It won't start, it won't idle.

[oblark]

After sorting out the clearance issue with the plenum chamber and the alternator I re-fitted the plenum chamber.

Went to start it and it fired up but as soon as I let go of the key it died, Tried starting with a bit of throttle and it runs but doesn't sound right. When I hold the idle at 1000 rpm on the throttle the AFR's are 18+ and hunts between 500 - 1000 rpm, when rev'd to 2000 rpm the AFR's are normal (14.7-15.0) and the hunting goes but as soon as you let go of the throttle it dies.

It's running the same ICV as with the ME7 manifold and it can be heard buzzing when the ignition is on, I tried giving the car some idle by adjusting the butterfly stop screw, all that did was make it idle at 1000 rpm for a few seconds then it would climb quickly to 3000 rpm.

Has anyone any ideas ?

Thanks

[M-R-P]

What ecu are you running mate? You tried any others?

[jamesy12345]

Air getting in somewhere?

[oblark]

What ecu are you running mate? You tried any others?

I'm running the COP ecu so I can't swap it over.

[M-R-P]

Hmm... As above, do the usual checks for leaks etc and start messing with the map.

You've not got the throttle on backwards or anything silly like that have you?

[oblark]

I'm going to remove the manifold tomorrow and check the face that bolts to the head to see if it's warpped when it was welded.

I mite make up 1.0 mm EPDM gasket if the manifold is slightly warpped.

[M-R-P]

Have you sprayed carb cleaner around the manifold to see if it's leaking?

[oblark]

Have you sprayed carb cleaner around the manifold to see if it's leaking?

The only when to keep it running is to tickle the throttle pedal as soon as I take my foot off the throttle it dies.

I could have done with an assistant :)

[M-R-P]

Might be able to pop in on my way home from Portchester tomorrow evening if that's any good?

[MoleT-5R]

Sounds like a leak at the manifold gasket to me, we had a similar problem on an MGB GT and as you've described Rob, the only way to keep it running was by tickling the throttle and as soon as you let it go to idle it died.
I did try to put this post up yesterday but the net was messing about and found this morning my was not hear, hope you get this sorted easily mate.

[Tee5alive]

I had a similar problem it was down to the butterfly sticking on gook in the intake. I gave mine a polish inside which helped but it still did it and turned out to be a small air leak as well. The intercooler feed pipe wasnt tight enough. You may have disturbed a vacuum pipe somewhere as I did as well with my big clumsy hands! These cars are all pipes and just one off shuts it down!

[kmb]

Just a thought - Has the throttle cable somehow slipped or become ill adjusted on your homemade throttle body part?

[oblark]

They be the problem.

http://i1067.photobucket.com/albums/u433/oblark/volvo%20850%20t5/850%20plenum%20chamber/20150811_170150.jpg (http://s1067.photobucket.com/user/oblark/media/volvo%20850%20t5/850%20plenum%20chamber/20150811_170150.jpg.html)

I would have expected 1.0 mm of warp in a cast aluminium manifold but it's warpped upto 3.0 mm so I'll have to take it along to the machine shop to get it machined true.

[stribo]

They be the problem.

http://i1067.photobucket.com/albums/u433/oblark/volvo%20850%20t5/850%20plenum%20chamber/20150811_170150.jpg (http://s1067.photobucket.com/user/oblark/media/volvo%20850%20t5/850%20plenum%20chamber/20150811_170150.jpg.html)

I would have expected 1.0 mm of warp in a cast aluminium manifold but it's warpped upto 3.0 mm so I'll have to take it along to the machine shop to get it machined true.

That would do it. Has it warped through the heat of the welding?

[MoleT-5R]

They be the problem.

http://i1067.photobucket.com/albums/u433/oblark/volvo%20850%20t5/850%20plenum%20chamber/20150811_170150.jpg (http://s1067.photobucket.com/user/oblark/media/volvo%20850%20t5/850%20plenum%20chamber/20150811_170150.jpg.html)

I would have expected 1.0 mm of warp in a cast aluminium manifold but it's warpped upto 3.0 mm so I'll have to take it along to the machine shop to get it machined true.

