Hi all,
I have a 2001 SFI v6 Blazer "W" engine. After sitting for 4 days, it will crank but not start. The throttle body is dry after cranking. Checked the pressure at the rail and have 62 psi. Pressure bleeds down to 58 in 10 minutes, 52 @ 1/2 hour, and 49 @ 1 hour. Seems ok pressure wise. Would a bad FPR not send any gas to the injectors? Poured gas in the throttle body and still no start. Someone asked another person in a similar thread if the tach moved when cranking...NO, my tach doesn't move. I don't know what this implies. I have always worked on my own vehicles...engine, suspension, fuel pump, etc. so I have no problem tackling this job, just need an idea of which direction to go.

Thanks,
Mark

 

I have a 99 blazer 4.3 LT. I've been struggling with a similar no start for over a week. I've got spark. The plugs are damp and smell like gas. Exhaust smells like gas after cranking. Fuel pressure is 61 (replaced the fuel pump last august for the 2nd time. put a Delphi pump in that time). Didn't check the pressure loss with time. The weird thing is that as I release the key from cranking the engine will fire. It's like the thing is flooded in my case which sounds different than yours. Don't mean to hijack the thread - just seems similar. I'm suspicious that the regulator isn't regulating pressure and I'm getting too much gas. Don't know how to check it and not keen on tearing into the plenum if I don't have to.

 

Tipshoe,
I have read hundreds of posts and yours sounds like a bad FPR. The fuel pressure regulator seal fails and leaks fuel into the intake manifold. The fuel runs down into one or more cylinders causing a rich mixture and flooding. Does your engine ever start? Just because it cranks does not mean it has spark. If your FPR is good (no leakdown) and your plugs are saturated, you may have a bad ignition control module. You can use a spark tester or remove the module and take it to autozone for testing. If you are going to test the module, then I would recommend testing the ignition coil too. They both are a lot easier to remove than the fuel pressure regulator.

 

OK - haven't checked back because I've been working on this frickin' thing. Replaced the distributor cap & rotor. They were only 8 months old, 7k miles but corroded like mad. Vehicle would start then but won't stay running. Runs 1-3 seconds and dies. So now I'm thinking fuel. It will run as long as I keep starter fluid in it. Hooked up fuel pressure gauge and spiked to 61 and then would bleed off. I'd had intermittent hesitation under acceleration prior to the no start issue so I assumed fuel pump. Still under warranty so I replaced it. Fuel pressure a little higher (63) but still bleeds and so now I figured it was FPR. Replaced it. Fuel pressure doesn't bleed as fast, but still drops with time. Meanwhile, same vehicle behavior. Starts, runs 1-3 seconds and dies. Can keep it running longer with starter fluid. When it runs it sounds good - it's not missing. I don't understand. It seems like a fuel delivery issue and the only thing left is injectors and I don't see how all 6 could be good enough to start but then cut out. I've checked the ignition coil resistances and they are in spec. The ignition coil and the ignition control are all in the same unit. I'm not sure of anyone around that can test it, but I'll track it down. It doesn't seem like spark to me since it WILL start now, but I'm running out of ideas.

 

I believe there is a fuel cutoff relay on your vehicle. You might want to see if it is cutting off fuel after start.

 

thanks about the fuel cutoff - that's where I'm heading next. Talked to a guy at the parts store - seemed to know what he is talking about. Guessing it is either:1)camshaft sensor 2)crankshaft sensor 3)oil pressure sensor. The computer assumes everything is cool and the vehicle starts. Once it doesn't get the info it needs it shuts down the fuel. I've got a friend who has access to a diagnostic scan tool - hopefully we can get into the sensors and see what is going on.

I had the ignition control module checked and it showed as OK. Not a real surprise there since it does start and will run on starting fluid.

The fuel pressure does drop faster than it should. I don't believe that is why the vehicle stops running though.

I'll post back once I get it going.

 

OK, most of my crap has been self inflicted. When this issue started I checked the coil per instructions in my Chilton's manual. I did not have battery voltage so I changed out the PCM (pre-flashed by NAPA). No change in vehicle performance at the time - still a no-start. Had a buddy help me and we figured out that I was checking the voltage incorrectly, so I had replaced the PCM for no reason (except stupidity). I was getting spark but replaced the dist cap & rotor per earlier post. Now it would start but not stay running.

Hooked a scan tool to it last night and got P1631 security password incorrect code. Turns out that a procedure needs to be performed in order for the BCM & PCM to like each other. If they don't match, the PCM cuts off fuel after 2 seconds and the engine dies. I tried a procedure that didn't work and then was successful with the one at the end of this link:
Exploring options for P1631 - Chevy and GMC Duramax Diesel Forum
Anyway, after this the truck fired right up and ran. So - this was originally a distributor cap and rotor issue that I turned into a big mess. I just couldn't believe the rotor and cap were bad after only 8 months. I have officially purchased my last Duralast branded part.

Pipefitter - it appears that my issue had nothing to do with what is going on with you. Sorry for not being any help. Thanks for the input.