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87 stopped running while driving now no spark?

87RangerXLTct

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My 87 Ranger died on me last week, was driving down the road and it just cut out. Pulled over and tried to start it again, it started after a couple minutes then when I put it in gear and let off the clutch it died again. Got it towed home, checked for spark and it has none but it's getting fuel.
Primary and secondary resistance are within spec for the coil. That lead me to the TFI module. Checked voltage at pin 3 koeo 11.6V, pin 4 was only .13 volts. My battery voltage was 12.4. So I think I either have a short somewhere or maybe a bad ignition switch? My negative battery cable is corroded where it bolts to frame and wire is bare. Was having trouble starting the truck in the rain or after it rained, it would eventually start but took a few minutes. Also was having driveablity issues with a hesitation/misfire underload or going uphill mostly at highway speeds, think thats unrelated but may have something to do with bad ground (neg batt cable).
I'm going to replace negative battery cable and see if I cant find a short in the tfi harness. Is there a way to test the ignition switch?
Any other ideas of why no spark?Thanks in advance
 


RonD

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Replace TFI module, anytime engine is under load it heats up under the hood, older TFI modules start failing when heated up, so........going uphill, or even accelerating causes more heat and so more misfires

Not sure how you are numbering the pins on the connector
Pin 3 Run/start should have 12v with key on, 11.6 is fine if battery is 12.4

Pin 4 will ONLY have voltage when key is turn to START, and it will be 9 to10v because starter motor is drawing down voltage.

Yes, clean up the Grounds
Battery to engine
Battery(or engine) to frame
Battery to Rad support and inner fender
Engine to Firewall<<main cab ground

TFI test page here: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

Download and PRINT the Worksheet
 
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87RangerXLTct

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Yes tested pin 4 while cranking, said to ground to distributor base but my test lead might've had poor connection. Do I have to ground to dist. base or could I go off a different ground say brakeline? I'll print that work sheet and give it another go with better ground connection.Thanks Ron for the help
 

87RangerXLTct

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Put a testlight on coil negative and cranked, it stayed lit just dimmed a bit didn't flicker. Would that indicate bad pickup module in distributor? Primary resistance was .7ohms secondary was 7,380. Rechecked pin 4 start voltage at TFI while cranking still had .13 volts this time I'm sure I had good ground. I'm stumped, don't want to throw parts at it, would like to accurately diagnose this so I'm not wasting time and money
 

87RangerXLTct

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Failed to mention test 9 voltage at spout connector while cranking was .5volts
 

RonD

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Starting voltage comes from the Neutral Safety Switch(NSS) or Clutch switch(Manual trans)

When you turn the key to START the ignition switch sends out 12volts either to NSS or Clutch switch, depending on transmission type.
If trans is in Park or Clutch pedal is down, that 12volts goes to Starter Relay(solenoid) on the fender, and activates the starter
This wire from NSS or Clutch to Starter relay has a Splice, and that wire runs to START on TFI module

Ignition switch------------NSS-------------TFI/starter relay

This START wire should be Red with Blue stripe at NSS, TFI and at Starter relay

And you could add a splice to Red/blue wire at starter relay, assuming starter works OK, and run that wire to START on TFI module

Did you get a chance to OHM TFI Module as shown at bottom of the Link aboves page?

If test light on coil was flicking then test was OK
And the pickup in the distributor can fail just not common, the TFI Module reads the pickup and then ungrounds the Coil like the old points setup did.
The TFI module is more likely problem than the pickup
 
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87RangerXLTct

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Ok so ended up back probing tfi connector to check start voltage while cranking and I got 9.29v. Back probed spout terminal at tfi while cranking and saw 4.67v. Must've had poor connection with my test leads before. Didn't get a chance to ohm check the tfi module, I'm guessing that's done with tfi removed from vehicle to get at top 3 pins?
From what I gather everything is pointing towards bad tfi at the moment? Only thing that puzzles me is not seeing a flicker at negative coil with test light, it dims instead could be my crappy test light?
Should I proceed with removing tfi module and ohm testing it?
Thanks for the help Ron!
 

87RangerXLTct

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Just to confirm I'm getting pip signal I back probed pip wire at tfi while cranking and got 4.46v from what I gather a good pickup module/Hall effect should average 4-5volts while cranking? Everything pointing to bad tfi now?
 

RonD

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Well the TFI module will ground and unground the Coil -, causing test light to flash

So if it is failing then that may not happen
The pickup inside distributor sets pulse rate(timing) for the grounding and ungrounding but does not actually do the grounding and ungrounding

Think of the TFI module as the "points", the pickup in distributor are the Lobes that opened and closed the "points"
 

87RangerXLTct

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I see.
Was able to ohm test the tfi module some numbers where off but not by much. Having trouble uploading pic of results. I ordered a new tfi module should arrive tomorrow at store.
 

87RangerXLTct

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Alright had the tfi module tested 4times at autozone failed all 4 times, went and ordered new distributor from advance auto with new module included. Also had them test tfi and it failed there as well. Had a motorcraft tfi module ordered through the ford dealership for $70 but I figure I'd go with whole new distributor and module for around same price considering bushings are near worn out on my current distributor and also read the Hall effect sensor should be changed along with tfi if possible.
Might eliminate some drivability issues I was having at the same time.
Noticed the injector harness had some cracked wire insulation probably due to heat exposure? Have a spare harness I'm going to swap in while I have upper intake plenum off. I'll tackle leaky valve cover gaskets while I'm at it.
Thanks Ron for the help. Truck should be running again in a few days.
 

RonD

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Sounds good.

use cork valve cover gaskets
Rubber gaskets should be used if you know you will be removing valve covers a few times, because they can be reused, they just may not seal as well as cork using stock valve covers.

Cork gaskets are not reusable after a few months go by, but they seal better because they absorb oil and swell a bit to seal any gaps.

Thin metal stock valve covers should be flattened around the edges as much as possible before reinstalling
The holes for the bolts are often deformed from over tightening so if you don't flatten them out they won't apply as much pressure on the areas between the bolts

Lower rear of valve covers is where the oil collects, so most common spot for leaks to start, double and triple check that area for flat clean seal

Remove distributor cap on old distributor and manually rotate engine so rotor is point at #1 spark plug wire location, crank pulley should be at TDC mark.
Then remove distributor, rotor will move a bit as you pull out the distributor, gears are angled
Put new distributors rotor in same position then reinstall for same position on cam gear
Distributor may not go all the way in/down, it is not in line with oil pump drive shaft
Rotate crank 90deg one way and back to TDC mark, distributor should "fall" into place, if not rotate 90deg the other way and back to TDC

You still need to fine tune spark timing with SPOUT connector unplugged and using a timing light, 10-12deg BTDC is spec
 
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