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TDC and Distributor

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  #1  
Old 03-25-2011, 09:40 PM
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TDC and Distributor

On my '91 F-250 5.8L I line the notch on the edge of the harmonic balancer up with the timing pointer, and the ignition rotor points about 90deg. away from #1 cylinder's post on the cap. I turn the engine 360deg. and the rotor turns 180deg., 90deg. on the other side of the dist. cap post for cylinder #1. Shouldn't the rotor be at #1 firing position when the cylinder is at TDC compression stroke?
I need to pull the distributor to change the PIP sensor (cranks, but no spark). As long as the engine doesn't revolve, and the rotor is pointed the same as it came out, it seems like it would all work the same. Right????
 
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Old 03-25-2011, 09:56 PM
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the notch on the harmonic balancer isnt the timing mark i dont think, i think you need to look for a small set of lines stamped into the balancer with numbers next to the marks. the center mark should be tdc
 
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Old 03-26-2011, 02:38 AM
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There are a few of us like you describe.

Latest thought is the pulley can slip so the marks have nothing to do with
reality.
Either way, it wants to be the same as the one that (used to ) works.

To answer your question,
IF the new dist goes in the same way the old one came out, you think it would work, that is
IF it worked in the position it is in.

Another way to check is to pull #1 plug and put in a plastic drinking straw and turn the engine with a wrench and stop where you think TDC is.

The other topic is to make sure the driveshaft for the distributor doesn't fall into the oil pan IF it happens to be one of those.
 
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Old 03-26-2011, 06:17 AM
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If your just pulling the distributor to work on it you don't need to line up the timing marks , just mark the base where it goes into the motor , and mark on the dist where the rotor is pointing , put it back to the same position it came out , then check the timing with a light when your done....Lew
 
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Old 03-26-2011, 07:50 AM
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All good to hear. I will pull the distributor today and put a new PIP sensor in. I guess statistically, it should be the TFI module, but I followed the test procedure at:

easyautodiagnostics.com/ford_ignition_module/distributor_mounted_module_1.php -

It shows the PIP sensor is bad by process of elimination. Hope they're right! I'm a nearly down and out residential construction contractor. Ouch!
Thanks guys.
 
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Old 03-26-2011, 11:33 AM
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Not exactly sure except for process of elimination.

What Lew said was great, mark Everything and whatever you do, don't let that engine turn with the distributor out.
Hide the key, block the wheels, make sure it's in neutral etc etc.

We had one guy with a hot start problem so he heated his distributor with a hairdryer, and it wouldn't start.
Blew it off with cold air and it started,
actually did that to a few different components and made sure it was the pip sensor by heating and cooling.

Some people say it's better or easier to just replace the distributor than to take it apart to fix.

Reminds me that I want to get an extra dist from a junkyard.

Do your fuel pumps run for a second and then shut off? with the key Just in the 'on' position?
or do they keep running?

Pls keep us posted.
 
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Old 03-26-2011, 11:46 AM
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I hear the fuel pump(s) every time I turn the key on for a second.
 
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Old 03-26-2011, 11:53 AM
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Originally Posted by martski
I hear the fuel pump(s) every time I turn the key on for a second.
Ok, so the pumps come on and shut off when you turn the key to the on position. perfect.

If they keep running, it indicates bad capacitors in the eec that sorta duplicates your no spark problem.

Depending on what part of the country you live in, (salt etc)
a simple connector check, connector plugs, grounds etc can also be a consideration.
Dielectric grease is best for those connectors btw

I really hope it's a cheap and easy fix.
 
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Old 03-26-2011, 12:26 PM
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Thanks. Me, too! I live in the greater Seattle area. Salt's not much of an issue. They use a liquid de-icer on the roads. It is pretty wet here, though.
 
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Old 03-26-2011, 08:47 PM
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I wound up pulling a distributor from an '89 F-150 5.0L at the salvage yard. On the Motorcraft.com website, the part #'s look to be the same for the 5.8L and 5.0L, but the prices are all over the place depending on engine size and tranny. What gives?
 
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Old 03-26-2011, 09:00 PM
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Rats! The spindle below the gear on the 5.0L distributor is a smaller diameter than the one from my truck. I made sure they'd take it back if it wasn't going to work.
 
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Old 03-26-2011, 10:09 PM
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Originally Posted by martski
. What gives?
The heads are further apart on a 5.8 than a 5.0 since the cylinders are taller. That means the distributor shaft has to be longer as well. Thats one reason they aren't the same. The other is that the oil pump drive shafts are different. I believe the 5.0 is 3/8ths thick & the 5.8 is 7/16ths.
 
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Old 03-28-2011, 02:33 PM
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On an auto parts store website, you can look at the vehicles that a part is compatible with, and the TFI from the 5.0L works with the 5.8L and all kinds of Ford vehicles. I tried the junkyard module on my distributor and we have ignition. I was pretty careful checking connections when running the easydiagnostics, so I wonder if the procedure is flawed, or if I didn't follow it right.
Thanks to all for the support. You are good folks.
 
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Old 03-29-2011, 02:52 AM
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YaY!

Glad you outsmarted it.

Now it's my turn to go find an 'extra' one.

Was it hard to swap out?
 
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Old 03-29-2011, 10:13 AM
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The TFI (ignition module)? Its fastened to the distributor with 2 screws. The electrical connection is several push in spades that point straight up toward the distributor cap. That's it. You're supposed to coat the contact area between the distributor and the module with silicone grease.
 


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