Hello,

I have an 5.0 EFI motor in an '85 F250 and recently completed an extensive rewiring of the engine/computer harness after the original one had rotted to a point that it was unreliable. After a glitch with the PIP pin being bushed back in the main ECU connector, it fired right up. However I found when I tried to set the base timing with the SPOUT connector removed it wouldn't start. Thinking the timing was off I played around with it and found after advancing the timing from it's previous position (whatever that was, read '0' with SPOUT in) it I could get it to start as long as I held the throttle open. But as I reduced it, right at around 1500 RPMs it shuts off like a switch was flipped. Again, this is all with the SPOUT removed. When I plugged the SPOUT back in it starts up even better than it had originally (it stumbled somewhat initially before all this). The timing with the SPOUT in now reads 20 degrees BTDC. So, I still have no idea why it's acting the way it does with the SPOUT connector removed. Any ideas?

Thank you!

Rick

 

I always start mine first and then pull the SPOUT. I have also experienced that it won't start with the SPOUT already removed.

 

Sounds like you may have some other electrical issues, on a previous 94 f150 found a wire under the main fuse box that corroded and separated, that was NOT a fun one to find ..... if only running at 1500 or above the thought was that base timing is quite a way off perhaps retarded position ?

Just timed my 92 302 yesterday and it started just fine with spout removed.

 

20 deg BTDC sounds awfully low for idle. It's been a while since I've checked mine, but I'm thinking it was closer to 40 deg. Could be that you're still around 10 deg AFTER TDC with your initial timing (or it could be that my memory sucks...)

 

Thank you for your replies. I have tried pulling the SPOUT while it's running at ifle and it dies. Base timing on these trucks is supposed to be 10 BTDC with the SPOUT pulled, yes? What surprises me is that it could be so different at idle between being controlled by the computer and not. The last time I messed with timing was on a '70 Chevelle, but I do recall you could be fairly far off the mark and it would still run, just not well.

Nothing Special: are you suggesting the my base timing is still very LATE? That could make some sense as, to get it to even run at all with the SPOUT pulled I had to advance the base timing (some random amount).

Thank you again for the help!

 

He is saying he thinks you may be at 10 ATDC instead of 10 BTDC. That would be 20 degrees LATE in your parlance.

 

Yes, jas88 is right, that's what I'm saying. But keep in mind that it's based on my foggy memory that when I checked the total timing advance on my 460 (at idle, with SPOUT in) I got way over 20 degrees (and I'm at 15 deg base timing). I'm thinking I had somewhere around 30 degrees of vacuum advance like that (~45 deg total advance). So if I'm remembering that right, and if your 302 has the same amount of vacuum advance at idle that my 460 has, that would mean that your 20 deg total is indicating that you have your base timing at around 10 deg ATDC.

But if any of those rather questionable conditions isn't true all of this could be way off base.

 

There is no vacuum on an EFI truck, but the computer uses sensor input to simulate that type of operation. Pull the SPOUT then verify your timing is set to 10 degrees Before Top Dead Center (BTDC). I agree the timing should be above 20+ BTDC at idle. IIRC my old F350 w/5.8L engine was in the 30+ range....

 

Sounds like the harmonic balance pulley(crankshaft) has slipped the rubber ring giving wrong timing readings. I had that happen before.

I have always started my trucks with out the SPOUT and never had one fail to start on base timing. Weird that yours does that.

 

Semantics. All engines with throttles have vacuum, and engines with computer-controlled ignition use a sensor to measure that vacuum. Then the computer decides how much advance to put in the timing. So there's no vacuum hose running to the distributor, but it still has vacuum advance.

 

I was trying to point out it's not vacuum advance as a direct result of having a vacuum line on an old style distributor, it's computer controlled. It's base timing plus whatever the computer adds in based on VARIOUS sensor input. Not only Manifold Absolute Pressure (MAP) but it also takes into consideration TPS, ECT, ACT and MLPS position.

I am agreeing with you to some extent, it's just the added details for a computer controlled EFI vehicle.

