Ever Heard??

SYKLONE866

SYKLONE866

New member
Anybody ever heard of a coolant temp sensor causing the trucks to run exceptionally rich because of a bad signal.....my truck is so rich that I have black soot like shit coming out my exhaust .....and all over my plugs.....

just wondering if anyone heard of this because a mechanic told me he had...

thanks in advance
 
ItsMyTy

ItsMyTy

Life is beter at 25 PSI
yep. when they go bad, or are unplugged, the ecm defaults to super rich mode. mine was so rich it was hard as hell to start. you should get a check engine light, though.
 
SYKLONE866

SYKLONE866

New member
SO WHICH ONE GOES TO THE ECM???? AND WHERE ARE THEY....i KNOW ONE IS IN THE FRONT OF THE INTAKE BY THE THERMOSTAT WHERE IS THE OTHER......

THANKS
 
92Ty#1524

92Ty#1524

New member
The sensor for the ecm is the on installed on the lower intake behind the AC compressor. The sender for the instrument panel is located on the side of the cylinder head between cyls #3 and #5. The later is a one wire sensor.

Had DM on the truck the other day. I'm reading 170 or so on the dash and 205 on DM. Has anyone else seen such an inconsistancy? I'm experiencing hot start issues and wondering if the ecm temp sensor is f'd up or simply the wrong one. After all, I bought it from NAPA. Had to look the part number up in a dusty catalog because it wasnt even in the store's computer. hmmm
 
S

Sy769

Donating Member
92Ty#1524 said:
The sensor for the ecm is the on installed on the lower intake behind the AC compressor. The sender for the instrument panel is located on the side of the cylinder head between cyls #3 and #5. The later is a one wire sensor.

Had DM on the truck the other day. I'm reading 170 or so on the dash and 205 on DM. Has anyone else seen such an inconsistancy? I'm experiencing hot start issues and wondering if the ecm temp sensor is f'd up or simply the wrong one. After all, I bought it from NAPA. Had to look the part number up in a dusty catalog because it wasnt even in the store's computer. hmmm
Click to expand...

Could be, although the stock gauges aren't that accurate.
 
92Ty#1524

92Ty#1524

New member
Yes, its possible. I just havent seen anyone complain about stock gauge accuracy other than boost. I'll probably have get my hands on a Raytec thermal gun from work and verify the temp at the ecm sensor location.
 
S

Sy769

Donating Member
Since you have the difference in the two gauges and are having hot start issues I would pick up a new ECM sensor.
 
C

Captain Morgan

Moderated User
92Ty#1524 said:
Yes, its possible. I just havent seen anyone complain about stock gauge accuracy other than boost. I'll probably have get my hands on a Raytec thermal gun from work and verify the temp at the ecm sensor location.
Click to expand...

then I guess you never saw my old posts. my stock water temp gauge was way off, thus why I run Trans Temp, Boost, and Water temp in my gauge pod. I think it has come up a few times that the stocker water temp gauge can be off just like the boost gauge. I know mine was.
 
92Ty#1524

92Ty#1524

New member
Morgan

Never saw your post. It's a new issue for me. Didnt notice till last night. Still scratchin' me head over it. Have yet to search the issue out in the archives.

How did you know something was wrong?
 
T

Thrillhouse

New member
so is this a SyTy specific sensor, or could this same problem happen on an older S-series? My Blazer runs ultra-rich with plenty of black goo spewing out the tailpipe when I start it.
 
C

Captain Morgan

Moderated User
92Ty#1524 said:
Morgan

Never saw your post. It's a new issue for me. Didnt notice till last night. Still scratchin' me head over it. Have yet to search the issue out in the archives.

How did you know something was wrong?
Click to expand...

like from what was said earlier. dash gauge vs diacom/datemaster.

noticed it was alot different. Hooked up the Autometer gauge from my El Camino for a test, and sure enough found the dash gauge was just way off the mark, or well, as much as you can tell from the oh so wonderful gauge GM gives us.... so i put a real water temp gauge in. I will probably swap it out to digital when I get my EGT gauge though....
 
InvisiBill

InvisiBill

Active member
I would say that my dash gauge is "precise but not accurate". Going from 100-260, the middle line should be 180, the 1/4 mark 140. With my stock thermostat, it would stay below the 1/2 mark (180) while DM showed temps around 200. With the 160, it stays below the 1/4 mark.

The gauge follows what the temp does, it just consistently shows ~40 lower than actual... I use the dash gauge as a relative indicator of problems, but I just ignore the numbers on it.
 
R

RARE_TY

New member
I just noticed that I am having the exact same problem with mine. So are you saying that I need to replace both coolant temp sensors?

Now just checking on this, but will the second sensor thats near the AC, would it make a difference that my AC is no hooked up right now and not working??
 
SYKLONE866

SYKLONE866

New member
Guys,

put on the new sensor and everything is better...now have to replace plugs and re check timing but I dont have the black smoke coming out anymore......thanks for the help
 
92Ty#1524

92Ty#1524

New member
Brian,

No. The AC has nothing to do with it. I refered to it merely as a reference point to locate the ecm temp sensor.
 
ItsMyTy

ItsMyTy

Life is beter at 25 PSI
that's good that you got it fixed!

on a side note, my stock temp, volt, and boost gauges are WAYY off. Reads 18v when it's really 14.5, 110 when it's 160 degrees, and the boost gauge just jumps all over the place. hmm... maybe i should look for another cluster :eek:
 
You must log in or register to reply here.
Top