Hey guys... well the Iroc is running alright, i'm happy with the power it has now but i know there is more but i gotta get some other things solved first. First off is when it idles and i rev it up it stumbles, i believe it is rich because as soon as i rev it once and clean it out i rev it again and its a very clean smooth rev, too rich? My next problem is at full throttle my max voltage is only about .750mv, so i'm thinking its 2 lean but no detenation has occured so that is good. I recorded the Igniton angle and at full throttle at 5250rpm it is at 17.2 degrees! why is this so low? is that the full about of timming or am i missing something? can someone help me here. Thanks

 

Are you using the stock system or aftermarket?

 

I am using a DFI system version 6.32

 

I don't know how much help I can be, but I'll give it a try.

17.2* max ignition angle? Have you adjusted the ignition map? It should take values up to 39*. Make sure that the map value matches the balancer. Assuming the balancer hasn't spun. Confirm your timing with a light and match it to the map. It helps to set all the values in the map to a single number such as 8*. Also clear the values in the spark advance map from the (i believe) global menu.

I use the bar graph on the fuel map as an indicator of rich/lean. I remember a discussion a while back in which it was brought up that the max voltage on the O2 when connected to the DFI was 0.8 or so. I've always meant to see if it goes up when disconnected, but haven't gotten around to it. I see about .8 max, and I'm running rich on the dyno (black smoke).

For the stumble, check the acceleration enrichment. Maybe you have too much.

 

Thank you, i'll give it a try and see what happens

as far as the ignition timming i can never get it to read as low as it is on the balancer(10degrees). On the values i have entered the total at 5,000rpm is is 28 degrees in the table, so i'm thinking that maybe the 28 degrees is the 17.2 plus the 10 which is close to 28..?? maybe i'm wrong here.

I thought my car was extremely rich but when i read the voltages i was like WTF.. i've had people behind me when i get on it and they say the smell the richness which i can also smell when i rev it up in my garage(with door open of course).

i also have the FMU full rich but the fuel pressure only hits about 55!! maybe i should open the fmu some and see if it leans out some. thanks for the help

 

Pardon my stupidity, but what's FMU (fuel management unit?)? Your fuel pressure seems high. What size injectors?

Timing on the map should match the timing on the balancer, at least when it's over 1000RPM. Check to make sure everything is connected correctly. Is the diagnostic connector over the wheel well plugged in?

 

Alright.. been a while since i've had time to look at the car but i'll go from memory, if i remember correctly the timming on the map reads 10degrees after 1 grand or so, which matches the timming on the blancer.

As far as fuel pressure, yes FMU means fuel management unit and that boosts fuel pressure as boost increases. I have 24lb injectors.

as far as using the air/fue ration on the fuel map, it never shows up as my coolent temp never reaches 150, lol. I have a low temp thermo(160) and a fan switch that turns on at 166 but the fans kick on at like 130! might have to go back to the stock fan switch.

 

First $hit can the FMU. You don't need it with DFI. With the FMU changing the fuel pressure, your fuel maps are pretty much worthless once you start making boost. FMU's are used to add fuel when you don't have any other means of doing so. You have DFI so add your fuel that way.

Second You really should change the stat or lower the temp setting for close/open loop. I had a similar problem and it was like driving around with the choke on since my engine was never reaching the 'normal' operating temp the computer was looking for. I solved alot of my problems when I replaced the colder stat with warmer one.

 

Ragtop... thanks for the help, when i get some time i'll take off the FMU and go from there. Also i see your from Des Moines, maybe we could meet up sometime if i'm still having problems, i live about a hour and a half from there(hour by camaro.) Do you ever go to any Dragstrips around? If not maybe you should come to Cedar Falls Raceway some time, if ya do let me know, i'll go 2. So do you think i should go to a hight temp stat or change the fan switch back to stock?

 

I suppose we could but after f@#king with the Accel crap for 3 years I never really got any better than knowing just the basics so I don't know how much help I'd be. There was a guy in Waterloo I spoke with about tuning. He used to do R&D work for Hypertech and was familiar CALMAP. He company name was Metronix. You might try him. I solved my CALMAP/Accel DFI problems by switching to a F.A.S.T. system. It's idiot proof and that's what I need. Pricey though.

Eddyville is our usual haunt. But the crew I hang out with has talked about hitting Cedar Falls a few times this summer.

I would switch the stat and the fan switch back to stock if it was me. I actually went a step farther and rewired my fans to seperate switches for manual control. But that's just me.

 

Also, in the Global settings for the ECU, you can change the temperature in which the fans turn on. Get a 180 thermostat and turn on around 192.

 

when i get some time i'll change the stat and fan switch back to stock.

Ragtop... when ya come up let me know. Also Mechtronics in waterloo has closed! they were the only place i knew of with a dyno and now they closed. I don't know how i'm gonna get this thing tuned with a wideband now. I have heard good things about FAST but i heard its expensive also. I may look into if sometime later on. Money is always a problem when your in High School.

 

I was afraid of that. I think Cerra Racing in the Quad Cities does tuning too. I know they have a chassis dyno. There is at least one chassis dyno in Omaha and I know he is an EMIC. Problem with him is he wants stupid money to tune the damn thing. Roughly $1000 bucks and he wanted my car for 3 days, yeah right

Money is always an issue no matter how old you are unless you are one of the 'few'. By the time it was all said and done, I spent the better part of $2400 for my FAST system. If I didn't have so much rapped up in the fuel injection/blower stuff on my car, I would have just bought a carb and a bigger NOS system.

 

well good news. I got the FMU off a few weeks ago, been busy since then and been crappy outside so i havn't had alot of time to drive the car. It runs alot stronger now that is not so rich. on a side note i could never get the air/fuel ratio thing on the bottom corner of the screen but i worked a little and got it, at WOT its 12.7(max on screen). So i still got some room to work.

Ragtop... i found out that there is a Chassis Dyno in Dysart, the guy ported my heads for me and one of my friends dad's is a good buddy with him and they had him build a motor for there 77 camaro, 350 bored 60 over that puts out 678hp :hail:. I'll have to check with him to see how much he charges, thought i would let ya know tho

Last... Questions
1. When i'm driving down the highway my air/fuel meter says i'm running at about 13.5, can i lean it out to about 14.7 for cruizing speed so that i save gas? i'm only getting like 13 or 14mpg right now and thats with 2.77's rear gears! thanks

 

You should be able to lean it out a bit. Without looking at the screen, I'm not sure how lean I run it, but it's a little to the right of center (maybe about a 1/4 of the way).