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Hey yall I have a 88 bronco with 680k miles on it. The engine is a 351 Windsor with an EFI system. My supervisor gave it to me for free after he couldnt figure out what was wrong with it. It sat and wouldn't start for a year with him. When I got it, One day it just up and started randomly and ran perfectly for a week. I changed the battery, fuel filter, and installed nickel sparkplugs to it. It cranks but wont turnover completely. I need help figuring out of its a compression, or fuel issue. Thanks very much !!!
How did it run when it "up and started"? A long shot guess is either coil or ignition control unit, maybe the distributor stater pickup. After 680K miles any of those could be suspect. Have you tried pulling any codes?
When it ran for a week everything literally ran perfect. It would turnover no problem and drive like a champ. When I was on the highway the last day it would lose compression and drop rpms to 1000 or less. I pumped the gas to keep the rpm up and for the truck not to turn off completely. When I parked it back at home I took the key out and the truck was still running so I popped open the hood and took the battery connectors off. Now it just wint fully turnover even though the engine is trying to.
It needs Air Fuel and Spark to run. Stayed running is a wiring concern or electrical
What's the engine oil smell like and look like ? Is there a strong fuel smell ?
Is there fuel psi at the rail when cranking and turning over
How's the spark when cranking ? Coil or ignition control unit and stater problems are common
Whats the air intake system like.
Sounds like a Diag flow chart and some time is needed
The oil is good and I added an oil treatment to it as well. The spark sounds strong when the engine is trying to turnover; the engine just cant turnover completely. There is no fuel smell and the psi looked good to me as well.
Update, i got a new battery, and air intake a couple days ago. I checked the starter relay, the fuel railings for pressure, and tried starter fluid today. It is most likely a spark problem and it is 30 degrees outside so that's not helping. The starter fluid got it to start for 2-3 seconds and it would cut off.
Last edited by BOOKIEXD; Feb 19, 2020 at 07:38 PM.
Reason: 88 bronco help