well that's just it, I'm not geting any codes, and when I have the ECM in field mode, it never goes closed loop anymore.
I have checked the TPS, reads ok and I have put a new water temp sensor (the old one went bad). I'm shocked that I'm not geting any code 13...I have verified the ECM and I'm geting the usual code 12.
I know I had trouble geting the O2 to heat up with my TES headers, but it would go closed loop after steping on it. Not anymore. The O2 has about 12000 on it, so before I go blame it, is there anything else I should check?
I'm thinking self heated O2....that should solve everything....

Thanks

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85 Z28, 355, edelbrock base, SLP runners (old style) 58mmTB, ported plenum, stock cam, fuel reg, TES headers, flowmaster, 3.23's posi, rear disc, shift kit, MSD 6a, 305 hypertech chip (YUUUCK!) best prior intake mods: 14.6 @ 94, 2.02 60' temp: 78deg, 80% moist, on radials.
69SS, black, 3,73's, TH400, 402 BB, roller everything (solid 246@50 622 lift)+stud-guirdle, 67 Vette heads ported and o-ringed, about 10:1 cr KB pistons, should be done this summer, goals: 500hp and lots of fun

 

Have you used a scan tool to find out why it isn't going closed-loop?

You can check all of your parameters and find out if you're not to temperature, for example, or if your O2 isn't getting cross-counts.

 

I don't have a scan tool...I checked all sensors I could think that are related to closed loop...haven't check the ECM grounds yet nor the O2 wire connection...but I'm more worry that the ECM is not sending a code, like I would think it should....

 

Very likely that things will act strange to you, if your still using the 85 ecm. It's the first year TPI, and really was kind lame in my opinion. I'd look into updating to at least a 89 code and ecm set up, or better yet 730.

 

yea it's in the plans...but for now I was just wondering why the heck I didn't get a code...I'll probably go with a 165 ECM, just because I like maf and for my car it's the best way...but lets not start debating that issue guys! hehe...I'm gonna test the car one more time, and if needed I'll put a new O2 in.

Thanks guys

 

I have the same problem with my 89 tbi and tes headers. At first it would not go into closed loop at all. After adding a new heated o2 sensor, it would go into closed loop at elevated speeds only (above 40 or so). Now it will go into closed loop when I step on it only, and no longer when I'm at elevated speeds. I haven't had time to play with it lately, but I have no idea what the hell is going on. I have a scantool and I get lots of cross counts.

 

well I just got done puting a bosh heated O2, and now it goes close loop, at least siting in the parking lot...haven't test drove the car yet...but I'm prety sure it's cured now!
thumbs up on heated O2!

 

Which heated O2 sensor did you use? How or where did you wire up the power and ground wires? I've been contemplating this myself for a little while since my O2 sensor is the last thing to meet the closed loop qualifications. Thanks!

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Greg Westphal
'87 IROC 305TPI/A4

 

BTTT.

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Greg Westphal
'87 IROC 305TPI/A4

 

Bosch 13077
one wire to the fuse box (that is activated by the key), with a 20A inline fuse (just in case), one wire to the ground (anywhere really...motor...frame) and one wire connected to the ECM. Got a small harnest in order to use the one on the O2, was like 8$...that way it's a nice set up...

 

What the heck does BTTT stand for? I wish there was some kinda a legend for all this stuff. My ECM (Part# brain) ain't too fast and I get lost sometimes.
rIc= k

ps: you see?

 

Thanks for the info Mirage! F22, BTTT stands for Back To The Top. I thought there was a page somewhere on thirdgen.org that explained a lot of these abbreviations, but I can't remember where...

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Greg Westphal
'87 IROC 305TPI/A4

 

Is it alright to leave the heater on whenever the motor is running, or is it better to turn it off once its not needed? Does anyone know what the stock ECMs do on cars that come stock with a heated O2?