Hard Start When Cold

[Lazabby]

I'm having a problem starting my car when it gets cooler (cold). The temperature doesn't have to drop much, say below 60 degrees and it's harder for the car to start even with a fully charged battery. A couple of months ago I had the car tuned at a dyno shop. Attached is my current tune. What should I tweek? Warm up Enhancement?

[nathanhardy]

The dyno shop probably in fact I know they didn't tune for cold starts. Actually they can't unless it's cold without guessing, sound like your crank pulse width and ase need some tuning it's pretty easy to tune out, diyauto tune.com has a tech artical that's very helpful on the matter.. That reason alone is why I'm paying to take tuning classes and not just trust someone else to tune my car because I want everything tuned out to perfection!!

[ewflyer]

Cold ignition advance is an important part of getting a reliable cold start. Oddly, some engines like less than normal spark advance when cold while others need more. My current project likes more advance when cold, up to 10 degrees more advance.

[lagos]

You need to take a datalog of the start up to see whats happening.
You probably don't have enough fuel, and need to add more cranking duty, but take a look at what the fuel is doing in the log first.

[dontz125]

Have you checked your valve clearances? Sudden hard starting when cold is a classic sign of tight intakes on a lot of bikes; I'm not sure if that translates to tappets and lifters ...

[Lazabby]

I think I am making progress. The temperature here is cooler (50+ degrees). I made a few changes to the program by increasing the Priming Pulse. I was able to get the car started. I'm wondering is I should increase it a little more or tweak another setting.

I'm thinking i still need to change settings in the Cranking Settings. When I had the car tuned at a Dyno shop they had Cranking RPM at 500. I read up on this and decided to move it down to 300. I have no TPS but it's set at 90 in the Flood Clear %. Should I set that at 0 or 100? For Cranking Fuel Pulse Rate I read that it's good to have it on alternate when dealing with engines that have higher number of cylinders. My car only has 6 so should my setting be at Every Event or Alternating Events?

Attached is my tune and log.

2016-01-01 Delorean.msq

2016-01-01_11.32.54.msl

[slow_hemi6]

Hard starting is most often too much advance when cranking. You are on basic trigger so you don't get the cranking advance setting. When cranking and it is using the map for advance it will crank and fire in the top left section dropping a few rows and maybe moving over one column then rapidly shooting to your idle map/rpm cells. Have a look at how I have changed your ignition map and where. Your data log showed you cranking at 14 to 24 degrees!

2016-01-02_10.20.42.msq

[Lazabby]

Thanks Luke,
I'll try those changes. Attached is another log I took earlier today. It took longer to start.

2016-01-01_16.11.20.msl

[slow_hemi6]

Ok so are you having hard start problems or is it taking a long time to kick over? Somewhat different problems. Taking a long time to fire is a different issue to solve. Usually too much fuel or too little or a spark issue - need to check it's sparking during crank and confirm the timing with a light when it's cranking.

[Lazabby]

Ok so are you having hard start problems or is it taking a long time to kick over? Somewhat different problems. Taking a long time to fire is a different issue to solve. Usually too much fuel or too little or a spark issue - need to check it's sparking during crank and confirm the timing with a light when it's cranking.

The turns over fine. It cranks. It just won't catch and start. I had a friendspray gas into the manifold and it started right up so I suspect it's just not getting enough gas. Perhaps the spark is off. I'm about to try the change in advance and I'll log it to see how well it starts.

[Lazabby]

Hi Luke, I made the changes to the ignition as you suggested and the car fired right up. Temperature outside is 60 degrees. It suppose to be in the 40s tomorrow morning so I want to try again to see if it fires right up. Thanks.

I have another issue that I'm trying to work out. I have a bogging down issue when coming off of a start. I don't have a throttle position sensor so MS has to rely on MAP in order to adjust for fuel. Unfortunately there is a lag causing the car to bog down. I'm in the process of getting a TPS installed but in the meantime, any suggestions on compensating for the lag more quickly? I'm attaching my current tune and the log I made just a few minutes ago. You'll see the same bogging down in my previous logs on this thread. Someone has suggested increasing the Fuel VE numbers when it's under load in the 600-800 RPM range.

2016-01-03 Tune with Ignition Changes.msq

2016-01-03_16.56.18.msl

[slow_hemi6]

Yeah it is not responding with any accell enrichment either. I use tps accell on mine so map isn't what I am used to. That said I have had a play with your accell settings and you can try it to see if an improvement. I have lowered your threshold a lot so keep an eye out for false triggering but given your log it should be ok. I also lifted your VE a little in a few cells which would help but to me the bigger issue is the accell enrich was not contributing.

