the flyin' scotsman

One of many projects I've yet to do is the intake removal to R&R all those 20 year old hoses, the idle valve, throttle body etc. Perhaps other who have BTDT can post on what symptoms they were having before and if they were cured after this work.

My idle has never been stronger and I've done most of the work already discussed in this thread and it was all the little things that added up to make it so. Your climate is similar to ours here in Canada; why not leave it 'till winter and do the entire intake, fuel injectors, fuel lines and all other WYAI and enjoy the rest of your driving season.

ZEUS+

With a drop in pressure when running you should be looking at the feed side side not the return. Is the pressure drop and roughness an intermittent condition ? How long does it take to clear up ? Ruptured diaphragms in dampers and regulators dont usually cause intermittent driveability problems. Vacuum at booster with engine off is normal. There is a check valve so brake power assist will not be affected when vacuum drops from engine load.

Peter F

Hi Zeus,

yes the problem is intermittent and sometimes it clears after a few seconds.
But it seems to get worse and now can take up to maybe 30 second to a minute before it clears.

Thanks/Peter

ZEUS+

With this intermittent condition, maybe an injector(s) sticks open. Remove and inspect spark plugs for fuel fouling. When this happens shut off engine to see if fuel pressure drops. Just one possibility. Have you tested for fuel pressure drop ?

the flyin' scotsman

Peter............have you tried the WD40 (or equivalent) trick down the idle actuator hose to potentially free up the valve should it be sticking?

Peter F

Hi Zeus,

all injectors was cleaned and tested last Year all within less than 3% from each other.
When I shut down the fuel pressure increase, will try tomorrow and see if it does when it starts to run bad.
Malcolm, everything under the intake is new including the idle actuator.
It has not occured to me that it could be faulty since it has been replaced?
Has anyone experinced this before?
Anyway I will try the WD40 trick and see if that helps.
Thanks for all advices, keep them coming.

/Peter

the flyin' scotsman

Smokes Peter...............it may be easier to list what you haven't done.

Good luck!

Peter F

Well it is for sure a big mystery to me,
I know there is a lot of brainpower on this forum and hope that someone can lead me to the light .

Cheers/Peter

the flyin' scotsman

It may help if you can further describe the 'rough' running.........to pin point the issue.

Peter F

If it happens when driving the car will barely run unless i pump the gas pedal up and down and it will still be jumpy and feels like it is power on and off with high frequency.(jumpy ride until it clears but the feeling is that it is going to die)
When it happens in the garage at idle it starts to hunt and sometimes even stop completely.
It starts right up but runs only for a short moment if I dont help it with pressing the fun pedal.(and when i do it also backfires and runs very lumpy)

/Peter

jpitman2

Try getting something to read mixture status fitted, and see if it indicates a change when it runs rough. If so, its fuel. If not , more likely ignition. I had a similar problem once - only when cold (another make) that I isolated to a specific cylinder; plug change didnt fix;lead change didnt fix;dist cap change didnt fix - whats left? eventually found that clearance between the trigger rotor and the inductive pickup was at high end of spec - closed it .002", problem went away - conculsion: 1 of the 1/16" dia bar magnets in rotor was weak! Another time I had a misfire, and I had recently replaced the plug leads so discounted those as the source of problem. In the end after going through everything else, I pulled them and tested, and found some corroded ends. Took them back to supplier and complained, and they said 'oh yes, we had to get rid of that type, they were prone to corrosion'....tell me about it! Moral, dont discount any part of the system as being faulty just because they have been replaced recently....
jp 83 Euro S at 50k