Hot start problems 1.9 Mi16 DFW Motronic M1.3

[B1ack_Mi16 67]

As title says really.

 

I remember having these same issues on my old blue 205 Mi16 back in year 2000. Never came to the bottom of it.

 

Now it seem like my new 205 does the same, starts perfectly when cold and semi cold. But on really hot engine, typ fan's are running, there is no chance getting it to start.

 

I suppose it can't really be much else than water or air-temp sensors that can be at fault?

 

Does anyone have resistance vs. temp. table for the air-temp sensor in the AFM?

 

[welshpug 1,657]

is it still doing it after changing the afm yesterday?

[welshpug 1,657]

from 405 haynes manual -

[B1ack_Mi16 67]

Ah thanks. Those values seem a good starting point.

 

It does it on the new AFM, but I think it also had the tendency on the other one, but as the coolant system wasn't totally sealed until yesterday evening I really didn't run it properly hot until then.

 

I might try to put a 2.5kOhm resistor in place of the water temp sensor next time it happens to try to fool the ECU to give more fuel upon startup to see if it is injector time related.

 

And of course measure the AFM.

 

Edit: BTW, is that Haynes page from the old or more recent 405 manual?

Edited February 12, 2018 by B1ack_Mi16

[welshpug 1,657]

workshop manual, the purple one.

[welshpug 1,657]

[B1ack_Mi16 67]

Thanks a lot for those.

 

Well it seem like the AFM itself is OK in both cases at least the Ohm readings between pin 3 - 4 and 2 - 4.

 

Edit: Measured the wrong pins.. so temp thermistor seem to be within spec on both.... 

 

Then I'm not sure why the engine seem to run much better on idle on one of them, maybe just due to the 3-4 and 2-4 pin readings are a bit higher on one of them?

Edited February 12, 2018 by B1ack_Mi16

[petert 586]

From the 'real' manual.

[B1ack_Mi16 67]

It seem to be the same thermistor on both water and air.

 

Anyways I've now done some more testing yesterday. And it would hot-start all evening long...

 

The problem seem to only occur if the engine is stalled by the brakes/clutch. Then it actually repeteable is hard to start, but will start sometimes if helped a bit with some opening of the throttle.

 

Maybe it drowns i fuel?

[welshpug 1,657]

maybe not enough fuel pressure?

[B1ack_Mi16 67]

Checked fuel pressure, and it holds for several hours after engine is stopped.

 

Pressure seem to be spot on as I had a gauge on it while fiddling around with the different injectors etc the other day.

[wld 3]

I had the same problem once. Turned out to be the starter motor not spinning fast enough when hot. Solved by replacing with a newer version with planetary gear.

[B1ack_Mi16 67]

It's for sure not the starter in this case. It spins nicely and battery is new.

But as problem now only occurs upon stalling the engine and not on a regular shut down and re-start I'm just leaving it.

 

Will see how it works out in real life when it's ready to be driven.