'97 Tahoe No start Good fuel Good spark

I am a forklift mechanic, accustomed to on board diagnostics being built into the trucks. Also new to these groups. Have been searching them. Prior to this condition a service engine light illuminated in the middle of a 2 hour freeway trip, I rompped on it up a hill. no drivability problems. Light cleared after restart on return trip. Then a couple weeks later tough starting, Once it did start, Rough idle. Then would run, And start fine. Then repeat the symptoms a couple weeks later. Now cranks fine, Long cranks >15 seconds cranking will hesitate like wrong timing, Or piston coming up on High compression. Fuel- 62psi and holds. Spark- checked with induction timing light. Changed the Cap, Rotor, Sparkplugs. #1 plug hole will blow my finger off when cranked. I do Not have a Tech 1 Scan tool, But have pulled the codes with a lesser tool. I have a P1406 EGR Valve Pintle Position Circuit Fault. And a P0306 Cyl. 6 Misfire detected.

2 days have been spent checking sensors Ohms and volts and fuses, None bad. I have access to Mitchell 1 On-line and have followed the basic testing as much as I can without the better Scan tool. Could module in distributer be bad? Something here isn't in sync. Last winter I completly went through the fuel system, Replacing pump, regulator, oil pressure switch, relay, connector and terminals at pump head. Any thoughts on this? don
Reply to
dmlakc
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It still could be fuel, you said it has pressure but you didnt say if the injectors are firing. Spray a good amount of car cleaner down the intake and see it it starts. That will tell you if its fuel for sure.

Reply to
Shoe Salesman

searching

finger

Engine has 137,000 on it, Carb. cleaner/Starting fluid gets a single back fire thru throttle body.

I am in process of replacing 3 Items;

-Timing chain & gears, Old one may be loose enough to not pass smog check.

-Manifold gaskets, Looks like oil seepage down front of block both heads, Also degraded around front coolant ports on heads.

-Distributor unit, Found loose, easily rotated by hand. Also suspect cam sensor bad inside. Two years ago, I broke the rear base plastic when removing the loctite screw. The repair used a steel plate beneath the cam sensor utilizing it's mounting screws. Probably not a good idea, But it did work.

Tip: If one is having problems loosing the Distributor Cap, Slightly heat the screw head (solder iron, heat gun) It will then loosen quite easily.

I will keep updating this as I find anything interesting. don

Reply to
dmlakc

light.

Well, The coolant leak was evident by discoloration of metal in the lifter valley and the drivers side head. Rust colored film adhered to oil coated steel. A gold hue. After replacing the intake manifold gaskets it ran rough, Then smoothed out after VCM relearn, Except for a slight ticking from the even cylinder head. I ran oil detergent, drained and refilled w/5w-30. I was just about ready to test drive it when the rough running returned. Code P0307, Then Code P0300. Shut it down. Pulled the valve rocker cover, Found #7 intake open, Loose rocker and pushrod. Manifold is now back off, I will do a compression test on all cylinders, Then pull the head or heads if needed. This intake valve or valves hanging open due to the coolant leak causing rough running, Was happening for about a month prior to my no start condition. Run rough for a few minutes, Run great for a couple weeks, Then repeat. It would don

Reply to
dmlakc

A 5/16" N.F x 1-1/2". stainless steel socket hex head bolt was found wedged between the seat and valve face of #7 intake valve! I have no idea how it got there! don

Reply to
dmlakc

GM employee's do that Quite a bit on the assembley line!! Some employee's just donnot Care.. I am 1 mile from Chevy Assembley plant in Flint, Mi

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Reply to
no one

Maybe this is the cause of the reported ticking in some of these engines? My wife says this ticking has been going on for months.

Reply to
dmlakc

And you think it waited eight years before it caused a problem?

Reply to
aarcuda69062

YUP

Reply to
no one

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