looking for advice on using a SAFC with 550 cc injectors

[Tamatalon39]

Ok so I just got my Talon running one of the problems i had once i got the car to start was the car was idle(ing too rich and was loading up so i put the factory injectors in and wala she runs nice

Skip to today, I dont seem to have the power that a big 16G turbo can produce. the car only hits around 10 pSI of boost. so I wanna go back to the 550's

Now I snagged the SAFC2 out of my eclipse and wired it up and my question is: is there a way to tune it so my car will idle with the 550s

I haven't built a boost leak tester but I have checked everything to the best of my ability with carb cleaner ( for vaccum leaks) and fixed a few thingds that I found. I feel that my car is running too lean because my A/F guage is sitting on the first led mark.

my mods are as follows Big 16g, FMIC, dejon piping GM maf, with translator, adjustable boost controller, some sort of aftermarket BOV. SAFC2.

 

[bryanwheat]

Before anything i would do a boost leak test. If you don't have a wideband or at least a logger than there is no way to safely tune the car with the safc.

 

[clipto]

I just switched from 550cc on my 14b, should idle just fine.How much fuel to minus is different on every car just check your wideband and find a good a/f ratio and minus some fuel.

 

[Kalub]

Your idle AF ratios should be controlled by your O2 sensor (the front one). Are you experiencing trouble with it? Even with the 550's you should not need to do anything except set the SAFC to use -18% global fuel because the 450's are 18% smaller.

When I put in my SAFC and 550's last year all I did was drop them in and wire in the SAFC. Set your fuel to be -18% globally and it should idle at or close to stoich. The ECU should, provided it receives proper input from the front O2 sensor, idle the car. Of course there are other issues that could arise. (TPS, ISC, Coolant, etc. A lot of sensors have a play in idling the car.)

Also, since you said when you switched back to the 450's it ran fine I would look at the 550 injectors themselves. Are you 100% sure they work properly?

 

[Tamatalon39]

the car came with the 550's installed but the car had a 6 bolt swap but had bent valves. so I am not sure if it ever ran. some people told me that I had to have a tuner to run 550s so I took them out and put stock ones in and the car has been running pretty good since,

my issue is that when I first got it running it ran really good easily over 10psi ( i didn't really pay attention) there may be something to the O2 sensor being bad, because I got a code once saying there was something with the O2 however I cleared the check engine light and it doesn't come back with an O2 code.

I do have a code 1500 wich say it is something the dealer has to determine. and something about the Evap system (most likely from the removed AC)

 

[ramsack]

You shouldn't rely on your O₂ sensor to keep the car idling after changing injectors. Check for boost leaks first. Carb cleaner is only going to find vacuum leaks in the manifold. There is not enough vacuum in the charge pipes to have any kind of flammable aerosol affect idle, unless there is a gaping hole, and then it simply wouldn't run. Also, if this A/F gauge you're referring to is the type you hook up to a normal narrowband O₂ sensor, it's nothing but a light show, and its only use is determining if the O₂ is cycling when it should. It will not give you any accurate reading a ratio outside of stoich, so it can't be used to tune with. Your EVAP code is because of a problem with the charcoal canister, not AC. Your vacuum lines are probably all sorts of a mess.

 

[Fehrion_sit]

im running 550cc injectors on a safc2, the car does idle kind of strangely, swaying back and forth between 680 and 730ish, as displayed on the safc, i always considered that normal because once car went into closed loop, the car held a consistant rpm. as for tuning, JNZ tuning in hatfield can help you further tune the car with safc after you get it to -18% global, id give them a call. i would make sure you exhaust all testing you can do yourself before you take it anywhere, itll save you money. in other words, make the boost leak tester !!!!

 

[mebetter]

Are you using a wideband or going off of narrowband readings? Also when is the last time you have checked and/ or replaced your 02 sensor?

 

[1LE]

Easiest thing to do would be to grab a datalogger and check the fuel trim values.

On my higher than stock compression engine with 550s, we ended up having to ADD 10% at low throttle openings, but had the expected -18 to -18% at WOT... Idles perfect.

 

[Tamatalon39]

Are you using a wideband or going off of narrowband readings? Also when is the last time you have checked and/ or replaced your 02 sensor?

I just got the car running so I havent checked or replaced the O2 sensor I am gonna do that this weekend. as far as the light show, I got that part but when it was running better the light show was in the rich range like i wanted it to be allowing for the higher boost . I do plan on getting a wideband. and better tuner in the future but money is an issue and i already have these parts.

I will look into a boost leak tester

Now about this datalogger what do you mean by that. like a code reader or something?? if so I have one of those. please elaborate as I am new to these cars.also I have all my vaccumm lines plugged , not sure what is meant by global 18% as I dont have any instructions.

 

[1LE]

Now about this datalogger what do you mean by that. like a code reader or something?? if so I have one of those. please elaborate as I am new to these cars.also I have all my vaccumm lines plugged , not sure what is meant by global 18% as I dont have any instructions.

Just reading the codes isn't good enough. Has to support reading data parameters in realtime (something like the Alex Peper datalogger - OBD-2 Vehicle Explorer Scan Tool Browser). Reading the Long Term and Short Term Fuel Trims will let you setup the low throttle position. For the high throttle position you'll need a wideband and preferably some dyno time. I can't remember if the mid-range is just automagically interpolated or can be set on the AFC.

*edit*

1995 DSMs have ECUs that are about 98% complete OBD-2. Consider it a "beta" version of OBD-2 ECU. Will work with standard OBD-2 datalogger, but there are a couple quirks. There's a readiness test that doesn't work and something else too IIRC.