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Missing/Shaking at idle...
Been happening for a few months, have changed MAP sensor, plugs, wires, cap, rotor, CTS, and o2 sensor.
Fuel pressure... Key On: 64-65 Leak Down: Doesn't go below 58-60 (20 minutes) Running: 60-62 Decided to pull plenum, and it looks washed-out, but cannot find any fuel leaking. https://cimg2.ibsrv.net/gimg/blazerf...da36acc93f.jpg |
That plenum looks like the fuel pressure regulator has been leaking does it have a hard time starting in the morning?
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Nope, starts first or second crank. Turned the key on with the plenum off and I don't see it leaking anywhere, has me stumped :icon_doh:
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It looks washed clean above and around #6 injector to the FPR it may be the line or the injector itself for #6 is leaking while running and that injector fires. Just a guess and my two cents
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4.3 vortec engines start on the first crank as fast as brand new cars. It's the second crank and the difference from the left and right sides in the pic.
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OK, engaged the pump to run with test wire for 30 seconds to 1 minute, still no leaks or fuel spray anywhere?
Is it possible to check the FPR besides engaging the pump? Also maybe a dumb question, but can you do a compression test with the plenum off? |
:icon_bump1:
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Originally Posted by KTS
(Post 694721)
OK, engaged the pump to run with test wire for 30 seconds to 1 minute, still no leaks or fuel spray anywhere?
Is it possible to check the FPR besides engaging the pump? Also maybe a dumb question, but can you do a compression test with the plenum off? Here's what I found once on the spiders: https://www.instructables.com/id/Poo...Vortec-Fuel-I/ And yes, You can do a compression test with plenum off. |
The best injector system tests are fairly complicated and/or expensive. The things that the average DIY’er can do are: The pressure test in the sticky Open the upper intake manifold as you have done for a visual inspection Inspect the spark plugs for signs of a lean or rich condition Look at fuel trims under different conditions for evidence of trouble If you want to further analyze your injectors you can do an injector balance test. This involves pulsing each injector in sequence with a pulse generator box while watching the drop in fuel pressure to see how the injectors are functioning. Another assessment of the health of the injection system involves looking at live oscilloscope traces. You can see poor function in the “pintle hump” and other waveform elements but this is out of reach of the typical DIY mechanic. It is because of this that most people just replace the injector spider if malfunction is suspected. If you decide to go this route, read up on the upgrade option. George |
Thanks for the replies everyone, I'm going to go ahead and replace the spider assembly. Looks like it is the original one, probably should be replaced anyway.
Anyone no where I can get new bolts for the plenum? I searched and cannot seem to find anyone that sells them. |
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