Have gas and spark but won't start

[fam_mechanic]

96 4.3w died started and died again. sprayed just abit of starting fluid in it and it started again.ran good 35 miles down the road it died,and now it won't start at all. I have good spark to the plug and also good fuel pressure. the whole injector unit think was just replaced. any ideas ?Fuel pressure regulator? goin out now to pull the plugs and see if they are covered in gas.

[jkdon]

I had some of those symptoms with my 97, ended up being the ignition control module. Little fins on the thing were full of crap and the thing would heat up and die. once it cooled down I had spark again.

hope it helps
Jkdon

[blazee]

Have you checked for spark at more than 1 plug?
Will it start with starting fluid?
What's the fuel pressure? I know that you said it was good, but most people assume that any fuel pressure is good. They don't realize that it takes at least 60psi of fuel pressure to reliably start these engines.

Do you have any kind of security system on it?

When was the last time that you did a tune-up?
How long ago was the injector assembly replaced? Did the problems start right after the work was done?

We need more info......

[fam_mechanic]

Originally Posted by fam_mechanic

96 4.3w died started and died again. sprayed just abit of starting fluid in it and it started again.ran good 35 miles down the road it died,and now it won't start at all. I have good spark to the plug and also good fuel pressure. the whole injector unit think was just replaced. any ideas ?Fuel pressure regulator? goin out now to pull the plugs and see if they are covered in gas.

Yes spark out of #1,#3,and #2 wires. although the fuel pump sounds louder than normal my gauge says right at 60psi. i sprayed starting fluid in it and it tried to start i beleive ,but kinda backfired some what,didnt know if this was from to much s/fluid or what.I have fuel up to the test nozzle but it wont start..As long as some one truns the key while i spray the s/fluid in the throtle body it seems to want to run.but than knocks from the starting fluid im sure.

[irq_23]

I am having the exact same problem, I have spark and fuel to the test port and I am stumped.

[marly87]

Originally Posted by jkdon

I had some of those symptoms with my 97, ended up being the ignition control module. Little fins on the thing were full of crap and the thing would heat up and die. once it cooled down I had spark again.

hope it helps
Jkdon

Yep! jkdon is probably right. Same thing happened to me.

[jkdon]

I'm not sure how you test that module guys, but I'm really thinking that is your problem. that thing stumped me for a couple of days. find someone with that motor and swap that module. right next to the coil. I screwed around with fuel pressure pulling plugs the whole nine yards, swaped the module and runs like a dream.

Jkdon

[fam_mechanic]

Originally Posted by jkdon

I'm not sure how you test that module guys, but I'm really thinking that is your problem. that thing stumped me for a couple of days. find someone with that motor and swap that module. right next to the coil. I screwed around with fuel pressure pulling plugs the whole nine yards, swaped the module and runs like a dream.

Jkdon

I was just wondering why the strting fluid would start the truck with the module out?If it wouldnt start with(liquid fire) I'd say the module also,but this has me stumped.The engine will fire everytime i spray the starting fluid,Is the the ether strong enough to fire the engine under the weakest of spark?also is the module under the cap like older chevy,or outside the cap? we have to of the same truck i will swap parts if needed,but as you know the distibutor cap can be a afemale dog to get to.

[jkdon]

I have a 97 Ls 4.3 with a leaking intake and alot of miles but the module thing started with me having the same starting symptons, but the only difference was when the thing was warm. always started cold. the module is located passenger side towards fire wall right next to the coil. Has like 3 or 4 fins on it and an electrical connector. pretty easy to swap out.

hope it works for you,

Jkdon

[fam_mechanic]

Originally Posted by jkdon

I have a 97 Ls 4.3 with a leaking intake and alot of miles but the module thing started with me having the same starting symptons, but the only difference was when the thing was warm. always started cold. the module is located passenger side towards fire wall right next to the coil. Has like 3 or 4 fins on it and an electrical connector. pretty easy to swap out.

hope it works for you,

Jkdon

Thanks again i will swap out just to make sure before i pull the tank.

[Neonbee]

Had the same problem with my 96 Blazer. Turned out to be the fuel pump. (I was getting gas.. but just not enough to get her fired). The mechanic told me the Vortec's need between 55 - 65 lbs pressue and mine was at 47. Swapped fuel pump and it fired right up.
Good Luck!

[kpmink]

2001 Blazer 4.3l
There are times when the vehicle doesn't want to start.
Other times starts just fine.
Now within the last few weeks when idling the vehivle cuts out.
It will start again when I try. Fuel pump????
I don't have a fuel pressure guage so i dont know what the pressure is.
just today cut out three times. My old lady drives this and being winter and all I don't want her to get stranded somewhere. Fuel pump is about $280....How about used with low miles....vehicle has 153,000+ miles....
I bought it with 59k...
Any ideas.....

[fam_mechanic]

Originally Posted by kpmink

2001 Blazer 4.3l
There are times when the vehicle doesn't want to start.
Other times starts just fine.
Now within the last few weeks when idling the vehivle cuts out.
It will start again when I try. Fuel pump????
I don't have a fuel pressure guage so i dont know what the pressure is.
just today cut out three times. My old lady drives this and being winter and all I don't want her to get stranded somewhere. Fuel pump is about $280....How about used with low miles....vehicle has 153,000+ miles....
I bought it with 59k...
Any ideas.....

Its really not that hard of a job to do.local autozone has one for 79 bucks.,also they will give you a tester for a small fee in wich they will return when you bring back the tester.Once mine did that and the number 4 plug was gumed up do to my oil returns being clogged.the truck always started just sometimes hard and hesitated at idle.

[Rmbodie]

Starting fluid only needs compression . NO spark needed . It will start diesels with bad glow plugs too . Most atuo parts chains can check the ignition module when out of the distributor . But its a cold test , I have had the same problem . Mine failed when it got hot . Replacing the module cured it . Its only about $18.00 . Rob

[Southern Comfort]

Originally Posted by Rmbodie

Starting fluid only needs compression . NO spark needed . It will start diesels with bad glow plugs too . Most atuo parts chains can check the ignition module when out of the distributor . But its a cold test , I have had the same problem . Mine failed when it got hot . Replacing the module cured it . Its only about $18.00 . Rob

Most failure to electronics is due to heat. Those fins that one of you where talking about are heat sinks, designed to draw the heat from the electronic components to that heat sink, where air can help cool it off. That's why it will start when it's cold and not when it's hot. It's called a thermal break down. Most electronic supply stores sell freeze stray to help you detect thermal intermittent problems. I thought I would add this as maybe a possible troubleshooting techique for those problems related to heat.
Southern.