Technical Barchetta running issues

[PB79]

Hi all

Thankyou for your time.
I have a 1998 Barchetta which has been in storage for years.
It has a running problem which is now all the time. when you start the engine it runs perfectly but after 30 seconds it will not rev and runs rough. This also happens if you start the car and hold the RPM at 3000 it start to run rough and the RPM slowly drops to idle. it does not always cut out.
There are no warning lights on and no codes stored. we have stripped and cleaned the throttle body/ idle valve. Fuel pressure appears ok.
We had a rather nasty top end rattle also but have replaced the belt and fitted a dephaser repair kit which has cured the rattle but not improved the running issue.
Thanks in advance for any help

 

[s130]

I was going to suggest the variator as 3000rpm (or there about) is where it takes effect.

However you mentioned you had fitted a repair kit.

That said I think the variator is still a possibility.

Check the wiring to the variator solenoid. Then remove the solenoid and check it for coil continuity and then operation. Also whilst removed check for any oil blockages.

The normal way to check variator operation is to raise the revs from idle and hold steady at 2700 to 3000 rpm. After a short while the revs with suddenly rise above 3000 rpm.

 

[PB79]

I was going to suggest the variator as 3000rpm (or there about) is where it takes effect.

However you mentioned you had fitted a repair kit.

That said I think the variator is still a possibility.

Check the wiring to the variator solenoid. Then remove the solenoid and check it for coil continuity and then operation. Also whilst removed check for any oil blockages.

The normal way to check variator operation is to raise the revs from idle and hold steady at 2700 to 3000 rpm. After a short while the revs with suddenly rise above 3000 rpm.

Thanks for the feedback S130.
we appear to have continuity on the solenoid and it operates. we have cleaned the oil way and carried out a flush and oil change.

Sometimes the vehicle will run perfectly for 20 minutes with no signs of a running issue. you can leave it at idle and all of a sudden it will run lumpy and try to cut out. it seems to be over fueling. This also happens if you rev the vehicle to 3000 rpm it can sit there happily for 2-5 minutes and the suddenly the revs will start to drop with no throttle response. all of these things sometimes happen within 30 seconds of starting but always reset if you restart. We originally were thinking Variator but as it seems to fault when left at idle, I am not so sure.
Do they suffer from ECU issues ??

Thanks for your help really appreciate it

 

[s130]

I understand the Hitachi ECUs in the "B" are very reliable. I've personally never heard of ECU issue.

Suggestions:

o check for air leaks post throttle body (don't forget the brake servo assist vacuum hose / valve / diaphragm - test the operation of the servo before your problem and after the problem occurs)
o one or more ignition coils failing to fire
o crank / cam sensors failing although these often play up when the engine is hot so from a cold start I wouldn't expect this to happen within 30 seconds or so
o fuel pressure either dropping or possibly going too high

It is just so difficult to cold diagnose over the web

Also have you grabbed a "B" workshop manual from this website as it explains in detail all about the fuel injection system etc.