I`ve got an 89 Chevy 350. Throttle body injection. I`ve lost oil pressure. If the lifters don`t get oil after a while can it cause the Exhaust valves not to open enough to hydrostatic lock the engine with excess fuel.? Engine runs about a minute then comes to a quick stop. Then wont crank as if the cyl. are loaded with fuel. Has anybody seen this happen. ( this adventure started on a post about s.b. Chevy timing chain jump). Sorry to be not hot rod related.
Did you chech the distributor shaft/gear /roll pin? and dont forget the shaft between bottom of distributor and oil pump......[which could have locked up] .
The reason your engine is shutting off is because there isn't enough oil pressure to keep the fuel pump relay winding supplied with voltage. Here's the run down. You turn the key on, the relay comes in and the fuel pump starts running. The relay stays in while you're cranking the engine.. After the engine catches, the voltage to the relay winding is "rerouted" thru an oil pressure switch.. If the oil pressure drops below requirements, the relay windings loose voltage and the relay is turned off, the fuel pump stops running and the engine dies. If you keep on trying to make the engine run without oil pressure, you're gonna do more than collapse some lifters.. "hydrostatic lock"??? As the***** hunter told his rabbit chasing***** dog..."You're barking up the wrong tree.."
Rusty that makes sense I heard about a 7 sec. cycle for the oil pressure to come up or the fuel pump is cut out . But why after it sits wont it spin? I would think the cycle would break when the key is turned to off. I will check the dist. shaft next Dont the make a tool to turn the oil pump with a drill? Before starting a new engine. I`ve been drivin the shoebox as a daily driver. I`ll be at the Fuel and Fire campout this weekend so I`ll get back on it Monday. Thanks foe the advise.
That explanation ain't my theory on how it works... That's exactly how the system is designed. It's purpose is to protect the engine from people who don't keep oil in the crankcase... I worked as a mechanic for nearly 40 years.. I witnessed the "birth" of the SBC, alternators, electronic ignition, pcv systems, smog issues, onboard computers and the f.i. systems on today's vehicles.. And I'm also very familar with rumpple bolt stretchers and kanutter valves.. Why does the engine turn over slow?? If you've been running the engine with zero oil flow to the bearings, they're probably running dry by now.. Which means they've started to score. The engine is in the early stages of seizure.. Running without lubrication, the bearing surfaces rapidly warm up and expand.. The starter just ain't stout enough to turn the engine over until things cool off.. This is what I was referring to when I said collapsed lifters are the least of your worries.. The fact that the engine runs at all eliminates the timing chain, slipped gear on the distributor shaft, or any other "timing" issues. Your problem lies exclusively with the oil pump and it's related components.. If you want to play around with the oil pump here's how to make a tool.. Get an old HEI distributor and grind the teeth off the gear.. Remove all the electronic components and strip all the advance mechanism off the "upper shaft".. Cut off the bar on the end of the shaft that the advance springs attach to.. Drop the modded dizzy into the hole and attach a 1/2 inch drill.. Spin the drill clockwise and see what you get for oil pressure.. If the drill spins really free, you probably got a bad pump or severely clogged pickup screen.. Be sure you got oil in the pan and a fresh oil filter.. If your truck was in my bay, I'd already have the pan off and giving the oil pump an autopsy.. I'm not trying to be a smart**** with anything I've been telling you, but you're making a bad situation worse by continually making the engine run with no oil pressure.. This subject is O.T. so, in respect to the guidelines of this board, I'd be more comfortable continuing this discussion thru e-mails..
Pull the valve covers...clean the sludge out of the drainback holes...oil is getting to the top but can't get back. This was a problem on the '88-'89 trucks...especially high mileage ones. Brian Brian
To all who have helped. The engine is now running. Last attempt was cranking the engine with plugs removed and injector wiring plugs disconected. Pumped all the raw fuel out. Put plugs back in hooked up 1 injector . Engine ran and smoked through the breather awhile. OIL PRESSURE came up after about a minute!! Shut down and reconected the other injector. Ran for 15 minutes. Water temp never came up. Replaced the temp sender (wich also controls amount of fuel). Still no gauge reading. Replaced thermostat (old one was stuck open). I never realized how much computerized engines rely on on non related things. All is well drove about 4 miles .so far so good. I am still concerned with the sludgy oil though. Anybody use that engine oil flush? Sorry for my post to be so far off topic!! I figured theres a lot of small block chevy out there and a lot of knowledge to go with it. ( I guess if I said this engine was in my 49 Ford it would have been on topic ?? Thanks again to all who helped
The typical sludge problem they refer to in previos posts are almost always caused by a reason [other than poor oil quality or lack of frequent oil changes]....I have always used chevy small blocks in my rods and my drivers ,and have learned a common ailment that plagues a lot of these type motors.If it is new enough to have an EGR valve[located on right intake near carb]....THIS is almost always your culprit. It malfunctions and causes at least two problems-One,it will cause exhaust to be continually fed to base of carb[after it should shut off] until it burns the base gasket out from under the carb [or throttle body]-letting it leak in and displacing the oxygen it needs to run right.....OR- another problem- it sticks open and causes the exhaust to continually flow into the head-intake middle port- causing the oil to overheat/break down and coagulate/crystallize in the valve cover area untill the oil does not drain back into the pan. it will then stand in valve cover until it causes it to leak by valve seals and in turn uses oil and smokes.....all because of a faulty[AND totally unnecessary] EGR VALVE. I remove it the instant I buy a motor..... thats the only sure cure!
Choprods - What's the original purpose of the EGR valve? Is this smog stuff? Thanks to all others posting here, Getting ready to build a sbc myself and I'm learning a ton.
EGR was indeed an add-on for smog. Designed to pump exhaust into the intake at times. Usually they get a piece of carbon stuck in them, which in turn, hangs them open all the time.
I think it s"purpose" was to warm the intake during warmup period then shut down. other than that I stated above -I cant say it has a reason........
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