2016-01-04_12.38.50.msq

[Lazabby]

Wow Luke,
I made the changes to the Time Based Acceleration Enrichment per your suggestions and the car didn't bog down once. It was a short drive and I plan to take it for a longer drive tomorrow. I had already bumped up the VE numbers in the low RPM/High load range so I dodn't make the smae changes you made. It seems like the car runs much better now starting right up and not bogging down, thanks to your help. What bugs me is I had taken the car to a dyno shop and they couldn't tune the car to get rid of these problems! And they're professionals. You're a champ!

I did notice on my short drive there was minor surging when I was trying to keep the car at a stady speed. That may be due to the changes I made to the VE table. I logged the drive but haven't had a chance to analyze it yet. I've attached my current tune and log. I hope to spend more time on it tomorrow.

2016-01-04 With AE Change.msq

2016-01-04_17.40.30.msl

[slow_hemi6]

You are getting some false triggering of AE now so I would move the MAP threshold up from 75 to either 90 or 95 and that should get it more stable. If you stop the false triggers that might stop the surge. If not that it's either unstable fuel or timing. Generally when you have a big jump between adjacent cells and it flip flops from one to the other. It seems like the fuel map could do with some leaning out in the decel areas also. The log did show a lost sync event 808.064s but I am not quite sure what that means for a basic trigger install? Something to sort out though as when it does it it brings back in ASE and drives the AFR rich.

[Lazabby]

I will make the change the "Accell MAPdot threshold" to 90 to see how that works and get back to you.

Under "Accel Enrich Settings" there is the "Wall Wetting AE". I have that turned off. Should it be turned on?

[slow_hemi6]

At the moment you have to fine tune a few settings and one AE table. If you go with wall wetting you will add the complexity of 6 more tables and potentially the lag settings. Up to you but at the moment I suggest you stick to basic and work on that.

[Lazabby]

I set the AE to 90 and went for a longer drive today after a two day delay. I did not notice any surging as a couple of days before when the AE was set at 75. There was a slight hesitation when giving it the gas from a stop so when I got back I changed the AE to 85 but I haven't driven the car yet at that setting. I feel that should just about do it. I started a log file about halfway into my drive which is attached. I had to compress it since it was too large.

Starting the car goes well but still a little longer than I'd like. Although it starts now when the weather is colder, I still think it can be tweaked a little more. THe suggestion from Luke was to change the advance which now allows the car to start when the weather is cold. How can I find out if I need to increase or decrease the advance a little more in order for the car to start more quickly? The log today won't have the starting in it so you'll have to look at my previous couple of logs to see the starting.

2016-01-04 With AE Change.msq

2016-01-07_17.28.07.zip

[Lazabby]

It seems like two steps forward and one step back. The car has been starting fine for the last few days and then all the sudden today it won't start! I tried increasing cranking PW, priming PW and ignition advance to no avail. Attached is a log and current tune. What's going on? I know it's getting fuel because the fuel pressure gauge on the fuel rail shows pressure. The cranks but doesn't start.

The issue *might* have something to do with the VR pot. I replaced an impedance wire. Here is an email from someone on this: The main difference between the V3.0 and V3.57 is the input impedance - it's higher on the V3.0. I have shipped this one with three resistor-on-a-wire jumpers to let you change the impedance. The one I
think will be the best bet is a 15K with green leads, and I have put that in your ECU. There is also a red 10K and a blue 20K - use the red one if it won't sync at low RPM, or the blue if it's having high RPM problems but low RPM is fine."

I was having some hgih RPM problem so a week ago I put in the blue wire. I wonder if I should adjust my VR pot. Perhaps there is low RPM interference.

2016-01-09 Hard Start.msq

2016-01-09_12.25.28.msl

[slow_hemi6]

As I said from an earlier log you did get a sync loss event. Now you are getting a lot of sync loss events.
I don't know how sync loss relates to your Basic Trigger, oddfire ignition. I thought only the wheel decoder triggering could show sync loss? To me it does looks like you are having problems with the tach input signal.
What type of ignition system is it, some type of GM HEI? and how do you have it connected. I am having a little trouble trying to understand why it would need extra series resistance added to the tach in.
Maybe jsmcortina could shed some light on why you are getting the sync loss events showing on a basic trigger setup? Still regardless it does point to a tach input that is not triggering correctly.

[Lazabby]

It's a long story. But the short version - Three of us converted two Deloreans (after one was already converted) to EFI three years ago. Things were going well until we used the 3.57 MS board to run both fuel and spark. Running on fuel was no problem but running on spark was a problem because of the sync losses. If we put a 3.0 oard on the car it ran fine but with the 3.57 board it wouldn't run. I beleive the issue was some kind of interference and thus we had to use the impedance wire. If you'd like to read a long thread about our conversion you can click here:
http://dmctalk.org/showthread.php?2083- ... EFI/page11

You can go to the beginning of the thread if you want to read about everything but page 11 starts taking about the MS we had. It took months to resolve the issue.

Shannon