Ahh that would do it, no gasket was going to fill that. A lesson to be learnt by others to machine the flange true after welding then

[oblark]

That would do it. Has it warped through the heat of the welding?

I would say yes :)


Ahh that would do it, no gasket was going to fill that. A lesson to be learnt by others to machine the flange true after welding then

Every day is a school day :)

[jamesy12345]

You can bolt the manifold to heavy plate to help prevent it deforming while welding

[claymore]

Yea, I had to true mine up on a piece of sandpaper clamped to a sheet of glass, but it wasn't as bad as yours Rob, I'm surprised you couldn't see that warp before fitting it :)

[oblark]

Yea, I had to true mine up on a piece of sandpaper clamped to a sheet of glass, but it wasn't as bad as yours Rob, I'm surprised you couldn't see that warp before fitting it :)

To be honest I thought the cast manifold wouldn't have warpped.

[claymore]

I know what you mean, but mine did as well :(

[Nealevo]

Dodgy workmanship if you ask me :-)

[jamesy12345]

To be honest I thought the cast manifold wouldn't have warpped.

turn the amps down :)

[Harvey]

turn the amps down :)

When I weld alu I pre heat it to around 100 degrees & like you say you can turn the amps down as the heating been done to the work.

[jamesy12345]

When I weld alu I pre heat it to around 100 degrees & like you say you can turn the amps down as the heating been done to the work.

Good idea. You didn't look like a welder when I met you Harvey :)

[stribo]

Good idea. You didn't look like a welder when I met you Harvey :)

Which begs the question, what does a welder look like? ;)

[Doingitsideways]

Good idea. You didn't look like a welder when I met you Harvey :)


Which begs the question, what does a welder look like? ;)

Not this guy :lol:

http://i1137.photobucket.com/albums/n518/doingitsideways/DSC_0583_zpssqaca7vx.jpg (http://s1137.photobucket.com/user/doingitsideways/media/DSC_0583_zpssqaca7vx.jpg.html)

[jamesy12345]

Which begs the question, what does a welder look like? ;)

...in my experience they usually look like they have been inhaling strange fumes!! Harvey was very lucid when I bumped into him at the Swedish Day


Not this guy :lol:

http://i1137.photobucket.com/albums/n518/doingitsideways/DSC_0583_zpssqaca7vx.jpg (http://s1137.photobucket.com/user/doingitsideways/media/DSC_0583_zpssqaca7vx.jpg.html)

Phwooar look at the Billies on that

[oblark]

turn the amps down :)

The manifold was welded by a coded welder as for the current he used I haven't a clue.


When I weld alu I pre heat it to around 100 degrees & like you say you can turn the amps down as the heating been done to the work.

The manifold was not pre-heated before it was welded but at the end of the day all the welding has the grand sum of f£$% all.
Spoke to the fabricators today about it warpping and he is surprized that the cast aluminium has warpped and has offered to machine it true for the grand sum of f£$% all.

[Harvey]

Good idea. You didn't look like a welder when I met you Harvey :)

Did years back but now it's just on site repairs to small parts......luckily.

[Harvey]

The manifold was not pre-heated before it was welded but at the end of the day all the welding has the grand sum of f£$% all.
Spoke to the fabricators today about it warpping and he is surprized that the cast aluminium has warpped and has offered to machine it true for the grand sum of f£$% all.

to be fair when people ask me to weld things it starts off with little things then next minute they want a set of gates knocked up FOC , now I just have say no as I have more important things to do with my time.
The last manifold I was asked to weld was water cooled just said no.

[oblark]

I do alot of work with the fabricators through work so the manifold was more of a big favour :)

[t5 pete]

What the ££££ or rubber duck is ampage gas welding for me non of that posh stuff Up norf
And ill just bolt my manifold to a rsj we got from pit lol