What happens during the cranking procedure?

Orthello · Post by **Orthello** » Mon Jun 02, 2008 3:38 am

What exactly happens during the cranking procedure? Why my question... Well... when my car isn't used for, say, about 9 hours or longer, starting is (a bit) hard. This morning I needed to crank it for about 5 minutes. (the colder the environment, the harder it gets) When I put the key in starter position the engine cranks as usual but doesn't start. When I release the key, the engine tries to run but stalls with a big sigh, possibly caused by a lack of momentum. After several attempts the engine starts (on key release!!) and idles as usual. Once the engine has run for a few seconds it's easy to start it again and again. It starts at the first attempt and when key is in starter position. It's only with a cold start (when engine hasn't run for about 9 hours or longer) when this behaviour occurs. My first guess (based on this old topic) is that the STS isn't available to the ECU. But this is just a guess as I'm not sure what happens (what the ECU does) when key is in starter position (STS = true/high) Ok... it nearly drowns the engine during a cold start. That is what I know. So what I think.... is that my engine doens't get drown during cranking. And because massive amounts of fuel should be injected during cranking.. well you get my point, right? What I still don't understand is that the engine finaly starts when I release the key (so when it drops back from ST to II) What is so different with ignition during cranking and normal operation? I didn't had the time to do any logging lately as I've been to france for a week, I had my (and my girlfriends) birthday on the 25th, a wedding last friday and we are in the process of buildig a brand new house. I will do some logging hopefully this week to see if STS is available to the ECU. Up till then I want to know what exactly happens during the crank procedure the get a better understanding of what is involved.

JaredKaragen · Post by **JaredKaragen** » Mon Jun 02, 2008 4:45 am

Are your sure the ECT/IAT tables aren't the cold-starting issue? I noticed them needing massaging even in California where the climate stays moderately warm. I noticed a change to my IAT table, and cranking table helped my cold starts... biggest hampering issue is I only have a chance to make adjustments during first cold starts because I live in Cali.

Orthello · Post by **Orthello** » Mon Jun 02, 2008 5:10 am

I'm 95% sure that isn't the issue. I haven't experienced this behaviour in the past 2 to 3 months. And it has been way colder. Once the enige has run for a few seconds (yes seconds!!) everything is fine. I can stop/start the engine without any problem or strange behaviour. And when we are talking seconds... ECT and/or IAT can not or hardly be changed in seconds I assume (haven't logged yet) so I doubt if ECT/IAT is the cause. Also the fact that the engine comes alive when key is released, sounds more like STS then ECT/IAT I think.

Post by **nate** » Mon Jun 02, 2008 9:22 am

Sounds like you need to ajust the PostFuel table... and probbabally your cranking table

Orthello · Post by **Orthello** » Mon Jun 02, 2008 10:00 am

I'll give it a try. Are there tips 'n tricks for adjusting the crank en postfuel tables?

relic1 · Post by **relic1** » Mon Jun 02, 2008 12:05 pm

crank table is just for cranking and it's temp sensitive. (sounds like your problem to me) Richen or lean to get the car to start quicker (depending on wideband readings right after the car starts, within 2 seconds of running) but keep it within reason, things can get funny if you go to far. Post startup, start the car and start wideband reading 5-10 seconds after it's running. Values let go after ~30 seconds. Pay close attention to the temp values to make sure you're adjusting in the right cells. Both of these adjustments can be done at the same time, but make sure your wideband is warmed up and calibrated before starting the car. (and that your setup keeps the wideband on the entire time, switching it off when cranking will skew the readings)

Post by **Bugermass** » Mon Jun 02, 2008 12:22 pm

GO to fuel trims, and look at your cranking trim, half the amoung. if its like -60 put -30 or -20 put -10 . that may help..

Post by **calvin** » Mon Jun 02, 2008 1:48 pm

You need to adjust 2 thing Crank table/Crank multiplier if starting not good Second right after start the postfuel table/multiplier comes into play. EDM ecu's do have an STS input i believe

Bindegal · Post by **Bindegal** » Mon Jun 02, 2008 2:38 pm

To really really see whatÂ´s going on... Power a wideband from a seperate power source/battery. Maybe even datalog directly from the wideband. This is probably the only way you can be sure to see the exact AFR during cranking. /Allan

Orthello · Post by **Orthello** » Mon Jun 02, 2008 4:56 pm

Gaskleppie had a little brainstorm session with me.... What about an ignition coil producing a weak spark during cranking and a full spark when key is released? Could that be a reason why the engine starts on key release?

Post by **calvin** » Mon Jun 02, 2008 4:58 pm

could be...

Bindegal · Post by **Bindegal** » Mon Jun 02, 2008 5:20 pm

Or it could be a simple issue of an ignition switch going bad... on some older cars you have to push in slightly on the key as you turn it to crank, or it wonÂ´t fire up. I see that sometimes here, because cars are so hugely expensive, our cars get pretty old

/Allan

JaredKaragen · Post by **JaredKaragen** » Mon Jun 02, 2008 11:16 pm

Bindegal wrote:Or it could be a simple issue of an ignition switch going bad... on some older cars you have to push in slightly on the key as you turn it to crank, or it wonÂ´t fire up. I see that sometimes here, because cars are so hugely expensive, our cars get pretty old /Allan

I have seen this many times

Too many

Post by **Gaskleppie** » Tue Jun 03, 2008 1:02 am

I see that sometimes here, because cars are so hugely expensive, our cars get pretty old Smile

Ah! I wondered why there were so many old cars in Denmark. Now I know.. I also wondered why there were so much cars laying around next to the road. Why's that? Seemed that some cars were lying there for quit some while...

Orthello · Post by **Orthello** » Tue Jun 03, 2008 2:54 am

This morning (let say.. about 2 hours ago) I was waking up the entire neighbourhood with my cranking ritual. (including Frank as I see his last posts timestamp

) I decided to remove all the OBD1 stuff and put back OBD0. Twist... crank... run!!! without a hitch! OBDx conversion in less then 10 minutes.

Conclusion... OBD0 rules.... OBD1 sucks!!!

. . . . . . Just kidding. For now I'll leave it as it is my daily driver. Twice a day this annoying problem stresses me out at some point. Not yet... but I was getting close. I'll contact some friends to see if someone has a B16 OBD1 distributor laying around which I can use to verify the ignition coil. OBD0 and OBD1 ignition coils are not compatible are they? So.... I put this on hold for now, as I'm way to busy to trouble shoot this issue at the moment. Will get back to it when I have a replacement distributor.