- Thread starter
- #201
What code exactly? The EGR codes are P0401 and P0402
EGR Temp Sensor Test Plug
- Thread starter LC4LIFE
- Start date
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P0125- Insufficient Coolant Temperature for Closed Loop Fuel Control. Not sure if it means anything or not? Do they all do this with the test unit installed? It has been running a little rough since I installed it but I did a lot of stuff all at once(I know, I know...) so really not sure if the test unit is actually causing an issue or if there is some other problem. I also have an O2 sensor heater code showing but that's been there ever since I had the exhaust done.
- Thread starter
- #203
Based on that, it’s likely unrelated to the EGR or the test kit.
Huh. Did some more digging and I bet I grounded out the shielding on the blue wire that goes to the O2 sensor when I replaced the pigtail. Damn this is such a great site for 80 tech!
Pretty sure the shield is supposed to be grounded otherwise you might create a long capacitor.
YupProbably the temp sensor hole.
EGR Temp Sensor Test Plug
Hi Everyone, I figured I would post up a small project I have been pulling together mainly to satisfy my curiosity about EGR bypass, testing, and making it look good. Many of us have experienced the P0401 code and normally it is an EGR related issue. As you will come to find out, especially...forum.ih8mud.com
Where can I purchase a test plug ? Mine is a OBD2 California emissions engine.
- Thread starter
- #208
Its also in the first post of this thread.
I'm about to order a kit for my '93. Do you (or anyone on this thread) have a diagram of exactly which vacuum lines get plugged with the bbs? thanks!
CrabCake
SILVER Star
I did this on my '94...worked well when it worked. I left the sensor in as the "plug" and I'm glad that I did. Long story short, after about 800 miles (a few months), my truck started running like crap intermittently...unfortunately I was 400 miles from home at Relic Run when it started. Tried to diagnose, but with both rich and lean codes from OBD1, not much to go off of. I did get it home, but it was a loooong ride home and had a buddy shadow me for the first 300 miles...last 100 it was basically misfiring the whole way. After a a few weeks of diagnostics, I finally went to basically just yanking on wire harnesses...every one that I could find while it was running....turns out that it was the bypass diode thingy in the plug that failed. Removed the kit and it ran like a champ again.
All of that said, I'm thinking of getting another one and putting it back in...I hate those hot EGR gasses burning up the rear 5-6 cylinder head gasket area.
All of that said, I'm thinking of getting another one and putting it back in...I hate those hot EGR gasses burning up the rear 5-6 cylinder head gasket area.
Did you plug the vac lines or just do the plug mod?
CrabCake
SILVER Star
I did the bb’s too. Pulled them back out and plugged the egr temp sensor harness back in to return to stock.
- Thread starter
- #213
You will get instructions outlining it all once you order it.
Hi, I am on the fence trying to decide if I want to live with the CEL for my OBD1 code 71 in my 94 or apply your solution.
But I want to first understand how the EGR system affects the ECM AFR map (I am fairly new in to the world of 80 series). Just want to make sure the engine won't run lean after we do this. I know that usually the EGR opens when at low load (cruising/idle) situations, and that since exhaust gas is effectively inert the ECM has to only feed in fuel to ignite the potion of the fresh air pulled in to the chamber. So with us stopping the EGR flow, and a chamber full of fresh air, how does the ECM know to balance the AFR accordingly? Is it solely the temp sensor reading that decides the AFR for EGR compensation? Then I assume the bypass resistor set to EGR valve closed temp reading range?
Thank you for any information you can provide.
But I want to first understand how the EGR system affects the ECM AFR map (I am fairly new in to the world of 80 series). Just want to make sure the engine won't run lean after we do this. I know that usually the EGR opens when at low load (cruising/idle) situations, and that since exhaust gas is effectively inert the ECM has to only feed in fuel to ignite the potion of the fresh air pulled in to the chamber. So with us stopping the EGR flow, and a chamber full of fresh air, how does the ECM know to balance the AFR accordingly? Is it solely the temp sensor reading that decides the AFR for EGR compensation? Then I assume the bypass resistor set to EGR valve closed temp reading range?
Thank you for any information you can provide.
- Thread starter
- #215
Your O2 sensors play the largest part in the AFR than anything.
FWIW I disabled the EGR in my 94' long ago and it's run just fine ever since. I can't think of anything beneficial from sending exhaust gases back into the intake.
The 02 sensor signals are what really help the engine run at the correct air/fuel ratio.
@lcforlife I just ordered a kit for my 93. Looking forward to getting it installed and getting to the "other side".
thanks!
thanks!
@LC4LIFE do you typically send out a shipping notification? I ordered it a few days ago and got a confirmation but did not see if it shipped yet. Are they made to order? Thanks.
- Thread starter
- #219
You will see tracking info once it ships. The only orders I see that are not shipped are from the last two days and those will ship at some point today. Without your order number, or at least your name, I have no idea the status of your order. You should check your junk mail too if you think you are missing the tracking info.
Thanks,
anyone know the PN to the plug that the kit mates with? mine disintegrated