I know this topic has been covered many times before but I've been going through various posts on installing boost pressure guages and which hose to T off from in the engine bay. I've looked at the top of the manifold. I have a MY94 so I'm not to sure on differences.

Some posts say that four leads from the spark plugs lead up to the distributor cap & unplug the lead on the right nearest to you & there should be a rubber cap covering a valve & to use that one!

I have four cables going from the coil packs to electrical connectors -can't see where they exactly go - don't look like normal spark plug leads though?? Can't find the distributor cap either??

Now on the inlet manifold there are 3 black pipes, 1 goes off to the top of my dump valve, 1 to a small black object (cylindrical but with a bracket) offside suspension turret near the boost control solenoid, the other 1 im not sure ! Again the pipes are different on mine 'cos they all point backwards and are together on the left of the manifold.

There is a place I could easily T into in the hose going to the small black object. However, I'm unsure as to which would be the best?

Any information on this (hose & difference of leads & lack of distributor would be greatly appreciated.

Johny.

 

Hi - just wondering if anyone could help with the previous post below? I've gone through quite a few previous posts but I don't want to have a trial & error in case I do something I will regret.

Cheers

Johny.

 

Try

 

Hi Johny

Sound like we both have the same problem
ie. We have older cars!
The inlet manifold on pre my95 cars are different we don't have high tension sparkplug leads we have low tension ones this is the first obvious difference and the second is the pipe layout is different.
unfortunately all the pictures and fitting instructions for boost gauges I have seen are for post 95 models.
I can e-mail you when I find out or if you find out first could you let me know.

Tony.

 

Lads,

Cheers for posting. James - my setup is different to that in the photo from your link. Tony - from what I can make out we have the same setup. I'll email if I get info.

If anyone could shed further light on this it'd much appreciated.

Regards

Johny

 

Think this is what you are after. Mine is a 96UK.



See the dumpvalve (shiny jobbie with blue hosing)? Follow the thin blue hose from this to the manifold. 3 hoses enter here side by side. Boost gauge can attach to any of these.

Mine fits to middle one. If you trace it back you can see the white T-piece and a blue tube which becomes black coming off the bottom of the T. That goes to the boost gauge.

Hope this helps.

Rich

 

re boost values.

On my uk99, i get around -700mbar on idle, just under 0 on low throttle, rising quickly to +1 bar at about 3-4000 rpm onwards.

Peak boost recorded in last two weeks since fitting the gauges is around 1.2 bar.

My feed for the gauges sender is from the top of the inlet manifold as shown in above posts.

Gareth

 

Rich,

Much appreciated for the info.

I tried last night and T'd into the pipes going to the "Pressure exchange solenoid valve".

The boost guage sits at 0 and when connected does so to but when the engine is running it goes way down -ve and when you come on good boost it only just goes above 0. Now I know this is wrong but there is a small restrictor in the T end to the boost guage. Not sure if this would cause it??

I expect what I should get is a 0 reading when idling, +ve when on boost and -ve when backing down through gears. Is this a right assumption?

Regards

Johny

 

Rich,

Just went outside and checked again (?) andI have mine the same.

First from the left goes to the dump valve (small black recirculating one).

Second goes to the "Pressure exchange solenoid valve" - the port on the right hand side pointing into the engine bay.

Third goes under the manifold - can't follow that one that well.


Just wondering how to get the guage reading 0 and +ve when on boost - 'cos I've seen guages reading way more than mine.

Regards

Johny

 

Johny,

Gareth is right. On mine, gauge is only at 0 when engine is off. Turn engine on and boost goes to -0.7 bar. Don't know the technical reason why. When you boot it, needle should move round to around 1.0 bar I think for your MY, unless you've upped boost.

Don't know why yours isn't working, guessing here:

Is the car accelerating normally? If it is, may be a leak in the pipe to the boost gauge or connection into boost gauge might not be good. It could be that restrictor too. Try asking the chaps you got the gauge from.

Can use the "going -ve" thing as a fuel economy device when cruising on motorway, The more -ve it goes, the less fuel you should be using (roughly). I had a car(944 turbo) that held at Zero until you came on boost (didn't have a -ve section). Some do some don't. Try connecting it to the other pipes, may behave differently????

Rich

 

Gareth / Rich,

Cheers for the info. I'll have a go again later this evening & hopefully I'll get it sorted.

Regards

Johny

 

Hi Johny,

I have a 99MY car, and my boost varies from -8 PSI at idle to around 15PSI at full welly. I think that's about -0.5 to +1 bar.

Make sure that your gauge is tee'd in close to the manifold. You don't want any restrictors between your gauge and the manifold - the readings will be wrong, and you may upset your boost control too. Order should be manifold -> your tee piece -> anything with a restrictor.

Make sure the restrictor stays connected to where it was !

Cheers

Steve

 

Hi Steve,

I,ve got the pipe coming from the manifold for about three inches, then there's the T. The pipe continues to the "Pressure exchange solenoid valve".

When it T's off there's a small restrictor in the actual T itself - so assuming the pipe I T into was previously okay thenI assume that the restrictor should go the boost guage end. This would slow down the reading but not cause the smallest delay for the Pressure exchange solenoid valve".

Would this be right??

Regards

Johny

 

I'm not sure I understand - did the restrictor come with your gauge ? Probably not. Tee in closer to the manifold than the restrictor.

The pressure exchange solenoid vents to atmosphere at regular intervals to allow the MAP sensor to determine current atmospheric pressure. It probably has a restrictor so that the pressure in the pipe drops all the way to atmospheric without whistling.

If you add extra pipework after the restrictor, boost control will be impaired (how much I don't know) since it will take time to pressurise your additional hosing through the restrictor, before the MAP sensor is seeing the same level of boost as is in the manifold. Interesting way of frigging some overboost though :-)

Steve

 

>The boost guage sits at 0 and when connected
>does so to but when the engine is running it
>goes way down -ve and when you come on good
>boost it only just goes above 0
>
btw, the engine must be under load to see any significant level of boost. If you are revving the engine whilst parked, that won't be enough. Get out on the motorway and plant it - should be a different kettle of fish.

Steve