83 Ranger Idle and Starting issues

[Fords4Us]

Good morning all. Our 83 Ranger has been having ongoing and slowly worsening carburetor issues, as the various feedback and emissions modules have failed. It's the 2150 Motorcraft, and we've already made the decision to do the Duraspark/Holley carb conversion. We haven't finished saving up for it, and we were hoping the Ranger would limp along until we could get our funds pooled to get going on that project. Looks like the Ranger had other ideas.

I started having issues with rough starts and stalling on cold mornings. I had experienced that in previous years, and had installed a block heater (fun project, BTW, I'd do it again in a heartbeat). That really helped. But then I started having issues with the engine stalling after it was already at normal operating temps. It was actually fairly predictable - about 5 minutes after I got in to drive somewhere, that first time I put in the clutch to shift, my idle speeds would go to zero and I'd be rolling along in a dead truck. I'd either have to pop the clutch or restart it. If I restarted it right away, it acted like it was either starved for fuel or for a spark. I'd have to keep the starter engaged for awhile before it would catch again.

Then over the holidays we left it parked for about 10 days. When I went out to start it yesterday, in supposedly "Ranger-friendly" temperatures above 50F, it wouldn't start at all. Strong battery, strong starter just kept turning over and over again. It was definitely getting gas because I could catch the whiff of raw fuel. We just had the oil and filters changed, so the air filter isn't clogged. Best we can figure, this is one of our beloved carb issues, getting more severe.

Any ideas for getting this thing going again prior to the carb conversion? Or is our beloved Ranger a paperweight until then? Thanks all, you folks have always been a big help as we've come to know and love (usually) our old Ranger.

 

[RonD]

From your description the carb is probably OK for now, you smelled fuel.
And assuming you haven't been seeing bellows of black smoke when it was running, overly rich fuel mix.

My guess is the TFI spark system is your problem.

Good read here: http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

The description of the stalling after warm up matches TFI module failing when heated, a common issue.

Simple test is to get some Starting Fluid(ether) and spray some in the carb, hold open throttle when spraying.
Then crank engine if it starts and runs then you have spark but it was weak so couldn't ignite the gas only mix.
If it doesn't start/fire then you have no spark.

Ether has a very low ignition point so any spark can ignite it, which is why they use it on diesel engines, even compression heat will ignite it.

Duraspark is OK but HEI conversion might be a better choice, have a read here: http://www.carbdford.com/tech/HEI/hei.htm

 

[Fords4Us]

Good afternoon, and thanks for your feedback. I had some time today so I went out and checked a few things. We've had really wet weather lately, and I wanted to rule out condensation in the distributor cap. After taking that off and seeing that it was bone dry, I went ahead with the ether test. Zero response. Didn't get so much as a hint of the engine catching and firing after putting ether right into the carb. We may run the test again over the weekend with me sitting right in the cab while my husband sprays the ether into the carb, so that there's no time delay between spraying the ether and turning the key. Not sure if a 1-2 second delay would make a difference but we'll probably rule that out just in case.

Bottom line though, we're probably looking at no spark, for whatever reason. I was intrigued with the TFI info you provided, and that's gone to the top of the list of suspects now. Is there anything else we can/should test for or check, before we go trying to replace the TFI module? Thanks again.......
Kath

 

[kimcrwbr1]

Check for spark from the coil first. Put a spark plug in the coil wire and set it on a good engine ground, Turn the key on run and check you have battery voltage at the coil pos and a little less on coil neg. If your not gett voltage at both wires the coil is bad. If you get voltage at both quickly touch coil neg with a jumper to ground and the plug should fire. Just quick touches do not hold the jumper on there very long. If you get good fire at the plug just crank on the starter the plug should fire. If it does your problem is in the distributor cap, rotor or plug wires. The tech library has a good diagnostic for the TFI ignition it could very well be the module but confirm the coil is working first before you diagnose the module.

 

[kimcrwbr1]

http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

 

[RonD]

+1 ^^^


Ether stays in a vapor for longer than 1 or 2 seconds, so you have plenty of time between spraying it in the carb/intake and then getting into the cab to crank engine.

You for sure have no spark.