2000 Blazer Long Start Time

[bhesson]

2000 4dr 4wd Blazer. 80K runs great, well maintained, just tuned up but over the past 6 months I have to hold the key for 8-12 secs before the engine starts up. It seems to be worse when cold. Thanks for any help.

[perrokonan]

i had the same problem but it eneded up being the gas pump and now it always starts right away on the first try

[BlazerLT]

Originally Posted by bhesson

2000 4dr 4wd Blazer. 80K runs great, well maintained, just tuned up but over the past 6 months I have to hold the key for 8-12 secs before the engine starts up. It seems to be worse when cold. Thanks for any help.

What did the tuneup include?

[bhesson]

AC Delco Plat. Plugs, wires, fuel filter, cap and rotor. The air filter is a long life K&N and I've got about 30k on it since cleaning it.

I have been having a problem with the Fuel Gauge bouncing wildly around and I've read I need to replace the fuelpump/sending unit because it's all one piece but I didn't think the pump was bad. It runs fine just takes a little longer to start than when I first got it.

[tannerdude]

My 95 Blazer had the same problem and now it will not start unless I attach a battery charger. I have a new battery and it makes no difference. Once it is warm it seems to start OK. Past posts seem to point to the fuel pump. I have CPI and measure 58 psi fuel pump pressure and drops back to 55 when running. Where do I go from here?

[BlazerLT]

Originally Posted by bhesson

AC Delco Plat. Plugs, wires, fuel filter, cap and rotor. The air filter is a long life K&N and I've got about 30k on it since cleaning it.

I have been having a problem with the Fuel Gauge bouncing wildly around and I've read I need to replace the fuelpump/sending unit because it's all one piece but I didn't think the pump was bad. It runs fine just takes a little longer to start than when I first got it.

Have your fuel pressure checked.

[scholzee]

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!

[bhesson]

ok, thanks i'll have the pressure checked