 

I tinkered with it some more before leaving for my graveyard shift at work. This time I played with advancing the timing in steps, trying to start it without the SPOUT, and pulling the SPOUT after it was running, all with the same effect. I even got it advanced to the point that the starter clearly straining against ignition as it turned over. At no point was I able to get it to run below 1500 with the SPOUT removed. The last thing I did today was pull the ECU and send it off to a place that repairs these things. I wanted to make sure all the capacitors were replaced anyway. Is it possible something in the fuel injector driver circuit is going dead when I get below 1500 rpm? Or, since the timing is supposed to be controlled by the module with the SPOUT removed, could I have a bad module? It's a new Motorcraft unit. Of course, either of those ideas is contradicted by observing that I was getting preignition (suggesting I have both fuel and spark) with the SPOUT out and the timing advanced sufficiently. It's all very goofy

Thank you once again for all your ideas!

 

OK I had the same very strange problem with my 92 f150. It would drive fine then 200 miles out of no where it would run really bad. Distributor was always 180 degrees off. So what I found to cause this is.
(Computer advancing the timing.) This is not true you say! Well fact! And a really cool thing about Ford trucks is they learn how to operate through the driver habits. When you start that truck, that truck is learning you so it knows what to tell the engine. Because of this the computer is telling the engine where the timing should be. Causing it to be wrong now. (Yes I know it sounds like bull) but it's not.
ok so now how do you stop this. Well you start with earasing the adaptive memory to the computer. Very simple! #1 Get a small piece of wire. #2 undo negitive battery terminal. (Don't let it touch any metal) #3 plug\clamp wire from disconnected negative to the positive. #4 turn head lights on (so all surculating power exits the system). Let sit for exactly 30 minutes. OK nit once you do that don't start the truck you must now set your timing. Piston to 10 degrees T.D.C. set distributor to number 1.
now you need to go to the E.E.C. test (located on driver side) somewhere next to it or around it there will be two wires to a connecter with a gray plug in it. Pull that grey plug out. Now start the truck and turn your distributor as needed to fine tune the engine. Once you have it running properly test drive it. (Take it slow and easy because the computer is going to run a series of test and is going to learn your driving habits) then after all that plug the grey connector back in and the timing should be set.
Now what you just did to your truck is erase any memory if had and set the timing where it should be. The computer will now know that's where it should stay. (Note it's gonna drive like a new truck off the lot minus the miles already there. So take it easy for the first day, then the computer will be set.)
Please excuse my lack of grammer and spelling. This was alot to type. Hope all is well.
​​​

 

OK I had the same very strange problem with my 92 f150. It would drive fine then 200 miles out of no where it would run really bad. Distributor was always 180 degrees off. So what I found to cause this is.
(Computer advancing the timing.) This is not true you say! Well fact! And a really cool thing about Ford trucks is they learn how to operate through the driver habits. When you start that truck, that truck is learning you so it knows what to tell the engine. Because of this the computer is telling the engine where the timing should be. Causing it to be wrong now. (Yes I know it sounds like bull) but it's not.
ok so now how do you stop this. Well you start with earasing the adaptive memory to the computer. Very simple! #1 Get a small piece of wire. #2 undo negitive battery terminal. (Don't let it touch any metal) #3 plug\clamp wire from disconnected negative to the positive. #4 turn head lights on (so all surculating power exits the system). Let sit for exactly 30 minutes. OK nit once you do that don't start the truck you must now set your timing. Piston to 10 degrees T.D.C. set distributor to number 1.
now you need to go to the E.E.C. test (located on driver side) somewhere next to it or around it there will be two wires to a connecter with a gray plug in it. Pull that grey plug out. Now start the truck and turn your distributor as needed to fine tune the engine. Once you have it running properly test drive it. (Take it slow and easy because the computer is going to run a series of test and is going to learn your driving habits) then after all that plug the grey connector back in and the timing should be set.
Now what you just did to your truck is erase any memory if had and set the timing where it should be. The computer will now know that's where it should stay. (Note it's gonna drive like a new truck off the lot minus the miles already there. So take it easy for the first day, then the computer will be set.)
Please excuse my lack of grammer and spelling. This was alot to type. Hope all is well.
​​​

 

You're right, I do say it's not true! Your computer will not advance your timing so your distributor is 180 degrees off.