Poor idle and stumbling can be caused by many set up issues but also by leaking/ poor sealing after market dump valves.

 

However there is another issue we are seeing more and more commonly in the workshop and with the advent of inexpensive dump valves on ebay and similar looks set to continue.

 

Today in the workshop was a classic example of this very issue, a zed came in that has been off the road for around 2 years, the engine was struggling to run and had a huge flat spot when statically revved, with an MOT booked for the afternoon I had to act fast.

 

Whilst it would tick over sort of when warm the ConZult diagnostic was not revealling too much, which is ok, it just means getting a little more involved. A boost leak test soon revealed a massive air leak and not too far from the intake area, with the after market dump valves in sight I instinctively went directly to the rubber bungs that are supplied with the ebay units, these are essential and form part of the installation when fitting the valves.

 

So you can see in the pictures below the rubber boots look in reasonable condition when in place or held in you hand, however pinch them between your fingers and the boot opens up, the rubber material is just way to soft and the constant flexing cause by the increased negative vacuum when on the gas then swapping to equalised pressure when backing off just wears them out.

 

Shame really as they fit so well, they are just made out of the wrong material, the other concideration is the deteriation of the boot goes unoticed and the effects slowly get worse until any idle or hesitation problems are too bad to live with as more air is drawn through the rubber boot rather than the air flow meter.....if you have these fitted to your zed it would be worth a check now!!

 

Jeff TT

 

 

[ATTACH=CONFIG]69027[/ATTACH]

 

[ATTACH=CONFIG]69028[/ATTACH]

 

[ATTACH=CONFIG]69029[/ATTACH]

 

[ATTACH=CONFIG]69030[/ATTACH]

 

[ATTACH=CONFIG]69031[/ATTACH]

Edited February 28, 201312 yr by JeffTT

Poor idle and stumbling can be caused by many set up issues but also by leaking/ poor sealing after market dump valves.

 

However there is another issue we are seeing more and more commonly in the workshop and with the advent of inexpensive dump valves on ebay and similar looks set to continue.

 

Today in the workshop was a classic example of this very issue, a zed came in that has been off the road for around 2 years, the engine was struggling to run and had a huge flat spot when statically revved, with an MOT booked for the afternoon I had to act fast.

 

Whilst it would tick over sort of when warm the ConZult diagnostic was not revealling too much, which is ok, it just means getting a little more involved. A boost leak test soon revealed a massive air leak and not too far from the intake area, with the after market dump valves in sight I instinctively went directly to the rubber bungs that are supplied with the ebay units, these are essential and form part of the installation when fitting the valves.

 

So you can see in the pictures below the rubber boots look in reasonable condition when in place or held in you hand, however pinch them between your fingers and the boot opens up, the rubber material is just way to soft and the constant flexing cause by the increased negative vacuum when on the gas then swapping to equalised pressure when backing off just wears them out.

 

Shame really as they fit so well, they are just made out of the wrong material, the other concideration is the deteriation of the boot goes unoticed and the effects slowly get worse until any idle or hesitation problems are too bad to live with as more air is drawn through the rubber boot rather than the air flow meter.....if you have these fitted to your zed it would be worth a check now!!

 

Jeff TT

 

 

 

 

 

 

Edited February 28, 201312 yr by JeffTT

[ATTACH=CONFIG]69032[/ATTACH]

The rubber boots also come with this type of dump valve also.

 

Jeff TT

 

[ATTACH=CONFIG]69033[/ATTACH]

Edited February 28, 201312 yr by JeffTT

The rubber boots also come with this type of dump valve also.

 

Jeff TT

 

Edited February 28, 201312 yr by JeffTT

Great thread Jeff...and loving the tech threads again:)

Great thread Jeff...and loving the tech threads again:)

Those top valves are the same as the ones I had on my old Zed

Those top valves are the same as the ones I had on my old Zed

I've made them bungs a few times from an old socket lol, find the right size turn the welder up and fill the hole.

 

They never leaked yet.

 

Good find jeff..

I've made them bungs a few times from an old socket lol, find the right size turn the welder up and fill the hole.

 

They never leaked yet.

 

Good find jeff..

I posted about this exact problem with my current zed when i got it. had horrible running issues on the day i brought the car, turned out to be not only the ECU temp sensor plug, but also the bungs for the OEM dump valves had deteriorated just after the maf. once the temp sensor plug was sorted out, i still didn't know what was causing me massive over fueling (looked like a diesel chuffing away) and the horrible running, went to check the maf thinking it might be that, and noticed those bungs missing with the clips still in place.

 

Replaced them for some proper bungs and been running good until the wiring loom finally gave up. (though thats now replaced :D)

I posted about this exact problem with my current zed when i got it. had horrible running issues on the day i brought the car, turned out to be not only the ECU temp sensor plug, but also the bungs for the OEM dump valves had deteriorated just after the maf. once the temp sensor plug was sorted out, i still didn't know what was causing me massive over fueling (looked like a diesel chuffing away) and the horrible running, went to check the maf thinking it might be that, and noticed those bungs missing with the clips still in place.

 

Replaced them for some proper bungs and been running good until the wiring loom finally gave up. (though thats now replaced :D)

i think my bungs are aluminium end caps with silicon joiners.

i think my bungs are aluminium end caps with silicon joiners.

Great thread Jeff...and loving the tech threads again:)

 

Seconded..... Cheers Jeff!!

 

Richard:cool3:

Great thread Jeff...and loving the tech threads again:)

 

Seconded..... Cheers Jeff!!

 

Richard:cool3:

Best buy some silicone bungs!

Best buy some silicone bungs!

like this one for example - http://www.ebay.co.uk/itm/330725834159?var=540062442766&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 :)

like this one for example - http://www.ebay.co.uk/itm/330725834159?var=540062442766&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 :)

walking stick ends fit a treat serious.My old man used a pair on his first zed.

Angle grinder + two spare Nissan wheel braces = job done!

walking stick ends fit a treat serious.My old man used a pair on his first zed.

 

we need to make this post a "sticky":wack:

we need to make this post a "sticky":wack:

 

Lol i know Bri,B & Q sell them.They fit really well honest.