Ok, what is an OBDI ECM?? I don't think my '86 TA has an OBDI ECM because I can't enter "Field Service Mode" by paperclipping A and B on my ALDL box after the engine is running. When I do that my idle just drops about 100 rpms and the SES light stays on solid and don't blink at all. Either I don't have an OBDI ECM... or my car is running so rich that the SES light isn't blinking at all... in which case I think my car would be having some issues and stinkin' like a biiiatch.

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1986 Trans AM
355 TPI
4 Wheel Disc Brakes
9 bolt Borg Warner Rear (2.77's....oh joy) :P
6" rods, approx. 9.7:1 Compression, Stock TPI (soon to be ported), 24#/hr LTI injectors (cleaned and flowmatched by Cruizin Performance), Hedman Shorty Headers, 3" exhaust with 80 series flowmaster, SBC 993 heads completely redone and modified for 1.6 RR, 1.52 RR (for now), Comp Cams XE262-14 TPI Cam, Holley AFPR, TPIS airfoil, MSD wires, MSD 6-AL Ignition, Hypertech 53,000 volt coil.

Track times to come.

 

Your car should enter diagnostic mode when you short those pins with the key on and engine off. It should blink the light 3 code 12s, then any other codes it has stored, then 12 3 times, then repeat.

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"So many Mustangs, so little time..."
ICON Motorsports

 

You didn't understand what I was saying. I'm not talking about extracting trouble codes from the ECM... I know how to do that. I'm talking about entering "Field Service Mode" to check if you're running rich or lean. Vader has posted about this many times saying that you can do this on OBDI ECMs... so what the heck is an OBDI ECM. Another guy says that on his 85 he can check rich or lean by starting the car first and THEN paper clipping the A and B terminals. Trying to get a little more info on the "Field Service Mode" thing because I know my car is running rich... I just wanna know how bad.

 

u can read my post, i had a similar problem
its called FIELD SERVICE MODE by 88camaro
i hope it helps

 

OK, gotcha.

OBD I (Roman numeral 1) is what the first generation of On-Board Diagnostic computers are now called. Nobody called them OBD1 until OBD II was specified by the federal gov't. as being required in whatever year it was, 93 or thereabouts. TPI belongs in that class of things, being the age that it is.

I don't know much about "field service mode" though, I've always used a scanner to check O2 indications when I've needed to deal with such things. Of course, if the O2 sensor is fornicated, then what the computer hears from it and reports either to the scanner or the light doesn't necessarily mean a whole lot; so if that's what's making you run rich, the computer might be hearing from the O2 sensor that it's got the injector duty cycle where it needs to be.

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"So many Mustangs, so little time..."
ICON Motorsports

 

hey, rev the engine when ur doing this, this always makes them run lean. maybe you ARE running really rich, or maybe ur O2 sensor isn't flucuating.

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake

http://www.geocities.com/david_angel_16

 

Well I'm almost 100% sure that I'm running rich but if I were running THAT rich I'd think the ECM would set a code 45 for rich exhuast.

 

I think you may be a little confused...the long flash/short flash thing does not indicate how rich or how lean it is..i/e it won't flash longer if it's way, way rich, vs. just a little rich.

Long flash/short flash is indicated at the rich/lean condition (450mv IIRC) of the o2 sensor output.