Vehicle will not start after intake gasket replacement

QVFD

MEMBER
2001 PONTIAC FIREBIRD
3.8L
6 CYL
2WD
AUTOMATIC
85,000 MILES

Replaced intake gaskets because of coolant loss. Only ran 1/2 a minute. Now will not start. Have 50 psi fuel pressure, start from all coil packs, injector pulse, somewhat low compression at certain cylinders. Slight
smoke puffing from throttle body small circular interior port when cranking. Vehicle ran perfectly before gasket replacement. Is EGR a concern? Could it be that the gaskets are presenting a problem? Replace plugs and first lubed the cylinders to correct cylinder wash down. Vehicle ran for several minutes, smoothly no missing. There are NO CODES SET. Can you help. Tony

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HMAC300

MECHANIC
48,601 POSTS

Check fuses under hood and then try resetting security system

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Wednesday, March 18th, 2015 AT 7:38 AM

THIS IS MIKE

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QVFD emailed response:

That was a great suggestion. The Theft System. I reset it three times. Vehicle still will not start. Security Light goes out shortly after I turn the key on for the 10 minute reset. Removed the upper intake yesterday to check for leaks and misalignment of gasket. All was well accept the PCV was stuck up. Replaced the valve. Reassembled the engine and still have a no start. Have 50 PSI fuel pressure at the rail, all coil packs are producing spark. Some of the cylinders have compression less than 100 PSI. There are no codes set MIL status. Vehicle ran just fine before I started replaced the gaskets. Never touched the cam senor. What do you suggest? Tony

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Thursday, March 19th, 2015 AT 11:33 AM

HMAC300

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Unfortunately you didn't go into great detail with your first question. However if you have less than 100 psi per cylinder then I'd think that the timing chain either broke or jumped time. This could happen if you got it running then revved it and due ot age and not knowing condition of chain/tensioner etc cause that. The low compression leads me to believe that because that is what happens when a chain jumps time. I imagine if you kept turning it over it would finally start because it would jump again close enough to start. It would run like crap however. If you test your compression on all the cylinders and they are in the 90-95 psi range then I'd really suspect timing chain. No compression should be less than 100 psi see pic

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Thursday, March 19th, 2015 AT 12:12 PM

QVFD

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2 POSTS

Did a proper compression test. Lowest cylinder was 50 and highest was 85.
Did a wet test on cylinder with 50 and it came up 25 points. The car ran perfect before I changed the intake gaskets. I agree, it looks like the timing has slipped. Vehicle has 85000 miles on it. Don't know what to do next. Customer will never believe this. Did a bleed down test on yo PSI cylinder. Could hear air through the intake until I rotated the engine. Then there was air out the tail pipe. Rotated the engine some more. There was no From intake or exhaust which I believes tells me that the valve are OK. Very slight blow by from dip stick. Can't or don't want to believe the cam timing has jumped. What do you suggest? Tony

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Thursday, March 19th, 2015 AT 2:20 PM

HMAC300

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Tell the guy straight up like you say and see if he will be ok tearing down for timing chain if not then broom it. It's not your fault hell it says 85k but may be way more or maybe it sat for a very long time. I had a car one time came for a no start, started it and blew two rods right out the oil pan he had used so much ether to try to get the damn thing running.