CRAIGO

Possibly is, but the amount of maps I've seen with the unchanged PnP value of 12deg cranking advance leads me to think not, or that people have just plain put up with poor start-up and not bothered tuning too much. Afterall a few people have said on this thread that they don't care that it takes a few attempts to turn the engine over when cold. The problem seems more apparent for me in colder temp regions. I had fewer start-up issues when my cold start temps were warmer at 10degC and obviously hot and warm re-starts are always fine.

Check your datalogs and see if your cranking rpm is exceeding it's value as timing will then be jumping from what is set as your cranking advance (PnP value is 12) and then to whatever timing value you have at your fixed map value.(PnP value is 80kpa)

Scotty15

Results:

Ambient 28 degrees F

Unplug coils, car turns over fine, although a little slow due to cold weather.

Turn key back and wait a second. Try it again. Exact same result.

Plug in coils, and-

Car turns over maybe one turn and then almost locks. Same ****.

Turn key back, wait a little so the wideband doesn't give me that code 4 bullshit. Car starts right up and runs perfect.

I'm convinced this is an ignition thing, at least for my car. And as I've said previously, I'm running Toyoda COPs, but it also did this with the stock ignition.

poobs

iTrader: (1)

So you are saying that timing will sudenly jump from cranking timing to whatever the spark table says?

So what do I change ? I'm not sure what to do ....

Scotty15

Make that, "Toyota".

I would also like to point out that this got worst for me after I went to the HiRes code. It really didn't do it at all before that.

wayne_curr

iTrader: (8)

Very interesting. What is it about timing that would cause the engine to stop cranking so suddenly like that?

When someone else heard my engine do it they suggested it was my battery so I replaced it. Still happens.

Scotty15

If the timing is too far advanced the engine is essentially trying to run backwards. It's a balancing act between the ideal (TDC), and the real world, where things take a little time to happen and you need to be advanced from TDC. It takes some time for the fuel to really catch and achieve a hot burn. So you need ignition advance before the piston reaches top dead center (TDC). If you are TOO far advanced the burn happens before the piston is at TDC and actually tries to push it back the wrong way. And it cranks hard. I hope that was clear, I'm not a very good technical writer. At any rate, I think this is our problem for whatever reason.

dgmorr

iTrader: (4)

I have an Adaptronic ECU and not MS, but I am having the same issues you guys are describing. I always thought my engine was hydrolocking, but it would happen on the first attempt after only a second of cranking - doesn't seem possible.

My engine actually started in reverse for a few seconds one time. Exhaust smoke started coming out the intake air filter - I am not kidding. I have my crank timing set to 7*. Is setting the timing less than 7* going to help anything? I always had a feeling the fuel was igniting too early while trying to cross the crank/min run rpm threshold.

poobs

iTrader: (1)

Great explanation !!!

JasonC SBB

Which of you guys have Toyota COPs and have the standard 1k ignition pullup resistors in the MS?

poobs

iTrader: (1)

I have a PnP and Toyota COPs

The COP harness does have a 1k resistor. I'm not sure of what a pull up resistor is ( ?)

BTW I had the same hessitation while cranking before I went to COPs....

CRAIGO

To prevent spark fluctuations during cranking I tested mine this morning by raising the cranking RPM threshold to 400rpm. It was -1degC and it started up first time which was a change. I've not analysed the datalog yet, but Ill check to see if the engine caught properly without cranking mode shutting off. (As that introduces VE and spark map values, ASE and WUE)

I will try retarding cranking timing too from my current 16deg cranking advance and see if that helps.

Scotty15

I have a home built MS1. It has 1K pull up resistors. I also have Toyota COP's

But the MS also did this with the stock ignition.

poobs

iTrader: (1)

How do you guys retard cranking timing ?

CRAIGO

I told you in post 15 Poobs

Braineack

iTrader: (62)

under spark settings, there's a spot for ignition advance during cranking...set it to whatever degree of timing you want while you crank. I've always used 18*

poobs

iTrader: (1)

Thanks, I missed it

Scotty15

18! I've got it at 10. Are you running the HiRes code?

Scotty15

There are a couple settings in the "spark setting" box I'm not sure about.

"Cranking Timing" can be time based or trigger return. Mine is set to time based.

There is another box labeled "Hold Ignition". Mine is set to 0.

I've read the manual, it's pretty sketchy on these. I didn't see anything about Hold Ignition at all. I'm wondering if playing around with these could improve things. But I don't want to just do it for fear of burning something up. Anyone know exactly what these do?

clay

iTrader: (6)

After reading that it helps with the "hydrolocking" on startup, I changed mine from 18 to 12 several days ago. It "may" be helping as it seems to do it less, but I'm pretty sure it's done it since the change. A few more days will tell me for sure.

Count me in with those who would like a better startup, but are dealing with it. Absolute worst case, it takes two tries to start.

poobs

iTrader: (1)

You guys are going to have to go on without me.

I just happen to look at my AFR tables and they are hosed so I have to go back to see what is screwing up all my settings.

This is so frigging weird that I may start a new thread