New Spyder. Now P0300

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gwmjr

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I have a 99 Tahoe w 5.7. For the past year have been getting P0300 when pulling a trailer. Followed the GM TSB and 2 weeks ago pulled both cylinder heads and found 3-4 valves binding on each head. Honed the valve guides and reinstalled the heads. Put in a new upgraded Delphi fuel spyder at the same time. Now the engine cranks easily but there is an obvious misfire which is confirmed by P0300. I have dealt with all the usual suspects - replaced plugs, wires, distributor, cap, rotor, ignition coil, egr valve. Checked for crossfire. Checked all the vacuum lines.

Hope someone here might offer some wisdom before I take it to the dealership.
 
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gwmjr

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Thanks for the reply. Yes, I zeroed the dist out. Ended up taking it to dealer and they found no compression on cyl 6 and 8. I had it towed back to my house and have reinstalled a new head gasket on the left cylinder. Should finish installing the intake today and will report back results.
 
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gwmjr

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Sorry. I meant the right bank cylinder head. I replaced that head gasket 2 days ago. While manually turning crankshaft balancer bolt to get #1 to TDC, I stripped that bolt. Ordered a new bolt and washer at local Chevy dealer which should be delivered today. Hopefully, will have time to work on it more tomorrow.
 
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gwmjr

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Why risk ripping the pulleys off if I do it by hand? Real men unbolt the cylinder heads with no tools.
 
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gwmjr

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Problem solved.

You were right, SunLitComet. I did not know you could turn the motor over by hand once the spark plugs are removed. Thanks.

By the time I installed the heads for the second time, I noticed the torque on the head bolts needed some attention. I had torqued according to the FSM in sequence to 22 ft. lbs and then to the various angles according to bolt length. On the first install, I did not go back for a third pass to insure all the bolts were to 66 ft. lbs. This resulted in the head gaskets leaking and no compression on some of the cylinders. On the second install, I made a third and fourth pass to make sure all the bolts were at 66. Now, no problems. If I have to remove the heads in the future, I will not follow the FSM preferred method of torque angles, but will use the secondary method of torquing to 22, then 44, then 66.

This project was not cheap, but a lot less than a shop would have charged. The only solution offered by the local dealer when they found no compression on 2 of the cylinders was to install a new engine for me at $3500. I followed the suggestions posted by SunLitComet on this forum for buying many of the parts from Amazon. This project has given my motor a new Delphi fuel injector spider, new water pump, new spark plugs, new pulley for the serpentine belt, new spark plug wires, new distributor, cap, and rotor, new gaskets throughout the top of the engine, new valve stem seals, and the assurance that the intake gasket is not leaking. I also no longer expect the P0300 code to occur when I pull my boat. Some of the valves which were sticking were so tight in the head that I needed a hammer to remove them. Including all the brake cleaner, gasket kits, cyl head bolts, intake manifold bots, torque angle guage, 5 gal of antifreeze, 4 gal of motor oil and a filter, KD valve spring compressor, craftsmen torque wrench, fuel pressure guage, 9 mm hone, honing oil, $100 diagnostic fee to the dealer, RTV gray sealant, my bill came to about $1275. (The additional install of the heads contributed about $250 to that total, of which, $100 was the trip to the dealer.)

The motor is running like new. The responsiveness to the throttle is tremendous. It has 205k on it now and I hope to make it to 300k. I also plan to check the fuel mileage this week with hopes of getting better mileage than the 10-12 mpg I have been getting.

This forum is a great resource! Thanks to so many of you who have contributed your knowledge and experience to it.
 

SunlitComet

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More power to you. the torque angle method is preferred but is usually doable with engine completely removed. it is possible while installed but can be cumbersome the alt method is the 22-44-66 three pass method.
 

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