2g idles like chit w/ 750's

[Z1500]

The car is a 2g AWD w/ DSMLink, 272's, Spoolin FPR, a big pump, and 750 disc inj. It runs great at WOT but the dang thing is soooo rich at idle it dies a lot. Does anyone have any tricks to get a 2g to idle with big inj? Should the inj. dead time be super high? 600?

Kevin

 

[HighPsi91]

The biggest injectors I have ever dealt with on a 2G were 650's. This was with a dsmlink, CA FPR, and supra pump. I had no problems getting decent idle. The only thing I can suggest is to possibly try less fuel pressure if you have the headroom up top. Setting deadtime may help some too. I am still a bit new to the whole dsmlink tuning methods myself. I still dont understand why deadtime is such a critical data point on the dsmlink yet my Haltech doesnt even have an adjustable deadtime.. nor did any 1G tuning methods ever take dead time into account. I guess I need a better explanation of this.

 

[Kevin Jewer]

You dont need dead time to tune. Its just another tool to make your tuning more accurate and more effective. With upgraded injectors on a dsm you are told to set your trims with teh car idling, then try it with the car moving, cause it will be different under load. This difference is the result of dead time being different from stock. If you get dead time right, you can have 0% LTFT at idle or at cruise, hence the method suggested for adjusting it int he DSMlink manual. You dont have to set it right, just use global to tune for idle, or cruise, and then tune for WOT using the sliders. But its there so might as well use it One thing to keep in mind is just like Global, dead time is applied all the time. So if you are tuned for WOT, and then change dead time (or global too of course) you need to recheck the tuning at WOT since fuel flow has changed. Hope that helped.

To the original question, start at dead time of about 300, and set global to get 0% at idle. Then cruise on the highway prefferably for at least 10 minutes and see what it is. Adjust according to the manuals instructions. If you need further clarification after reading the manual (read it!) let me know.