The no spark mystery continues

[Kmcbride3956]

So I’m guessing I need a new distributor. Or can the pip sensor just be changed? Anyone have any advice for me about this? Also, where is the hold down clamp for the distributor? I can’t tell how you remove the thing.

 

[RonD]

And just checking but you did physically check that the distributor shaft is turning correct?
If not then no pulse(PIP) signal

Yes sensor can be changed but pulling the distributor would be needed

Have a look here to see where the bolt to remove is: https://www.therangerstation.com/forums/index.php?threads/distributor-hold-down-bolt.21941/

If possible rotate the engine by hand so the rotor on distributor shaft is pointed at where #1 spark plug wire is on the cap.
Crank should now be at correct TDC mark
Pull out distributor

When you put it back in, assuming you didn't turn the engine, make sure rotor is pointing at #1 again and you are timed, well close engine to start and use timing light

 

[bamabones]

I thought I should start a new thread on my truck because the one I had started before was about a separate issue. So I have an 88 4 cylinder 5 speed ranger that was given to me because it wasn’t getting spark and the previous owner gave up on it. I had to replace the coil because the tip of it was broken off. After replacing that I started checking the ignition control module and found that it had a bad ground. I fixed the ground but still no spark. I also found a few other wires that were cut or otherwise messed up. The wires going to the MAP were cut so I fixed them, still no spark. Then I found the wire going to the oil pressure sensor was cut. I decided to test this wire by putting my test light on the positive side of the battery and touching the wire with the test light. It didn’t light up, leading me to believe that there is a problem in that wire somewhere. I traced that wire to the large wiring bundle that also connects to the ICM. I then traced all that back to the computer. I took off the passenger side kick panel and found the casing around the computer to be wet. So I pulled the computer and opened it up. It looks dry and I don’t physically see anything wrong in there but I don’t know how to tell just by looking at it. So now I don’t know if I should replace the computer or not. Obviously it’s been getting wet every time it rains, but I don’t know how wet, and if it’s just the case, or if water has gotten inside. The truck seems to have some wiring issues at the very least because I have found 2 different areas that didn’t have continuity. I don’t really know what to do next. Replace the computer? Attempt to trace every single wire? I am not a professional mechanic, and have a limited amount of knowledge when it comes to wiring and electrical components. Any suggestions?

didn't really have time to read the above comments but being new to truck mechanics I will give you the advice that I can and its simple, a little something I picked up from being an aircraft mechanic............. check your fuses if you have fixed something that was recently broken before moving on.

 

[Kmcbride3956]

RonD, yes I had my wife turn the starter while I had the cap off and watched the rotor turn. Thanks again for your help, I’ll update when I make progress.

 

[RonD]

RonD, yes I had my wife turn the starter while I had the cap off and watched the rotor turn. Thanks again for your help, I’ll update when I make progress.

Good, sometimes our "assumptions" waste alot of our time, and money, lol

In my case I have wasted alot of time on different engines with what I "know" is correct when it isn't, I assume its correct, lol
Firing order is my Achilles heel, I can check it twice, even 3 times, and miss the obvious

 

[Kmcbride3956]

RonD, I think I finally figured out which pin is number 56 on the wiring harness to the computer. Is it the one with the solid blue wire? The harness only has 2 blue wires, one solid blue and one blue with a green stripe. If I tested the correct one, it only had .14 volts while cranking.

 

[Kmcbride3956]

Oh and when I tested for continuity on that blue wire, it didn’t have continuity. However I also just decided to test some of the other wires at the harness where they attach to the computer and found that only like 4 wires had continuity. Is that normal? Doesn’t seem right to me, but I’m out of my league with this stuff anyway. Believe me, if I could afford to take it to a mechanic I would, but I can’t so I need to try and figure this out on my own. But I am learning!

 

[RonD]

Yes pin 56 should be Dark Blue wire(no stripe) and runs to TFI module's PIP, which is the top wire on connector

Continuity means a wire tests as 0 or low OHMS when you connect OHM Meter to each end of the wire

Continuity means no breaks or corrosion on that wire.

