Kv6 fault codes

Darrenbunn6969 · Aug 12, 2021

Hi everyone it’s been a long time since I posted on here as I wrapped engines and had no issues until now. A few weeks ago my engine light came on so read the fault codes which indicated a failing O2 sensor however the next day started the engine no warning lights and ran fine so I deleted engine codes see photos bellow. A week later engine light came on so read codes again and got a different set of codes relating to MAF sensor this is confusing as this engine does not have a MAF sensor ? . So I am at a loss as to what is the actual fault. The engine light comes on and goes of . Symptoms are the engine stalls sometimes. When driving slow it will surge forward. Sometimes a slight misfire and general rough idle sometimes. If anyone can help would really appreciate it thanks in advance.

J_D · Aug 12, 2021

Vacume leak can cause lean running and rough.
Where to check I don't know, there's only one expert on the kv6 engine who'll give you a more informed answer soon

Darrenbunn6969 · Aug 12, 2021

J_D said:
Vacume leak can cause lean running and rough.
Where to check I don't know, there's only one expert on the kv6 engine who'll give you a more informed answer soon

Thanks

Nodge68 · Aug 12, 2021

J_D said:
Vacume leak can cause lean running and rough.
Where to check I don't know, there's only one expert on the kv6 engine who'll give you a more informed answer soon

Look at the crankcase vent pipes for cracking (they go brittle with age), the small ones are at manifold vacuum, so will cause a lean mixture if damaged.

I've highlighted the important one with red dots.

Darrenbunn6969 · Aug 12, 2021

Nodge68 said:
Look at the crankcase vent pipes for cracking (they go brittle with age), the small ones are at manifold vacuum, so will cause a lean mixture if damaged.will have a look and update you now my engine is stalling any chance it gets

I've highlighted the important one with red dots. View attachment 245349

Darrenbunn6969 · Aug 12, 2021

Hi thanks Nodge I’ll have a look . If it’s not the pipe ? Any other ideas just in case

Nodge68 · Aug 12, 2021

Darrenbunn6969 said:
Hi thanks Nodge I’ll have a look . If it’s not the pipe ? Any other ideas just in case

Well it's clearly an issue that is effecting both cylinder banks, so this discounts the O2 sensors.
I'd look for air leaks on the inlet plenum, or the pipes going to it.
It's possible the brake booster has failed, which would allow a constant draw of fresh air in, leaning out the mixture.
Of course it could be a fuel pressure problem, which again would lean the mixture.
When was the fuel filter replaced? its possible it's the original, in which case it could well be blocked.
You can test the fuel pressure with a fuel pressure test gauge, as there's a test port on this engine. The fuel pressure should be about 4.5 Bar or roughly 60 PSI, IIRC.

Darrenbunn6969 · Aug 12, 2021

As far as I know fuel filter has not been changed fuel pump was new 8 months ago. I’ll have a good look around change fuel filter just for cuiosity where is the fuel pressure sensor on this engine ?

Nodge68 · Aug 12, 2021

Darrenbunn6969 said:
As far as I know fuel filter has not been changed fuel pump was new 8 months ago. I’ll have a good look around change fuel filter

If the pump has been replaced, the filter comes as part of the assembly. However was the pump a good quality replacement, or a cheap ebay pump? I've seen some cheaper pumps produce low pressure, even when new.

Darrenbunn6969 said:
just for cuiosity where is the fuel pressure sensor on this engine ?

There isn't a pressure sensor. The engine fueling requires a set pressure of around 60 PSI, the ECU then calculates fuel volume based on the set fuel pressure. The mixture can be tweaked using feedback from the O2 sensors, however if the fuel pressure is too low, the ECU will flag a weak mixture code.

Darrenbunn6969 · Aug 13, 2021

The fuel pump I purchased was bearmarch. Had to swap the fuel gauge sender for the old one as a full tank registered empty vice versa.

Kv6 fault codes

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