Died going down road, turns over but won't fire

[gslaugs]

Mayday. Rookie mechanic. 1986 2.9 liter cut out going down the road and now won't restart. Battery is fine, 35 psi fuel pressure at manifold. No fuses in box burnt out. Turns over like a champ but won't fire. What's my steps in troubleshooting the ignition system?

 

[adsm08]

Start by replacing the ignition module.

Postin' from teh Galaxy

 

[joeyd3713]

same damn thing

Having the same sort of problem. maybe we can get together and figure this out on here.

Here we go

I have an 88 4x4 2.9. just finished new header install and decided to go for a drive.

I started the truck and within 3 seconds it died. a small plume of smoke came from the driver side under the hood where the wiring harnesses are. I quickly grabbed he wires and felt a hot fuseable link. I noticed that I had lost my check engine light when the key is turned to on. I had no spark at the coil. I have since changed the ignition control mod. the battery is charged the alternator is good and I installed a new eec relay. My check engine light is back my truck cranks strong but still no spark at the coil I have done wiring tests that have ruled out the coil.

What am I missing? I am no mechanic but I can turn a wrench and run a trout line. any suggestions thanks!!!!!!!!!

 

[RonD]

Mayday. Rookie mechanic. 1986 2.9 liter cut out going down the road and now won't restart. Battery is fine, 35 psi fuel pressure at manifold. No fuses in box burnt out. Turns over like a champ but won't fire. What's my steps in troubleshooting the ignition system?

Have a read here for TFI ignition: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml
Print the Worksheet, and follow the steps

 

[joeyd3713]

try here

Mayday. Rookie mechanic. 1986 2.9 liter cut out going down the road and now won't restart. Battery is fine, 35 psi fuel pressure at manifold. No fuses in box burnt out. Turns over like a champ but won't fire. What's my steps in troubleshooting the ignition system?

this has been a helpful place for many. try here let us know what you find!

http://easyautodiagnostics.com/ford_ignition_module/distributor_mounted_module_1.php

 

[RonD]

Having the same sort of problem. maybe we can get together and figure this out on here.

Here we go

I have an 88 4x4 2.9. just finished new header install and decided to go for a drive.

I started the truck and within 3 seconds it died. a small plume of smoke came from the driver side under the hood where the wiring harnesses are. I quickly grabbed he wires and felt a hot fuseable link. I noticed that I had lost my check engine light when the key is turned to on. I had no spark at the coil. I have since changed the ignition control mod. the battery is charged the alternator is good and I installed a new eec relay. My check engine light is back my truck cranks strong but still no spark at the coil I have done wiring tests that have ruled out the coil.

What am I missing? I am no mechanic but I can turn a wrench and run a trout line. any suggestions thanks!!!!!!!!!

So the EEC relay was the reason the CEL wasn't working?
EEC relays powers the computer and ignition system, and fuel injectors.

There are often 2 power paths for the coil, only one is active at a time
While cranking(START) the coil gets 12volts
While running(RUN) the coil gets 8volts

You can try running a jumper wire from battery to coil "+", then crank the engine, if it starts remove the jumper and see if it keeps running.
If it doesn't start then either coil is bad or it is not being Grounded.

An ignition coil sparks by powering the Primary coil and then cutting the power, that generates a spark on the secondary coil.
Coils are given 12volts(8volts) while the key is on, the Ground(-) is used to power and un-power the primary coil.

Electronic ignitions work the same way "point" ignition systems did/do, only difference is the method used to Ground and unGround the coil.
The "points" are the Ground, when "points" closed the coil powered up, when "points" opened(no ground) the power was cut, spark was created.
"Points" rode on a cam in the distributor that opened and closed them for the number of cylinders in the engine.

In electronic ignitions they use a sensor(instead of cam), and transistor(instead of points), to power and unpower the coil to get coil to spark at the right times.

Check out the TFI link in above post to test ignition system

 

[joeyd3713]

EEC relay

The relay was not the reason. One of the Fuseable links was the culprit. I changed the relay just because i had one and it was the original in the truck. I have only owned fords (about 12 of them) I have a lot of extra parts. Ron, Do you happen to know where to look or trace the ground for the coil I am still not getting spark i'm lost. The wife is starting to stare....

 

[RonD]

Did you look at the link above, it has the test points for grounds.
The computer also Grounds the system, so it needs a good ground, but generally Fuel Pump won't come on if computer grounds are bad, generally as there several computer grounds.

Have you tested the coil with ohm meter?

Good link to book mark here: http://www.auto-diagnostics.info/ford_eec_iv
Can test grounds and voltages when problems occur

 

[joeyd3713]

sorry Ron

Ron, I honestly couldn't find the link the first time I looked, Thank you.

I have located a problem wire I know need to trace it. It is a little larger out of the harness and is light tan with a yellow line. just had another bit of smoke from it and it almost melted. obviously have a short there. on the other side of the connector it has the blue 20gauge fusable link

 

[RonD]

AutoZone has a nice on-line repair section:
Google: autozone 1988 ranger wiring

Click on the link, there were 4 wiring diagrams for an '88 Ranger/BroncoII, I didn't see the T/Y wire but maybe looking at it will help you.
Also check out the '87 diagrams as wiring can overlap on early '88

 

[joeyd3713]

ok so here is where i am

I have traced the power loss to the two fuseable links that are connected to the pink and green wire... and the grey and yellow wire... I get all of my power back but no spark. something in line with those two wires lies my issue.

 

[RonD]

Have you tested the coil?

Remove the "-" wire on the coil.
Remove the Coil wire from the distributor and place it so it is about a 1/4" from a ground.

Turn on key, make sure you have 12volts on the "+" terminal of the coil.
Use a jumper wire and Ground the "-" on the coil, then remove the ground, you should get a spark at the distributor coil wire, if not coil is bad.
Each time you ground and remove ground you should get a spark.

 

[gslaugs]

it was the ICM. turns out that thing is pretty important! Thanks everyone