Fuel Pressure on a 1987 5.0 SO

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Fuel Pressure on a 1987 5.0 SO

Reply #15 – August 16, 2010, 09:30:00 AM

Quote from: thunderjet302;331908

At this point I swear it has to be spark knock......

How can I tell? Is spark knock going to hurt the motor? I hate to sound dumb here, I've just never heard of it. I know the plugs and wires are a couple years old, I tried swapping a couple plugs around just to see if it changed, and I didn't notice a difference. I've seen a lot of threads where people have similiar problems, they do a complete tune-up and its still there, lol. I don't want to be one of those people, lol.

How can I tell the difference between spark knock and an injector click? Would spark knock be something that touching the valve covers or intake and such would allow you to feel something? I tried looking at the motor running at night for sparks or an arc, as someone else suggested, I didn't see anything.

Fuel Pressure on a 1987 5.0 SO

Reply #16 – August 16, 2010, 12:47:22 PM

Yes, spark knock, aka detonation is NOT good for an engine.
I'd look into the timing, make sure it's set to factory specs for the engine itself, (i know you've swapped that v8 in there, right?)
and get that sorted out first.

Spark knock usually only occurs under a load, or else with a higher compression engine on low octane gas, or really py timing/or timing advance not functioning correctly.
Do you have a timing light, and know how to use it?
How's the gas? Although in a stock 5.0 I wouldn't suspect that to be so much the cause, but you never know.

Is the Spout connector plugged in? It has to be unhooked to set timing, then plugged back in to run correctly...

If you're not sure where it is, you can google it, or I can snap a pic of mine. It should be on the harness that connects into the distributor, about 6-10 inches away. It's a square little thing with 2 wires, and it pulls out, to take the timing advance function out of the system.

Fuel Pressure on a 1987 5.0 SO

Reply #17 – August 16, 2010, 02:07:03 PM

The Timing was set, it is currently at about 12 degrees. It was set with a timing light, the spout connecter was u plugged to do it. I have tried running premium gas, with an octane booster, just to see. There was no difference. The plugs look okay, they could maybe stand to be replaced, but again, this didn't happen before the intake gasket was swapped in. The spout connected is back in place. I didn't check the gap in the plugs when I took them out, but I feel like that wouldn't have changed from putting the gasket in.

Would you be able to feel spark knock, near the cylinder? Also, when creating a situation where the sound is present, the timing can be changed +/- up to ten degrees retard and advance and the noise does not change. One way the engine dies, I forget which way, but the noise can not be "timed" out.

Fuel Pressure on a 1987 5.0 SO

Reply #18 – August 17, 2010, 12:49:26 AM

I know you pulled the distributor already but I'd do it again. Set the #1 cylinder to TDC again and make sure the distributor is pointed at the #1 cylinder and stab it in again. I keep getting the feeling that it is still off because the issues you've been having came up after you pulled the distributor.