90 Gt Vert, The Bananna Spider

Jul 7, 2005
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Codes 41/91 are typically both related to the O2 sensors not reading correctly. Most of the time it is the ground wire not being hooked up. There is a ORANGE ground wire with a ring connector that mounts to the back of the intake. You should see it on the passenger side where the throttle body is coming from the main wiring harness.

The car can also run without the IAC valve too, so you can just adjust the throttle set screw on the throttle body to lower the idle speed to the correct idle range you want. Just make sure to do this on a completely warm engine
 
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Dontknowchit

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Jul 31, 2017
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Codes 41/91 are typically both related to the O2 sensors not reading correctly. Most of the time it is the ground wire not being hooked up. There is a ORANGE ground wire with a ring connector that mounts to the back of the intake. You should see it on the passenger side where the throttle body is coming from the main wiring harness.

The car can also run without the IAC valve too, so you can just adjust the throttle set screw on the throttle body to lower the idle speed to the correct idle range you want. Just make sure to do this on a completely warm engine
If it is this wire, than I believe it is connected, at least the part that is out of the harness. I had a leaking rear main seal that I replaced but it slung oil all over the back of this engine. The ring terminal is caked with dirt and grease but it is connected. It seems like it is connected to the back of the block or one of the heads tho.
 

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Dontknowchit

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Jul 31, 2017
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.....it drove.....on the road....even did a little mini burn out. VICTORY!

Alternator is charging but can't keep up with the e fan. Its a 2002 6g from a 3.8 sn95. Fan is from a contour. Fan is epic, tornado F3 level, may have to step up the alternator to aftermarket. Do i need more than 130a?
 

90sickfox

I didn't really have an issue with the stink...
SN Certified Technician
Mar 2, 2015
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If the alternator is wired and working properly you shouldn't have any problems.
 

Dontknowchit

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Jul 31, 2017
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Ok. Installed new IAC and still getting the shutdown at start up until warm. After warm it seems to idle ok-ish, lil rough. Still getting o2 sensor codes. I checked the orange ground wire and it feels to be solidly attached to head, can't see it. Can I cut it and just ground it to the firewall to be sure ground is good? Should I test anything else for 41/91 codes and new sensors installed?
 
Jul 7, 2005
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What year is your car again?
Auto or Manual?
What computer is in the car A9L or A9P?
 
Jul 7, 2005
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You need to first confirm the jumper wire is in the correct location as there is differences between Manual and Auto transmissions. This connector should be on the passenger side typically under the MAF or on the side of the strut tower.

1524499731978.png
 

Dontknowchit

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Jul 31, 2017
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So jumper the connector and pull codes or test with a meter? I've not seen this pic from richker before. Is it on a checklist?
 

Dontknowchit

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Jul 31, 2017
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I unplugged what I think is the correct plug/harness. Is this it? So do I make a jumper wire to the inputs as shown above to run codes? Male or female side? Do I measure with a meter?
20180423_205338.jpg
 

Dontknowchit

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Jul 31, 2017
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Can anyone tell me what stanglx2002 was getting after here? Do i jumper and then pull codes or test with meter across the shown ports? My computer is from a 93, is that ok?
 

General karthief

wonder how much it would cost to ship you a pair
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That is a diagram for the jumper wire on the o2 plug related to transmission used, Go to veryuseful.com to verify wire colors.
Do you have a repair manual?
 
Jul 7, 2005
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Can anyone tell me what stanglx2002 was getting after here? Do i jumper and then pull codes or test with meter across the shown ports? My computer is from a 93, is that ok?
The jumper wire should already be there. I just wanted you to confirm that it is in the correct location for a manual transmission. People all the time just swap in wiring harnesses and not know there are small differences. Normally the jumper wires is a purple with yellow stripe.
 

Dontknowchit

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Jul 31, 2017
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Just thought I would update my thread. Life got in the way and car had been sitting, tinkering occasionally when I had time. Got to dive in over the last 2 weeks. Solved my issues with TPS and the shutdown. Essentionally, at idle, the 100a alternator cannot keep up with both contour fans on high. When the power was drawn low enough the efi would shut down. By unplugging one of the fans and fixing a few vacuum leaks I was able to take the car out for a drive today. Died twice, upon engine deceleration or at idle so I suspect more vacuum leaks. With the alternator keeping up with the single fan on high I was able to easily restart and continue on my way. Removing the air pump and egr next. In my attempts to find all the leaks. Cat tube is already welded shut anyway. Turned a corner today, I was super excited. Just wanted to share with people who care;)
 

Dontknowchit

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Jul 31, 2017
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Ok gang coming back to the well again for some help.
After capping one of my intake vacuum leaks things got much better but before I check and reset timing I want to be sure this stalling issue is not more vacuum leaks. (I did mess with timing while replacing the TFI module)

Situation: Stalls on cold start and occasionally randomly, at idle. Have to rev to keep cold running. Once warm, idles smoothly for most part, occasionally, randomly, will idle stall. RPMs are steady mostly, no surge. (IAC, ignition switch, fuel filter and pump all new, MAF, TB, FPR, TPS S&P shakers all clean and checked.)

After removing EGR and air pump I had a lot of vacuum likes to mend. Tab/Tad selinoids were broken as was the EGR regulator. They were all leaking everywhere.
So now that they are all out I have 2 small vacuum lines coming out of the passenger fender. I ran them to the capped off B/R feed on the vacuum tree. Charcoal Canister vacuum lines still connected. A/C is capped, brake booster and speed control lines into the drivers fender are attached. PCV and FPR lines look good. Anything else I am missing? My HVAC controls in the car do not work anyway, should I just cap the B/R port and cap the pass fender vacuum lines? Current codes are all related to the EGR and Air pump (31, 67, 81, 82, 84)

Any ideas? I feel like I'm just missing another vacuum line off somewhere. Car pulls STRONG, really have enjoyed a few drives but want more reliability before I go very far from home.
 

Dontknowchit

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Jul 31, 2017
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No, I did not want to per the checklist pending any additional mechanical issues. You think it is time?