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Ivan, ASE Certified Master Technician
Category: Car
Satisfied Customers: 4871
Experience:  ASE Master Tech w/ 20+ years in the field. Self employed for 9 years. Member of AUTOLAB radio show.
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Parked..another thought timing chain jumped, and another..fuel pump

Customer Question

Hello, Parked my car last night, went to leave today and the engine would spin over, fire up, make a loud noise and quit. Tank is 3/4 full, so it's not out of gas. A neighbor thinks some sensor on the engine, another thought timing chain jumped, and another thought it's the fuel pump. I sure have plenty of backyard advice. But I need advice from an expert. Thank You, XXXXX XXXXX
Submitted: 9 years ago.
Category: Car
Expert:  Ivan replied 9 years ago.

HelloCustomer Let's start by gathering data and we can narrow it down. Since we have so many thoughts, let's start with the basics. Remove all 4 spark plugs and lets perform a compression test. disable ignition. Install the compression guage and crank the car. Allow 5 cycles then take a reading. The needle should hop 5 times. Make sure all 4 cylinders are measured the same way. You should see 125-150 psi on each cylinder. Whatever the reading is, all cylinders should be very close to each other. If you find compression readings varying greatly from cylinder to cylinder, suspect a timing chain/belt issue. Let me know what you find.


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Customer: replied 9 years ago.
Ivan, We were out of town for the Minnesota State Fair, that's why you haven't heard back from me. I have a friend coming over tomorrow night with a compression gauge to help. You referred to 4 cylinders, this is a 94 Pontiac Grand Prix with an 8 cylinder engine. If 4 cylinders on one side test out evenly what then? Another backyard mechanic wondered if a water pump pulley has given out, I answered WHAT? He didn't seem to have been drinking. Stan
Expert:  Ivan replied 9 years ago.

Stan, I am going to presume your car is Canadian. In your first post, you indicated a LeMans, The last Lemans we had in the US was a 4 cyl. If your car is Canadian, I'm sure we have an equivalent model here. What displacement is your engine and is it a 4 or 2 door car. I want to figure out which vehicle platform it is, so I can rethink my approach. Same test applies for compression testing, However do all 8 cylinders. Same deal. Erratic compression readings confirm a timing chain issue. By any chance is your engine a 5.7 Lt1 style engine?



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Customer: replied 9 years ago.
Ivan, I was mistaken as to how many cylinders there are. This is actually a V6 cylinder engine. I have accepted that I'm in over my head with this problem. I had the car towed to a dealer for the repair of what ever it is. Thank You for your responses. I will hit the accept button and go from here. Again, Thank You, Stan
Expert:  Ivan replied 9 years ago.

6 cylinders sound more like it, now we can be assured we are talking about the same car. Stan let me know if you need any help, second opinions, anything. I'm here for you. Have a great night, and I'll keep my fingers crossed that it's something minor.