You are getting some bad info here
On a 1985 model year the spout timing plug that needs to be removed to set the base timing is right near the distributor/
It is on the loom that feeds the TFI module (buried in a van)

 

So far, he hasn't been able to find it there. The picture I posted shows the spout taped to the wiring harness on the E350. That picture is of a later 80's model though. Somehow I thought his was a later model than '85.

Well, dumb me. Just went to first post and read 1985 model......

 

When performing a engine vacuum test you should hit WOT for long enough for the vacuum to build back up to what it was at idle
That is the main test except for base engine concerns like valves etc.
So if you have 16 inches at idle and you floor it, you need to see how fast and just what vacuum is achieved as the rpm goes to max (5000) or so rpm
If it only returns to eight inches you got trouble

 

That was what I was thinking
The pictures are confusing and the later ones with the remote TFI do have the spout somewhere near that picture showing the fender apron
His 85 we really need to see a pic of the dist and harness to the tfi to see

 

Ive realized where the confusion of the years are, my introduction paragraph makes reference to my personal truck and how Ive used this site to keep it running for all the years I've owned it. So I apologize for that, I shouldn't have brought that information into this. The RV which is causing me all this heartache is a 1988 E-350 RV conversion chassis (E-350 cab with a strip chassis for up-fit). It has an EFI system. The distributor does not have the SPOUT near it, there is a multipin connector that taps into the main wire harness. The TFI module is still located there. The SPOUT is where I am assuming Yardbird has the photo posted of, but mind you this is a 34 year old RV, which right off the bat in its life it was sent to Holiday Rambler Corp to get up-fitted, so there is a bunch of wires pulled through various access points and taped to other wires. So i need to dig through wires as it isn't (at least from my eyes) sitting out in the open.

I will run another vacuum test with idle base, and try to get the motor to hold at 5k rpm to see what the gauge attains. I know i had it up to 2500rpm for an extended period of time (the throttle linkage must have gotten stuck with lack of repeated use) and the vacuum seemed to just hang at 10hgin. But I will do more of a formal test.

As far as tapping off the intake, can I use the port for the MAP senor or will that cause too much computer fluctuation and will botch the test. I know that port is the easiest nipple to get onto and its direct off the intake. I am not sure where the vacuum for the brake booster originates from, but was assuming somewhere off the intake.

 

Don't use the MAP sensor port. There should be a vacuum tree with caps on some of the ports somewhere on the intake.

 

All you need to do on the vacuum test is make sure that it gets back to 16 or whatever after a brief WOT and then that passes and you are done
I will try to find out exactly where the timing spout on a 88 E 350 is. just beware there is 2 identical plugs on the harness
That one pictured with the arrow is might be it ( it may also be the timing tab I referenced in post 5)
You need to disconnect it with a timing light installed to see what it does
If it is the timing spout the timing will drop (not necessarily to 10 degrees)
If it is the timing tab the timing will jump up 10 degrees

 

Ok, so forgive me, i did this quickly last night right before night set in. I found a split with a cap that connected to the PVC that has a line that goes directly to the back of the intake manifold. The stub is tight on the inside of the vacuum gauge hose, but I am not sure if there is a restriction on vacuum since the capped side is only an 1/8" ID, if that. But anyway, I hooked it up and started. At low end idle, which is me not touching the gas pedal it bounces between 8-12in, if i hold it at idle its 12in, if I slowly gas up the vacuum drops initially but returns to 12in, until i go past 2000 RPM when it begins to fade out. At slowly opened WOT (or at least what sounds like it) the vacuum sits around 5-6inhg. When i let go of the gas pedal the vacuum goes through the roof until it sets back to idle. On a quick WOT the vacuum zeros until i hold the pedal where it then just comes back to around 6-8inhg.

Now of secondary note, I put the gauge back on the brake booster to see if the test would yield the same, the brake booster line is wider diameter, and i get a base reading there of 12-15 on bad idle, 15 when I hold it at idle, and then repeats everything that happened on the other test, just instead of 6-8inhg, its more like 8-10hg.

On another note, If I leave the brake booster vacuum unattached the motor idles at 800rpm and doesn't sound like it want's to die, If I plug up all the vacuums it goes into the low idle where it barely runs. I don't have anything attached to the intake, its literally breathing straight. So I am intrigued why it runs better with an open vacuum line. It still backfires like the dickens and doesn't seem to have anymore power, but I didn't pull any spark plugs to see what they looked like after that.

 

It runs better with an open vacuum line if it is too rich
That way when you cause a vacuum leak it speeds up and runs
A small or large vacuum source and or leaving the component disconnected has no effect on the vacuum test (should have) (your experience differs)
Usually use whatever manifold source is easiest
Your initial timing must be low if you are only getting 8 to ten inches of vacuum at idle
Matters not for the test though might be the gauge
Do you have an air pump on it? (backfire) thru the exhaust?

