free hit
counters
GT3 Vacuum Pipe - Page 2 - Engine/Ancilliaries - The Lotus Forums #ForTheOwners Jump to content


GT3 Vacuum Pipe


BigErch

Recommended Posts


Upgrade today to remove Google ads and support TLF.
On 05/05/2016 at 14:21, Vulcan Grey said:

I think Ian is right. Looks like the map sensor line is connected to the vacuum pump outlet, if I'm not mistaken...

That's certainly a weird looking setup (with that rubber loop). Is that the vacuum pump outlet or inlet with the thin black pipe on it?

I thought I saw two thin vacuum lines in the photo and that one of them might be for the heating and airconditioning? The ones under the dash are this thin. However, if it is the MAP line, maybe someone stuck it here by mistake with the rubber elbow, too.

Link to comment
Share on other sites

 Sorry, I'm not being clear. Unfortunately I don't have the sticker on the underneath of the rear hatch so I had printed off Travis's image. It doesn't make the connections to the pump that clear, I was hoping someone could post a photo or even draw me a diagram :)

Here's my pump below. If the first photo correctly shows the MAP sensor then it is connected directly into the bottom in/out of the pump (you can see the rubber elbow). I can connect this back onto the inlet manifold but what connects onto the pump in it's place?

DSC_0813.JPG

DSC_0814.JPG

Link to comment
Share on other sites

  • Gold FFM

 

1. THE MAP SENSOR CONNECTS TO A RUBBER ELBOW ON THE REAR OF THE INLET MANIFOLD.

2. THE VACCUM PUMP CONNECTS TO THE EBPV AND THROTTLE JACK SOLENOIDS, AS IN THE DIAGRAM THE TRAVIS POSTED.

3. THE VACUUM PUMP MAY ALSO CONNECT TO THE HEATER/VENTS AT THE FRONT OF THE CAR.

3. THERE IS NOTHING THAT CONNECTS TO THE VACUUM PUMP INLET. NOTHING. ZILCH. THAT IS THE LOWER OF THE TWO CONNECTIONS ON THE LEFT HAND SIDE IN YOUR PHOTO.

4. RE-MAKE THE CONNECTIONS.

5. SIT DOWN AND HAVE A NICE GLASS OF MALT.

6. BOOK APPOINTMENT WITH SPECSAVERS (ASSUMING YOU CAN READ THE TELEPHONE NUMBER).

7. JOB DONE.

Margate Exotics.

Link to comment
Share on other sites

Yes, definitely connect the MAP sensor back to the intake manifold. 

 

The lower white port on the vacuum pump is for air outlet and should not connect to anything. 

The top black port connects to the hose that goes to the cabin area to control the heater flaps.

The white port connects to nothing.

GM10098493.JPG

 

 

  • Like 2

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

Link to comment
Share on other sites

Just wondering how the car ran at all. Would the vac pump be generating any damaging positive pressures (in relation to the MAP sensor)?

 

Anyway, another problem solved by the forum :) (albeit with lots of shouting).

 

I can guess where you won't be taking your car for it's next service, Archie :P

Link to comment
Share on other sites

If the MAP sensor was disconnected you should have had violent hesitations once you hit boost, but would otherwise have driven ok just cruising leisurely.  I had that happen at a driving school track day and you will definitely feel the result of that hose blowing off or being disconnected.

My advice if you're going to the trouble of reconnecting from intake to map sensor, buy some thick walled silicone tubing and be gone with those rubber elbows and just have a straight vacuum line from intake to map- they are a problem waiting to happen as they cannot withstand heat and just rot with time and either can provide driveability issues due to a vacuum/pressure leak - both at the ac controls and at the intake manifold-especially if the engine starts getting oily.

  • Like 1
Link to comment
Share on other sites

Travis, thanks for the info about the white port. It looked like it should be connected to something and I didn't want to start disconnecting/connecting tubes without getting the full story.

Ian, I'm going to work on it today and I'm keeping my fingers crossed the MAP sensor is ok.

Paul, the violent hesitations is exactly what I experienced so that's a good indication I'm on the right track. The rubber elbow connectors on these pipes are both cracked so your other suggestion sounds like a good plan.

