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87 T-Bird TC running realy rich with rough idle

September 03, 2011, 03:36:43 PM

My 87 thunderbird turbo coupe is running very rich gas mileage has gone way down to like 16 mpg. The check engine light is on and only goes out when decelerating from highway speed with it out of gear. I have had it in the shop three times, changed out TPS twice and put in a pig tail to correct for a wiring problem, changed out the ECU and still has the problem. The ECU was a remanufactured when I took it in the third time the bird wouldn't idle at all. After changing the ECU it idled great fo the first 10 - 15 miles then it started going back to it's evil ways. The O2 sensor is new and I changed out the spark plugs and cap wires and rotor. I'm at a loss where to go from here.

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87 T-Bird TC running realy rich with rough idle

Reply #1 – September 03, 2011, 04:40:59 PM

is it giving you any error codes?

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87 T-Bird TC running realy rich with rough idle

Reply #2 – September 03, 2011, 05:19:11 PM

I have not checked the error codes yet.

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87 T-Bird TC running realy rich with rough idle

Reply #3 – September 14, 2011, 06:10:31 PM

the codes I got were 14,42 and 65.

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87 T-Bird TC running realy rich with rough idle

Reply #4 – September 15, 2011, 01:01:55 PM

Co
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87 T-Bird TC running realy rich with rough idle

Reply #5 – September 15, 2011, 01:08:31 PM

Orange wire on turbo that is ground for O2 sensor
My vote.

Didn't see a code for it but ECT and IAT were bad on mine when it did that, also what ECU you running and is your car stick or auto?

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87 T-Bird TC running realy rich with rough idle

Reply #6 – September 15, 2011, 07:01:12 PM

CODE 65 Check intermittent HO2S (signal or ground)
Here is the code SOURCE ALL DATA ^^

Here is my O2 ECM Ground PIN 49 (ORG)(HEGOG) This is when i had a stock computer. This is normally on the turbo bell. I always move them.

http://i600.photobucket.com/albums/tt88/tomrenzo/family305.jpg

You can also check the O2 Voltage at 1400RPM'S and monitor it's voltage for TOGGLE. But with the codes you are getting it is quite clear you are stuck RICH. This will also check for O2 issues. Is the O2 heater circuit ok?? Just a thought Good luck

http://www.rothfam.com/svo/reference/volumeH/1988/Section%2019%20-%20EEC-IV%20Pinpoint%20Tests%20FA-KR.pdf

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87 T-Bird TC running realy rich with rough idle

Reply #7 – September 15, 2011, 11:15:49 PM

You may want to look at the ECT.  I think this tells the ECU to lean out the mixture when the engine is at operating temp...if the ECU never gets the signal that the engine is at operating temp it won't know to lean out the mix...just a thought.  Also if the FPR is is running high it could dump more fuel thru the injectors than expected...Just another thought.

Mine was throwing a 42 (as well as a few others) when I got & the intake looked like it had a 1/8 inch of black puppies in it... I ended up doing a head job & replaging the ECT, O2, FPR, TPS & a bunch of other stuff(prety much everything but the knock sensor) ...Not sure you want to go that route but it did make mine run better.

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87 T-Bird TC running realy rich with rough idle

Reply #8 – September 15, 2011, 11:16:01 PM

You may want to look at the ECT.  I think this tells the ECU to lean out the mixture when the engine is at operating temp...if the ECU never gets the signal that the engine is at operating temp it won't know to lean out the mix...just a thought.  Also if the FPR is is running high it could dump more fuel thru the injectors than expected...Just another thought.

Mine was throwing a 42 (as well as a few others) when I got & the intake looked like it had a 1/8 inch of black puppies in it... I ended up doing a head job & replaging the ECT, O2, FPR, TPS & a bunch of other stuff(prety much everything but the knock sensor) ...Not sure you want to go that route but it did make mine run better.

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87 T-Bird TC running realy rich with rough idle

Reply #9 – September 16, 2011, 05:25:02 AM

Also

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87 T-Bird TC running realy rich with rough idle

Reply #10 – September 18, 2011, 08:14:43 PM

I was leaning towards the The TFI module and the Distributor due to the car stumbling like it has lost its place. Not favorite idea to pull the distributor and rework it since it is my daily driver but you gota do what you gota due. I had a shop replace the O2 sensor and that has not fixed it. When reset the idle according to a thread on this web  site it helped a lot to keep the old bird from dieing at stop lights. But when I went to reset the TPS after adjusting the Idle the measured voltage with throttle closed was around 4.5 volts then When I moved it towards WOT the voltage dropped to around 1.5 volts DC. This confused me because I was expecting it to be backwards from this. Maybe I did not check it right. Not sure if the IAT sensor is good or not. The ECT maybe a problem due to the car always showing cold unless I sit and run without moving. The ECT was replaced just prior to my purchasing the car. About 50k miles ago. You guys have given me a lot to look at and I appreciate your help. I am glad I stumbled onto your forum. Thanks again.

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87 T-Bird TC running realy rich with rough idle

Reply #11 – September 18, 2011, 08:18:39 PM

By the way it,s a 5 speed manual.

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87 T-Bird TC running realy rich with rough idle

Reply #12 – September 18, 2011, 08:20:56 PM

The ECM is a A178-4309 part #. Not sure how to tell otherwise.

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87 T-Bird TC running realy rich with rough idle

Reply #13 – September 18, 2011, 10:33:56 PM

Clea

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87 T-Bird TC running realy rich with rough idle

Reply #14 – September 18, 2011, 10:50:10 PM

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