fuel problem on 1g, not enough fuel

[Eagle 5]

Ok, Ive been trying to get my fuel trims to level out and it seems I can't get them to do much. Heres the problem.

I have ak eydiver stage 3 chip compensating for the 660cc's etc, all that fun stuff. I have emailed Jeff and he has checked over my chip and says that it is all correct. Basic setup is 255 hp pump, 660's, afpr, MAFT with 3" gm sensor.


My problem is my base fuel pressure is up around 50 psi, and I have the mid knob turned up to +35% fuel... and I still can not get the mid and high trims down. They were pegged at 139 but I did finally get them to move down to around 137 mid and 131 hi. I can't add anymore fuel on the MAFT and I dont want to turn my fuel pressure up anymore, I already don't like running it at 50 psi base when it should be at 37 psi base. I'm sure my afpr and fuel pressure gauges are fine. Couple questions though

- could my fuel injectors be so clogged they are causing a problem? Though when I had the VPC in it, my car was running waaaay rich. Thats why I dont think its the injectors.

- Is it possible I was sent a 2g maft instead of a 1g maft or is there some way I can check it to see which one I have? Maybe the wrong one was sent or heck, maybe I clicked the wrong button back when I bought it but I'm sure I didn't and I still have the receipt for it

I have the MAFT set to the 3" gm settings. base injectors set to 430cc trying to help with the fuel.

Any ideas? Is there a way I can check to make sure I have the correct MAFT? Also, if someone can tell me which of the 3 wires go to the connector which connects to the air sensor from the MAFT I would like to know. I extended my wires so I could mount the unit in the car. Maybe I somehow mixed the wires up because I believe there are two grey wires and maybe two brown wires. Thanks.

Also posted on fullthrottletech.com, hopefully someone maybe has an idea that I dont have or has had a similar problem

 

[andytalon]

I have the same problem, except, I got 450cc, AFPR(set at 37psi), Lean log, about 43 counts of knock at 4000rpm and a 16g, my trims are 139 low, and med-high 100, No boost leaks, I have heard you can set it to the recomended 2g base fuel pressure and get 100 trim, I havn't tried it yet but when I get around to it I will, and tell you what happens. I can't help you, but im on the same boat, anyone that can help us please do, really great! Thanks

 

[Eagle 5]

Can someone show me a pic of tell me which three wires go to the wiring that goes to the gm air sensor? I know 3 wires go to it but I want to know which 3 from the MAFT unit go to it. Just wonder if its possible I switched two wires by accident when I was installing it. I have the unit in the glovebox so I had to cut the wires and extend them. Didnt realize there were a couple wires that were the same color. Just wanted to make sure I have the wires hooked up right.

I checked my settings on the MAFT and everything is setup for my car. Something else we noticed a few months back was that when I was boosting the airflow single was pegging the maximum it could read. I have the double airflow signal in the Keydiver chip and I ahd it setup right in my palm pilot, but it was pegging the max setting and my friend and I thought that was odd for that to be happening on a big16g.

I really want to get my car running right and I dont like having my base fuel pressure up around 50 and having the mid knob turned to +35% fuel. and my fuel trims are still lean.

 

[dnhieu]

there is only 1 wire to tap. its one tha taps at the rpm wire on the cam angle sensor.

also are you adjusting your base knob untill you get your fuel map so your trims are right? remember the base knob is left to make rich and right to make lean. when you get all your fuel trims around 100 make small adjustments on your low mid and high knobs.

hope that helps
david

 

[tstkl]

if you are running a gm maf in blow through, the settings will be WAY off. I know mine and a lot of others I have talked to were. i know this doesnt help since you still dont have much of a way of lowering your fuel trims, but this might explain why your running so off. I personally am subtracting 25% at wot and adding 25% (i think thats a tad to much though..) and my mid is at +5%

 

[Eagle 5]

if you are running a gm maf in blow through, the settings will be WAY off. I know mine and a lot of others I have talked to were. i know this doesnt help since you still dont have much of a way of lowering your fuel trims, but this might explain why your running so off. I personally am subtracting 25% at wot and adding 25% (i think thats a tad to much though..) and my mid is at +5%

it is in blow thru, though a friend has his in blow thru but doesnt have the problesm I do. I have the base setting at 430 cc (lowest it goes) but that doesnt help. It took me turning the mid knob up to about 30-35% in order to get the mid and hi trims to even move down from 139. Now I'm not sure that it means those numbers are right. I wonder if maybe Is hould just get it to run well during normal driving using the butt tuner, then at wot I can use my palm pilot and change the wot knob there and just make sure I dont have any knock under wot.

would that work?

also I know there is only 1 wire to tap into. What I did was I have the MAFT unit mounted inside my glove box, so I had to extend the wires. Well I cut all the wires at once, and realized later that there were I think 2 grey wires. So, I'm not sure hooking those up wrong would cause anything or not.

I'm going to email keydiver again and ask him about the blow thru setup and see if maybe that is the problem. Thanks for the help and hopefully its just something simple like that that can be fixed.

 

[dnhieu]

okay this might sound dumb but it worked in lowering my fuel trims. go ahead and change the fuel filter if you have not in along time. i just changed mine and i have to completly retune my car because its running rich as shit. here is an example, my mids went from 114% down to around 101% and my high went crazy at 114% to 89%! im running so damn rich up top now that im shooting flames .

also you might need to start looking into some bigger injectors so you have a little more play with the maft translator.

hope that helps
david

 

[Eagle 5]

okay this might sound dumb but it worked in lowering my fuel trims. go ahead and change the fuel filter if you have not in along time. i just changed mine and i have to completly retune my car because its running rich as shit. here is an example, my mids went from 114% down to around 101% and my high went crazy at 114% to 89%! im running so damn rich up top now that im shooting flames .

also you might need to start looking into some bigger injectors so you have a little more play with the maft translator.

hope that helps
david

the fuel filter only has around 7000 miles on it. I'm already running 660s. I have a keydiver chip to comensate for them. I"m just curious as to how I went from running a VPC and running way rich, to running the translator and running lean now. I just dont quite get it. If you have the translator can you look and let me know which 3 wires from the box go to the GM sensor? I just want to make sure I didnt connect a wire wrong and have that screwing it up somehow. Thanks.

 

[dnhieu]

i dunno what your talking about. there is only ONE wire to splice and the other 2 are just plug-in-play. its dark out right now but i will look tomorrow morning for you. if your having to try to figure out which wires to splice to get it to work with the gm sensor there are some problems!

 

[Eagle 5]

i dunno what your talking about. there is only ONE wire to splice and the other 2 are just plug-in-play. its dark out right now but i will look tomorrow morning for you. if your having to try to figure out which wires to splice to get it to work with the gm sensor there are some problems!

no I know there is only one wire to splice. That is the rpm signal. I have that done no problem. There are two connectors for the MAFT though, the one goes to the sensor and the other plugs into the stock wiring harness. Those are the plug n play.

Well, I mounted my MAFT box inside the car. In order to do this, I had to extend the wires so I cut the wires and added length to them. The clip for the sensor has three wires going to it, the clip to the stock harness has however many. Well, both of them have a grey wire I believe (they both have a same colored wire just forget what color it is). I want to know where the three colored wires from the sensor (like the three that go to the plug n play clip) connect to the MAFT box at. Like if all three of those wires are next to each other on the box or if they are spread out.

Hopefully that makes a little more sense.