EEC-IV connector and wiring seen here: http://www.auto-diagnostics.info/ford_eec_iv

Pin 36 is SPOUT and should have 0 OHMS to TFI wire next to PIP wire, I think its a Yellow/light green stripe wire

Not sure what other wires you were testing

Dark Blue with green stripe wire is for the MAP sensor, just FYI

 

[Kmcbride3956]

Yes pin 56 should be Dark Blue wire(no stripe) and runs to TFI module's PIP, which is the top wire on connector

Continuity means a wire tests as 0 or low OHMS when you connect OHM Meter to each end of the wire

Continuity means no breaks or corrosion on that wire.

EEC-IV connector and wiring seen here: http://www.auto-diagnostics.info/ford_eec_iv

Pin 36 is SPOUT and should have 0 OHMS to TFI wire next to PIP wire, I think its a Yellow/light green stripe wire

Not sure what other wires you were testing

Dark Blue with green stripe wire is for the MAP sensor, just FYI

Okay, then i was on the correct wire. So I suppose that there is a problem in that wire somewhere because it didn’t have continuity. I just had the meter set to give a beep when it found continuity, so I didn’t look at the actual reading on the meter but it sure didn’t beep and it would on some of the other wires. Well I just thought about this, does it matter if the distributor cap is on and plugged into the coil when I do this test? Cause it’s not.

 

[RonD]

No, the TFI connector needs to be unplugged as does the computer and you connect tester to each end of the dark blue wire

 

[Kmcbride3956]

Got it. I was doing it wrong then, go figure. Makes perfect sense now that you say it, how else would you know if the wire is good or not! Duh. If nothing else, at least I’m learning about something I didn’t have a clue about before.

 

[RonD]

I’m still working on this no spark issue on my 88 4 cylinder. I replaced the distributor just now because I got to the point that I thought something was bad with the crank position sensor on the old one. Of course it’s not starting still with the other distributor. But when I put a spark tester in line from the negative coil to the distributor cap, it will flash on briefly twice when I turn the key on, but doesn’t light up at all when cranking. I did test the positive coil while cranking and it was getting 10 volts. Any ideas?

You don't have a "crack position sensor", only distributorless engines do

You have a Hall effect sensor in the distributor, it acts like the "points" did in an older distributor
The hall effect sensor sends out a pulse to the TFI module each time distributor shaft shows piston at TDC, so on a 4 cyl that would be 4 pulses on each rotation
The coil should have 10volts on "+" while cranking
The TFI module is hooked to "-" on coil, it grounds the coil with key on to "charge it up" then unGrounds it when Hall effect sensor sends a Pulse, unGounding is what causes the SPARK
The TFI grounds "-" again until next pulse from hall effect sensor

You can make an ignition coil spark by powering it up and then removing power, + or -, - is used because it was easier with "points" in a metal distributor, lol, and they just stayed with that.

 

[Kmcbride3956]

Okay, I get that part. Still no spark from the coil when I crank it. The replacement distributor came with a new TFI so now the truck has a new coil, distributor, cap, and TFI. I feel like I have to be getting close to figuring it out, or that it’s going to be something simple that I’m overlooking. Guess I’ll start the testing all over again tomorrow with the new parts. Even if the thing is way out of time, it should still spark correct?

 

[RonD]

Yes, if distributor shaft is turning and the coil and TFI module both have 9-12volts the coil should be sparking

One thing that can be overlooked is the TFI ground, usually the lower wire on the TFI module

These are the wiring on the two different TFI modules, grey and black: https://www.stangnet.com/mustang-forums/attachments/tfi_5-0_comparison-gif.250293/

The Grey is probably what you have, the START should have 10v when cranking, as should RUN, but RUN will change to, or be, 12v when key is in RUN
The reason for 10v is because starter motor draws alot of AMPs and system voltage drops down to 9-10volts while cranking

The coil NEG should Pulse Ground as distributor spins
You can set engine and distributor at #1 TDC then pull out distributor and spin it by hand(or use old distributor and TFI module), cap off, and see if coil is sparking.

Should get 4 sparks per 1 rotation of the distributor shaft

 

[Kmcbride3956]

Okay, and the TFI and Coil both have 12 volts with the key on. But no spark. So I will check the TFI ground again. Yes, I do have the gray TFI. I will test these things and report back my findings! I hope I get this thing figured out soon.