Hi. 383 le3 build, tuned for 42lb injectors ran way too rich not just at idle, but even at higher rpms it would not correct. plugs and wires, opti connections, fuel pressure, vacuum leaks have been checked. Car runs good on stock injectors with no surge whatsoever, only moderate lope. Dced O2s after this, and idled briefly, was still horribily rich on 42s (my tuner is doing all this, im far away from Edmonton).

Blms were initially 128 to 130 both banks at anything over 1400rpm with switching 02 voltages. The car is now Running switching voltage
on one bank with a steady 128 BLM, and a maxed 160 blm and 350 mv at 2,000 rpm on the other bank, still on stock injectors. It will almost not even run with the 42s.

I started this off in lt1 tech, everyone felt its a tuning issue so im introducing this in the tuning forum. Im thinking the 160blm bank should be the normal one on stock injectors!

 

No offense towards whoever is doing the tuning but make sure he is adjusting the minimum injector pulse and not just the injector rate. Try zeroing out that table and see if it doesn't behave.

 

I'm confused. Why are you running stock injectors at a 42lb/hr constant, as opposed to the 24.91lb/hr factory setting?

 

Tuner is unable to find minimum injector pulsewidth under ecm constants. Any trick to finding that table?

The injector size was set for 42lb/hr because those are the injectors I want to run, but it ran too rich. 4yrs ago, these injectors ran fine and they were sent for cleaning recently where they flow them as well, and those guys said the injectors are ok. The reason the injectors were switched to 24s was beacuse it was felt there may be a problem either either with the program or the injectors, and this was one way of testing that theory (theories).

 

The injector constant needs to be set to whatever the injectors flow.
The injector constant and min pulse width are both found in "Tables" -> "ECM Constant Table" (in Tunercats)

 

42lbs is incorrect for an injector constant, read this cut and paste.

•Fuel injector flow; if you swapped injectors, especially to a type rated at a psi different than 43.5. In that case, divide 43.5 by the other injector's test psi (39 for Ford/Bosch). Take the square root of the number (to remove the square from "pounds per square inch [psi]), and then multiply that by the new injector's rated flow. For example, if you're using the Ford SVO/Bosch style, you'll want to multiply their rating by 1.056 (24#=25.34, 30#=31.68, 36#=38.02, 42#=44.35, etc.).

 

They are lucas injectors (delphi), which I understand are set to run at stock fuel pressure, so sqr root of 43.5/43.5 would = 1. Tuner is 100% sure he has no minimum pulse width table in his tunercat software, which is version 2.23. I bought tunercat and the $ee definition file several years ago but have had harddrive failures and no trans am for the last 4yrs and dont have my registration information.

Would it be possible for me to email my tune to someone to check the min injector pulsewidth? Thanks so much

 

If you or your tuner take time to email tuner cat he will set you up with the newest version of the software and the definition file.

I will take a look at the tune for any abnormalities if you email it to me.
<---- email link over there.
A scan would also be helpful.

The wildcard seems to be that the injectors were cleaned and rebuilt along the way perhaps something is wrong with one or more of them now.

 

if it was me i would use the bigger injectors and tune it to them , when u start messing with injector PW to compensate for the bigger cubes and heads u start to actually change the timing ,beacuse the piston is only coming up for so long and with ur cam and overlap it such a waste and i would almost be willing to bet if u installed bigger inj. and tuned to there size u would lay down more hp then screwing with the PW to get it to run right with the stockers

 

I don't see anything wrong with the tune at all. The pe enrichment values are pretty big, but other than that nothing is out of the ordinary. Min pulse width is 1.4 ms or so. Injectors are 44lb in the tune you sent. Voltage offset is stock.

Start looking at the big injectors or maybe a pressure problem as the culprit. Maybe one or more injectors is stuck open or locked up.

I really tried to find something wrong with the tune, but its just not there. You got hardware problems or a corrupt tune file.

 

People are said earlier that min pulse width should be reduced. Is 1.4ms too long? Thanks a lot for looking at it by the way.

 

I'd be really concerned about this tuner messing up my car given what you've told us.

 

The car runs rich not only at idle but at higher rpm. I would think that minimum pulse width and /or too much cam overlap should only cause problems at low rpm, and as per suggestion earlier on, that there may well be a mechanical issue, or it could be a combination. Please keep the thoughts coming, this car has been out of commission for wayy too long. If I figure this out, I'll be sure to let everyone know.

Thanks everyone.

 

Swapped pcm after nothing else worked, and now the car idles perfect on the 42lb injectors with 42lb madz tune. I never thought the pcm could be faulty in that way. Just thought i'd update incase anyone has the same problem.

 

sounds like the problem im having.. thanks for keeping this thread updated.