solerizr

91 Pickup SR5 3vze

I took my truck in for the headgasket recall because my vin number had not had the service performed. When i got the truck back from the dealer, it had two strange problems. I took it back three times and each time they would tell me the problem was fixed, but it actually wasn't. I have come to the conclusion they are all retards or just don't care, and have decided to tackle the problem myself.
First, the truck takes forever to warm up. If i let it sit and idle, eventually it will almost come to halfway on the temp gauge, as soon as i move air through the radiator on the highway or even the neighborhood roads, the coolant temperature drops significantly, usually below "C". I have taken out the old thermostat, and installed a new one, both were tested and worked properly. No pressure is building in the coolant system yet there are no leaks or loss of coolant. Also the heat always seems to work properly and the heater lines are hot. WTF!?

The second and less irritating problem is a mystery hesitation it developed after the headgasket job. About two or three minutes after i start the truck and before the thermostat gauge would normally move, the truck will exhibit a hseitation and dying out problem when you push the gas, however only under no load. If you push the gas in neutral or with clutch in, it will hesitate, the rpms will drop and then respond normally. Sometimes it will afterfire once the gas is let off. If the truck is allowed warm up even a tiny bit, it runs great under all conditions and the afterfire goes away. No codes. The plugs, wires, cap and rotor have since been replaced along with the t-stat.

Can anyone shed any light on these seemingly mystery problems? Thanks guys, i just got done doing both diffs for a regear of 5.29, and love it, now i just want to enjoy a problem free truck for a little while.

solerizr

Bump. I'm thinking of trying a TPS.

Tracey98277

well the afterfire sounds like a timing problem, have your exhaust manifolds ever gotten red hot? without your daignostic ports shorted, take your timing light and watch the crank, does it advance when you pull the butterfly and rev it? also, does your timing need advanced? also check TPS/VAMF. is your t-stat pigtail worn/broken anywhere? have you flushed you cooling system ever? it could have a blockage some where. is the coolant line going into the TB hot? if not then the IAC will stay open. the t-stat not getting hot coolant will make the computer see the engine not at operating tempurature and try to give it a cold start idle when the water jacket is hot. lots of things to think about.

thedanned

This may be a dumb question so forgive me, but are you sure the coolant is actually cooling down? IE could it be an electrical problem relating to your temp gauge. Let the truck idle to warm, check the temp of the upper rad hose, drive down the street until the gauge shows cold then hop out and check the temp again. If its still warm there is something wrong with the gauge, wiring or sending unit. Under normal conditions the heater should not be blowing hot while the temp gauge reads cold.

Tracey98277

that is probably the most likely problem with the t-stat. thats what i was getting at with the t-stat pigtail being worn or grounded somewhere it shouldn't be. hope you find it and get it fixed.

1990yota-pickup

go to SEARS and get a IR thermostat which shoots a ir laser and point ot at the engine while its running. you will know in a matter of minutes if your running hot..

solerizr

I'm not at acess to my tools at the moment, but i will look around for the things mentioned tomorrow afternoon. One thing i noticed driving the truck around town today was if i shut it off and leave it, and come back twenty minutes later the temp gauge will have indicated that the engine has actually warmed up to about halfway on the gauge since the coolant stopped circulating through the radiator. Same if i let it sit and idle long periods of time. I'm pretty darn sure nothing is overheating; the radiator hoses are usually lukewarm to the touch; the temp gauge seems to be functional.

The truck has also always run pretty rich. Anyone who drives behind me can smell that lol.

As soon as i drive it next i'l check and see if the coolant is hot going to the TB.

Thanks for the food for thought, i'l have updates hopefully tomorrow.