Tuning an 88 5.0

[Zfan]

Maybe a stupid question but what does it entail to get a "Tune" for my sons 1988 Coupe. It is a mass air converted 5.0 with B cam, Trickflow heads, 1.70 roller rockers, RPM intake, 70mm throttle body, Pro Mass Maf with 24 lb injectors. Transmission is a built AOD, 2800 stall and 3.55 gears.

Nothing fancy, I know but I am a Chevy guy for the most part who is a carb guy to boot...LOL that said I do not know shit about tuning a fuel injected motor!

Any recommendations would be greatly appreciated.

Thanks
Mike

[TRAXX]

If it has an adjustable fuel pressure regulator on it, you can tweak that a bit. Then you can adjust the timing (make sure you take out the spout connector). Beyond that, gonna have to pull out the wallet and get a chip (you get what you pay for, custom tune being the best) or go for a programmer like a PMS.

[greenbullitt]

put a wideband on it and work the fuel pressure and timing...thats the cheap way anyway. I didnt notice, does it have an adjustable fp reg? with only a bcam it may not need anything fp wise

[turbos66coupe]

Most tuners will tell you, you can do a lot With fuel pressure, throttle position and base timing. You won't gain much with an exspensive custom tune on that car

[TENGRAM]

Unless the CEL is coming on you don't need to mess with fuel pressure or the throttle position sensor. Just bump the timing up... a lot.

A good tune can change the shape of the timing curve, fuel enrichment, delete emissions functions and checks, etc. Without it the ECM is going to find something near stoich AF ratio no matter what you do; if it doesn't, it will set the CEL off.

[turbos66coupe]

Well ill clarify my statement he needs to make sure fuel prs and tp are in spec and functioning properlly, I've sen a lot of people think they need a tune do to some sort of driveability issue. Making sure tp is under 1.0v and fuel prs is between 32-39psi and timing isn't to far advanced or retarted Most tuners in this area wouldn't spend the time on a car with such mild set up unfortunatly at least that's been my experience.

[greenbullitt]

Unless the CEL is coming on you don't need to mess with fuel pressure or the throttle position sensor. .

not true. When dealing with "calibrated" meters, it doesnt take much to get a skewed one. Fine tuning other adjustments can correct the wot a/f.
If the meter does its job well, everything else can be oem spec and work well.

[Diabolic]

I would skip the adjustable fp regulator or even messing with it. Adaptive learning will bring it right back to stoich in closed loop in just a short matter of time. Great trick for wot blasts at the track if you are having a slightlean condition. What MAF meter is in the car?

[TENGRAM]

not true. When dealing with "calibrated" meters, it doesnt take much to get a skewed one. Fine tuning other adjustments can correct the wot a/f.
If the meter does its job well, everything else can be oem spec and work well.

Yeah, I'll give you that... at least, regarding the fuel pressure. Still, if your meter is that outta whack then it's best to replace it if possible or get a real tune.

I don't know what the "Pro-Mass" MAF's reputation is but unless it is a huge meter it should be okay since it's only compensating for 24 lb injectors.


The TPS, on the other hand, absolutely does not need to be adjusted. It is a fixed sensor and has quite a large range of acceptable closed throttle voltages (0.50-1.20v*). No adjustment will make any difference in performance once the ECM finds the new closed throttle value. I know it checks every time the vehicle is started and I believe it checks regularly while running.

*because of inaccurate voltmeters and voltage fluctuations, I usually recommend 0.80-1.00v

[greenbullitt]

abaco makes a nice meter from what ive seen