VHPD running rich

[samsul]

In January I took delivery of an SV with the VHPD engine in it. My dream Seven. In the four months since I have been unable to use the car properly. The car appears to be running too rich. Even at minuscule throttle openings, as soon as I back off, I get cannon fire out of the exhaust. Initially, I thought this was because the car wasn't running to temperature and therefore wasn't getting off it's cold map. I have now ruled this out as a possible cause, as the car behaves in the same manner even when running at temp. 

 

In trying to sort this issue, I have:

 

- Replaced the rad

- Refurbished and replaced the heater matrix

- Checked and confirmed that the thermostat works (74C)

- Flushed and replaced the coolant

- Fitted a new lambda sensor recommended by Caterham

- Fitted new coolant temp sensors (ECU and gauge)

- Replaced a small piece of the vacuum line, which had a leak

 

I tried to run a spare Emerald but this is corrupted so nice dice. I therefore have to run the standard VHPD ECU for now. As you can imagine it has been a frustrating start to new car ownership but I love it and want to get it sorted. So what am I missing? Where should I look next? Any help appreciated.

 

Thanks,

 

Sam

 

 

 

 

 

 

[Dave Hardcastle]

Hi Sam, I'm no expert but surely the next step is to have it professionally mapped on a rolling road?

[BigCol]

Where’re you based Sam?  I am sure folks on here will then point you towards a local expert.

As Dave suggests, a re-map could be useful but personally I’d seek advice to discount all the potential cheaply-sorted issues first!

[Paul Richards]

Not sure that any of the things you have done would really cure rich running and I’d suggest that a 74c thermostat is too cold. Standard thermostat is 88c but most will use a 82c. 
As suggested a rolling road mapping session with the Emerald will sort it if it is running rich. However the backfiring you are experiencing could simply be caused by air getting into the exhaust system. I’d check for leaks around the primaries and cylinder head. 

[samsul]

Thanks, I haven't found an obvious exhaust leak but the car is "fumey" so will keep looking. Is there a specific way to test for gasket leaks on the primaries?

Is there a MAF/MAP sensor and can I simply test it with a multimeter?

[Jonathan Kay]

Do you already have a wiring diagram and other factory documentation? Please let me know if you need a copy.

Jonathan

[Paul Richards]

A simple way of testing for leaks is with a small piece of tissue on the end of a stick or similar. With the engine running hold it near joints and look for the tissue “fluttering”.

[Ralph45]

Hi Sam, contact Steve Greenald and have a chat. If it’s an ecu,  pretty much  any description, or mapping thing he can and I’m sure will, sort it for you. Message me if you need his number , however I’m sure it’s in many posts on this site. Been there before and he’s sorted it for me.

Ralph

[samsul]

1 hour ago, Jonathan Kay said:

Do you already have a wiring diagram and other factory documentation? Please let me know if you need a copy.

Jonathan

That would be really helpful - thank you

[Jonathan Kay]

Private Message sent.

Jonathan

[simon_h]

Standard rover vhpd cals were rich. It was a race car cal so it wasn’t that important to them at low speed. It’ll just about scrape a mot pass which is all it ever had to do to be allowed to sell it.

There is normally a map sensor on the rover ecu’d cars. Follow the vac lines that link each inlet runner if it’s not obvious and sitting on the bulkhead like they normally are. If it had an emerald fitted it might have been removed as they tend to be run alpha/n rather than manifold pressure so it could be doing the best it can with no load input into the rover ecu

Edited April 29 by simon_h