AFR ?

[PJG1173]

I have seen this before. my tbi 4.3 used to do this under a load for extended periods of time (chewing through the mud). manifolds would glow read hot. had a buddy tell me that this is typical of tbi's. I turned up fuel pressure and no more glowing manifold problems but was a little rich in other areas.

[In-Tech]

If your fuel pressure gauge is accurate, shim that regulator till psi is 13, huge difference in fueling with a couple lbs of fuel pressure on a low pressure TBI system. Note, there is a 70 second power enrichment delay in the BAMP program. That's not doing you any favors either.

[mike454]

yes I had ran into that before on the fuel pressure too. I will get it up to 13 and double ck my gauge, its an older Mac but on low pressure a lb or 2 either way wouldn't help.

I talked to the guy that bought the truck new and he says its had this issue since before the warranty was out and the dealer couldn't straighten it out after swapping everything....engine and all.

so we'll see.
on that pe delay set it to 0 correct?

mike

[In-Tech]

During tuning I usually set the delay to 0, then after finished I like to add a short delay as it helps fuel economy when driving around town and lot's of transients that might trip un-needed PE.

[mike454]

ok, i modified the FPR to make it adjustable... got the fuel pressure set to 14 psi,it will go to 16 max with the screw i used.
that brought the afr down some overall,and runs better... I havnt checked the manifold temps yet,but ill bet they are lower,with more fuel available now.
I did 2 short logs (attached) if maybe someone could take a quick glance at them and offer areas of improvement i appreciate it....( i'm new to all this but eager to learn)
Next i need to figure out how to be able to log the wideband readings in with the tunerpro logs.
i did change the wot delay to 2.0 as in-tech suggested
Any other kinda universal changes thats common on all these bins?
Thanks mike

[donf]

ok, i modified the FPR to make it adjustable... got the fuel pressure set to 14 psi,it will go to 16 max with the screw i used.

I am very curious what the dead head pressure and volume on your pump is. I replaced my pump before even starting a tune. Most now are not up to the task volume and pressure wise after so many years. Don't tune around a low volume, low pressure pump. I used a 30 psi big block pump in my 5.7 van, just to make sure the regulator is what is setting the pressure.

[mike454]

its a new (has 5000mi on it) airtex for the 93 truck
if i'd been in on that i wouldve had them get the 94/95 model to get the higher pressure
i will deadhead it while ive got the gauge hooked up