Need Rebuild Help
 

hey everyone. JUST finished my rebuild and the project is almost to an end. i wanted to verify a couple of things before i get "too" worried.

I'm unsing a power fc. i did tell the comp i have 550 / 1300cc inj. and set the lag for the 1300 at 0.10ms like recc by tuner. thing is it tends to idle like a bridge port or even if i hold it at a certain rpm. but if i accel it slightly to lets say 2.5-3K. it revs up smooth as a baby and perfectly even.

I'm running a full single setup, rats nest removal etc etc. walboro 255lph pump. stop rebuild with stock ports and all OEM internal parts. with brand new housings.
injectors are wired up correctly. plugs set up correctly.

My wonder is the stock pfc map is supposed to run a stock port motor perfectly. but iirc when you go single you had to tell the pfc alot of stuff before it ran smooth. should i move on and get the tuning done? or does anyone have some recc for me to check before i keep going. thanks!!!


Los

bump =-)

I don't see how the bigger secondary injectors are going to affect idle. Those don't even kick in for several kRPM. Similarly, I don't see how single versus twin turbo setup is going to affect idle. Now you do mention stock ports, stock primary injectors, and an upgraded fuel pump. Have you verified proper fuel pressure? If your regulated pressure is higher than stock, then even your stock primary injectors will put out more fuel than the PFC thinks. You also mention removal of the rat's nest. There is room to make mistakes with so many hoses and auxiliary systems. For example: throttle air screw (TAS), dashpot adjstment, throttle position sensor (TPS), wax rod adjustment, accelerated warmup system (AWS), idle speed control (ISC) system. Many of us have experienced idle problems with the PFC even without extensive changes to fuel pump, injectors, turbos, and rat's nest. It boils down to a proper mechanical adjustment before letting the PFC take over. I suggest geting a good mechanical adjustment of your throttle body done before tuning. Try Chuck Westbrook's tuning notes, contact him here: cewrx7r1@yahoo.com

i did remove the aws, and all associated hardware. But i haven't touched ANY adjustment of the t/b since it did run a year ago with stock ecu. i guess i should go ahead and reset everything down again eh? thanks for the insight!

any other idea's to check just in case?


Los

There was just a discussion on the datalogit forum regarding injector lag. The upshot of it was increasing lag makes the injectors stay open longer resulting in richer conditions. The guy in question was having idle problems. He too had an upgraded fuel pump. The stock pressure regulator can be overcome by an upgraded fuel pump. The ideal solution is to replace the regulator so you maintain "ideal" fuel delivery pressure even though you now have more volume capacity. I've read 43.5 psi is the standard pressure delivery to the injectors.

If you want to run higher pressure than stock, then you need to adjust the injector settings so that the fuel delivered is what the PFC thinks. Do you have a wideband? It is kind of hit and miss trying this stuff without knowing what your AFR is. Assuming it is idling too rich (because of increased fuel pressure), then reducing the lag or entering less than 100 correction value on the primaries should help. I've never done this and I don't know what I am talking about, so if you blow up your engine, it is not my fault! There is a PFC commander menu that lets you "try" these kinds of changes temporarily called Fuel / Timing Test Correction - it displays in the menu as "IGL/T. Fi" You could go in there and change injection adjust from 1.0 to something less, start at .95, then try .9, etc. and see if you can obtain good idle. Turn off your ignition and back on to erase this temporary setting. If you can get good idle doing this, it would seem to confirm it is idling rich and therefore your fuel delivery pressure is probably higher than it was.

I previousy said "Those don't even kick in for several kRPM" in regards to your bigger secondary injectors. This wasn't very accurate. My understanding is that the PFC uses the capacity values for the injectors to determine when it ought to cut in the secondaries. At the point when it kicks in the secondaries, it recalculates the ms so that (ideally) there is a seamless transition to running on both sets of injectors. So when the secondaries kick in isn't strictly RPM related, but is injector duty related. Bottom line is your secondaries have nothing to do with idle because you are not at high enough injector duty to cause them to kick-in.

I think the TB adjustment is a good idea, but if the problem is along the lines of fuel pressure and injector issues (as we are discussing above), then it might be a waste of your time in the short term. That said, TB adjustments were required on my car to get good idle with the PFC, even though the stock ECU idled OK. I have stock ports, injectors and fuel pump (with improved wiring), but I do have most exhaust and intake modifications, FWIW.

An experienced person knows that maps are not "One Size Fits All" even though they do come close for idle and cruise timing and fuel.

I suggest that you learn how to use the COMMANDER. It can be jused for diagnostic purposes as well as for tuning. Especially the IGL/IGT/IJN screen under the SETTINGS menu.

Here you can adjust timing and fuel. Thus you can also diagnos ignition and fuel problems. Try reducing fuel first.

PAY me and I will fix and tune your engine, I do live in Houston.

Wish I lived in Houston!! :jump:

CHUCK IS THE MAN!!! :jump:

Since you bought my notes package, you can ask me questions.