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…. slightly, with use of Redline SI-1 PEA based cleaner, and extensive “water cleaning” of the intake??
S-10 forum suggests I have a clogged catalytic comverter, and, therefore, exhaust restriction (because even though there is a sizable hole at back of muffler, that’s post-cat.)
Now.. “The engine still shakes” but I’m noticing a slight to at times significant improvement in power delivery…
I still need to check fuel pressure
I still need to check “timing”
AND, sometimes it takes longer to crank, a la a trademark of in my experience has signified and usually been with that symptom fuel something-or-another (like pump.) But what if.. and this is a WAG here.. an injector got “clogged,” and is still being stubborn??This the 1994 Chevy Blazer with the infamous 4.3L Vortex V6 (L35) with the VIN W spider injectors, not the other one.
Thanks in advance.. and yes, please ask any questions.
This engine ran better than a new car and at the end of nothing other than a long highway run, it had lost power and was no longer firing on all cylinders. Things changed since then: All 6 plugs with ACDelco CR43TS (were previously Rapid Fire “14”s,) wires ACDelco new, and cap and rotor, I believe but don’t exactly know 100% were ACDelco.
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[quote=”KableGuy” post=160891]When was the last time the fuel filter was replaced?[/quote]
It’s probably never been changed.OH. I ALMOST FORGOT: For some weird reason, I sometimes have to push the spark plug boots back down on the “points” of the distributor. They don’t come off, but about “4” of them go “up” to the point where I have to push them back down to “click” onto the dizzy. I wonder if it’s the same at the plugs. Routing does appear to be correct, I have a Haynes manual diagram and I’ve double-checked it. Can triple check (routing) but I do believe it is right..
So. Fuel filter. Hmmmm.
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^^ For reference: here is what it has improved FROM. IT has gotten better since this video. And please ignore me saying “It has been diagnosed as” .. It hasnt.. I haven’t gotten a diagnosis, but I got to posting here because I know a bunch of folks that are good at “guessing.”
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+1 for fuel filter maintenance if needed.
If you don’t have a vacuum gauge for testing, you can remove the upstream O2 and go for a test drive. If the misfire goes away, then yes, there is a restriction. You’d want to reinstall the O2 and disconnect the back end of the cat from the rest of the exhaust. If your misfire comes back, then the cat is plugged. If the misfire stays gone with the exhaust opened behind the cat, then something else farther down the exhaust is plugged up. Don’t count the holy muffler out yet, there could still be something clogged at the front of the muffler. Does it seem pretty quiet in spite of that sizable hole?
Remember that fuel pressure regulators go bad often enough on the spider injectors too. It could feed a misfire problem and explain the long crank times. When the regulators start leaking, they most often foul out the number four cylinder IIRC. The pressure regulator can be replaced by itself if need be. Find scanner danner on youtube and he’ll have a video just for this engine.
The poppet nozzles get clogged often enough on the injectors as well. Do some fuel pressure drop testing if you can to verify any restrictions. As long as they’re not completely blocked, an injector cleaning service at a shop should get them opened up and working normally. I had one of my poppets completely blocked and I used a nitrogen blaster to open up the poppets, but that’s a rare device to find in any shop.
This should get you started. Keep us posted and good luck.
[quote=”no_common_sense” post=160902]+1 for fuel filter maintenance if needed.
If you don’t have a vacuum gauge for testing, you can remove the upstream O2 and go for a test drive. If the misfire goes away, then yes, there is a restriction. You’d want to reinstall the O2 and disconnect the back end of the cat from the rest of the exhaust. If your misfire comes back, then the cat is plugged. If the misfire stays gone with the exhaust opened behind the cat, then something else farther down the exhaust is plugged up. Don’t count the holy muffler out yet, there could still be something clogged at the front of the muffler. Does it seem pretty quiet in spite of that sizable hole?
Remember that fuel pressure regulators go bad often enough on the spider injectors too. It could feed a misfire problem and explain the long crank times. When the regulators start leaking, they most often foul out the number four cylinder IIRC. The pressure regulator can be replaced by itself if need be. Find scanner danner on youtube and he’ll have a video just for this engine.
The poppet nozzles get clogged often enough on the injectors as well. Do some fuel pressure drop testing if you can to verify any restrictions. As long as they’re not completely blocked, an injector cleaning service at a shop should get them opened up and working normally. I had one of my poppets completely blocked and I used a nitrogen blaster to open up the poppets, but that’s a rare device to find in any shop.
This should get you started. Keep us posted and good luck.[/quote]
Damn. #4 cyl was the worst lookin plug. Wow. Nice attention to detail! 😀
And I saw the trick about unbolting those two bolts, where header goes to cat.. I want to spray PB Blaster to increase my chances of smooth removal.
Will re-read, and see what I can do. Fuel filter will likely be next. I did it in 15 minutes once, yes got rained on with fuel, biggest issue was rust. Of course, cool car, first thing a.m. when it’s time.. because it’s gas, duh.
Will keep posted.
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