 

If you can't find the spout, set the timing with a vacuum gauge like I described earlier. It sounds like very low timing or a timing chain jumped.

Doing the same thing over and over won't chang anything. You need to try other things to rule out possibilities, and maybe fix your problem. Everything points to timing, so concentrate on that.

 

Sorry for the months long delay, Spring time is a busy season for me, so I have this RV parked off my driveway while I try to get projects done around the house. I had done the suggestion of yardbird, I loosened the distributor, sets marks for where I am at now and rotated the head counterclockwise first, The vaccuum gauge did not move and the motor slowly ran worse until it died around a 1/16-1/8 rotation. I then reset and moved the distributor in another direction, the motor did not take when to moving that direction and sputtered and died almost immediately going that direction. So after that frustrating end I bagged even looking at the RV i am so frustrated with it. At this point nothing explains why I have 4-5 cylinders that are working ok and 3 that just don't work. They have fuel, they have spark, they have compression. I've read about bank firing issues but my non firing cylinders are opposites from each other. The cylinders that are not firing are literally next to each other on the distributor though, I could unplug 3 wires in a row on the distributor, its like there is a dead spot with something larger. Cylinder 4 fires which is the next plug wire on the distributor, just not 100%, but once it gets to 5 its good to go again. Is there any chance the computer for the EEC-IV system went out? Like I said, I have not found the SPOUT, I have not touched anything in that regard since we drove it back from Vermont, where it ran great. The timing however shows like the SPOUT went missing, or something went missing, since its just running at around 10 BTC.... It just up and crapped out while driving on the highway. The way the motor acts when I try to adjust the distributor, the timing is meant to be where it is at, which would make sense since it ran great prior to what ever happened. I have some sense that the valves are working since the compression test fielded the need to rotate the motor multiple revolutions to attain peak compression vs having it right away, but I can not confirm that, other than I know they get fuel since they are fouled, and the motor backfires, so there is fuel getting into the exhaust. I have also yet to see a check engine light on for anything, even when I was unplugging vacuum connections, such as the MAP. So if anyone has seen this issue related to the EEC-IV I am all ears there, or if there is something I am missing obvious, otherwise I'm throwing in the towel and I guess its either sell, scrap or find the time to tear that pile of crap motor out. Thanks for all your understanding.

 

Have you inspected the dist cap and rotor closely for cracks, burnt post, ect? I had a hairline crack in a cap that was pretty much impossible to see. The symptoms were a miss at idle and a backfire out of nowhere at random times.

 

Damn straight inspect the cap and rotor and ohm out the wires or replace them.
8k ohms per foot roughly is the ohm spec for the plug wires
I will find a harness and show you where your spout connector should be
So it's the square black connector in the photo below you need to disconnect to set the base timing to 10 degrees
Good luck
To properly set the timing disconnecting the spout is a must

 

The old distributor looked fine before I replaced it, and when I did replace it the symptoms were the same. ( I replaced the entire distributor assembly, not just cap and rotor). I even replaced the ignition module instead of putting the old one on the new distributor. Its got new wires on it too. It has newer plugs in it, I replaced those prior to going to Vermont. I think I did swap plugs with 3 and 4 with no difference. All are at the right gap. As I have been saying, it makes no sense. Something went out that isn't obvious, which is why I ask about the EEC system going out. I know I haven't found the SPOUT to remove it, so it *should* be still connected, but I get 10BTC right now with it running. Are the injectors controlled by that system? What times them to fire, I have pulses but is the pulse at the right time? I haven't been in disagreement that its a timing issue, since I have Fuel, Air, Spark and compression, but something is causing it to run like its starving for air, have low vacuum, low timing and causing 3 cylinders to be dead, with the other 5 running rich (richer than usual I think, the truck always had carbon build up, i don't remember them being this heavy though). The injectors on the dead cylinders were changed, and I hear them all ticking (the old ones ticked too, but thought maybe they got gummed up). Again thanks for your time and input on this Cold Case of an engine.

 

Well just for shizzies and gizzies I pulled my ECM out to at least see how much one would cost if it was that. I also opened it up to make sure none of the capacitors leaked. I don't see anything unusual inside, other than some dirt and a rust looking stain (maybe some water got in there?). I just know from other threads the prime suspect would be the capacitors leaking out which I don't see, unless someone with a better eye can spot something. I don't think spending $250 for another one is going fix the issue, unless someone can say for sure something looks off in there. I mean what other avenue do I have, other than tearing the motor apart to confirm I have valve movement? Which even then, if that is confirmed I won't have resolved anything. I just hate being stuck, without a definitive route. I've never encountered something that no one has an answer to.