New to the forum, but hope someone can help answer some questions.
Have been driving the Suburban with very few problems for over 60,000 miles. Just after getting it with 149,000 miles, we replaced the PMD, have since replaced the main pulley (dampner pulley)...after knocking out the seal on the A/C compressor and the alternator bearings. New lift pump, both new batteries.
Two days ago, we had driven about 600 miles with engine running great, and pulled up to a turnpike gate when we noticed a new sound. I looked under the hood and the engine was rocking from side to side. Looked at the engine mounts, and the right side had some slack, so I thought that was the problem. Took it to the nearest dealer and had the mounts replaced. That was not the problem. Codes showing were 78 waste gate; 13 engine shutoff valve; 36 injector pulse width wide; and 92,93,94 cylinder balance. Ran test with delay off on injectors and determined that Cylinder #2 and Cylinder #7 were not firing. Checked fuel quality from filter drain, and it was good, clean (I had just serviced all filters and oil changed). We then ran compression tests and found all cylinders except #2 and #7 tested 385 psi. #2 & #7 registered no pressure. Since these are sequential cylinders in the firing order, is there something that could cause no pressure? No leakage by air test to coolant, and no loss of coolant. I was planning to remove injector #7 next, but maybe I am just wishing. Appreciate any help you can give.
Dave
Have been driving the Suburban with very few problems for over 60,000 miles. Just after getting it with 149,000 miles, we replaced the PMD, have since replaced the main pulley (dampner pulley)...after knocking out the seal on the A/C compressor and the alternator bearings. New lift pump, both new batteries.
Two days ago, we had driven about 600 miles with engine running great, and pulled up to a turnpike gate when we noticed a new sound. I looked under the hood and the engine was rocking from side to side. Looked at the engine mounts, and the right side had some slack, so I thought that was the problem. Took it to the nearest dealer and had the mounts replaced. That was not the problem. Codes showing were 78 waste gate; 13 engine shutoff valve; 36 injector pulse width wide; and 92,93,94 cylinder balance. Ran test with delay off on injectors and determined that Cylinder #2 and Cylinder #7 were not firing. Checked fuel quality from filter drain, and it was good, clean (I had just serviced all filters and oil changed). We then ran compression tests and found all cylinders except #2 and #7 tested 385 psi. #2 & #7 registered no pressure. Since these are sequential cylinders in the firing order, is there something that could cause no pressure? No leakage by air test to coolant, and no loss of coolant. I was planning to remove injector #7 next, but maybe I am just wishing. Appreciate any help you can give.
Dave
