Blazer starting and heating issues

[gharris79]

My 90 Blazer starts hard when cold (starts/stalls) before finally staying running. I've installed a new fuel tank, sending unit and pump. Could this be a bad pump or possible dirty fuel filter?
The truck also heats up(maxes out gauge) before dropping to normal temp the raises up again. It don't boil over but seems air locked. I've recently replaced the thermostat thinking this could be the issue but it still does it.
Also when I start the truck it turns over slow and won't start when warmed up without a boost. Could this be a starter issue?

[Monkey Uncle]

Regarding the hard cold starts, have you checked to see if the choke is operating properly?

[blazer74]

90 would be TBI, no choke.

Starter, battery and cables.

Not uncommon for starter drag from heat soak on squares, not starting is extreme.

[blazer74]

Pegging the temp gauge seems a bit much.
Where is the sender at? In the head or intake.
Going high until the thermostat opens then dropping down I’ve seen but not going back up again. That was with the sender in the intake on the engine side of the thermostat.

Hand held thermal temp gauge to verify actual temp. Overheating will make your starter drag worse.

[Irish_Alley]

Where is the sender at? In the head or intake.


Hand held thermal temp gauge to verify actual temp. Overheating will make your starter drag worse.

he should have one in both spots, one for the ecm one for the gauge.



i know my 94 would run hot then cool back down due to low coolant

[Irish_Alley]

also is your check engine light on?

[gharris79]

I changed the coolant temperature sending unit on the intake and put a new gauge sending unit on block. Since I changed these the check engine light has been on and is still doing it. I replaced the one on the intake again and the light went out. The truck had a set of aftermarket autometer gauges in it when it started doing this so I replaced it with factory gauge sending unit.

[gharris79]

Also debating on removing the thermostat to see if it keeps doing it.

[Irish_Alley]

before you replace anything you should test it. the T-state shouldnt be just removed. if you want to test it boil it and see if it opens