bene

iTrader: (16)

I'm trying to figure out why this car I'm looking at is dying in gear while sitting at the light and it also hard for the car to idle when it is cold start up.

Idle speed in park/n and g has been changed already.

It's a 370 forged, ported stock heads, 240/242 cam, w/ 92/92 intake and stock 26lb injectors. It has been tuned not by me but still have some issues.

Any pointers or help is appreciated.

Frost

iTrader: (45)

do we get a scan or at least a file? What are the rest of the setup details? compression? stall?

That is NOT enough injector either.

bene

iTrader: (16)

TCI SSF 3500 is the stall, compression is 10.5:1
I will get the scan and the tune after work.

bene

iTrader: (16)

How do I upload the tune and the scan??

bene

iTrader: (16)

Figured it out...

Here is the scan and the tune

RoDan

That thing is way out of injector looking at the log. To fix idle issues, you really need to log idle parameters.

I have a couple cfgs that work pretty well. I'll attach them here. "Idle_log" is the one I tweaked. It has a histogram that it will log to that works great. You simply start the logging, and start your car from a cold state (i.e. it has been sitting for a while) and let it fully warm up.

Then, once you are done with that look at the populated histogram, (1 and 2 are the same) and it will give you a list of values that you should use to replace the numbers in your "Idle Airflow" table. It is found under Idle>Idle Airflow>(Base Running Airflow)Idle Airflow.

Hopefully that will help you get a lot of the bugs out of the idle. Then, since it is an automatic car, you will want to start it from cold and put it in gear so it has a load on the motor, and log until fully warm (remember, this is at idle do not touch the throttle!). Then copy the values from the histogram to the In Gear portion of the "idle Airflow" table mentioned previously.

Once you are done there, your next steps would be to upgrade injectors, and work on getting your VE dialed in, and it will most likely change your idle some. You may not even be able to get it to idle well until you get the VE down low better, which is hard. Once you get the VE dialed in, just simply repeat this process if the idle is not quite right. You may also need to play with idle timing as well as timing down low on the timing curves. Good luck!

Frost

iTrader: (45)

you just as well replace the injectors now before going any further. Much of the tuning work will be lost with the swap, so get it done first.

bene

iTrader: (16)

He is saving up his money for the injectors. For now he wants it to be daily driven w/o any issues.

Thanks RoDan for the pointers although I can't open that zip file somehow.

RoDan

He won't lose the tuning work when he swaps injectors if he gets the IFR table correct for the new injectors. Sure, he will have to go back and fine tune again with the new injectors, but it should be fine as long as he gets the IFR correct. If he goes with some huge *** injectors, it will mess his idle up but if he goes with some standards like SVO 42#s and such, the idle characteristics are unlikely to change much.

Bene, here change the extension from .txt to .cfg. See if that works. I don't know why you cant open the zip file.

edit: I also attached the injector calculator too, just in case you need it. Change it's extension to .xls since it is an excel spreadsheet.

Frost

iTrader: (45)

sounds like a good plan, you happen to have the ACTUAL offset values handy?

There will be more work than IFR and short pulses.

bene

iTrader: (16)

The injector calculator is nice. TY.

idle log is still unreadable. What program did you use with? All I'm seeing are`squares and symbols.

RoDan

I agree, but tweaking the pulses and all of the fine tuning associated with changing injectors is not necessary if you stick with a smaller injector, such as the SVO 42's which would be great for that motor. I dialed mine in with ease by simply changing the IFR and knocking down the minimum pulse width just a hair.

With injectors, It has been my experience that you do not need the exact offset values, as obviously they will vary from injector to injector (making it impossible to have the actual offsets). If the VE is good for stockers, and you do a proper injector calculation when you go to new injectors, you will be in the right zip code. Probably on the same block, but you won't know the house number. You then simply bring the VE back to the injectors with minimal logging using a wide band.

The idle should not drastically change, as the IAC is what really needs to be dialed in not so much the fuel, it will be hard to read AFR at idle anyway with a cam like that most likely. Frost knows his **** though, so if he says I'm wrong or going about it the wrong way don't hesitate to follow his instruction. I'm just trying to lend a hand is all.

I'll try to re post the file. I can open this zip fine, so hopefully you can as well.

Frost

iTrader: (45)

No you are right, If your numbers are good then things will be close, but there always seems to be some other touchup needed. 42s do need different short-pulse tables. Many people don't update them and are fine with a fat decel though.

RoDan

I just used the stock tables and short pulses, except I dropped the min pulse slightly, but if you know the short pule tables for some SVO 42's that'd be cool. I didn't realize needed different short-pulse tables really, I just winged it. I'd like to see if changing them had any positive effect though.

Mike454SS

iTrader: (4)

RoDan,

I'm curious why you're logging desired idle airflow in the histogram rather than the actual dynamic airflow that the engine see's at idle?

It was my understanding that if the VE was dialed in well, then logging actual airflow versus coolant temp would net you the appropriate numbers to put into the Base Running Airflow Idle Airflow table. I'm not sure I understand this correctly.

What I've seen with larger injectors, and especially with Ford SVO and other similar injectors...is they're a bit slow/laggy at low pulsewidths...most people probably notice a stick shift car popping a bit more under decel while in gear.

shortturn

The desired air is wht it tryig to achieve from corrections idle trim