Will not start

CLARKBRIAN

MEMBER
1995 CHEVROLET S-10
4.3L
V6
4WD
AUTOMATIC
201,325 MILES

Will not start without priming with starting fluid. I have replaced the fuel pump, filter, hard lines from tank to engine, distributor cap, button, distributor, ignition coil, air flow sensor, plugs, and wires. You can smell the fuel after you crank it a couple times. I have tested my fuel pressure and made sure I was getting spark through the wires at the plugs, I was. Once you spray the fluid in the intake it starts right up and runs pretty well. Doesn't have a miss or any hesitation in it while running just cant get it to start with out the primer. I have also redone the intake gasket and all that. I have the spider injection in it and I just cant figure out what it is. I have been told my injectors and distributor but the distributor is new and again when it is running it has a lot of power and runs and even idles smooth. Do you have any suggestions on what I can do or try to figure out what this problem is?

5 Replies

HARRY P

MECHANIC
2,292 POSTS

Out of curiosity, what is the fuel pressure reading with the key on, and engine off? These trucks need a minimum of 60psi to start. 58psi will not do it. 59 might do it, but probably not. They're very finicky about fuel quality and pressure. Also, have you changed the fuel pressure regulator yet? A bad regulator can cause all sorts of weirdness. Here's our set of tests for the pump and regulator: https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator?

Also, is the service engine light on? A trouble code there could easily be the problem. Let me know.

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Friday, December 28th, 2018 AT 9:01 PM

CLARKBRIAN

MEMBER
3 POSTS

No sir no engine codes. I do have a scan tool because I thought the light wasn't working. Only code it pulls is 02 sensor now. When I tested the fuel pressure with the key just turned to on not started was 62 psi. Running pressure is a little high but not much at 67 psi. I did also buy a regulator and out on. Some one else told me since I have the split intake on there, in the middle there a black box thing that controls the fuel and air mixture with the three fuel lines running off each side. They told me to replace that but I don't know what it is called or where to get one but it don't make since because when it is running it has all the power it should and like I said it runs excellent. Just getting it started. Thank you for helping with that idea, I have tried that.

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Saturday, December 29th, 2018 AT 3:38 PM

HARRY P

MECHANIC
2,292 POSTS

Ugh, those spider injector setups are a bit of a pain. And they're a common problem in the mid-90's S series trucks. Diagnostics can be tricky on them, but here's a how-to guide on YouTube: https://www.youtube.com/watch?v=AAfr9KupSVM

And here's a write-up that I like much more than the video: https://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/testing-the-spider-fuel-injector-1

Definitely check the spider. Also, are you sure about those fuel pressure readings? Because the idling fuel pressure should be 5 or 6 psi less than with the key on, engine off, and not 5psi more, like you stated above. If it's going up while idling, you've got some sort of funky thing going on in the fuel system, probably the regulator (which you already replaced). So that's a little befuddling to me.

Finally, there are two different 4.3L engines in 1995. I think the differences are in the injection mainly. Would you mind posting your VIN number here so I can look up which one you have and possibly be able to guide you more accurately.

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Saturday, December 29th, 2018 AT 8:42 PM

CLARKBRIAN

MEMBER
3 POSTS

Yea, I will have to actually give you the motor information. This truck is four put into one and the motor came out of a Blazer. And yea I am sure of those readings. I thought the readings was wrong also and kinda thought that may had something to do with the issue. Could the regulator even though replaced be bad? I know I have ran into that issue with some other parts on it. All I really know for sure about that 4.3 in mine is its the spider injection Vortec. Ill have to ask the guy I got the truck from what exact year the motor is. I think he said it was a 1995 also but I am not 100%. This truck has been confusing since I got it about a year and a half ago. Simple things aren't even simple with this truck. When I get back out to it ill send you the info. I am going to try switching out the regulator again in a week or so. Currently fixing my Ranger. Also thanks for the videos. I saved them so I can re watch and try and keep troubleshooting this engine. Everything I have come across on the internet says the 1990's era Vortec is a 50/50 shot at getting a good one.

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Sunday, December 30th, 2018 AT 12:39 PM

HARRY P

MECHANIC
2,292 POSTS

You might also try getting another fuel pressure gauge to put on it, since it's reading so high while idling. There may be some sort of issue going on there. For some reason I'm thinking that has to be related to your issue, and if we can hammer it out, we'll have it starting and running like it should.

I also wanted to ask if you've replaced the fuel filter since putting in the new pump. Generally, it's strongly suggested that you do it at the same time as the pump, because sometimes a failing pump can kick up some junk and clog up the filter.

As for the Vortec itself, the core of the engine is about as rock solid as they get. But those early spider injectors are somewhat problematic and so are the fuel pumps. My 2002 Blazer is all stock, with 207,000 miles on it. And I use it to run rural mail routes four to six days per week. I beat the ever loving crud out of it, and it just keeps going. The engine (essentially the same as yours, with some updates) sounds like it has about 50,000 on it, and the transmission still shifts about that smoothly too, And trust me, I do not baby it. Stop and go up to 650 times in a day. I have been through a few fuel pumps though :D. I'm on pump number four right now. Thank goodness for lifetime warranties.