looking for an explination of Cranking fuel. trying to solve a warm no start do to a

ok have a LQ9 lsa super charger with a p59 ecm. bigger Deka 96lb injectors,trucknorris cam. I have a no start when warm unless I let it sit or spray brake clean in a vacuum port. Im trying to tune this problem out. The pcm is well grounded and is getting power. Im very certain its a tune issue. can anyone explain in how to increase my fuelling while cranking warm. Im looking at the cranking fuel charts and Im very confussed.

I did post a tread yesterday about this issue but thought it was a voltage problem. I proved today that it is not by comparing my setup to other trucks and vans of the same year... yes GM p59 sends 6 volts to the injectors key on engine off and 8 to 9 volts with it running. I think this is for the ecm to check the injectors and wiring for resitance or a open.

fuel transient boil tables.. maybe.. was for me..

See if this helps. Should run decent as long as map and injector data are correct.

Quote:

---

Originally Posted by 04silverado6.0

See if this helps. Should run decent as long as map and injector data are correct.

---

His other thread indicates he doesn’t have injector data.

I do see the unknown part now. 96 at 3 bar? 4 bar?

thank you. will give it a try

the injectors are 96 lbs at 58 psi fuel pressure. 80lbs at 43 psi fuel pressure.. Im running at 58 psi. and yes these are unknow no part number but know good injectors but I only have Deka data but they are not Deka. long story but I know they are good injectors

How do you know they are good injectors? Good injectors are not the same as "they open and release Fuel".

And even "good" injectors aren't good if the data isn't right.

And I'll try and stop beating this dead horse from here on out.

Trying to solve a warm start fueling issue with unknown injectors. Imagine that......

You shouldn't have to mess with that at all.

Getting injectors with good injector data would be a proper start.

Checking fuel pressure while it will not start is also super important. TOO high or too low will cause things like this.

not exactly unknown, but yes.

fuel pressure has rised to 70 psi after shut off but will decrease in a short time. The check ball in my regulator does leak down a little by my design. I was think vapor lock too. Still will have the no start when the psi is at 58 psi. also get liquid fuel when tring to purge the system.

they are known good injectors. Thats all I can say.

thanks everone... I just want to say that the injectors are known to be good injectors. I cant say how I got them but I can say they are good injectors from a good company. Well somewhat good company. The only information I have on the is a data sheet for 80lb Deka injectors that I got. They are not Deka injectors but I think they are close. Very close. I have in my tune file have the Deka injector data in there already. I have no other issues with my car besides for this warm statup. Im trying to learn how to use HPtuner so I can solve this problem but also know so I can help others. I know that most injectors dont give you Cranking fuel specs. Im think that where my issue is. Remember I have a supercharger on the this car that the p59 was never designed to control. Im asking for help understand the crank fueling.

Im useing 80lb Deka data. should be very close

One more kick at the dead horse.

Good injector data does include "cranking" fuel specs since that is basically all the other data beyond flow rate. At this point I don't think you have any clue what a "good" injector is based upon all of your talk about resistance being the same as "GM". And any injector that doesn't have some sort of a part number on them is crap.

04silverado6.0.... thank you. it runs better but still have the no start concern when warm. how or where did you get these numbers?

gtstorey....ok thanks for your feedback but no helpful. Can you help with the question I am asking about cranking fuel. what does it mean exactly.

That was pulled from a similar build i tuned. Just a decent startup tune basically.

04silverado6.0...well thanks again... Do you by chance know anything about cranking fueling? I know most people dont touch it. but any information would be great