Hard starting 97 S10...again????

[97 S Blazer]

Pardon the long post, looking for some troubleshooting advice on my 97 4.3L Blazer. Currently I am once again having a couple issues, the vehicle is difficult to start, cranks fine but doesn’t seem to fire and start as a fuel injected car should. Currently, when the car is cold (simply sitting overnight, not necessarily cold outside temp), as the vehicle is being cranked usually in 3-4 second bursts, it will seem to fire slightly. As the 3-4 second cranking bursts continue, it will fire slightly more, usually by the time I have gone through 5-10 of the cranking bursts the vehicle will start. It acts as if you are priming the fuel system, finally resulting in starting. After the vehicle has been started, it will fire right off even after sitting for a few hours.

The other issue is, at times turning the key results in nothing happening. The instrument light come one, you just turn the key and nothing happens.

Last year, the vehicle stopped in the middle of the highway, the shop diagnosis was that the fuel pump not supplying fuel. The shop installed a new Delco pump. Things seemed ok, even the turning the key and nothing happening issue seemed to improve until a couple of months ago and now again intermittent key issue and the difficult to start issue.

Over the course of the last few years, I have replaced the electrical portion of the ignition switch 3 times, 2 Delco and 1 Napa supplied part. While it seems like replacing the switch has seemed to improve the issue of turning the key and nothing happening, the problem hasn’t totally disappeared.

The starter has been replaced last year, based on a diagnosis of the repair shop of the starter drawing high amperage. When I took the starter to the local parts store, they weren’t able to duplicate the high amp draw but as I had the original starter out of the car, I went ahead and replaced the starter.

At this point, rather then throwing more money and parts into it I would like to get some systematic testing suggestions from those here on this board.

I won’t be able to really dig into it until this weekend but would like to answer any questions that anyone may have before then. Thanks in advance.

[MT-2500]

Originally Posted by 97 S Blazer

Pardon the long post, looking for some troubleshooting advice on my 97 4.3L Blazer. Currently I am once again having a couple issues, the vehicle is difficult to start, cranks fine but doesn’t seem to fire and start as a fuel injected car should. Currently, when the car is cold (simply sitting overnight, not necessarily cold outside temp), as the vehicle is being cranked usually in 3-4 second bursts, it will seem to fire slightly. As the 3-4 second cranking bursts continue, it will fire slightly more, usually by the time I have gone through 5-10 of the cranking bursts the vehicle will start. It acts as if you are priming the fuel system, finally resulting in starting. After the vehicle has been started, it will fire right off even after sitting for a few hours.

The other issue is, at times turning the key results in nothing happening. The instrument light come one, you just turn the key and nothing happens.

Last year, the vehicle stopped in the middle of the highway, the shop diagnosis was that the fuel pump not supplying fuel. The shop installed a new Delco pump. Things seemed ok, even the turning the key and nothing happening issue seemed to improve until a couple of months ago and now again intermittent key issue and the difficult to start issue.

Over the course of the last few years, I have replaced the electrical portion of the ignition switch 3 times, 2 Delco and 1 Napa supplied part. While it seems like replacing the switch has seemed to improve the issue of turning the key and nothing happening, the problem hasn’t totally disappeared.

The starter has been replaced last year, based on a diagnosis of the repair shop of the starter drawing high amperage. When I took the starter to the local parts store, they weren’t able to duplicate the high amp draw but as I had the original starter out of the car, I went ahead and replaced the starter.

At this point, rather then throwing more money and parts into it I would like to get some systematic testing suggestions from those here on this board.

I won’t be able to really dig into it until this weekend but would like to answer any questions that anyone may have before then. Thanks in advance.

You have to good gas have the proper fuel pressure up to specs and good spark and injector pulse.
You need to check it for that.

[97 S Blazer]

Thanks for the response.

The vehicle has had this issue over several hundred gallons of gas, purchased from several name brand stations, as after starting it runs fine and starts easily after the difficult initial instance, I am thinking gas quality isn't a problem.

I will check the fuel pressure this weekend. What is confusing me is that it starts fine, after the morning ritual. If the pump pressure was not sufficient, wouldn't it be an issue all the time?

Thanks again

[MT-2500]

Originally Posted by 97 S Blazer

Thanks for the response.

The vehicle has had this issue over several hundred gallons of gas, purchased from several name brand stations, as after starting it runs fine and starts easily after the difficult initial instance, I am thinking gas quality isn't a problem.

I will check the fuel pressure this weekend. What is confusing me is that it starts fine, after the morning ritual. If the pump pressure was not sufficient, wouldn't it be an issue all the time?

Thanks again

NO. No. no.
Just the opposite.

On a cold start you full fuel pressure to squirt the injectors o a chev. 4.3 and 5.7 engine.
Like 60/66 lbs pressure.
Anything under 63 lbs. pressure will not squirt the injectors on cold cranking.
But lower pressure down around 50 lbs.will start and run all day when engine is warm.
Check the cold cranking start pressure and if it is under 62-63 lbs.
That is your problem.

[97 S Blazer]

Ok, so I hooked up the fuel pressure guage, turned the ignition on and I had a whopping 51 lbs of pressure. As mentioned, just last year (just 14 months) I had a new Delco pump installed. Could the problem be the fuel pressure regulator? Can I test that, or do I need to just buck up and have the stinking pump replaced again and hope that will fix it?

[maxwedge]

Pinch off the return line somewhere and recheck the pressure, should 65 or over, if not the reg could be leaking, or the pump is bad, filter clogged.

[97 S Blazer]

I am back from vacation and I need to now return my attention to the Blazer.

I did a pressure leak down test on it (key on to build pressure of approx 55lbs), key off, and it maintained pressure for over 10 minutes.

I also cranked the car while the pressure guage was installed. I don't know why (does it matter?) but the fuel pressure when cranking was in the mid 40 lbs for pressure. Is there any significance with this? Or is it just that the pump isn't working right?

If I have to replace the pump, I want to do it just once more.

Other then adding a new fuel filter, are there any other precautions that I need to address to ensure this pump lasts?

One more question, as noted in the original post, I have replaced the ignition switch several times due to when turning the key, nothing would happen. This particular issue disappeared when the pump was last replaced. When the car became hard to start in the last few months, the issue has returned again intermittently. Anyone have any ideas on how these issues could be linked?

[MT-2500]

Originally Posted by 97 S Blazer

I am back from vacation and I need to now return my attention to the Blazer.

I did a pressure leak down test on it (key on to build pressure of approx 55lbs), key off, and it maintained pressure for over 10 minutes.

I also cranked the car while the pressure guage was installed. I don't know why (does it matter?) but the fuel pressure when cranking was in the mid 40 lbs for pressure. Is there any significance with this? Or is it just that the pump isn't working right?

If I have to replace the pump, I want to do it just once more.

Other then adding a new fuel filter, are there any other precautions that I need to address to ensure this pump lasts?



One more question, as noted in the original post, I have replaced the ignition switch several times due to when turning the key, nothing would happen. This particular issue disappeared when the pump was last replaced. When the car became hard to start in the last few months, the issue has returned again intermittently. Anyone have any ideas on how these issues could be linked?

Check and or replace fuel filter and then.
As Maxwedge said pinch off return line and check pressure.
If not over 65 min. to 95 lbs replace pump with a Delphi/delco fuel pump.