My junk car is having trouble idling, I know or I've heard these things are horrible to deal with. At throttle and while is going its got zero problems idling under load or just idle is hard for the mini ram. Even idling to a stop it will shut off. Its been a problem for a while. Any suggestions of where to look in the tune? I've got a WBo2 and just about everything needed. The setup is twin turbo and has a holley 58, VE learn get most of it? Or is it gonna be a timingxVE

 

For reference... The early-mid 90's LT1/LT4 cars with the Miniram style short runner intakes run about 25° BTDC at idle in gear at ~600 rpm. These manifolds like some spark timing.

On mine as well, I'm also running open loop idle up to about 1200 rpm before switching to closed loop. I dialed in the AFR I wanted with the WB. I find that the idle is more stable, the throttle-tip in is much sharper, and I don't have so much variability in the idle quality over different air temps during the seasons.

Lastly, they also like significantly more AE delta TPS... and from my experience, significantly less AE delta-MAP. Adjusting the AE in that proportion seems to also make the throttle much crisper and less laggy on overall acceleration.

EDIT: One other thing... make sure your injector voltage offsets are correct if you're running non-stock injectors (which I'm sure you are with a turbo). In terms of driveability and manners, even fractions of a millisecond on the offset values can make a difference. This also requires that your batter voltage and ignition voltage (fuel pump voltage I believe its referred to in the datastream) match eachother very closely (I have mine to within ~0.25V with proper gauge wiring and use of relays to minimize voltage drops).

The alternative unfortunately is you end up chasing your tail trying to get the fueling correct.

 

If ignition and fuel pump voltage differ, why not select the most stable one (ignition) in the BIN.

Don
Williamsburg, VA

 

you can do that on $8D. Not sure about 6E.

But excessive voltage drops are never good anyway...

 

It was a real question on why not change sources.

I am $8D. I have electric power brakes in the coupe. The pedal / master cylinder is mounted under the floor on the chassis. The car is low and there is not enough room for a vacuum booster. The choices were hydro boost or electric. The electric system uses a very high pressure pump to provide high pressure to a third section of the Master Cylinder (special MC). The pump draws a lot of current when running. But normally, it only runs ever so often as you get about ten stops before the accumulator ball is low on system pressure.

Recently, something went wrong, and the pump would not shut off. I was logging at the time. Brakes reverted to manual (fortunately), but the car idled terribly (open loop). I checked the log and the FP voltage was down to 13.8 and the Ignition voltage was a constant14.2. On prior logs, there was some variance, but much closer together, maybe 14.2 vs 14.1 etc. Apparently, the brake pump shares the same circuit as the Fuel pump. I haven't been able to test it yet (no brakes-waiting for rebuilt pump), but seems to me that I can change the bit for the voltage reference for the injectors to the Ignition voltage and have a more constant reference voltage

Don
Williamsburg, VA

 

Agreed the ECM should be using the voltage that the injectors are seeing. Otherwise the injectors will be doing something different than what the ECM is commanding.

 

Thanks for the information gentlemen. Yesterday I was messing with things on the tune and everything I changed made the car not want to start. I reverted back to a older bin, it started right up. I've looked at all my data on the WUD and everything seem good. No crazy voltages. I do however have a trunk mount battery, I know I should have the alternators power wire to the battery and I should have a ground from the battery all the way to the engine block. I do have everything grounded to the chassis. I got at least 5 grounds or 6.

The other thing I did yesterday was adjust my throttle body, the set screw. It idled at a steady 750 my tune is set for 600, but once the CTS read near 140° the surging and idle issues began. Same stuff happened when I drove it to and from work. Had a couple minutes of good steady idle but once the temps got up it began to die and surge.
My initial timing is 0 and I'm asking for 8 at idle. I've gotten the AFR close to 14s/13s. I've done some work with the idle I think it's as good as it can get, but eventually the thing wants to turn off.

 

For injectors I got some mustang 42lbs injectors. And I have swapped out the pump with a walbro unit. My fuel pressure is around 55-60, injectors liked the higher PSI. Also when the car heats up my voltage does jump a lot. I guess the car dying and starting again is the reason for that. Other then that when the car is steady I get with .4-.2.

 

What's the injector p/n? Do you have the datasheet for them and correct voltage offsets entered into the calibration?

 

No data sheets. I got them off of eBay. EBay guy stated that they are 12ohms. If there is anyway to test that myself I should do that. It also said that the injectors were Bosch style injectors.

Previously I was driving the car because my Honda broke down so I had to bring out the 30 year old camaro. But I got idle issues once the car got passed 140 degrees. The car was sputtering and losing its idle. Day my Honda is broken again and I brought it out. Anyway I had less then a gallon of gas in the camaro, I filled it up with about 4 or 5 gallons of 91 and the whole trip to the junkyard and back it held its idle pretty well. A steady 690-710 rpm. It surged a couple times here and there died once, but before if the thing got to idle it would surely die. Most of the time it came to idle smoothly. After a idle the part throttle misfire seemed to be a little better.
​​​​​​

 

Can you find the part number molded on the injector body?

 

Yes sir I found it. I'll type it out and also post a picture

0-280-150-558.

 

https://www.thirdgen.org/forums/diy-...ml#post6299624

Here's some info on those.

Might try updating your voltage offset tables with these....

 

Man is that gonna be it? I don't know what to think if that's going help the car out and fix some of the problems. I just updated the tables on the bin. Tomorrow I'll go ahead and upload it. See what she does and how the car reacts to the change. Thank you so much for that piece of information. I don't think I would've ever thought of that.

 

I am looking for a base tune file for ebl as well.. i have a 89, auto, miniram, zz409 cam, afr heads.. i dont know what tune is on it now as my mechanic installed it and i cant get ahold of him to ask questions.. i did notice that it smokes a little, runs rich (AFRs are in the mid-high 16's, and just drinks the fuel..any help or tune file would be appreciated...