS downpipe.

NB the select moniter shows no engine problems or Det.

Can anyone advise a fellow scooby owner?

awaiting the kind response from others

TC

Just only the other day I got the problem above
superchip with

TopCat

come someone must have a clue?

Ian Cook

If you didnt have the D/P when the chip was done, you may need to take it back and get them to remap it, any engine/performance enhancements made to the car will affect the ECU mods !

Ian Cook

Sorry, just read it again, and may have misread the first time ! so my advice may be completely useless, ignore me !

TopCat

Ian, Thanks for the reply, that would be true if it was a link/Unichip but the Superchip is ready made.

someone help!

TC

Hoppy

Top Cat, it's not something as simple as a missing balance weight from a front wheel is it? Sorry, no offense intended

Richard Hopkins

TopCat

Hoppy, no offense taken, it is obvious that you have experianced the same when cruising, I will check and let you know.

thanks for your response, I hope others read my prob and could relate and assist.

You take care and I will go and check now

TC

TopCat

Hoppy: I have had new wheels just put on a few weeks ago, and all the weights are still in tack and I can't see anything missing.

So just to re-explain the car drives well when doing everything but cruising from 90-100+ is when it start juddering and get worse if you try to push through it.

Help!

TC

Ian Cook

The only way you would know for certain that the wheels were balanced correctly would be to have them done again ! Just looking a the balance weights will prove nothing i am afraid ! (not intended to sound condescending)

When you say it judders, is it through the steering, or something else ? ie does it feel like its holding back ?

If it gets worse with speed and is coming through the steering, it does sound like the wheel balancing though !

Bob Rawle

If by cruising you mean "off boost" then there is something wrong, the ecu is probably fueling the car too lean (or rich) based on an incorrect map or maf reading or ... you could also have a failing lambda sensor. Best get whoever fitted the superchip to make sure that nothing is wrong in that department. By "valve turned off" what do you mean ? If the select monitor reads all ok was that with it connected when the problem occured ? that would show up what was happening as all the sensor outputs can be checked under the fault conditions.

Bob

TopCat

Ian / Bob,

The bleed valve screw has been turned right in, so it's not being used. All that is being used is the piggy back chip for the timing and fuel. and its still hitting 18psi max, with the valve it was hitting anything from 20-25psi dependant on how much you loosen the screw on the valve. I will keep it at 18psi.

However I have the car booked in with SS in 2 weeks I can't wait that long.

The great news is I was reading the section regarding the surging engine problem on the BBS, someone was having the same problem as me at 95mph, but did not have the same mods. I thought it must be worth a try so I took of my dump valve and de-asembled it has cleaned and hit it with some WD40, and took it for a blat on the A40 WOOOOOOOW! so problems crusieing..I had a dump problem, I did'nt even get a chance to really understand the benefit of the SS down pipe apart from the noise.

When passing SS prior to making the above appointment due to the fact that they were closing in 30mins, Pete C took the time to put a select monitor on the car and did say the air being dumped does not looking right on the graph, so when I come back he would have to try another dump V and other test.

Thank goodness for BBS and initiative!

Gentleman,
Thanks plenty for your assistant with my almost world ending experiance.

TC

Bob Rawle

Great, good that its sorted, so it was a fueling issue, be aware though that the Superchip does not control fuel or timing, it does nothing more than fool the ecu so that it does not cut boost... AT ALL ... so if a pipe comes off then boost will just keep going, keep an eye on the boost guage at all times.

TopCat

Bob,

I am no expert so many thanks for the tips, I have asked around for another ECU tip and have been told by a few that for the age of my car MY97 40k miles that the Unichip would be the best option as I can remove it when I sell the car. Also Changing means I have already flushed 450 pounds away on that S/chip from a Scooby dealer. I was also thinking of the Link, your expertise.

What do you think Bob

TC

Pete Croney

Hi Bob

I went out with TC and thought it was the dump valve as I was seeing wild spikes on the A/F correction graph.

At this speed, TC would have been around 0 psi (+14 absolute) but fluctauting due to gradiants/small changes in throttle position. I guessed that TC's dump valve was sticking and being a VTA, this was giving the weird readings.

TopCat

Once again Gentleman,

Thanks for your assistance with this problem.

And Pete that Down pipe is the bowl oaks!!!

see you soon when I'm next in the hood

TC