Intermittent long crank time: Chevy truck V6 S10 Blazer

This little Chevy truck runs great, but has issues starting.

We quickly narrow down the problem as a fuel delivery issue.
But the tough part is how to isolate the fuel system components to determine which one is at fault? There are no rubber lines on this system so the "quick and dirty" pinch test will not cut it here. We have to get creative.

Another relevant video from ScannerDanner:

Actron CP9680 handheld scanner:

Enjoy!
Ivan

[HomieHektor]

I like how you overkill your diagnostics for the sake of education, you leave no stones unturned ...Thanks Ivan 🤝

[charlesgildea]

Best video and description i have viewed to date on any automotive repair on You tube. Comparing it to hundreds at least. Than you

[joemikos]

Very impressive Ivan, way to think outside the box. I met you at last year's ETCG's meet and greet. Absolutely love these videos and will say one of my favorites was with SMA "Twisted Cam"! Spent 25 years in the field with 20 off bc of cancer but recently making a comeback. I volunteer at my church...we have a shop with 5 lifts. it's pretty amazing, we gave away 25 cars last year and fixed hundreds for ppl with no money. Look forward to more vids. Thank you

[mathiasjohani]

Ivan, Eric-o, Paul Danner, you have taught me so much...Love you all.

[stephendenn]

you're a genius. I love your style. Always thorough. Even when you've found the problem you continue your diagnosis to make certain there are no other problems.

[chungaleta]

OHHH More S10 vids. Best truck ever LOL.
I guessed this one right away since it happened to me and it was the check valve. (2.2L doesn't have the spider system though) I never thought I'd be giving you a piece of advise, , , but, If the pump is good, they sell an external check valve that can be installed in the return line without the need to do a major job. I learned that the hard way. Also, if the customer decides on a new pump, go dealer. I put one of those $50 Ebay pumps and it lasted 2 months and had to pay for the full job again.

[dantehennessy]

Thank you for actually getting into the science instead of just saying what to look for.

[wmichaels]

Clever work around to dealer special tool that is a shut-off valve installed in-line at filter, IIRC.

Thanks for a good video!

[agmcme]

I had a 1995 GMC Jimmy and the fuel pressure regulator went bad. It was not sequencial FI it just had what looked like a TBI with the spider attached to the nozzle. Mine was the aluminum clam shell intake. Like you said back then the dealers wanted a grand in labor and wanted to replace injector. I found a regulator kit and just replaced regulator for about 100. Leakig fuel had washed the one side of the intake clean. Great job finding the fuel pump leak.

[josedejesus]

Nice, very nice diagnostic way! You do not leave any stone unturned! Thank you!

[robertcharles]

Good job bro, love the detail given to pursue issue. Most people have no idea how much time and expertise is involved in diagnostics. After you spend all that time they look at you and say, "I'll fix it myself or take it down the street to El Chapos". When you hand them the diagnostic bill they say, " You didn't fix anything!"

[Starcrunch]

Thanks! Timing is perfect as I am diagnosing 3 of 4 Astro vans with similar starting issues. Was cap and rotor on one van, I can hear the spark jumping outside the plug boot on another, and I'm chasing crank sensor wiring chafing on the third. Thanks for another avenue for testing.

[johnbaker]

Love the way you "think" things through, before swapping parts.

[bobsoft]

Whenever you have bleed off on these vehicles, you connect into the fuel filter outlet to check if its the FPR or the pump check valve. GM Specs are pressure must be 73 psi to 108 psi at the pump. Deactivate the fuel pump. Pressure must remain above 55psi for at least 10 minutes. If this leak down test fails, there is a leak inside the fuel tank. If leak down is within specs on this test, and leak down at the service port is excessive, there is a leak in the plenum.
Sorry if it was mentioned in the video. I didn't watch it all. I owned one of these vehicles for over 10 years and got to learn all its quirks.

[davebrewster]

I've got the same exact problem with my '03 5.3L. I've now got something to take to my really good 'backyard mechanic'. Thanks.

[richardcranium]

call mme a packrat but here's a tip---- when you change fuel filters take 2 minites with a hack saw or cutoff tool to take the nipples off the ends. need a plug just squish the end in a vice and a drop of braze and wallah !!! need an adapter? most brass compression fittings tighten right on them. you can tee 90 or 45 ells etc. sometimes the most usefull tools are ones you make yourself. oh and btw it just figures you'd have a bicycle pump laying around lol

[SmittySmithsonite]

Blazer ... ugh! I don't miss mine (was actually a Jimmy, but same thing basically). It's out back on the hill cut into a million pieces, lol. Rest of it's parts are all over the world now. That was my crash course into OBD-II about 7 years back - I got so frustrated I parted it out! LOL! DEFEATED!

I had a similar yet opposite fuel pressure problem in a '92 Volvo 940 wagon, which was very strange. The check valve would intermittently block output of the pump! Car would start and run like a champ in the morning, but drive a mile down the road, it would croak and need a tow back. Wait a half hour to an hour, and it would fire back up again. Eventually it got to a point where it would have to sit all day long before it would restart. Acted just like a failing ignition coil, so that's where I started. I watched my timing light blink all the way through the stall. Could hear the fuel pump running with every key cycle! Fuel pressure gauge told the tale. 0 psi when it was a no-start. I was avoiding the pump at first, because the owner had just replaced it less than 6 months prior. Goes to show, "new" or "recent" doesn't mean GOOD!

I yanked the pump to see what was going on. Put it in a container full of acetone, and powered it up on a battery. Pump was wizzing away, with not a drop of fuel coming out. I started tapping the ground wire for a rapid on-off cycle of the pump, when I heard a POP - had a 6' geyser of acetone, lol. Pump was good, check valve bad - since it's part of the pump, gotta throw a new pump in there. Was a Walbro pump too - they're normally pretty good units in my experience.

That was an interesting one for me! Wish I had a decent camera to shoot that one. Think it would've made for a great video.

[wyattoneable]

I've seen that before. It ended up being a faulty check valve in the fuel pump. (98' 5.7 Chevy).Oh...well there you go, you found the same issue. Cool. Nice additional test.

[baxrok.]

Nice diagnosis Ivan. Plastic fuel lines, ugh. There are some great comments here on the system as well. Thanks!

[stephendee]

For future reference, because there are zillions of these 4.3L engines: If you're going to replace the fuel pressure regulator on one of these intakes with the poppet spider (which you didn't this time), you can replace the poppet spider with a more reliable injector spider from the later models. This is usually a good idea because the effort to get into the upper intake plenum is significant and the spiders are known problem areas.