$8B Temp Sensor issue 2.3l HO Quad-4

**BigBanks78** · 07-19-2023

Hello Its been a while.
I just installed a rebuilt Quad-4 HO and went back to $8B. I kept getting the ses light after start up so i watched the data stream and seen the temp sensor reading 250+ degrees F until the engine temp gets to 121 F then reads normal to at least 192F. I checked the engine with a laser thermometer and the sensor boss temp was the same as the data stream. I tested a new sensor today by plugging it in without installing in the engine. the outside temps here are 95-100F, the new sensor read 256F while in my hand so i plugged the old sensor back in with the engine running and at 182F and the data stream went back to 182F.

Do i have the wrong type of coolant temp sensor? Did I scramble the code some how, I have had to build history tables and dashboards in the adx, maybe user error? Is there any new developments with $8B?

I always appreciate the advice!!!

**NomakeWan** · 07-19-2023

Rather than checking the datastream I would check the sensor's resistance to make sure it's working as expected.

If the sensor is good, then next you need to check two things.

1. You saw the SES light is on, but you didn't say what actual code was being thrown. This is very important. Please check to see exactly what code is being set.
2. Especially if the SES code has nothing to do with the coolant temp sensor, I would suspect your ADX is using an incorrect translation for the coolant temp sensor.

I have zero experience with $8B so I cannot offer specific advice. But always, always start with the basics.

**BigBanks78** · 07-20-2023

Originally Posted by NomakeWan

Rather than checking the datastream I would check the sensor's resistance to make sure it's working as expected.

If the sensor is good, then next you need to check two things.

1. You saw the SES light is on, but you didn't say what actual code was being thrown. This is very important. Please check to see exactly what code is being set.
2. Especially if the SES code has nothing to do with the coolant temp sensor, I would suspect your ADX is using an incorrect translation for the coolant temp sensor.

I have zero experience with $8B so I cannot offer specific advice. But always, always start with the basics.

I looked for the resistance specs when i bought the new sensor but figured it was a bad sensor based on passed experience so i didn't dig. New and old sensor both switch at the same temp, I will check the resistance as temp climbs and get the specs. The SES stays off if I wait till the sensor reads 121F or above and then kill it and restart. Yea i guess I forgot code 26 I think, high coolant temp. I probably got a bad one out of the box. I only asked because I built a dashboard and must have picked the wrong coolant temp pid cuz it read 60F when above 100 and hadn't had time to try again. (not the same adx)

**NomakeWan** · 07-20-2023

If the SES is indicating a coolant temp fault, then you have an incorrect sensor, or a faulty sensor. Pretty cut and dry.

**BigBanks78** · 07-22-2023

Originally Posted by NomakeWan

If the SES is indicating a coolant temp fault, then you have an incorrect sensor, or a faulty sensor. Pretty cut and dry.

I only have a code when the engine is less than 120F and the datastream says its 250F setting code 14. The code doesn't set after its warm. $8B as far as i know uses the same temp sensor as $0E (or is it $OE). The same part number "standard ignition, TX3" comes up. The sensors, all 4, 2 brands, have 3000 ohms at 70F and about 200 ohms at 220F with no jump in ohms at 120F. This sensor worked fine with code59 but not when i use $8B also works fine in my $0E 7.4l C3500 and this sensor is the only one that comes up when searching the most common ecms talked about here. It very well could be the wrong sensor, I just haven't found another option.

**BigBanks78** · 07-22-2023

Hey,
I checked the ohms on 4 different sensors from 70F to about 220F, range was 3000 @ 70, 200 @ 220. The ohms climbed smooth with no spikes. this sensor is the same used on the 7427 and 90's vette. stock form was a 1990 grand am. Yea and sorry I was getting code 14 coolant high not 26 QDM, then today after good and heat soaked I got a code 15 coolant low........ wheres the "slapping my forhead" emoji... Im going over the wiring for the 50th time but after that I guess ill deal with it :)

**NomakeWan** · 07-22-2023

Originally Posted by BigBanks78

I only have a code when the engine is less than 120F and the datastream says its 250F setting code 14. The code doesn't set after its warm. $8B as far as i know uses the same temp sensor as $0E (or is it $OE). The same part number "standard ignition, TX3" comes up. The sensors, all 4, 2 brands, have 3000 ohms at 70F and about 200 ohms at 220F with no jump in ohms at 120F. This sensor worked fine with code59 but not when i use $8B also works fine in my $0E 7.4l C3500 and this sensor is the only one that comes up when searching the most common ecms talked about here. It very well could be the wrong sensor, I just haven't found another option.

