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PhilJ, ASE Certified Technician
Category: Car
Satisfied Customers: 604
Experience:  Master ASE certified, dealer employed for 10 years, shop foreman
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isuzu amigo: cylinder..loud humming sound..less compression..vechicle

Customer Question

Philip, i know you are avolvo expert but this time i have a question for a isuzu amigo, 6 cylinder, 3.2L engine. You were very precise and helped me greatly.
A month ago i experienced a loud humming sound when accelerating from the engine and there was less compression, the vechicle bearly moving when accelerating . This truck run like a champ. I towed it to a friend's shop to check it out. It would still start ran fine at idling but no power in drive or reverse position. There was a faint rattling sound coming from the right cylinder. At first he suggested that I replaced the engine and on a second thought after checking around the engines i found are over 100,000 miles. My truck only has 46,000 original miles. We decided to rebuild the engine because i thought it made sense instead of inheriting someone else problems. I bought all of the necessary parts.I took the heads to a machine shop with 30+ years of experience. They thoroughly cleaned the heads, replaced the valve seals, grinded and correctly reset the valves with the proper clearances because the engine has soild lifters. i also replaced the oil and water pumps, connecting rods and main bearings. piston rings, all the gaskets because i bought a complete kit.

My friend has been working on it with csution and have assembled all the parts to at least start the vehicle. He told me it started but didn't leave it to run for long. To my disappointment, the next day he tried to start it again and wouldn't start. Now i noticed some signs before this problem such as the engine check light being on and sometimes flashes.It will go away for a few days and comes back on. It was diagnosed before and found that one the injectors wasn't sprayng properly and i was advised to start using premium gasoline and if that doesn't work to replace the injectors. Sometimes, when i am trying to start the vechile, there is a big back pressure (loud popping sound ) that would come through the air filter chamber that would force open the lid of the housing.
Philip, i know you a volvo expert but i trust you because you have given me the right advise and you saved me money on my volvo repairs. May be you use your expertise to help again this time by talking to your friends with an isuzu expertise to help me. May be you help yourself. I have already invested a modest sum in this project. I hope you had a joyous New Year's day and happy New Year to you.
Submitted: 5 years ago.
Category: Car
Expert:  PhilJ replied 5 years ago.

PhilJ : You say It pops in the intake chamber? Sounds like timing is off. What year is that truck? If your engine runs after your rebuild that is a good thing. Did you replace the injectors? What fault code is stored now? I'll see what I can do for ya.
Customer :

Phil, at this points the mechanic is saying that the shop that did the valve job on cylinder head didn't do it right, There is no compression from the valves. i am taking the heads back to the shop to be rechecked again. The vehicle is a 2000 Isuzu amigo with a 6 cylinder, 3.2L engine. The engine started once and did not start again.' Please try your best for me. thank you Phil.

PhilJ : If they didn't do it right I don't think it would have started at all. I think something wasn't timed right and bent all your valves. If the valves are bent then it wasnt assembled correctly if no damage is found then I would suspect bad head job.
Customer :

phil, thank you very much for your response. I am taking one of the heads back to the machine shop this morning. Precisely, if the valves are bent your conclusion is right and then see what the next step is going to be. If the valve job wasn't done as you said, I don't think it would have started. I will keep you informed of the developments.