4.6 with microsquirt3

[mikey446]

Hi, please could you have a look at an msq for me, I have fitted a 97 4.6 sohc npi engine in my boat it has 19lb injectors, pi cams,cold air intake, open exhausts running 95 octane unleaded, as its in a boat its always under load so tends to be above 60 kpa load unless on idle! it does perform quite well but at constant cruise seems to be a bit lumpy. I have tried using wb sensors but they seem to die within a couple of hours of startup! I can only assume damp air must be getting sucked down the pipes once the engine has stopped. If i can be confident of a good timing map i can work on the fuel but not knowing either makes the job difficult. many thanks.

 

[a91what]

if you keep killing WB sensors they are placed incorrectly. you could try an EGT sensor, you really do need some way of telling what the AFR is. Have you made an attempt to find the stock timing map?

 

[a91what]

Hi, please could you have a look at an msq for me, I have fitted a 97 4.6 sohc npi engine in my boat it has 19lb injectors, pi cams,cold air intake, open exhausts running 95 octane unleaded, as its in a boat its always under load so tends to be above 60 kpa load unless on idle! it does perform quite well but at constant cruise seems to be a bit lumpy. I have tried using wb sensors but they seem to die within a couple of hours of startup! I can only assume damp air must be getting sucked down the pipes once the engine has stopped. If i can be confident of a good timing map i can work on the fuel but not knowing either makes the job difficult. many thanks.

lol what tuning software are you using? I believe this is an MS2 correct? what firmware are you running?

 

[mikey446]

Hi it is ms2 rev 3.83000 being a marine enviroment i used a microsquirt 3 , i have included a picture of one of the manifolds showing the o2 sensor position.

thanks.

 

[mikey446]

I have tried to find a stock map but have only been able to find maps before the factory ecu added adjustments so not knowing how the ford ecu is programmed they have only been of minimal help.

 

[fj1289]

This is fairly old but a couple questions

How much time does the engine spend idling? How have you tuned for idle? If you are using the WBO2 to tune the idle you may be much richer than you realize and that may be what is killing your sensors. Short open headers cause a lot of back flow at idle and low load conditions. I have a motorcycle we tried a short exhaust on (race only with large nitrous shot and the WBO2 showed way lean when we had a good idle - much leaner indications than with an open full exhaust)

To help prevent thermal shock after shut down, you may be able to add “flapper valves” to the end of your exhausts - similar to old diesels or VW Bajas