DTAForum.com - a forum for the DTA ECU

Simple Q - Does anyone know if a Snap On Timing Light with an inductive clamp can be used on the 'std' wiring to a COP?
If not - I'm guessing I could just make a HT 'Jumper' between COP and Plug?

Try it, however I would worry it might be picking up the wrong bit of the signal if not designed for active or dumb coil in this way

for COP, I always use a short High Tension extension, like this one (sample, I used one I got from Pico Scope):

https://www.ebay.com/itm/124631682172

a lead jumper would be best. But yes, a lot of the time it will still flash off the LT wiring.

Following on from previous question, I had a play with the car on Wednesday and got it running and running fairly well - i'd had a very high idle that couldn't be adjusted out and although the vacuum ports were blocked they were obviously leaking enough air - once properly blocked engine started and was idling at 1k rpm. Now my query is, how do you resolve the numbers on a DTA scope trace to the numbers you have to add to the DTA parameters - running engine trace below. I'm asking the Q because I just don't see the correlation between the two. Mine is a 2.0L Zetec engine which everyone seems to say has a Crip @ 90 deg. and a Cap @ 45 deg. I've also got DTA maps that suggest Crip @ 83 deg and the one that is running nicely is @ 72 deg. Changing from the 72 to the 83 resulted in unstable running and to 90 - it stalled completely! I've yet to try the timing light as there was too much going on, all at the same time, to add to the confusion and i'm honestly not sure if it would clarify or confuse me more LOL!

I've read the section in the manual multiple times but stating 'take the scope numbers and input them into the parameters' doesn't help a village idiot like me!

I would not just randomly take the scope numbers. The ecu cannot know where TDC is to suggest that number.

Obviously that trace is with all plugs removed. Install plug in cyl1 and the trace will change to give you an indication as to where TDC cyl1 falls on such a trace.

I'm not sure if the ecu the uses that to suggest where the missing tooth is relative to TDC though

This is a cool script/program running for the USB Autoscope, which can diagnose and give info on engine health.

It's a pity no aftermarket ecu can offer such things. The ecu's could easily have the ability ! they have all the info needed. And it's cool the way it gives the user a visual representation of how it sees the crank trigger wheel too.

stevieturbo wrote: ↑Fri Sep 09, 2022 2:04 pm I would not just randomly take the scope numbers. The ecu cannot know where TDC is to suggest that number.

Obviously that trace is with all plugs removed. Install plug in cyl1 and the trace will change to give you an indication as to where TDC cyl1 falls on such a trace.

I'm not sure if the ecu the uses that to suggest where the missing tooth is relative to TDC though

That trace is with the engine running (at approx 1250rpm) actually. Here is an earlier trace with just #1 plug in for reference - I don't know if the peaks are TDC or the troughs! Its annoying that when in scope mode, after data is collected it suggests what the angle is likely to be X or Y (obviously 180 deg apart) but the saved pic doesn't capture this info! Maybe a screenshot saved would be a better choice? Whatever, the question remains - how is the relationship between a suggested number (35 in my case - very reliably) and the Crip angle entered in s/ware determined?

That's weird. I'd have expected a mostly flat trace with just a single bump, indicative of cyl1 compression.

I believe the height of the lines to some degree represents rotational speed, and in the case of a VR sensor a higher voltage. Although not 100% sure. I never have seen a proper description of what the lines actually mean or represent

Whoops - could have been cranking / trying to start with cam sensor disconnected - what sort of plank am I !