Most Likely Cause? - New Stalling issue (1 Viewer)

[BTG88]

One for the brain-trust -

1975 2f - with a Mark-rebuilt carb, headers and electronic ignition. New to me vehicle. Been driving for the last three weeks. Running well, idled smooth and even at full-off choke. Would start instantly cold with only a short tap on the gas pedal - no choke needed.

Today, stop off for 30 minutes at the store. Come back out and now the engine starts and dies. Will only run on half-choke, otherwise dies. Checked the clear fuel filter and all looks good - but will probably replace anyway. Took off the top of the carb, hand throttled and got the gas squirting. Did not see any debris in the bowl. Disconnected the idler solenoid and grounded to the carb. Did not make a difference.

I thought going from running fine to issues would be something electrical, like a loose wire, but not such luck. Thought that bypassing the emissons computer would indicate some issues there, but not to be. All vacuum lines look good, but will check will carb spray tomorrow.

Any other pearls of wisdom? PO had the vehicle for 10 years, so within that time period the carb would have been rebuilt.

 

[thebigredrocker]

So you didn't have Mark's rebuild the carb 3 weeks ago? The PO may have hired it done up to 10 years ago?

Is your fuel filter plastic? I've read where guys are having problems with those standing up to RFG.

With your engine running on 1/2 choke can you shine a light into the primary and see fuel spray from the primary nozzle? If so your idle curcuit may be plugged up.

 

[BTG88]

So you didn't have Mark's rebuild the carb 3 weeks ago? The PO may have hired it done up to 10 years ago?

Is your fuel filter plastic? I've read where guys are having problems with those standing up to RFG.

With your engine running on 1/2 choke can you shine a light into the primary and see fuel spray from the primary nozzle? If so your idle curcuit may be plugged up.

The fuel filter is one of the clear plastic ones with the replaceable element. The PO put in a new fuel tank, all new fuel rubber fuel lines, and has the filter placed on the non-header side, down below the battery.

In the 10 years that the PO owned it, he put less than 10,000 miles on it, so the carb rebuild did not see a lot of action. Having read a lot more on the subject, I think the likely culprit is the idle solenoid being gummed up, so that even when I grounded it, it did not move. Also, to your point, I am gettting spray from the primary nozzel. Will be spraying it today to see if that will work and checking for vacuum leaks.

Thanks for your perspective.

 

[Curt]

The idle solenoid when not operating requires use of the choke. You can here it click when the key is turned to the ON position. Sometimes they can be taped with a hammer to unstick them.

 

[thebigredrocker]

If you end up pulling your solenoid to inspect it, definately blow some compressed air in the hole on the carb. The solenoids I have bench tested usually retract about 5mm or more when 12v was applied. If the I.S. seems gummed up when the rod retracts or releases you can dribble some carb spray or gas down the rod while pushing it in. Let it soak for a bit and work the rod up and down.

If you get your IS funtioning and still see fuel spray, then you may have a gummed passage or blockage due to a small bit of rubber hose.

 

[Ming89FJ62]

check the fuse for the engine - if the idle solenoid shorted it will blow the fuse - IIRC is a 10 amp

 

[BTG88]

Success! I opened up the carb and soaked it with Gummout, including giving the solenoid a bath. Repeated 4 times within several hours. I also changed the connections for the solenoid with new ones, cleaned the fuse block and put in all new fuses. Started it up on full choke and let it run for 5-10 minutes to burn out all the gunk. Once it smoothed out, shut the choke off completely and it idles beautifully. Thanks for all the input!

 

[thebigredrocker]

Cool.
Might not hurt to run corn free fuel if you have a local service station that sells it. I've read the RFG is hell on the rubber accelerator pumps. Hopefully you still have a pump with the leather material. It not, I would have a spare handy. That accelerator squirt is key.

If you don't have a cabin mounted vacuum gauge, I highly recommend looking into one. I mounted a vac gauge pod on my steering column and man is it ever helpful.
Cheers

 

[BTG88]

Cool.
Might not hurt to run corn free fuel if you have a local service station that sells it. I've read the RFG is hell on the rubber accelerator pumps. Hopefully you still have a pump with the leather material. It not, I would have a spare handy. That accelerator squirt is key.

If you don't have a cabin mounted vacuum gauge, I highly recommend looking into one. I mounted a vac gauge pod on my steering column and man is it ever helpful.
Cheers

Yes - I looked that up on-line (Realgas.com) and there are couple of places within about 15 miles. I think I will also more regularly put in the anti-ethanol additives (might be snake oil, but for a few bucks...).

Will be carrying a spare accelerator pump, fuel pump, fuel filters, can of gum out, etc. just in case. Thanks

 

[Ming89FJ62]

realgas.com isn't the site - pure-gas.org lists non-ethanol gas stations nation wide

 

[BTG88]

Right - pure-gas.

Anyway - Back to the drawing board - This morning, upon start-up, the engine fuse blew. This was one of new ones I just put in. Now the struggle begins to find where the short is!

 

[Ming89FJ62]

unplug the idle solenoid, replace the fuse and try it again

 

[BTG88]

Same result.

 

[Ming89FJ62]

then you have a short somewhere in the harness - possibly at the firewall penetration. Time to unwrap the harness and start looking - or just replace the wire to the solenoid and run it back to the fuse block. You'll have to abandon the old wire. There are several "hidden" splices in the wire harness - I'm not sure if the idle solenoid falls into that category or not. Let the fun begin

 

[65swb45]

Run a wire straight from the coil + . That's how they did it on the early ones from the factory.

 

[thebigredrocker]

Here's a link to some of coolermans electrical schematics:Coolerman's Electrical Schematic and FSM File Retrieval

As you know it's probably something simple. Obviously it's time to figure out what is all on that circuit and if anything has been spliced in by the PO. Hopefully it's just a dangling wire under the dash.

 

[BTG88]

Run a wire straight from the coil + . That's how they did it on the early ones from the factory.

Brilliant Mark - it worked! Engine is purring along nicely with choke fully off. Now to trace the original wire and replace so I don't have a wire crossing my engine bay. Nothing dangling at under the dash, so I guess the break is somewhere else. This has me wondering if it is time to consider a full re-wire of the 42-year old harness. I spy any number of wires with ends not connected to anything. This is a vehicle I plan to take camping, so reliability is a priority.

 

[65swb45]

Brilliant Mark - it worked! Engine is purring along nicely with choke fully off. Now to trace the original wire and replace so I don't have a wire crossing my engine bay. Nothing dangling at under the dash, so I guess the break is somewhere else. This has me wondering if it is time to consider a full re-wire of the 42-year old harness. I spy any number of wires with ends not connected to anything. This is a vehicle I plan to take camping, so reliability is a priority.

Buy me a sometime.

 

[BTG88]

Buy me a sometime.

I can do better than that. Putting together a list of parts I want to buy from you. Will call when completed. Thanks again.

 

[65swb45]

I can do better than that. Putting together a list of parts I want to buy from you. Will call when completed. Thanks again.

Sounds good.