1997 S-!0 Blazer Starting Issue

[fish2222]

Hey guys... I am having a weird problem with my 97 S-10 Blazer with the 4.3 in it. It will not start on mornings that are under about 45 degrees. When you turn the key on, the fuel pump runs. It will get 60 PSI of pressure. When you try to start it, it cranks and cranks and cranks, but does not fire. Whats weird though is that sometimes, if you tap the throttle pedal, or sometimes if you hold the pedal to the floor, it will spit and sputter. After you crank it for 2-3 minutes, it will finally start even if you dont touch the throttle. If the temp outside is above about 45 degrees, the thing will usually start right up every time. My 96 S-10 pickup with the 4.3 in it had this same issue even up until I sold it. I never could figure out what the problem was with it. In the Blazer, I have replaced the fuel pump, and the fuel filter, and it doesnt seem to have helped it at all. Once it starts, it runs and drives great though. When I checked the fuel pressure, it would go up to 60 PSI when I would turn the key on. When running, it runs about 55 PSI at idle. When I shut it off, it would drop to 50 almost instantly, and within 5-6 minutes, it would drop to 40 PSI. I have a new regulator here to try, but it seems to be doing its job right. Do I need a new spider? I have heard there is a new design out there to fix issues like this, but I cant find anyone that has tried it yet to see what it would do. Help!!!

[fish2222]

Well, this morning I finally had a chance to hook up the fuel pressure gauge before I attepted to start it, and it was about 35 degrees last night. First turn of the key, 20 PSI. Second turn, 25 PSI. After about the 10th time, it finally made it up to 55 PSI and started. Up until that point, it would not fire at all. Does this sound like a regulator issue? It did the same thing when it was cold last year with the old fuel pump too.

[BlazerLT]

Sounds like a weak battery, a regulator or a weak pump.

It is also a 1997 so an ignition switch problem can't be ruled out either.

[fish2222]

Well, I put a new regulator in it last night, primed the system, and it started fine. This morning, I came out and tried to start it, and I had to try it 3 times before it started. I dont think its the ignition switch problem, as the fuel pressure seems to climb until it starts. I dont know if i should try another pump or not now.

[MT-2500]

Originally Posted by fish2222

Well, I put a new regulator in it last night, primed the system, and it started fine. This morning, I came out and tried to start it, and I had to try it 3 times before it started. I dont think its the ignition switch problem, as the fuel pressure seems to climb until it starts. I dont know if i should try another pump or not now.

For a cold start the injectors need 63-64 lbs of fuel pressure to fire.
2-3 lbs low and they will not squirt fuel.
Check the direct/full fuel pump pressure you should have 85-95 lbs full pressure with a good fuel pump.
If it is getting full voltage and good ground and good fuel filter.

Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

[BlazerLT]

Originally Posted by fish2222

Well, I put a new regulator in it last night, primed the system, and it started fine. This morning, I came out and tried to start it, and I had to try it 3 times before it started. I dont think its the ignition switch problem, as the fuel pressure seems to climb until it starts. I dont know if i should try another pump or not now.

Dephi or Carter pump or it is the stock unit?

[fish2222]

Its a delphi. I replaced the pump only, and not the entire fuel bucket.

[someguy000001]

Aw nuts I have the same problem with my '97. Took me a week and a half with the 1/2 hour of daylight I have after work to replace the fuel pump and filter. It drove like a champ the day I finished fixing it, but in the morning it cranks and cranks. Did you ever figure out a solution Fish? *crosses fingers*

I haven't checked the fuel pressure since I replaced the pump, but I intend to soon. It was wet and rainy when I tried to start it this morning, so I'm going to give the ignition system a looksie in the next couple of days. I haven't changed the rotor or plug wires since I've owned it, so maybe?!?

[someguy000001]

Ok got mine sorted out.

New fuel pump and filter, 55 psi key on, pouring gas down the throttle body did nothing.
Coil continuity fine, then I found this:



Looks like my rotor burned through the distributer cap shorting to the mounting screw. I'm trying not to beat myself up too much for replacing the pump unnecessarily. It's the original pump, and good Lord would it have sucked if it went a month from now during the winter.

Why did it drive fine the day I replaced the pump? Strange.

[MT-2500]

Originally Posted by someguy000001

Ok got mine sorted out.

New fuel pump and filter, 55 psi key on, pouring gas down the throttle body did nothing.
Coil continuity fine, then I found this:



Looks like my rotor burned through the distributer cap shorting to the mounting screw. I'm trying not to beat myself up too much for replacing the pump unnecessarily. It's the original pump, and good Lord would it have sucked if it went a month from now during the winter.

Why did it drive fine the day I replaced the pump? Strange.

From the picture you need to reset he dist camshaft retart.
It is way off.
Rotor is not ceentered to fire at the plug wire terminal.
Replace with a AC delco cap and rotor and get it set before it burns up another cap and rotor.

[BlazerLT]

I don't know if that is needed, it is just arching to a close metal object.

The one thing I am concerned with is if the person used a delphi pump as the replacement.

[MT-2500]

Originally Posted by BlazerLT

I don't know if that is needed, it is just arching to a close metal object.

The one thing I am concerned with is if the person used a delphi pump as the replacement.

BlazerLT
Is the dist needing set what you do not know if needed?
A complete picture of the bottom of the cap would show it a little better but it looks like the camshaft retard setting is way off and that may be what burnt a hole in the cap.
If rotor does not fire at the center of plug wire terminal it will fire some place way off from it and cause spark to jump way to far or burn up cap and rotor.

[BlazerLT]

True, or the cap could have been cracked and exposed the screw as a conductor.

Seen it happen on a couple of occasions.

How can the timing jump that much without removing and improperly installing the distributor?

[someguy000001]

Here's a better pic of the whole underside of the cap:



I knew something was up the second I popped off the cap. Strong smell of burned plastic. I thought the rotor might have been rubbing or something but it's unmarked.

My Haynes tells me that the retard is set by the pcm, but I'll give the distributer a twist tomorrow to see if it's not tightened down or something.

The new pump is a Deplhi. I got it from here:

http://store.getgmparts.com/fg0071.html

Best price I could find. I was a little worried when I didn't get any order confirmation email and I couldn't find any reviews of the site, but it showed up a couple days later. It says Delphi on the box.

Thanks guys!

[MT-2500]

Originally Posted by someguy000001

Here's a better pic of the whole underside of the cap:



I knew something was up the second I popped off the cap. Strong smell of burned plastic. I thought the rotor might have been rubbing or something but it's unmarked.

My Haynes tells me that the retard is set by the pcm, but I'll give the distributer a twist tomorrow to see if it's not tightened down or something.

The new pump is a Deplhi. I got it from here:

http://store.getgmparts.com/fg0071.html

Best price I could find. I was a little worried when I didn't get any order confirmation email and I couldn't find any reviews of the site, but it showed up a couple days later. It says Delphi on the box.

Thanks guys!

Are the terminals on cap burnt on one side or straight over to rotor?
It is strange where the hole is burnt so far from the cap terminal.
When you get it back together have the camshaft retard setting checked on a scanner. If it is over 2 degrees - or + you will need to adjust the dist.
Also check wires and plugs if spark can not go threw the wire to plug it will find someplace else to go like threw the dist cap.
Good luck