The important thing to recognize here is that the datastream is not setting Code 14. If Code 14/15 are being set, that means the ECM is actually seeing those inputs from the coolant temp sensor. That rules out a bad conversion in the ADX or your interface software.

Setting a code means the ECM actually detected a fault. So what you're seeing in the datastream is indeed what the ECM is seeing.

Bad sensor, wrong sensor, or sure, bad wiring between the sensor and the ECM. Check your grounds, too.

**BigBanks78** · 07-22-2023

Originally Posted by NomakeWan

The important thing to recognize here is that the datastream is not setting Code 14. If Code 14/15 are being set, that means the ECM is actually seeing those inputs from the coolant temp sensor. That rules out a bad conversion in the ADX or your interface software.

Setting a code means the ECM actually detected a fault. So what you're seeing in the datastream is indeed what the ECM is seeing.
Bad sensor, wrong sensor, or sure, bad wiring between the sensor and the ECM. Check your grounds, too.

I have many redundant grounds from past diagnosis but i will go thru the wiring. I recently switched from Code59 and the temp sensor worked fine. yea I know the ecm is setting the code and the adx is just a translation the english from ecm-ese, I do know i can screw things up with the best of them so in my edit escapades I just figured I may have changed something inadvertently and screwed up the temp stuff. Hot code when Cold and cold code when hot....wierd

**BigBanks78** · 07-22-2023

I will try to find the deffinition but do u think code 15 coolant low is a low coolant level instead of low coolant temp? I do not have a coolant level sensor, not sure if there was one stock but some do have a oil level sensor.....

**steveo** · 07-22-2023

code 15 was never coolant level, it means the coolant temp sensor reads way too low or is unplugged

**Terminal_Crazy** · 07-22-2023

Originally Posted by BigBanks78

...something inadvertently and screwed up the temp stuff. Hot code when Cold and cold code when hot....wierd

That comment above alerted me.
You temp sensor is the correct NTC or PTC type ?? (Negative or Pos Temp Coefficient).. It will scale the wrong way if wrong type is connected.

Mitch

**steveo** · 07-22-2023

yeah seems likely
you can confirm which type is required by grounding the signal wire and viewing the log
this confirms the wire is not broken at the same time

**BigBanks78** · 07-26-2023

Originally Posted by steveo

code 15 was never coolant level, it means the coolant temp sensor reads way too low or is unplugged

Ok, I got to looking and that stuff would b an idiot light. So I been meaning to add some stuff I found but wont have time to type it all till after work in a couple hours....

**BigBanks78** · 07-28-2023

Originally Posted by steveo

code 15 was never coolant level, it means the coolant temp sensor reads way too low or is unplugged

Ok so I just picked a reply button at random.

I may have fixed the SES when warm. I was comparing 1988-91 wiring diagrams and f7 was the "high fan" in 88, f7 was nothing in 89 and the coolant light in the dash in 1990-91 Grand am. I changed my high speed fan settings as a warning temp and wired low as high fan. No light when warm yet and the Idiot light doesn't either. Engine and wiring are from a 1990 Grand am, I will rewire that and see what happens. Ive been really busy so havent checked for broken wires. Ill c if i can try grounding today

**BigBanks78** · 08-09-2023

I grounded the wire and datastream displayed 303F while just unplugged it displays 32F. There r 4 options for coolant temp in the adx,2 400k and 2 348k. Im guees 1 set is for C and the other is F.After changing the high fan to a warning light I no longer have any codes tripping but SES still comes on if the engine is below about 125F. If I warm it up and then kill and restart, the SES stays off. Also the datastream connect and warning light at the bottom when collecting data does not flash that its seeing a code when the light is on at cold start. I read as much as i could find from old threads and there were several senior members here discussing a SES they couldnt figure out so I may b running into that... Everything else seems to b working the way it should except the old problem I had with zero knock retard recovery, sometimes it shows 1* retard from starting. Kill it and restart and it goes away. But the more I mess with it the better it runs, using the $8B spreadsheet.