I recently installed a set of PTE 1000cc injectors, upgraded to V7 (9410715 rom), but have frustrating warm-start issues. By warm starts, I mean after the car has been sitting for about 30minutes to a couple hours. The car cranks and starts decently fine during a fresh cold start, and starts almost like stock if I immediately start after turning ignition off. During these warm-like crappy starts, if I hold the gas pedal 50% down, it starts much better, so there's probably too much fuel to start with. When I don't hold the throttle open, sometimes it takes several seconds to start, sometimes it takes 2-3 crankings to start, and sometimes when it does start, it catches at a low rpm (ie: 100-500rpms) before slowly rising to life.

I've dialed in the injector scaling and latencies pretty well at this point (.5% mid trims, 4% idle trims). I'm using 812 as the scaling value and .744 as the latency for 14v. It probably doesn't help that I have a mini-battery that measures 11.8v before starting, but I never had a problem with it when I had stock injectors.

I have searched countless threads and tested several settings to no avail (as suggested by the people who have apparently solved their issues). I've tried increasing, decreasing, zero'ing several tables in ecuflash. I've even started a journal as to what my settings are for the day, what the coolant temps and battery voltages are before I start, just to see what improvements or degradation there is. Maybe I just haven't dialed in the right combination of settings yet, but as I slowly trial-and-error every day (since I don't have that many opportunities to test in a day), I would greatly appreciate it if anyone can help point me in the right direction as to how to properly troubleshoot, log, and dial in a good warm start.

 

look for the table cranking primer initial pulse and decrease the warm startup values. Holding down the peddle to start means your too rich.

 

I've read mfred's post on advanced fuel control, but it doesn't seem to be defined for the 9410715 rom yet, as far as I've read. Do I need to change roms to get this defined? Here's what I have available with regards to injectors (is the name different?).

 

Whoops saw your post a little more clearly.

Yes thats the right table.

 

When it comes to Injector Cranking Enrichment IPW Adder (Main), I've tried decreasing them, zero'ing them out, and currently have large numbers there--all from 93F and up and still no luck. Are these values really sensitive to how exact you have to be, because I've just done broad sweeping changes so far?

 

If its not helping your lower voltage latencies for the injectors are probably too high. You mentioned you have a mini battery too. Try logging the voltage the car drops to when starting and decreasing the latencies in that area until it starts up like you think it should. Also log the coolant temp instead of guessing where to edit the tables.

 

K, I'll start to focus my efforts on that table now. Yes, I've been keeping a journal of battery voltage and coolant temps--all for this purpose. Do the other tables have any effect on these startup issues (ie: Injector Cranking Primer Enrichment, Post Primer Enrich Decay, Post Primer Enrich, Start IPW latency mcsec)?

 

Injector Cranking Primer Enrichment - Yes it effects initial fuel input
Post Primer Enrich Decay - It is the time the car runs in "enriched mode"
Post Primer Enrich - Enriched mode is a fuel adder for a time above after car is running
Start IPW latency mcsec - supposedly is the 14volt latency for the injector but i saw no marked change in my car

 

Theoretically, I'm guessing I need a low number for Injector Cranking Primer Enrichment since I have large injectors? I've already scaled it down relative to stock injector size (as per formula in Merlin's tuning bible).

How long (in seconds or minutes) does the car run in enrich mode? It seems like my car is relying on STFT to make my car rich during a cold start, but when the car is fully warmed, STFT is back to normal.

 

Yes bigger injectors mean you need less ipw to start.

Unknown really no one took the time as far as i know of to figure out what the time intervals are. I doubt its more than a minute though even at the highest setting.

 

Just to test to see if things respond, I drastically reduced my latencies in the lower voltages (pic below). It started ok, but then as soon as I turned on my HID lights, the car almost died out on me cuz the battery voltage dropped pretty badly, causing the injectors not to fire soon enough. I guess these latencies respond

 

There are actually two tables that control fuelling during cranking. One table sets the amount of fuel for a single primer pulse at the moment the starter is engaged while the other sets the fueling while the starter is cranking. I've had a few people ask about getting these tables translated over to 9417, but to be honest, I don't think that having these tables to tweak would help you. My personal experience with injectors having warm start issues is that its possible to reduce fuelling during cranking to help warm starts, but its not consistent. The issue is that your injectors are leaking small amounts of fuel after shutdown. Hot starts are fine because there hasn't been enough time for a significant amount of fuel to leak out, and cold starts are ok because the fuel rail pressure eventually drops to zero, the injectors stop leaking, and the fuel eventually evaporates or dissapates.

 

You seem to confirm my journaling results. I have not found any consistent pattern in coolant temp and battery voltage with when it starts up well or crappily. My car has been able to start up well and crappy with a range of battery voltages (11.7-12v), and within a range of coolant temps (96-210ish).

The only time it consistently starts up well is immediately after shutdown.

Do any 1000cc injectors not leak like this? Switching over to rom 9653xxxx probably wouldn't cure this issue then, right?

 

FIC1100s (high Z injectors). Great injector. Don't think you'll find a bad review on the entire site.

 

I'll definitely start considering the FIC 1100s. They seem pretty expensive to justify for the time being though. I'm sure my mind will change after a few more weeks of this warm starting issue.

Another question. If the issue is indeed leaking injectors after shutting the car down, is the fuel going into the combustion chamber, thereby seeping it's way pass the cylinder seals and into the oil?