help me tune my startup

[rocklizzard91]

ok i am fed up with my starting issues.
i have a very good tune otherwise. so one she starts she runs like a champ. pulls hard. returns to idle. all good.
however, i usually spend at least 2min trying to start the thing
today i even flooded it after trying to adjust everything. which made me late for work since i had to bum a ride

anway, does anyone have a special procedure they like to follow to tune startup?
i would love to have it start right up after only one or two cranks, just like a normal car.
but heck. where i am now, i would take starting in 4-8 cranks. it'd beat my 2min starts.

where should i start adjusting.
im using tunerstudio, but i have megatune too if you only are familiar with that.

thanks for any help!

[grippo]

I think the mistake many people make is to start adjusting instead of trying to figure out what the problem is first. As with many engine problems, the first step is to determine if the problem is in the ignition or fueling. The first thing I would do is make a short datalog of a cold start cranking. Check the rpm and trigger+/- column and see if it is losing synch or not. If it is holding rpm and trigger+/- doesn't change, then check spark timing during cranking. Is it where you would expect, something like 10 or so deg adv, not 30 or 40 or way retarded. You could also check your coils are good by looking for spark as soon as it fires.

If spark is good, then it is probably fuel. Is this a random problem or does is it always a problem. Is it only cold start or both cold and hot start ? Does it happen on cold days more than warm days ? It sounds like you should have enough experience by now to easily answer these questions and that will help people to be able to help you. ( Iw ould tell you that the first step with fuel is to find out if it is too lean or rich, but I assume you have tried that.) Also look at the fast idle system, does it start but immediately die out, or it doesn't fire at all. It sounds like the latter. To me that would mean: needs more priming pulse; needs time for the fuel pump to prime because it has a bad check valve and there is no fuel in the line; or not getting ignition synch. Make sure you aren't using WOT because that can trigger flood clear.

If you haven't already done so, read the starting tuning section in the megamanual - there is a lot more info there.

[rocklizzard91]

I think the mistake many people make is to start adjusting instead of trying to figure out what the problem is first. As with many engine problems, the first step is to determine if the problem is in the ignition or fueling. The first thing I would do is make a short datalog of a cold start cranking. Check the rpm and trigger+/- column and see if it is losing synch or not. If it is holding rpm and trigger+/- doesn't change, then check spark timing during cranking. Is it where you would expect, something like 10 or so deg adv, not 30 or 40 or way retarded. You could also check your coils are good by looking for spark as soon as it fires.

If spark is good, then it is probably fuel. Is this a random problem or does is it always a problem. Is it only cold start or both cold and hot start ? Does it happen on cold days more than warm days ? It sounds like you should have enough experience by now to easily answer these questions and that will help people to be able to help you. ( Iw ould tell you that the first step with fuel is to find out if it is too lean or rich, but I assume you have tried that.) Also look at the fast idle system, does it start but immediately die out, or it doesn't fire at all. It sounds like the latter. To me that would mean: needs more priming pulse; needs time for the fuel pump to prime because it has a bad check valve and there is no fuel in the line; or not getting ignition synch. Make sure you aren't using WOT because that can trigger flood clear.

If you haven't already done so, read the starting tuning section in the megamanual - there is a lot more info there.

i will check to make sure timing is around ten. i know i have spark because it will always start. sometimes it just takes FOREVER
today i tried not using a pring pulse before starting. and that helped a lot.
it started significantly faster. no more 5 min starting sessions

it will usually take a long time. so its not intermittent.
on a rare occasion it will start right up like a normal car.
but only when warmed up already and on a warm day

i currently have no fast idle system. should i have one?
also i know sometimes it get super super rich because it will flood and i have to do the WOT flood clear.
however, two days ago it was so flooded that the flood clear mode had no effect. i think the sparkplugs were completly soaked.

as for the megamanual, i will have to do that

[trakkies]

I reckon you need a fast idle system for a cold start. Several ways of doing it - look at the MegaManual for the options. A Bosch extra air valve is perhaps the simplest - and requires no connection to the MS.

The rule of thumb is that if it starts better from cold with more throttle it's likely too rich.

But don't ignore the basics like excessive voltage drop when starting - does it start better if the battery is left on charge overnight?

If disabling the priming pulse makes things better, sounds like it is too rich.

[grippo]

The thing about the priming pulse is that it is re-energized every time you turn the key off, then on. So if this helps starting, it means you need a larger prime; if it hurts, as in your case, then you don't want to turn the key off, then back on.

[rocklizzard91]

The thing about the priming pulse is that it is re-energized every time you turn the key off, then on. So if this helps starting, it means you need a larger prime; if it hurts, as in your case, then you don't want to turn the key off, then back on.

should i be using a prime?
how much of a prime?

[grippo]

Yes you probably should, but not as a way to re-prime the fuel pump. So make sure fuel pressure stays up overnight. Then start with a small prime and go from there. If it won't work for you, you can make up for it with the cranking pulse, but priming will generally provide a bit quicker start.

[drmiller100]

just for grins, when you are trying to start the car, do you give it a little throttle?

it seems to me if an engine was cold, and couldn't get enough air, it is going to have a tough time getting going.

And I noticed you didn't have a fast idle air circuit.