Tremek Car Video Forum

BOTLFEDLT1 · 08 May 2007, 04:58 am

Experiencing poor fuel mileage and have exhausted all of the normal fixes (i.e. proper tire inflation, new plugs/wires, clean airfilter etc) ? Something that might not be so obvious that can cause crappy mileage is a faulty coolant temp sensor. I just found this out yesterday and thought Id share.

I was changing my water pump and decided to test the sensor before putting it on the new pump with a multimeter. The sensor was showing infinite resistance (i.e. open circuit), so it was telling the pcm that the engine is always cold, so in turn, the pcm tells the injectors to spray more fuel as if its in warm up mode.

01mmmz28 · 08 May 2007, 05:24 am

wow, good find. glad you got it worked out.

Traction Issuez · 08 May 2007, 06:01 am

my buddy was pissing and moaning about poor fuel mileage the past week or so, then came by saying he wants to change his t stat, i asked him why, he said the gauge never warms up and the car runs better after an hour of hard driving.....i pointed out the fact that the rad hoses were up to normal temp and changing the t stat would do sweet fuk nothing and to change the temp switch... he has yet to get back to me.

97talon · 08 May 2007, 06:37 am

I had (well i guess have since I haven't fixed it yet) the same problem with my talon. Sucked because until the ***** warmed up I got no heat :banghead: . Made for some long cold drives in the winter.

BOTLFEDLT1 · 08 May 2007, 06:38 am

Im not sure how it is on your buddy's car, but on an fbody, the sensor for the gauge and the pcm are separate - you could have a malfunctioning gauge sensor which is telling you that the car never warms up, but its the sensor that tells the pcm what is going on that will affect fueling.

Quote:

Originally Posted by Traction Issuez

my buddy was pissing and moaning about poor fuel mileage the past week or so, then came by saying he wants to change his t stat, i asked him why, he said the gauge never warms up and the car runs better after an hour of hard driving.....i pointed out the fact that the rad hoses were up to normal temp and changing the t stat would do sweet fuk nothing and to change the temp switch... he has yet to get back to me.

Traction Issuez · 08 May 2007, 06:52 am

it's a 86 v6 camaro. i seen two sensors on the intake in the water passage. i guess we'll see when he gets back to me.

08 May 2007, 04:58 am	#1 (permalink)
BOTLFEDLT1 Fanatic Tremekian Join Date: Feb 2006 Posts: 952 BOTLFEDLT1's Gallery	Fuel economy Experiencing poor fuel mileage and have exhausted all of the normal fixes (i.e. proper tire inflation, new plugs/wires, clean airfilter etc) ? Something that might not be so obvious that can cause crappy mileage is a faulty coolant temp sensor. I just found this out yesterday and thought Id share. I was changing my water pump and decided to test the sensor before putting it on the new pump with a multimeter. The sensor was showing infinite resistance (i.e. open circuit), so it was telling the pcm that the engine is always cold, so in turn, the pcm tells the injectors to spray more fuel as if its in warm up mode. Last edited by BOTLFEDLT1 : 08 May 2007 at 06:35 am.

08 May 2007, 05:24 am	#2 (permalink)
01mmmz28 Veteran Tremekian Join Date: Dec 2005 Location: On a national search to find burgh a dentist that will work on baboon teeth. Posts: 4,732 01mmmz28's Gallery	wow, good find. glad you got it worked out. __________________ 2001 Z/28 LS1. Texas speed cam 231/237 598/595 112 lsa, .660 lift springs,7.4 hardened pushrods, lid, LT headers,TSP X pipe,Texas speed "true duels",Richmond 4.10 gears, stud kit, Thunder racing girdle cover, Spec stg 3+ clutch, ARP rod bolts, clevite main and rod bearings, 25% underdrive pulley, SLP 85mm MAF,black ZR1 rims 315/35/17 Nitto DR's, BMR subframes, BMR LCA's, Edelbrock TQ Arm, BMR pan hard bar. Tuned by R.P.M. Performance. All labor done my ME !!!!

08 May 2007, 06:01 am	#3 (permalink)
Traction Issuez LuCiFeR Join Date: Sep 2003 Location: hanging eddy wu from a tree and beating him Posts: 11,903 Traction Issuez's Gallery	my buddy was pissing and moaning about poor fuel mileage the past week or so, then came by saying he wants to change his t stat, i asked him why, he said the gauge never warms up and the car runs better after an hour of hard driving.....i pointed out the fact that the rad hoses were up to normal temp and changing the t stat would do sweet fuk nothing and to change the temp switch... he has yet to get back to me. __________________ 1st MEMBER OF THE KEEP IT TO THE STREETS FOUNDATION. go fuk yourself rams, my sig was just fine.

08 May 2007, 06:52 am	#6 (permalink)
Traction Issuez LuCiFeR Join Date: Sep 2003 Location: hanging eddy wu from a tree and beating him Posts: 11,903 Traction Issuez's Gallery	it's a 86 v6 camaro. i seen two sensors on the intake in the water passage. i guess we'll see when he gets back to me. __________________ 1st MEMBER OF THE KEEP IT TO THE STREETS FOUNDATION. go fuk yourself rams, my sig was just fine.

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