Hello All,

Ok so I have a 2001 Blazer, 4x4, 4.3 with 92,000. When it is hot outside my Blazer is stalling when I stop at signs. Runs great when I am on the gas or if the engine is cool. Also had trouble starting for a couple days.

Things I have done already: new Crank Sensor, engine coolant sensor, fairly new fuel filter.

Was told my timing was off and my harmonic balancer was off by a auto place after they diagnosed it.

Please help any thoughts....

Thanks

 

Also I have checked the fuel pressure and it was good.

 

1) Does the SES light come on with the bulb check?
2) Is the SES light on while driving?
3) If so, what DTC's are in memory?
4) After you replaced the crankshaft position sensor, did you perform the crankshaft position sensor relearn? (it MUST be done)
5) What is the fuel pressure with the key ON, engine OFF, and fuel pump running?
6) What is the fuel pressure 10 minutes after the pump shuts off?

"Was told my timing was off and my harmonic balancer was off by a auto place after they diagnosed it."

If the outer ring on the dampener slipped, the dampener should be replaced. However, just because it slipped, will not cause ignition timing to change, or be "off". They're feeding you a line of crap, probably because they don't understand the system. Checking ignition timing is done with a scan tool, (Timing lights are obsolete and totally worthless on this engine). The scan tool indicates how many degrees of advance the PCM is applying. GM does not publish specific ignition timing specs on this engine. Ignition timing for each "cell" is programmed in the PCM and is not adjustable. If camshaft retard is not adjusted correctly, it will affect how the engine utilizes the amount of degrees that the PCM is applying. If the crankshaft position sensor relearn was not performed, ignition timing, injector timing, and cylinder misfire identification, (among other things) will all be incorrect, and the SES light will not turn on.

 

First off thanks you for responding with such detail
1. Well my check engine light has been on for a year now but for a different code: p0410, secondary air injection malfunction. When I researched that it was a bunch of discussion about smog checks. DOnt need and Blazer still ran good at the time so didnt fix the pump. When this first started happening in June I borrowed a code scanner from the auto parts store and nothing new came up. But was wondering if it didnt read anything new because the engine cooled back down a bit.

No I did not do a relearn how do you do that?

When I checked fuel pressure it was about 60 I think (was a little while ago). But I did not check 10 min after the pump turned off.

How do I adjust or check the camshaft retard?

Thanks

 

When a DTC sets, it will remain in the history file for a certain number of drive cycles or drive trips depending on the class of DTC. If the fault is not detected, the PCM clears it from the history file. Disconnecting the battery has no effect on the history file, but it will turn the light off if there are no hard faults present.

The crankshaft position sensor relearn can only be done with a capable scan tool. The el cheapo ones at the auto parts stores can't initiate it.

Might want to check fuel pressure and leakdown and post it.

Camshaft retard is viewed on a capable scan tool. It is adjusted by turning the distributor.

 

So could I have a fuel pump that is failing when the vehicle is getting hot?

 

Vehicle/engine temperature will not cause the fuel pump to fail. There have been some issues with the fuel pump module connector getting hot and melting causing the terminals in the connector to lose contact. If/when that happens the pump will either become intermittent, or totally quit. The connector has been redesigned and that cured the problem. Most replacement fuel pumps come with a new style connector and it gets soldered to the vehicle harness:

 

Well off to do some checking on my girl, will update soon with hopefully some good news!