'85 Stalling

[85foxinva]

Good day fellow 'stangers , I just got an '85 GT speed carb. The odometer reads 37k original miles. The car in my opinion is a near perfect survivor. The only issue I'm having is it stalls when I get into higher RPM's or shifting into 5th gear. It will bog down and seems to be fuel starved. I coast to a stop and after 2 or so trys, she starts right back up and the issue comes back after a mile or so. I have no knowledge of this cars history other than what information I got from the seller who is a classic car dealer who bought it from an auction and Carfax (which indicates one owner and a decent maintanence history). I know the gas has a bad smell, like its old. I put fresh gas in it mixed with about 2 ounces of Seafoam. It's a carb. car, and I have zero experience on them. I was told to check the fuel filter, which I have on order. Other than that Im lost. Any help would be appreciated. I want to enjoy this classic in the coming warm weather. Thanks

[emerygt350]

Yeah. Get that filter replaced. It sounds like fuel issues. I am not much of a carb guy anymore but others on here will point you in the right direction.

[massacre]

Like said above ^^^
Fuel filter is first thing i would do

[85foxinva]

Thank you, I will check the filter when the new ones arrive. I'm also looking at replacing the carb with Holley 600. I saw a YouTube video of a company replacing the stock 4180 with one and it looks like a plug and play setup. I intend to keep any and all stock pieces just in case somewhere down the road this car could increase in value since I won't put many more miles on it. Just want to enjoy a few spins in it from time to time.

[emerygt350]

I wouldn't put anything new on there until you are sure your gas is clean.

[85foxinva]

I wouldn't put anything new on there until you are sure your gas is clean.

Thanks for that. Yeah I think I'll probably check the fueling system,filter and pump. It's not too complicated. I certainly appreciate any and all advice I can get.

[emerygt350]

I have noticed that many on here think the 4180 is a good carb. For a stock engine it may be worth using. Many threads on rebuilding them are on this forum. Easy to find if you use Google rather than the built in search.

[85foxinva]

Yeah? I intend to keep the car stock or stock-ish. Not going to be an everyday driver, just an occasional cruiser and car show.

[emerygt350]

If it were me I would keep it till everything is running like new then make a decision. At least you know it's jetted perfectly. Rebuilding carbs is kind of soothing too.

[85foxinva]

I start the car up and let it run in the mornings. This morning I tached it up to about 3000 and held it there for almost a minute and it stayed steady, no bucking or hiccups at all. As I said before, I have no experience with carb cars. I assume this does'nt replicate driving under a "load" so it I really can't gleen much from it until I change out the filter and go back out on the road.

[emerygt350]

Yeah, you could even have a failing fuel pump and you likely wouldn't know unless it were under load. Might want to pick up a cheap inline fuel pressure gauge while you are waiting. Again, those can lie if the pump can't keep up at load. I wonder if there is a cheap bluetooth fuel pressure sender out there. Does your 85 have an electric or mechanical fuel pump?

[85foxinva]

Its a mechanical fuel pump. I just got the new one delivered today, I'm going to replace the filter as well. Probably be sometime in the next week when I can get to it. I appreciate all your input. I don't consider myself a great mechanic, but I enjoy wrenching on my own stuff. And I'm not too proud to ask for help, that's why I joined Foureyedpride. By the way, I do have a fuel pressure guage,but theres no shrader valve to attach it to that I can find.

[emerygt350]

Yeah, with a mechanical pump you wouldn't find one. You could pop in an Inline gauge but truthfully, it isn't worth it. You need to see it when the engine is under load. If you are replacing the fuel pump, no point in putting in a gauge. However, stuck floats in a dirty carb could result in the same issues. No harm in a new pump though.

[Carbsovertech]

Put filters before and after pump. Run the old gas out. Get some barrymans and give er the Italian tune up and some fresh gas. Watch a couple vice grip garage videos., you’ll see what I mean. Sometimes a a carb needs a good whack as well…usually a screwdriver handle is enough. Let’s see some pictures.

[85foxinva]

Ill send a few from my phone

[85foxinva]

[85foxinva]

[85foxinva]

[85foxinva]

[85foxinva]

[85foxinva]

There you go. Hope I didn't break any forum rules.

[emerygt350]

Very nice looking car.

[85foxinva]

Very nice looking car.

Thank you. Back in the day my uncle had a brand new '85 and he let me drive back from the racetrack and it's been my favorite mustang ever since. I've owned a '91 GT(still have it),2001 GT,2011GT and 2015 GT (still have it).

[qikgts]

Great looking '85 and welcome to the site!

I'd start troubleshooting this by looking at the float levels making sure they are set so that with the sight plugs removed, the fuel level is right at the bottom of the hole. If you barely wiggle the car fuel should drip out/run down out of the hole. You can find a ton of videos on the tube explaining how to do this. It's totally simple, carb 101 stuff.

Another thing I would do is take a paperclip and bend it so you have a straight end to poke with, and run it down all the air bleeds visible on the top of the carb with the air cleaner off. It's important none of them are clogged up.

Finally, while you're there, do a good visual inspection around the carb and make sure you have no vacuum leaks or any dried out vacuum hoses. Replace them if they looked cracked or appear brittle. The '85 has a rather complex vacuum system so if you're keeping things relatively stock you want to make sure it's all in good shape. Also make sure the ignition system is in good shape and timing is set correctly and at about 10-12 degrees at idle.

There are also a few simple mods that can be done like upping the jet sizing, going bigger on the squirter/accelerator pump discharge nozzle and changing the accelerator pump cam. Combined they can make a significant difference in driveability with todays ethanol laced fuel.

These 4180's are simple, great running carbs for stock and lightly modded vehicles! Happy wrenching!

[85foxinva]

Hey again, been digging around and researching, and I think the fuel pump is leaking. I pulled the oil dipstick and it definitely has gasoline in it. Needless to say I am going to replace the pump and do an oil change before I take her out again. Hopefully that solves the stalling issue. Any advice is appreciated, Thanks.