Little niggles

**kenholland** · 5-31-04, 15:38

Well, apart from working this morning, I spent the day fitting the FSE and trying to sort out a vacuum problem on the new engine.

Dave, you remember that my #1 VRIS actuator was very sluggish compared to the others when I start the engine? I reckon this is down to an air leak somewhere. So I replaced every vacuum tube with that nice new blue stuff I picked up at Japfest, double-checking the connections against the vacuum diagram as I went.

A few of the old tubes were definitely a bit crusty and things improved slightly. But I'm sure I can hear a hiss from under the intake manifold on tickover. I can only surmise that the tubes around the vacuum chambers or the chambers themselves are leaking.

So, my next step is to remove the intake and check. I think I'll leave it until I can afford a phenolic spacer set though and do the job all together next month.

Can you foresee any problems running with a small vacuum leak? (Apart from the obvious drop in performance that is.)

Cheers,
Ken

**Ian F Chequer** · 5-31-04, 16:41

If there is a vacuum leak air will be being sucked into the inlet manifold without being filtered first and without the flow rate being monitored by the flow sensor.

The greater the level of manifold vacuum the worse the problem will be. Best vacuum is usually when the engine is idling (throttle nearly closed) so you may see a slightly erratic idle.

I was asked to look at a very old Citroen AX GT about 18 months ago which misfired, overheated and didn't return good fuel economy. On this car the regular air filter had been replaced by a performance one which did not have nipples for one particular hose which went into the inlet manifold. The clown who'd actually fitted the part had simply taped up the end of the hose which had proceeded to leak. When I used a self tapping screw to seal the end instead the engine worked a little better, but still lacked acceleration because the vacuum advance hose was also disconnected. I said his best way forward would be to source an original air filter assembly.

The sensors in the exhaust will correct for the fuel / air ratio imbalance to some extent but you may still get odd effects under (say) hard acceleration. However the ECU may not register a fault. You might also get pinking / overheating but the knock sensor should detect this and retard the ignition to suit.

regards,

Ian Chequer

**kenholland** · 5-31-04, 16:54

Cheers Ian.
There's definitely some vacuum - I just think it's down on what it should be, and with no vacuum gauge, I can't accurately tell.

Looks like I may have to get the Outlaw kit sooner rather than later then.

Ah well...

Ken

**xedos 6** · 5-31-04, 19:39

Ken if it helps I have a pair of vacuum gauge's , you might need to get a "T" section adapter to use these in line to get the readings , wonder if john's books give some readings as a base to work from, but just checking the lines should show whats happening.

pm me if you need to borrow them

roland

**kenholland** · 6-2-04, 12:43

I've been thinking (always a dangerous thing...) and I think I may have found the vacuum leak.

What does the vacuum tube from the airbox do? As far as I can see it's only there for the EGR system.

Without EGR, that tube connects the VRIS solenoids directly to the airbox and doesn't go via the EGR solenoids. Take a look at this:

My system connects the pink hose from the VRIS 'T' straight to the red hose into the air intake tract.

Can I just get rid of the pink hose and that 'T' and use just the light blue hoses from VRIS solenoids to vacuum chambers? What do you think?

Ken

Ken

**Einstein** · 6-2-04, 13:54

You're right again Ken

the small pipe going to the airbox, is part of the EGR system.. it vents exhaust gases back into the inlet to be reburnt.

The pink hose gives vacuum to the EGR control valve to operate it.. the solenoid valves divert the gases from the red pipe to the airbox.

I would block off the pink one before it goes to the solenoids, and not take it to the inlet manifold.. you are definately losing some vacuum at the moment.

John