96 Chevy Blazer 4.3 Vortec, 4x4 4 door. towed to shop with a broken fuel line (Out Line - going to motor from fuel pump) replaced fuel line with dealer line which was exact fit. Still wouldnt start after replacing line.

Figured maybe in-line fuel filter was clogged so replaced it with new one. Still wouldnt start.......

Checked Fuel Pressure only had 34 lbs. I know blazers need 60-66 lbs so I replaced the fuel pump. Went to start up and started right away ran for about 10 seconds and bogged out.

Tested Fuel pressure again and have 63 lbs so I know fuel pump is working properly..... But does not run for more than 3 seconds now even after cycling fuel pump a few times or spraying starting fluid in throttle body.

We have spark obviously otherwise it wouldnt start at all. Checked Codes and nothing came up (new Genesis 4.0 system) Previous saved codes for this vehicle were for the Mass Air Flow Sensor malfunction.

Tried replacing Mass Air Flow Sensor with new one for giggles knowing it was probably not that and after doing so made no difference. Returned Mass Air Flow Sensor and put former one back on.

Next step blew out the lines with compressed air and felt air at other end and nothing came out. So I know the lines are not clogged. (From in line filter toward pump, while pump was unhooked)

Today I tore off the top of the motor, cleaned out the Throttle Body, the idle air control valve, (cleaned off) the fuel injectors, the Fuel pressure regulator and everything that encases it. I will be putting this back together tomorrow morning when I arrive back at the shop, hopefully this works.

My problem lies in the fact the person who had it towed said it was running "great" before the line blew off the fuel pump and starting pissing fuel out everywhere and wouldnt start after that. So I'm kinda stumped now where to go if this does not work.

Does anyone have any suggestions about what else I could check? Mind you this, I have owned 5 blazers (83, 88, 89, 94, 02) and absolutely love them, I have worked on blazers before my own and others and never had a problem like this. I'm just kinda stumped at this point. So any suggestions would be greatly appreciated.

Thanks,
Lrain.

 

any ideas anyone?

 

#1 Don't use starting fluid, you'll end up with bigger problems, Use carb cleaner or gasoline only.

Fuel pressure at 63psi if fine. If you have spark at the coil, the crankshaft position sensor and primary ignition are fine. Next step is check for a good hot, blue, (not orange) spark at each spark plug. It's common on the 4.3L for condensation to accumulate on the underside of the distributor cap causing crossfire and no start situations. Check the vent holes in the distributor base, make sure they're not restricted with debris. These engines are fussy when it comes to secondary ignition parts, (distributor cap, rotor, wires and spark plugs), make sure you use AC Delco only. Post your results.

 

^^ Captain Hook always has some good info.

Something else to consider is maybe a faulty FPR on the spider injection. Although I'm not sure how one would test that (Maybe the DIY section will have some info on that though)

 

Fuel pressure regulating at 63psi tells us the regulator is doing its job, (provided it doesn't leak). The regulator is a simple design and rarely fails on the CSFI system. There are far more regulators replaced due to misdiagnosis than actually go bad.

 

Have you checked the relays

 

Verify the fuel pressure when the truck is running bad or not running at all. The pump will make pressure at sometimes and fail to make it others. If the pump is failing due to worn brushes it just cant do its job as well all the time.

 

ok so after cleaning out throttle body, idle air control valve, throttle position senson, taking off top plasic part of motor to get to spider and regulator I realized fuel was just sitting in the cylinders (once I took out spark plugs it just poured out of the holes).

I gave them time to dry cleaned off ends of plugs and for giggles wanted to see how the injectors were working so I unhooked the coil and with plugs out I had turned it over to see if we had a trickle or a stream of gas out of the spark plug holes where the injectors shoot out and 4 of the injectors were just shooting the gas out not a slow trickle. Well now knowing that I am under the impression it's the injectors that are bad and flooding the spark plugs on start.

Whats bothering me is that when the car came in the lady claimed it was running great before the fuel line off the pump blew apart so we replaced the line that was broken still no start, next tried the filter thinking it was clogged, still no start, replaced fuel pump when it showed 33 lbs now have 60/63 lbs, still no start, decided to clean out throttle body while it was off and all it's sensors, still no start, found out it was bad injectors (hoping) and we can go from there. Do these usually all go at once lol? I mean hell this is turning into a nightmare We arent even charging the lady for list price just our price on the parts because it's going to cost so much and only about 2 hours labor to help the poor girl out but really......

 

No way to prove it but the bad fuel line would have created rust particles that stayed in the lines, found their way to the injectors and clogged them.

The debris might have circulated the fuel system and affected all of the components.

I had a similar issue on a 2000 that once the lines were repaired no other problems were found. Probably just a coincidence that they all failed about the same time.