I read the tuning guide on this site and so I finally went out to get some data.

First I want to tackle the Lower VE tables like suggested.

So had the car in park and went in 100rpm increments from 700rpm to 1600rpm.

All of the above ranges showed BLM at 160 while Kpa was between 28-32. I will deduct or add a little as necessary to get the 30Kpa figure and change the VE values.

What could make my car run that lean, even when I take the car out for a drive I look at the laptop and the BLM are always above 150!

The only time they dip below 150 is if sometimes I am going downhill and the motor is slowing down the car.


Don't understand why my BLMs are so out of whack. If I adjust the lower VE table I will have to do the same for the upper table right?

Cause how can I have a higher VE number at say 1000RPM and 30KPA then at 3000RPM at 30KPA. Will I have enough room to keep adjusting my VE values higher.

I am thinking just going across the whole table and increasing all the VE values by the same mark and then see what that does. Thinking of increasing the numbers in each block by say 10%

Is that a good idea?

Looking forward in hearing some opinions.

 

What ECM and BIN? Have you tried adjusting the Injector Constant to start?

BTW, you Kpa readings are much lower than what I experience, except on deceleration. That could be a sign of either and exhaust leak or vacuum leak.

 

Glenn, I am running a stock 1992 TPI BIN in my 86 TPI MAP car. ECM is 1227730.


I have not made any adjustments yet just been sorting through the rpm and blm ranges.

As far as exhaust leak well I have one small pin hole in the pipe going into the muffler. I don't think this could be causing trouble or could it?

There are a few BLMs around 130 etc but they are far an few between. Most of the time in the 150's!

 

Start by lowering the injector size constant to confirm that the BLMs are responding as expected. If you have a "305" and used the AUJP, then you have the Injector Constant set to 22# (used by 350s) instead of 19# (as used by 305s).

Again, it's a good idea to give "full disclosure" of your car if you want the problem diagnosed. Right now, with the limited info, it is all "guessing".

 

Yes I have a 305 that has about 20K miles on it since complete rebuild.

I ordered a memcal from a parts store in the USA and I ordered a GM stock 305 1992 TPI memcal. So the injector size should be correct, I will have a look at it in WinBin and see what I find. I know TunerCat is much easier to follow might get that to play around with as it seems much better than WinBin.

I'd like to give you more information but I don't know what you need to know. I could send you my data log if you wanted to have a quick scan through it.

Just to be clear on something since I am running lean I should lower the constant. I would have thought increasing it to give more fuel, well that is just me

 

No, increasing the Injector Constant makes the ECM think you have larger injectors and need SHORTER pulse widths (and thus leans the mixture). Decreasing the Injector Constant makes the ECM think you have smaller injectors and need LONGER pulse widths (thus richening the mixture).

Do that first to see if it is JUST a calibration problem with the eprom or a mechanical problem with the engine like a weak fuel pump, vacuum leak, flakey sensor, clogged injector, etc.

 

Glenn,

Thanks for the help! One last thing say the Injector constant is set at 19. What would be a reasonable deduction to start off with?

Would 18.7 be a go to get things started or am I better off justgoing down by .1 increments and burning a chip each time and checking the outcome?

Thanks,
Mike

 

Try 17. This is more to see if the calibration is OFF. You should DEFINITELY see a major richening. If not, then you have a mechanical issue to deal with - not prom related.