88 TBI runnin like crap!

on the side of the block is the switch for the fan that out in front of your radiator and the other one is for your gauge you should have a small sensor that screws in below your thermostat just to the left

humm i'll have to look again.

What pig said, the coolant temperature sensor (CTS) is gonna be on the intake next to the thermostat. That's the one that the computer uses to adjust the fuel mixture. When they start going bad they usually read colder than the coolant actually is, mixture gets richer, if they go really bad they can read as low as -40F and it'll flood your engine so bad it will stall (this actually happened to me on my old '92, drove me nuts trying to figure it out because it would run for a little while then stall and not want to restart.) Unless of course you live somewhere that it gets -40F and in that case I say move the hell outta there..

You can test your CTS with an ohmmeter. What I do is use an IR temp gun, with the truck fully warmed up, and shoot all around the thermostat housing until I get the hottest reading I can get. With the correct thermostat in there (195F) should be close to 195-200F. Then unplug the CTS and put the ohmmeter leads across the two pins on the sensor. Here's the readings, thanks to Chevytech on chevytalk.com:

Coolant sensor approximate resistance specifications:
177 ohms @ 212 deg. F. or 100 deg. C.
241 ohms @ 194 deg. F. or 90 deg. C.
332 ohms @ 176 deg. F. or 80 deg. C.
467 ohms @ 158 deg. F. or 70 deg. C.
667 ohms @ 140 deg. F. or 60 deg. C.
973 ohms @ 122 deg. F. or 50 deg. C.
1188 ohms @ 113 deg. F. or45 deg. C.
1459 ohms @ 104 deg. F. or 40 deg. C.
1802 ohms @ 95 deg. F. or 35 deg. C.
2238 ohms @ 86 deg. F. or 30 deg. C.
2796 ohms @ 77 deg. F. or 25 deg. C.
3520 ohms @ 68 deg. F. or 20 deg. C.
4450 ohms @ 59 deg. F. or 15 deg. C.
5670 ohms @ 50 deg. F. or 10 deg. C.
7280 ohms @ 41 deg. F. or 5 deg. C.
9420 ohms @ 32 deg. F. or 0 deg. C.
12300 ohms @ 23 deg. F. or -5 deg. C.
16180 ohms @ 14 deg. F. or -10 deg. C.
21450 ohms @ 5 deg. F. or -15 deg. C.
28680 ohms @ -4 deg. F. or -20 deg. C.
52700 ohms @ -22 deg. F. or -30 deg. C.
100700 ohms @ -40 deg. F. or - 40 deg. C.

Richard

sweet, very helpfull! but i think i found the answer. the oldschool scanner i have does indeed display the temp it's sending back to the comp. the internal (dash) gauge would read 215 (ish) wile the computer was getting 190 to 195. do you think i need to replace the CTS? wile driving today (with the scanner) plugged in the truck started it's shit again. i went though and noticed that the TPS was reading a voltage of .98 at no throttle when just 15 minutes ago i set it at .40 - .43, so i thought maybe the sensor moved, so i proceeded to get back home and during the drive back home it came back down to .40 it would never do that in the driveway when i idle tested it. or when i tested it with the truck not running but turned on. the little shit only seems to act up when i am moving, therefore making it impossible to figure out, if i didn't have the programmer it would have taken me forever to figure this out!!! glad i didn't have to pay someone for this!!! so i'm guessing it's time to throw a new TPS at this beast.

If it's only happening while moving might be a bad/loose connection somewhere screwing everything up. That kind of stuff can be a real PITA to track down, too.

As far as the discrepancy between what the gauge is reading and what the CTS is telling the computer, I wouldn't replace the CTS just yet, 50/50 it's wrong or the dash temp gauge sender is wrong. That's why I compare with the readings from the IR temp gun.

Richard

hay pig put a carb on that thing.

if i dont finsh this dually ill have a bad ass 502 forsale

erik

are you confused son? lol this responce dosn't seem to fit anything in this thread. haha and in no way to i want to make this thing get any worse mileage then it already does!

i thought this was pigs problem with his dually sorry

but ya the weed here in the nw is soo good

dudes on ludes should not drive man

erik

haha I would but I have to much money in it try'n to keep it on the computer, hell I have more money in my throttle body then most people buy accessories for their cars