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87 ranger no spark issues

foreverproblems

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Hey guys, pretty new to this forum though i have been referencing it heavily as of late to figure out what is going on with my 87 ranger. its is the XLT 4x4 model with a 2.9L Cologne V6 engine in it. I bought it a few weeks ago and everything seemed fine but then the truck would "go hunting" while in idle and eventually die; after it warmed up it was fine. Last weekend i drove 2 hours north and it did fine but then after a short break i was driving it around the city and it died at a stoplight, it gurgles and sputtered when i let the clutch out and then died. Since then it will not start. Checked the fuel pump relay and its good, can still hear the pumps humming when i turn the key over. The engine cranks but will not start, volts in battery are good. bought a spark tester and tried it on a spark plug, no spark. tried it on the ignition coil, no spark. took the distributor off, everything looks good, took off the TFI module and took it to get tested and it works fine. cleaned the distributor and put it back on and still no spark. I get no flashing check engine light and do not have a ODB-1 tester but i tried doing it by jumping a connection across the diagnostic connector signal return and the self test input and still nothing. Thing is driving me nuts. Anybody have any ideas? Truck cranks like a champ but no spark. Please help!
 


adsm08

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Probably the TFI even though it passed the bench test. Those testers don't load the module the same way the system does, and so a good bench test doesn't necessarily mean a good unit. I made a point of having several spares around when I had 2.9s.
 

foreverproblems

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Probably the TFI even though it passed the bench test. Those testers don't load the module the same way the system does, and so a good bench test doesn't necessarily mean a good unit. I made a point of having several spares around when I had 2.9s.
Assuming the TFI is good, what else could it be? Would a faulty PCM relay cause this issue? I don't get a check engine light at all, even when cranking. don't know if this has something to do with the PCM or naw. Thanks for the help
 

RonD

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Welcome to TRS :)

If fuel pump is working then EEC(PCM) relay is OK
But CEL should come on with the key, so probably a burned out bulb, PCM is getting power or, as said, fuel pump wouldn't start up

TFI is a self contain spark system, computer assists spark advance but TFI starts the engine.

Good read here with tests for TFI: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

Obvious but have to ask
Rotor is turning when engine cranks, right?
If you haven't looked............

Spark starts with the hall effect sensor in the distributor.
It has 3 wires, a Ground, Reference voltage, and PIP out
Ford calls this the PIP(profile ignition pickup) sensor, it generates the PIP signal.
With cap and rotor off
Key on, spark tester on coil
Put a feel gauge or knife tip in front of the PIP sensors window, you should get a spark each time you insert and remove the feeler gauge.
If not then PIP could be bad but it does pass thru the TFI module so................

And just to test the coil.
Key on, spark tester on coil
Unplug TFI module connector, find the Coil wire, it runs to "-" on the coil.
Use a jumper wire to ground and then un-ground this wire, you should get a spark each time coil is un-grounded.
If not then make sure coil "+" has 12 volts if not that's your problem, if it has 12volts and grounding and un-gounding didn't produce a spark then replace coil.

Coils are very simple devices, power it up with 12v and ground, when you cut the ground it will spark, if it doesn't then it is dead.


PIP signal tells TFI module when to cut ground to the coil, like points did in old distributors, points open ground cut, points close coil powers up.

TFI is just one step past that, but it uses no moving parts that wear out and need to be adjusted every few months like points needed.
Module is basically heavy duty transistors that switch coil's ground off and on, with PIP signal, it also has a timing circuit that can advance or retard spark timing once PIP signal is established, so it all starts with PIP.
PIP is also the RPM on the tach, if you have a tach and it is no longer moving when cranking engine that could mean PIP is not present.

PIP is sent to the computer so it can time the fuel injectors, so one other test for PIP is to have everything hooked up, then crank the engine a couple of times.
Pull out a spark plug and it should be wet with fuel
If it is dry then no PIP.

Computer(PCM) sends spark advance "advise" to TFI module on the SPOUT(spark out) wire.
This is used because computer has access to TPS(throttle position sensor) and MAP(Manifold pressure) sensor.
Old distributors had vacuum advance, so spark advance could match throttle position and intake vacuum(engine load).
SPOUT is in essence the "vacuum advance" for the TFI system.
And like the vacuum advance it is not needed to start engine, just operates better with it :).
This is also why you disconnect SPOUT jumper to set base spark timing.

EDIT:
I read your post again, you have a new spark tester.....................can you test if it works on another vehicle, just don't like relying on untested "test equipment", lol, you can end up chasing your tail.
Even a lawnmower or motorcycle
 
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foreverproblems

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Alright so this is where i'm at currently. I got a new TFI module and put it in. When i cranked the engine i got spark on the coil but still no start. Sprayed some starter fluid in the air intake and cranked again. Once more got spark but no start, repeated this process about 3 or 4 times with same results. Spark but no start, even with starter fluid. Fuel pumps are still humming. Then, i noticed that i wasn't getting spark anymore. Tried cranking it a few more times and same thing. no spark. However, i get a slight, weak spark every now and then when i turn the key on/off. Don't know what that could be. Thinking about replacing the distributor but don't know if that is what it is. Coming from the ignition coil are two wires, a green one and a red one. The green one then splits into two wires but then converge to a third which as rubbery black box on about 3 inches long by 2 inches wide before turning back into a green wire. Any idea as to what that could be? Thanks for the help fellas
 

RonD

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Green wire on coil is the Ground, it goes to Tach and to computer and to TFI.
Red wire is 12volts, it goes to Ignition switch, also TFI module.

Test the coil.
Weak spark is either low voltage at coil, or bad coil
Test if you have full battery voltage at coil +, red wire
Then unplug TFI connector and ground and unground the Green wire on that connector.
Should get a nice blue/wire spark, yellow is weak
 

foreverproblems

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Green wire on coil is the Ground, it goes to Tach and to computer and to TFI.
Red wire is 12volts, it goes to Ignition switch, also TFI module.

Test the coil.
Weak spark is either low voltage at coil, or bad coil
Test if you have full battery voltage at coil +, red wire
Then unplug TFI connector and ground and unground the Green wire on that connector.
Should get a nice blue/wire spark, yellow is weak
Okay. so here is where i am at: pulled out the distributor again and noticed there were 2 teeth missing, got a new one and put it in. the truck now has consistent spark across the ignition coil and the plugs are getting spark. Truck still will not start. I sprayed some starting fluid in the air intake repeatedly and still no start. With/without starting fluid truck will sputter/pop like it's trying to get going but cannot get there. it's not a fuel issue as i can still hear the pumps humming and the spark plugs are wet after priming, meaning the injectors are doing their job. Tested it repeatedly and am still getting consistent spark but no start. tried it with jumper cables on it to keep the voltage up and still nothing, got the same sputtering/popping. Any more ideas?
 

Andy D

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Betcha the plugs are gassed. Pull them. If they smell like gas . Either get new or cook them on a grill for an hour or so. G'luck
 

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