Ford XFlow - MS3 - Difficult to start

[bytesandbolts]

Hey guys,

I've got a 1.3 Ford XFlow turbo running with a single 750cc injector using a modified carb inlet in my Mk1 Escort.

On a typical day it can be very difficult to start from cold once it has been sat overnight, usually takes a few cranking attempts with some pedal movement to get it going (usually after a backfire or two). However once it has been running for a minute or two, you can flip the ignition off and on again and it will usually start again with no issue. The engine was tuned a year ago and the car runs great when it eventually fires up.

The main issue is that I am experiencing sync loss during cranking and have been trying to overcome this issue for sometime now.

After reading on some of the other threads, I thought the issue may be possibly down to too much/too little fuelling during crank? So I set the priming pulse to 0.1 and had a play around with cranking pulses. However I just tried cranking with both fuel pump and coil pack fuses removed, and I'm still getting sync loss.

Sometimes if the car is really struggling to start, we attach a booster pack when cranking which does seem to help.

I've attached my current tune and a log file of the car starting.

Any ideas/comments would be greatly appreciated.

Thanks,

-Dan

[billr]

Post a run log (.msl) too. Has the injector dead-time been actually measured, has the fuel-flow been measured? With those big injectors dead-time is going to be especially critical.

[bytesandbolts]

Just to clarify, I am only running a single 750cc injector in conjunction with a single 48mm Jenvey TB.

No I have not measured the injector dead-time, nor have I measured the fuel flow. To the best of my knowledge adjusting the dead-time value should not make a difference to the sync loss I am encountering whilst cranking, when both the fuel and coil pack fuses are removed. Ideally I would like to fix the sync loss whilst cranking issue before I move onto any further issues.

I have uploaded two log files.

- log_2.msl - Was recorded less than half an hour ago (Note I was tinkering with the car earlier and it's still slightly warm, so the car starts pretty easy).
- log_3.msl - Is a previous log file I had that shows more of the sync issues I'm running into when starting from cold.

[grom_e30]

yeah with sync loss like that will be difficult to get it going, what type of sensor vr, hall? adjust the gap slightly closer?, maybe check the trigger pots on the main board if you look at your tooth log page 4 you start getting a slightly longer tooth after the really long one looks a bit odd, have you got a composite log of the sync issue

edit.. was there a specific reason why the noise filtering is on? i played with that before not really knowing what i was doing and gave me a world of problems.

[bytesandbolts]

If my memory serves me right it's a VR sensor nabbed from a Zetec in a Mondeo.

I don't know an awful lot when it comes to adjusting those pots, can you offer any tips.
I'll try and get a composite log for you regarding the sync loss issue.
The noise filtering got turned on by our dyno guy when we mentioned we had difficulty starting from cold (couldn't say whether it made any difference tbh).

I will get the car out after lunch and have a tinker.

[bytesandbolts]

I disabled the noise filtering. The car started on the first attempt after 5-10 seconds of cranking.

I'm attaching the composite log below (note the engine doesn't have a cam sensor input).

[grom_e30]

your failing to see quite a lot of teeth for the first 3 pages of that log not until page 4 that you see them all and it sync up, my car has sync after 1 full rotation of the engine where as yours takes probably 36 engine rotations or so to sync up, id be looking at the sensor gap and also chech the trigger pots are adjusted correctly have a look here:

http://msextra.com/doc/ms3/ignition.html#tachint

[bytesandbolts]

Thanks for the tips, i'll try the suggestions later on today.

[bytesandbolts]

The VR sensor bracket was about 2mm away from the toothed wheel, after moving it to about 0.8mm we are not longer experiencing any sync issues whilst cranking They car starts much easier than before now after only a couple seconds of cranking.

I still believe I need to play around with the cranking pulse settings, as well as investigate measuring the injector dead-time.

If you alter the dead-time (currently set to 1.0), can anyone say if I will have to alter my VE table settings to compensate for the change?

[BigLou240sx]

If you alter the dead-time (currently set to 1.0), can anyone say if I will have to alter my VE table settings to compensate for the change?

Your VE table will likely need some adjustment, concentrating mostly in the idle/low load region (where small pulsewidth is more affected by the change in dead time compared to larger pulsewidth regions - a change in .1 ms of dead time is a higher affect on a 3ms running condition instead of 10ms condition)