Truck goes out of timing oddly.

[Westep1986]

Hello all,

new to the forums here. I’m having an issue with my ‘86 Ranger, which has the 2.9L. I have recently changed the ignition module on the side of the distributor, and reset the timing. After resetting the timing the truck sounded great! No misses or anything. Took it on a test drive to be sure and I let the engine wake up to normal running temperatures. However, when I park the truck, shut it off, and let it rest for a few minutes and I go to turn it back on it sounds terrible and I check the timing again when the spout connector is disconnected and it’s NOWHERE where it should be. If I let the truck rest overnight and go back out in the morning it does the same thing, totally fine until I shut it off and let it rest. Any ideas? Thanks.

 

[RonD]

Welcome to TRS

Reads like a bad TFI module, even if new
These had a heat issue, not sure if anyone actually found what the heat effected in the TFI module but effect it it did

When engine is running engine bay has air flow so some cooling, when you shut off the engine there is a "heat soak" as cooling stops, no water pump and no fan, so everything under the hood gets hotter, and that may be putting the TFI module "over the edge", just guessing
After cool down it works fine again

I can't see the hall effect sensor inside the distributor causing the described issue
And with SPOUT disconnected it can't be computer doing it

Did you use the white heat sink grease on the back of the module when you installed it?
They do run very hot so need to dissipate that heat to distributor case
Ford changed to remote mounted TFI modules in later years because of this heat issue

 

[Westep1986]

Welcome to TRS

Reads like a bad TFI module, even if new
These had a heat issue, not sure if anyone actually found what the heat effected in the TFI module but effect it it did

When engine is running engine bay has air flow so some cooling, when you shut off the engine there is a "heat soak" as cooling stops, no water pump and no fan, so everything under the hood gets hotter, and that may be putting the TFI module "over the edge", just guessing
After cool down it works fine again

I can't see the hall effect sensor inside the distributor causing the described issue
And with SPOUT disconnected it can't be computer doing it

Did you use the white heat sink grease on the back of the module when you installed it?
They do run very hot so need to dissipate that heat to distributor case
Ford changed to remote mounted TFI modules in later years because of this heat issue

We used what came with the module, I would assume that’s what it was, but I’m not 100% sure. In addition, I turned the distributer clockwise and switch the plugs around so that way the module would be farther away from the valve cover and unfortunately the issue still persists. Thanks

 

[adsm08]

Pull the distributor out and check the gear.

The drive gear is held to the distributor shaft by a roll-pin. While not a common point of failure because it is under almost no stress normally, it is possible for the roll pin to fail and allow the gear to slip on the shaft. When that happens it causes all sorts of odd issues, lack of power, spark knock, stalls, hard starts, normal running, sometimes all in the same trip.

I had this happen to me a few years ago, and I was pulling my hair out for months trying to find the problem. I even went out and bought another car to drive while I tried to figure out what was wrong with the truck.

 

[Westep1986]

Hello there folks. A little update about my truck. I finally caved and took it to one of our mechanics after replacing the Distributor, TFI module, coil, spark plug cables, and Engine control module. Once at the mechanics he determined that there was no fuel filter in place, just the empty canister where it goes, so he installed one and threw in a new fuel pump just in case. He then used some sort of special machine that cleans the injectors. He replaced a few other parts like the idle air control module, and part of the throttle because it was causing the idle speed to be inconsistent. He had thought he had engine running pretty good, but after a few days of driving around it still sputters at higher rpms, not as bad, but every now and again it misses and the higher the rpm the worse it gets. Also, it doesn’t like to start again after I’ve been running it for a bit, the engine will turn over and over, but it won’t sound like it’s even trying to start. Any ideas, tests, or questions would be greatly appreciated, Thanks.

 

[rusty ol ranger]

Hello there folks. A little update about my truck. I finally caved and took it to one of our mechanics after replacing the Distributor, TFI module, coil, spark plug cables, and Engine control module. Once at the mechanics he determined that there was no fuel filter in place, just the empty canister where it goes, so he installed one and threw in a new fuel pump just in case. He then used some sort of special machine that cleans the injectors. He replaced a few other parts like the idle air control module, and part of the throttle because it was causing the idle speed to be inconsistent. He had thought he had engine running pretty good, but after a few days of driving around it still sputters at higher rpms, not as bad, but every now and again it misses and the higher the rpm the worse it gets. Also, it doesn’t like to start again after I’ve been running it for a bit, the engine will turn over and over, but it won’t sound like it’s even trying to start. Any ideas, tests, or questions would be greatly appreciated, Thanks.

Did you change the spark plugs?

Pull codes?

Possible MAP issue?

@RonD @adsm08 @PetroleumJunkie412

 

[Shran]

I have had issues with MAP sensors but on the other end - won't idle unless you feather the throttle.

Hate to suggest throwing more parts at it but a weak coil could cause things like this. Coolant temp sensor, throttle position sensor can also cause issues - you can test these before replacing them.

Leaking fuel pressure regulator is very common on 2.9 trucks and can cause a hard start when warm. Pull the vacuum line off of it and see if any fuel is present...should be dry.

