I have a 2001, 4.3L, 138,000 miles, running pretty solid until this morning. Last night was wicked cold, single digits, sub-zero wind chills. Went to start it today, nothing. Fuel Pressure at 50 psi with key on, engine off, drops to 48 after 10 mins; however in checking forum and doing test as Captain Hook indicated, 12v jumper to the fuel primer slot next to the relay, gauge jumped to 60 psi, fell to 54 as soon as the jumper was removed then fell off into the 40's after 10-15 mins. Is there something in the ignition that would explain the difference in reading going from 'key on' test to the '12v jumper to the primer port' test?

Related repairs over the years, fuel pump replaced twice, first replacement was aftermarket, learned my lesson, has a Delphi unit in it now, and it's about 2 years old....spider assembly, including fuel regulator, fuel filter, replaced last summer to tackle reoccuring misfire in cyclinder 4.

I'm thinking I'll have to drop the tank given the numbers but just wanted to throw out the discrepency in numbers between the 2 tests methods that I did to ensure there isn't something I'm overlooking or not checking for. Or something weather related since that's the only significant factor between running smooth to not running at all ??

Thanks again for this forum and any input anyone can throw my way.

 

I have a similar issue. Started fine one morning, went to the store, went to leave and it started then it died as I was reversing and no longer started. Had it towed home and checked the pressure with a gauge and got about 45-48psi with key on engine off and had to use starter fluid to get it started and the pedal floored and it got to about 55psi. It ran for about 20 minutes and then died while in park and didn't start again. There is fuel getting to the valve on the engine and no leaks that I can visibly see. Have you found any solutions? I see you changed a lot and I haven't done anything bug yet and was hoping for a guide to the more important issues.

 

Sounds like the fuel pump. Can you do a test on the fuel line after the fuel filter? Check my post in "engine and trans" topic called P1133 Code, you can see and read what I did.


https://blazerforum.com/forum/engine...33-code-83799/


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I had to narrow down my issue, doing this I ruled out the fuel pump. Im yet to change the regulator....to cold out.

 

I am not sure how to test it since the line after the filter is nylon tubing. I was able to get it started for a few minutes then it died again. Could a clogged fuel pressure regulator cause this type of problem? I gave it a couple of taps and that is when it started for the small amount of time. Just some background on it- its a 2002 Xtreme with just over 101000 miles. Replaced parts in October including catalytic converter, 2 O2 sensors, plugs, wires, cap, rotor, fuel filter, and air filter. I have been running it minus the left side upstream o2 because the plug for that hole was stripped and I couldn't get it drilled and tapped since then. Could be part of the problem? Only codes that were showing was the one for the missing O2 and for misfires. Haven't been able to recheck it because the battery drained while trying to start it and reset the computer.

 

Sorry for delay in replying. I dropped the tank and replaced the pump, which took care of the problem. Noted when I took the old pump out though that the filter screen at the bottom of the pump was pretty dirty; tank was clean though. Guess I got bad fuel at one point or over time, may need to look at additives for the fuel or better grade fuel. Replaced the fuel filter again too. Running good since.

 

Glad you got it fixed for know. If you get ambitious in the spring drop the tank and give it a good cleaning. Lot's of youtubes on the subjected.


For now I would, sorry, change the filter again and like three pint's of dry gas. Its just straight ethanol and will help burn any water that got in the tank. Run it till its low then a fresh full tank.