2002 Chevy Blazer
4.3L V6 4WD

Alright, so my truck has been out of commission for 3 weeks now and tonight I poured 350 bucks into what I thought would fix it and no luck... so here's the story

Driving home from work a few weeks ago and my truck starts bogging, spikes in rpm's and then boggs again, like a vehicle does when it runs out of gas. when I got it home and tried to start it the thing would turn and turn and then literally cough back at me in the air intake...

after playing with it for a week I decide to go get a fuel injection pressure gauge. Hook it up and it goes to 60-66 psi. but as soon as the fuel pump shuts off I loose all pressure,literally it will drop back to zero in a split second. So I look in my fuel penlum and the top of my block is soaked in gas. I talk to a couple people and they both said I have an internal fuel leak, its either my fuel pressure regulator, or my injectors. Well long story short I decided to save myself sometime (in the off chance the cheaper fix didn't work) and bought all new fuel injectors, fuel meter, and FPR. Put all that stuff in tonight, reassemble my engine, and pressurize the system (pretty sure it's pressurized) but my truck is still doing the same thing, granted my battery has gotten worn out so I couldn't really try and try and try to get it to turn over, but it was doing the same thing (turning and coughing). Oh and before I tried turning the truck over, I hooked the pressure gauge back up. it was sort of doing the same thing where it would go to 60-65, but it hesitates for just a second or two before the pressure drops now. I did look in my air intake penlum and it was definitely dry, especially compared to what it looked like with the old fuel meter body and injectors... I did just replace the fuel filter a year ago too...

Let me know what you guys think, I can't keep putting money I don't have into this thing, I really thought the injectors were the trick, and though I'm not counting it out (since I haven't had the greatest chance to turn over my truck with the wore out battery) I just wanted to see if you guys have run into similar issues or can as least say "yay" or "nay" to what I'm doing!!

Thanks!

 

To start with if the top of your block was "soaked with gas" you didn't do anything that didn't need doing. You need to put a hot charge on the battery and check the leak down from the pump with it isolated to see if the check valve is shot. But you now it may just start up and run great with the hot battery.

 

A cut-off valve/tool placed in line with the fuel filter and pump will allow you to test the pump, and the FPR.

I had a leak at my fuel pump, in the hose that leads from the pump to the top of the pump assembly where it exits the tank. No way to find that without the cutoff tool.

 

Ok so here is what I've come up with looking at it today.

The charged battery didn't help. it continues to turn but will not fire. I did some research on testing the fuel injection and PCM, just in case that I have a bad PCM and was sending a bad signal that was telling an injector to stay open. What we ended up doing was disconnecting the fuel injector electrical connector and hooked up the fuel pressure gauge, cause in theory (my own scary thought) was if there was no signals being sent to the injectors they should all be shut and no leaking fuel... right?? well I charged the system and it did the same thing it was before jumped to 60 psi and then dropped off. so I'm to the point where I will bypass the fuel filter and check the pressure, but I have a feeling the tank will have to be dropped and the fuel pump changed out...

 

Repus,
I have a 1999 jimmy, it is a 4.3 and I have a similar problem. In order to get my engine to start I have to do this. I have to turn on the key listen for my pump to run and the insant it stops crank the engine, it will start fine. I checked the pressure at the test port on the rear of the engine just above the oil pressure sender. Pressure with the key just in the run position is 62 lbs, but as soon as it gets to 62 lbs it drops way down and will not start. When I do the crank thing as soon as the pump stops it starts and runs fine. Then like other people are posting here, it starts and runs fine and will restart fine all day. But next day it is same thing, all over again. No one can start my jimmy but me. So I have done some research, there must be a check valve inside the pump inside of the tank. Don't get me wrong, it could be a a bad fuel oressure regulator too. But since my jimmy runs so well with no ck engine light and no codes, it must be a problem inside the tank. It could be a small leak in the special hose used to go from the pump outlet to the connector inside the tank going to the external fuel outlet that your hose clips to. Or a pump problem or a check valve problem. So many different things have to working perfect or these 4.3 engines will not start. Your firing back through the intake makes me think you either have a cam sensor inside of the distributor, or a bad coil. I am replacing my fuel pump module and will post here the out come.
Jack C.

 

Get yourself (or make it) a test fixture, to figure out if it's the pump or the pressure regulator.
I had a hole in the gas line that leads from the pump to the top of the pump housing, giving a reading similar to what you list.
With this tool, you place a shut-off valve after the fuel filter. When the pump is energized fully, close the valve to check if the fuel regulator holds pressure. If pressure holds, regulator is good. Turn the key to on (not started), let pump energize, turn key off with valve open. If pressure drops, it's the internal pump assembly leaking.

Thanks to a write-up Captain Hook e-mailed me, I made a gauge to check the pump pressure.

The gauge was made with parts readily available from Napa and Ace Hardware.
Napa 730-5013 steel fuel line repair fitting, 3/8"
1 ft 3/8" hose, 2 clamps.
Ace - 3/8" ball valve
3/8" male to barb fitting (for the hose attachment)
3/8+ male/female adaptor (because the steel tube hit the ball of the valve)
Captain Hook's parts were somewhat different, but close to the valve (lower unit in the picture above). I clamped the open end of the hose onto the output of the fuel filter, and steel tube into the pipe to the injectors.
Once the fuel pump primed, I shut the valve as soon as the pump stopped.
Pressure gauge registered 52 psi steadily. As soon as the valve was opened, the gas went back thru the pump, and pressure went to 0 immediately.

About $20-30 to make the shut off valve. Cheap Insurance before buying an injector assemby (~$450) or a new pump assembly($300+)

 

Alright, I'm at my wits end...

I replaced my fuel injectors, fixed leaking gas into my intake manifold.

I replaced my fuel pump, fixed my fuel pressure leak, and now I'm maintaining constant fuel pressure!

BUT!

When I turn my truck over it sounds like it used to when it was working. However it still jerks to a stop in the process of turning it over and it wont fire... we're thinking maybe my starter relay or selenoid is shot... thoughts??

 

OK, don't end your wit's just yet. Sounds to me like timing or bad spark. You said the trucks been sitting. Start by taking off cap and rotor and cleaning them with some abrasive. There's a port in the distributor that let's condensation dry. If it's a bit obstructed, corrosion. When your in there check for play in the distributor shaft. If there is don't lose it. The entire unit is surprisingly cheap. Starter I don't think the issue.

Oh yea ps your plugs might be soaked.

 

Just another little tip if the engine had an extreme amount of gas in it, change your oil and check or replace your spark plugs ( only use AC Deco plugs), if they got fouled out with gas, your not going to get proper spark detonation..and yes having a charged battery is a must for these trucks..I`m working on the same timeline for my balzer not working, I put in a Brand new AC Delco fuel pump and spider injector assy and the truck ran for 30 minutes and bam the new fuel pump died,,,,,,, waiting on a warrantied new pump..

 

Sounds like you have done a lot to your vehicle. Next thing to replace is the cam sensor. It's inside the dist. the wiring harness plugs into it. Just remove cap and rotor then with the same star screw driver remove the two screws and replace it. Autozone has them, and while you are down there take you ignition module,let them test it. I had a similar problem with a 5.7 engine and it was the coil. When I tried to start it, it seemed like it was out of time. It would back fire and try to start just wouldn't. I swore it was a timing chain until I checked the position of the rotor with number one plug out and up on top dead center. I had just put a new coil on it a few months before. I picked up a used coil from a 4.3 (same coil ) and plugged it in ran a ground wire to it and it started fine. I hope my experences with my 4.3 will give you some help. Let me know what you find out.
Jack C.