88 e350 RV 460 timing issues?

[alwaysFlOoReD]

I bought a 1988 RV 460ci EFI [for cheap], the PO figured the timing chain skipped a tooth. I tested for fuel and found the high pressure pump was fubar, so replaced it and it fired up. Idle was erratic and vacuum was low @ ~13-15 psi. OK, maybe the chain WAS gone....tore it down and NO, chain is fine. Crap. So now I need help in diagnostics. I pulled the distributor so I could get at the TFI and will test that tonight or tomorrow morning. While the front of the motor is off I plan on replacing the sparkplugs and doing a compression test. There is very little room to work on plugs/wires when the motor is together and the rad is in place.

Is there anything else I should look at?

PS; the unit is 40 miles from home and no parts places close by.

 

[RonD]

Yes, take compression gauge with you and some oil
Do dry and wet compression test before reassembly
Could be beating a dead horse if rings or valves are the issue

1988 460 should be 8.5:1 compression ratio, putting it at about 150-155psi, sea level

If compression comes out good then could just be a bigger vacuum leak causing the low vacuum, old brake booster, PCV, ect.....
Soapy water in a spray bottle or flammable starting spray would be good to test for that


Spark timing, SPOUT off, is 10-12deg BTDC

 

[alwaysFlOoReD]

K, thanks.
I figured on doing a compression test. I'm at 2800 feet above sea level, what does that do to the compression numbers?

 

[RonD]

3% loss per 1,000ft, so you would be at about 7.5% loss, so 11psi less

Vacuum would be lower as well, 16-20" would be expected, instead of 17-21"(0-2,000ft)

 

[alwaysFlOoReD]

#2 and #3 wires were swapped.

 

[RonD]

That would do it.

So smooth running now?

 

[alwaysFlOoReD]

It's not back together yet. That thing is a pain to get at #1, #2, and #5 plugs. I did the compression test and got 0 psi on #1, #7 and #8. All the rest were at 140-155 psi. I re-did the tests on the low cylinders a few times and two came up to 130 or more. The last one is still at 50. I'm hoping that it's stuck rings or lifters that will work loose in time. I'm going to seafoam and put in a quart of tranny fluid into the motor oil to see if that helps. It will be buttoned up tomorrow so will see how it runs then.

 

[RonD]

Yes, Van engines are usually not easy to work on

 

[alwaysFlOoReD]

Anyone know where the spout is? Drivers or passenger's side? Toward front or back? I'm getting frustrated!

Found it drivers side of the distributor.

 

[alwaysFlOoReD]

Well....the motor sucks. The plan is get it towed to where my stuff is. Then buy a new work truck, and swap the motor out of my f250 work truck into the motor-home.