Thanks to everyone for all the help, as for the shouting I don't think that kind of behavior is acceptable on this forum. It's easy, if you're finding a topic annoying or boring just stop following it.

cheers Archie

Link to comment
Share on other sites

I had the same issue on my S4 last year. It's been mentioned many times over on the forum that the MAP line rubber elbow at the manifold end cracks and when I had this issue a new rubber solved it. So I'm embarrassed to say that after doing an engine out maintenance job over the winter that it all fired up lovely except it was running rich and being over compensated with fuel by the BLM to run. i checked everything and couldnt see a problem (obviously not well enough). :o

I even dragged http://www.thelotusforums.com/forums/profile/17252-ian29gte/ and http://www.thelotusforums.com/forums/profile/4129-sparky/ to look at the Freescan at Brookland because I just couldnt work out why it all appeared to show "OK" with no error codes and even they couldnt see anything wrong. Of course they said "Have you checked the MAP sensor line" to which I replied "yes it's fine". Now I realise it wasn't having removed the rubber elbow and found tiny cracks at both ends and two on the inside of the elbow but only visible when you bend it outwards.

I had already ordered a bag load for future use but sods law they hadn't arrived by Saturday morning so off to the motor factors, replaced it the pub car park and bingo, runs as sweet as anything. Naturally replacing a tiny rubber elbow on a hot engine is a total b*tch job with copious amounts of swearing but it went on in the end. Compared to the other end of the MAP tube which is soft and supple, this end it rock hard and shiny so the localised heat really knackers these quickly.

So I thought "heat shield" this morning. Here's what I have done and it'll go back on the car today. Silver heat resistant sticky tape wrapped around the rubber elbow from end to end and then rubber heat-shrink over the ends to hold it all in place.

I'll let you know how long it lasts!

IMG_1220.JPG

IMG_1223.JPG

IMG_1224.JPG

Link to comment
Share on other sites

  • 1 month later...

I'm no psychic but I'll bet money you will have another problem as this is a band-aid fix both in practice and looks.  :cry: Don't become one of the "Dreaded Prior Owners" with these type of repairs. How will you know if it has cracked underneath the foil?

THOSE RUBBER ELBOWS ARE PROBLEMS WAITING TO HAPPEN and are the source of an untold number of Esprit driveability issues!!  Replace with some black thick wall silicone hose from the intake to the MAP sensor of the correct size and you will never have a problem again.  The factory lotus elbows were never good enough for an engine compartment environment (or probably anywhere else on the car as they crack at the ac controls causing the diversion valves and defrost flap to cease functioning and your electric vacuum pump to run continuously if you have a later model stevens).  I have had this happen on both my deceased 1993 and my current 1995.  It is no coincidence either. Putting some foil on it won't solve the underlying issue. Just bite the bullet and get rid of the plastic tubing and elbows completely.  When the elbows crack they don't immediately create an issue, but you can bet they have an effect on fuel trim because the reading at the MAP is not exactly correct as you are bleeding off pressure/vacuum, which results in less power as the MAP is not getting the true reading for the condition of throttle.

The plastic tubing can even blow out of these elbows if they get oily enough in the engine compartment. 

Link to comment
Share on other sites

2 hours ago, Paul93Lotus said:

I'm no psychic but I'll bet money you will have another problem as this is a band-aid fix both in practice and looks.  :cry: Don't become one of the "Dreaded Prior Owners" with these type of repairs. How will you know if it has cracked underneath the foil?

THOSE RUBBER ELBOWS ARE PROBLEMS WAITING TO HAPPEN and are the source of an untold number of Esprit driveability issues!!  Replace with some black thick wall silicone hose from the intake to the MAP sensor of the correct size and you will never have a problem again.  The factory lotus elbows were never good enough for an engine compartment environment (or probably anywhere else on the car as they crack at the ac controls causing the diversion valves and defrost flap to cease functioning and your electric vacuum pump to run continuously if you have a later model stevens).  I have had this happen on both my deceased 1993 and my current 1995.  It is no coincidence either. Putting some foil on it won't solve the underlying issue. Just bite the bullet and get rid of the plastic tubing and elbows completely.  When the elbows crack they don't immediately create an issue, but you can bet they have an effect on fuel trim because the reading at the MAP is not exactly correct as you are bleeding off pressure/vacuum, which results in less power as the MAP is not getting the true reading for the condition of throttle.

The plastic tubing can even blow out of these elbows if they get oily enough in the engine compartment. 

The foil was to act as a heat shield. I have a spare supply of elbows in case a swap-out is needed. However you;re probably right that it would be better to have a different tube from one end to the other and ditch the rubber elbows completely.

Likewise I'm reverting my single coolant header tank into two - one for the engine and one for the chargecooler. But's that's for a different topic....

Link to comment
Share on other sites

When I was refitting my Turbo, I broke the thin black plastic vac hose, then looked at the dreaded elbow which was also cracked so replaced both with silicone vac hose straight from the manifold to the MAP sensor.  That was 3 years ago and no issues.  Its also worth pointing out that the GT3 differs to other Esprits slightly, in that there is no throttle Jack.  If anyone is still haveing issues with vac hoses on a GT3, let me know and I will take some pictures of mine, which also has a dump valve fitted.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...