 

[RonD]

+1 to all the above ^^^

If you can get it to where you have a Crank but No start then do the 50/50 test at that time
Pull the air tube off the upper intake, spray fuel into the intake, and try to start engine
If it starts right a way then spark and its timing is good, but you have a fuel delivery issue
If it still doesn't start then its a spark issue
50/50 instant results

From your description it reads like fuel pressure is dropping under load
Because the canister filter was removed previous owner may have come to the same conclusion so removed the filter because of that
BUT................there is another filter inside the gas tank on the bottom of the fuel pump, common name is "the sock" because it looks like a sock attached to the bottom of the pump and lays flat at the bottom of the tank
It filters the fuel before pump sucks it in
These also get clogged up so limited flow at high demand, i.e. higher speeds

 

[adsm08]

I've seen the roll pin that holds the dis gear on break. That causes "interesting" issues with timing.

It's also one of the experiences that made me desperately want to ditch TFI for EDIS6.

 

[Westep1986]

Thank you all for the great replies! Yesterday I replaced the spark plugs and put in motorcraft brand. The ones that were in there didn’t look too old nor did they have abnormal wear n tear. I also threw in a new MAP sensor. This combination really helped a lot. Truck seemed to have a bit more power, it got rid of the engine stuttering at high RPM’s, and it even got rid of the issue where I would shut the truck off after using it, and then it didn’t want to restart. However, after feeling victorious, I went to fill her up with fuel and just as I was about to pull into the gas station she died. No stutter or coughing like she was running out of fuel, just as if a switch was flipped, died. Thankfully I was able to roll next the fuel pump and fill her up, though I only had to put in about a half a tank. After that I tried restarting and she sounded like she wanted to start, but just couldn’t. Realizing I had issues in the past when the engine gets hot, I rolled out of the way and sat for bit. Then after about 30 minutes or so I was able to start the truck but it would stay running for about 4-5 seconds and then die. This morning I went and got the truck, she started and idled fine, and I drove her the 10 miles back to my house. Only now the engine stutter is back, but only when it’s under some pressure, but I can put my foot down and it will sort itself out and run strong. I didn’t have the tools available to do the 50/50 test yesterday but I will keep them in the truck so if it happens again I can test it. I also plan to look at the fuel pressure regulator today. Update: I check the Fuel pressure regulator And there was no fuel coming out of the vacuum line. Next, I looked at the Inertia Switch, and it looks fairly new, and resetting it did nothing. I went to just take a drive down my driveway and the truck ran for a few seconds and shut off again. Did the 50/50 test and it's definitely an ignition issue, sprayed starter fluid in the intake and it didn't help in the slightest.

 

[RonD]

In 1994 and earlier Rangers spark system is a separate device, in your model its the TFI system
Engine computer is separate and not used at all for spark on start up

So no start on 50/50 test means spark system is not getting 12volts when engine is cranking(its a separate power wire)
Or TFI, hall sensor or coil is not working

Try putting a test light or volt meter on Coil "+" terminal that you can see from the cab and crank engine over, volts will go down but should stay above 9.5v, not go to 0v

If voltage is being cut to spark system then its just like an OFF switch as you described

There is a red/blue wire that comes from ignition switch that activates starter motor AND powers the TFI module and coil when key is turned to START
Then when key is in the RUN position a red/green wire from ignition switch takes over and powers the TFI and coil
So 2 separate wire paths

The one common thing between these 2 pathways is the ignition switch, so test for 12v in RUN and START

Long shot but not a no shot, is the SPOUT signal and engine computer
Engine computer does effect spark timing like vacuum advance did in the older systems
It does this using the SPOUT wire to TFI module
Because the engine will restart but then die(usually a fuel issue) it could be the Computer is the issue and advancing or retarding the spark too far causing the engine to die and not restart
Unplug the SPOUT connector to take the computer out of the spark system
The TFI module can run spark with just RPM advance, engine would be sluggish to drive but will run fine that way

 

[Westep1986]

In 1994 and earlier Rangers spark system is a separate device, in your model its the TFI system
Engine computer is separate and not used at all for spark on start up

So no start on 50/50 test means spark system is not getting 12volts when engine is cranking(its a separate power wire)
Or TFI, hall sensor or coil is not working

Try putting a test light or volt meter on Coil "+" terminal that you can see from the cab and crank engine over, volts will go down but should stay above 9.5v, not go to 0v

If voltage is being cut to spark system then its just like an OFF switch as you described

There is a red/blue wire that comes from ignition switch that activates starter motor AND powers the TFI module and coil when key is turned to START
Then when key is in the RUN position a red/green wire from ignition switch takes over and powers the TFI and coil
So 2 separate wire paths

The one common thing between these 2 pathways is the ignition switch, so test for 12v in RUN and START

Long shot but not a no shot, is the SPOUT signal and engine computer
Engine computer does effect spark timing like vacuum advance did in the older systems
It does this using the SPOUT wire to TFI module
Because the engine will restart but then die(usually a fuel issue) it could be the Computer is the issue and advancing or retarding the spark too far causing the engine to die and not restart
Unplug the SPOUT connector to take the computer out of the spark system
The TFI module can run spark with just RPM advance, engine would be sluggish to drive but will run fine that way

I finally figured out what it was.....the ignition module. Threw a new one on and all the problems I was having went away. Thanks for all the replies, so happy to have it up and running.

 

[RonD]

Good work

Thanks for the update