Surging/stalling! problem or tune?

[djj62478]

My car has Edelbrock 6025 heads, trick flow track heat upper and lower, comp cams xe274hr cam, 1.6 rockers ,75mm mass air and throttle body, shorty headers, of road H, and flowmaster dumps. Car surges when 02s are plugged in and will surge heavily till it dies and doesn't like to restart. With them unplugged it starts up fine slightly surges just for a couple seconds then evens out like it's okay you could take it for a ride for a little bit like maybe a couple times around the block. It's fine at stop lights and stop signs although I haven't driven it too far. It seems like every time I go to back it into my driveway that it will stall out and doesn't like to restart again until the car cools off for a while. You could get it started but you really have to keep the gas mashed to get it running again and then it runs like crap and keeps stalling until it cools off. Don't know if it's a coincidence that it's when I'm backing it in or if it would just do that anyway. Just wondering if you think there's an issue somewhere, or it's a tuning issue because of the amount of work done to the car working with the stock computer? I called a performance shop near me to have them check the car out and just look everything over and they basically said that it needs to be chipped and Dyno tuned that it's never going to run correctly with the mods that are done.

 

[gkomo]

With those mods, still running the stock 19lb injectors and MAF?

Stock ECU should be able to handle a H/C/I + mods combo fairly easily.

 

[djj62478]

30lb injectors 255lph fuel pump and 75mm mass air. Calibrated for the injector

 

[AeroCoupe]

Just me but I’ve never liked the Acell injectors. Not saying they are all junk but you hear about them having more problems than the OEM units or the Bosch.

 

[djj62478]

Just me but I’ve never liked the Acell injectors. Not saying they are all junk but you hear about them having more problems than the OEM units or the Bosch.

They are motorsport injectors

 

[Noobz347]

I've lost count of the number of times I've said that "calibrated MAF" and 30 lb injectors is where it starts getting hairy.

In general, those MAF meters are calibrated(-ish) for Bosch injectors. Even then, it's crap-shoot.

If you have an OEM MAF and 19s sitting around, I'd def try it. Like mentioned, I don't see anything in that combo that needs 30s.

The alternative of course, would be a digital tune.

Do you have the transfer functions for the MAF and for the injectors?

 

[CAMTWO1070]

30lb injectors 255lph fuel pump and 75mm mass air. Calibrated for the injector

A stock pump is (edit): 88LPH making a 160lph the perfect upgrade...When you up the flow and volume to 255lph you also raise the pressure...When I put a 255lph pump in my F250 w/351w I had to put a Kirban adjustable FP regulator as the fuel pressure was reading 46psi with key on and 43psi with engine running and as you can see on the 351w/383 and 410stroker builds i have FP gauges on the fuelrail aswell as on the dash too to monitor my fuel pressure at all times...


In any even until you can see the actual innerworkings of an A9L tune youll realize everything is hrdbaked into the sya=stem so any type of perceived trickery doesnt come without a tradeoff........

I use a QH chip and BE program....When you start with a S0Z binfile you start with a binfile that already has emmissions deleted and Base Sum Addresss set to Zero which is quite important to successfully changing thebtune without implications of hiccups..

Everytine the ECU does a self check etc against the numbers theres an integer used to verify the tune isnt corrupted and thats a 8192 BSA..Everytime te ECU does a self diagnostic it uses the BSA and when it fails the check funny quirks appear....



Heres where im talking about.....My numbers are on the left and stock A9L on the right...........Youll notice my CheckSum is different too...The checksum changes when the tune is changed....This is another problem for the BSA.

It plays heavily on the last 4 entries and why changing the idle manually without changing it in the tune creates constant conflicts/hiccups................

Heres a recent datalog I made....the spikes in the datalog are throttle blips...Notice how quick the rpms spike from 848 to 2500-2800rpms and back down...It takes changing alot of settings to make the idle magically obey........Good Luck

 

[AeroCoupe]

The stock pump on all injected Foxbody Mustangs is an 88lph pump.

 

[CAMTWO1070]

The stock pump on all injected Foxbody Mustangs is an 88lph pump.

Yep youre right...Its been awhile since i had a bone stock vehicle...LOL

.I got mixed up with the pump we used to put into the Mustangs to upgrade them and makes adding a 255lph more than double the safety needed to avoid fuel starvation and more the reason for the adjustable FP regulator..... Thanks

 

[djj62478]

So I went out again today and was having all kinds of surging issues as usual, base idle reset, computer reset, another smoke test, couldn't even get the car to idle on it's own to do the base idle... So I went out to check the voltage for the 02 sensors on the ecm. Well look what I found. Car started up after removal it surged a little then caught itself and I drove it around town for 10 mins and it only surged once but for like 3 seconds then didn't again. Anyway without further ado here's what I found.

 

[Noobz347]

Oh, noes. LoL