s-10 blazer cold starting problems

[phatmatt2g3]

i have a 97 s-10 blazer that is very difficult to start in the morning. I have to turn it over several times before it starts. Once it warms up it's fine and can be shut off and started with ease. Also if it won't start in the morning, if i put a little gas on the throttle body it starts right up, first try. can anyone suggest some possible causes? thanks

[sykopenguin]

Turn the ignition on a few times but dont start the car.....after about doing that about 5 times....turn the ignition all the way and see if the car starts....post the results back here when you do this....may be a fuel pressure related problem.

[J-Ri]

The problem is the battery is on it's way down and/or fuel pump. With the starter cranking, the battery voltage drops too low for the pump to build enough pressure. It could also be a coroded connection to the pump.

[BlazerLT]

1.) Check battery voltage with a voltmeter.

2.) Replace your Fuel filter if not done.

3.) Check fuel pressure.

[ricksza]

Sounds like the typical leaky fuel system (injector, regulator).

[BRUCE ARNDT]

Originally Posted by phatmatt2g3

i have a 97 s-10 blazer that is very difficult to start in the morning. I have to turn it over several times before it starts. Once it warms up it's fine and can be shut off and started with ease. Also if it won't start in the morning, if i put a little gas on the throttle body it starts right up, first try. can anyone suggest some possible causes? thanks

HAD THE EXACT SAME PROBLEM, POOR STARTING THEN RAN FINE, ON MY 99 S-10 4.3. TURNED OUT TO BE A BAD CHECK VALVE IN THE FUEL PUMP. DIAGNOSED BY FUEL PRESSURE TEST. FOUND IT WOULD PUMP TO 65 PSI, WHEN PUMP STOPPED, PRESSURE FELL FAST. REPLACED PUMP ASSEMBLY ($229.00 AT AUTO ZONE) FINE NOW.

[blazee]

You need to check your fuel pressure with the key on and the engine not running. It should be a minimum of 55-60 psi (it should be more for trouble free operation).

Read this it is taken from an article about CSFI:

**
From a service standpoint, however, this system has its weaknesses. There are two problems that have ended up being pattern failures. First, the system runs at higher fuel pressure than what we are accustomed to seeing, 56-64 psi. The poppet injectors will not open reliably with much less than 54 psi. I believe it was the Vortec cold hard start problem that was the inspiration for the concept of checking fuel pump rpm by means of the low current probe and the lab scope. The problem occurs during cold mornings when battery voltage is not what it might be. During cranking, voltage to the fuel pump drops. The rpm and consequently the pressure of the pump goes below the level necessary to open the poppet valves. Some of these hard starters took months to diagnose because a tow truck driver would hook up his jumper, and voltage would rise high enough to gain the extra two or three pounds of fuel pressure. Or, the vehicle would be towed in during the cold morning, but by the time the shop got around to checking the vehicle, the ambient temperature had warmed enough to kick up battery voltage, and the thing would start. Techs who were in the habit of not looking stuff up would see over 50 psi on their gauges, and, of course, that had to be enough! Sharp guys like Jeff Bach (current probe guru) and Jim Linder (the injector guru) learned how to scope the fuel pump waveform with the lab scope and calculate pump condition and rpm, almost to the point of being able to predict what day of the year the vehicle would fail to start!
**

To test:

Originally Posted by BlazerLT

1.) Check battery voltage with a voltmeter.

2.) Replace your Fuel filter if not done.

3.) Check fuel pressure.

Although I would probably check the fuel pressure before replacing the fuel filter, if it was low then I would replace the filter. And check the pressure again.