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Paul Webster

start up advice

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mazda mx5 vvt running extrme . car runs and idles perfectly i am just having problem getting it to start nicely , when you crank it first time it will not start let the key go and crank it again and it starts straight up . fuel pressure is good spark is good .it doesn't make any difference what temp the engine is same. 

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Thanks for the logs. When looking through them it looks like the MAP reading is varying between the two logs. This is then affecting the amount of fuel being injected and the ignition angle being applied.

Successful start:

start.thumb.PNG.8d47cc7ffc361c0e6573d8ef

Unsuccessful start:

non_start.thumb.PNG.d584d88d39628c0b2d02

The logging is at 10 Hz, which is fairly slow and may explain the difference. Would you mind changing your logging rate to 40 Hz and doing the logs again?

Logging_rate.thumb.PNG.a3c7560633e55d214

Scott

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Thanks for the new logs. One thing I noticed in the unsuccessful start log is that 'Prime Fuel' (pre-crank prime) shows as 0.0ms. Where-as in the successful start log the prime fuel is 29ms.

The Pre-crank Prime only occurs for the first time you crank the engine after the ECU powers up. From what you said in your first post the engine doesn't start on the first attempt, but then does on later attempts. Try turning pre-crank prime off and see how this affects the starting.

Scott

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hi Scott

thanks for the advice did as you suggested but it still did the same thing but put my mind on the wight track turned out to be a relay that on first crank was not powering the injectors but was the second crank all sorted now.

thanks

paul 

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