Trouble Tuning the Edelbrock Performer 1406 Carb? Read On...

[85GT-79FJ40]

Yeah I just took it for a cruise and it's way better. Still seems to have a slight hesitation from coasting to light load but I could just be too picky. Boy when you stand on it now it gets up and goes like I had always expected it to. 175 HP isn't too bad I guess.

[brianj]

Yeah I just took it for a cruise and it's way better. Still seems to have a slight hesitation from coasting to light load but I could just be too picky. Boy when you stand on it now it gets up and goes like I had always expected it to. 175 HP isn't too bad I guess.

Go to the next step up springs, and that will probably go away.

[PaceFever79]

Yeah I just took it for a cruise and it's way better. Still seems to have a slight hesitation from coasting to light load but I could just be too picky. Boy when you stand on it now it gets up and goes like I had always expected it to. 175 HP isn't too bad I guess.

Try going to the next heavier set of springs... they are simple to change. I've even swapped different springs out on the road in parking lots. Keep fine tuning the springs until that off idle hesitation cleans up. It's different for every engine.

[85GT-79FJ40]

Thanks guys I'll try that tomorrow. I've got orange/bronze colored ones in there now. I've got like 5 different sets.


Update: Put in a set of pink colored springs that seemed to be the next size up just by looking at them. That off coast to light cruise hesitation is gone. Drives nice and smooth now and goes like it should when I stand on it. I'm a pretty happy camper.

[brian84foxbody]

Wow excellent reading!! I'm about to throw my Holley in the garbage. Won't lean out and I was debating on a Edelbrock. This made up my mind I'm switching over. Thanks all!!

[Renoron]

Good evening all,

I just had to register to this site tonight after following the OP's thread and completing my tune. Unbelievable to say the least! Wish I had seen this 7 years ago.

Here is some background. I purchased a non-running 1976 Toyota FJ40 with a 289/302 (?), C4 mated to Toyota stock transfer case 7 years ago. Truck had a burnt up wiring harness. Got that fixed and had it running. Carburetor is the 1406. Back then, I messed with jets and rods to get it to run better. But, it never really ran perfect. It's always had a bog just off idle and idled kind of rough with noticeable raddle in the cab. I had learned to live with it all these years.

Well, fast forward to last week. Truck started to give me choke issues in the morning. Hard time getting it to come off choke and fast idle. So, I decided to buy the rebuild kit. After cleaning all the crud out of the thing, it ran better and the auto choke works flawlessly now. But, the bog just off of idle was worse now. That brings me to today. I found your post and went right over to Summit racing and purchased the stock 1405 rods/jets/spring kit. After dinner I installed everything. Fired the truck up, set the screws, and went for a test run. Not even a slightest hesitation! Can't believe I lived with the problem all these years. Timing wasn't touched at all. Funny part is, it's always passed smog. The hesitation was always really noticeable in the snow and made for an interesting drive.

I had thought about installing a Ford Mustang efi system. But, this engine has the early firing order and doesn't warrant the cost of new cam, etc. I think I can live with this setup now til the engine gives up the ghost.

Thank you so much for posting!

Respectively,

Renoron

[PaceFever79]

Hey, welcome to FEP

I'm glad you found the post useful!

[IDMooseMan]

Ditto. Glad to have you here and welcome to FEP.

[PaceFever79]

Renoron,

I had to look it up but one of our members is also into the Toyota Land Cruisers

http://vb.foureyedpride.com/member.php?5479-85GT-79FJ40

[85GT-79FJ40]

Yes, but I had to sell mine last summer. It certainly won't be my last though. As soon as i'm happy with the drivetrain in my Capri I'm dragging another FJ40 home. I really miss my 79 but I think I'll go with an earlier one this time around.

[JGrono]

This is a great thread, and I think I found and easier way to look at jet and rod changes. This is based off a 1406 with the base .031" accelerator pump nozzles for power mode. The different lines are the different rod sizes.

It would be great if anybody has kept track of tuning changes and wants to post how well (or not well) their results fit with these charts. I am going to clean them up to make them easier to read, and if anybody is interested I can post them up. The chart will be different for the 1405, but if there is interest, let me know and I will post that too.

[brian84foxbody]

This is an excellent write up but I'm inexperienced at carbs, bought a used 1406 off craigslist threw it on and car runs good until I punch it once. After that I have to feather the accelerator to keep it running. I'm guessing floats? Should I rebuild it and tune it to a 1405? I'm using the Holley 110gph mech pump. Motor is a stock 351w with a mild cam, 19 vac at idle. Like I said it runs hard when I punch it but after that it's done.

[JGrono]

You could check the float levels. If I had to guess I would say that it is too lean...

Without having to take the carb apart or too much trouble...

The simplest thing to do would be to move the accelerator pump up a link. Drivers side of the carb, near the front, there is a linkage which has three holes. If nobody messed with it, it should be in the middle hole. Move it to the hole closer to the passenger compartment. This will provide more fuel when you slam the pedal.

You should be getting enough fuel (unregulated fuel pressure might be too high). If that still doesn't help, and you have already tuned it using the idle mixture screws in the front, you might as well take it apart and check the float levels.

The floats could be stuck or out of adjustment. Check that when carb is apart.

Passages could be blocked, Spray carb cleaner and compressed air into and out of every hole you see when carb is apart. Especially check the IMS screw holes and the two sticking up through the airhorn.

The needles and seats might be sticking or clogged up. Check them when it's apart.

The accelerator pump might be hanging up, take it out and re-oil it.

Since you have decent vac readings, you probably don't have a vacuum leak, but it wouldn't hurt to check again and completely eliminate that.

If I were you, I would get a rebuild kit and plan on rebuilding it while you have it apart. If you take the carb apart and answer a couple questions, I can probably tell you how recently (if ever) it has been rebuilt. If you have any questions, let me know.

If your engine is really running that badly, a rebuild will probably make a world of difference, then you can tune after that.

If you are dead set on changing the rods and jets, swap out the jets during the rebuild. Then you can swap rods all day long easily to tune it.

The 1406 is probably too lean for you, and the 1405 is probably too rich.

[JGrono]

I forgot about this... make sure your choke is set up properly. Hopefully, before you adjusted the idle, you made sure that it was fully open... otherwise this could cause that problem if your idle was set from a choked position.

[Johnate0]

I plan on replacing my troublesome old Holley with an Edelbrock before Spring. Since I know next to nothing about tuning carbs, I was wondering if I posted the specs on my engine, if anyone could give me an idea of what size carb and tuning kit I should be buying? Later on today I'll be pulling out all the paperwork and invoices for the engine overhaul and I'll post what cam and intake manifold went into it. It's an '83 5.0, T5 with pretty much stock-spec everything except the cam and intake.

[Blainer]

I plan on replacing my troublesome old Holley with an Edelbrock before Spring. Since I know next to nothing about tuning carbs, I was wondering if I posted the specs on my engine, if anyone could give me an idea of what size carb and tuning kit I should be buying? Later on today I'll be pulling out all the paperwork and invoices for the engine overhaul and I'll post what cam and intake manifold went into it. It's an '83 5.0, T5 with pretty much stock-spec everything except the cam and intake.

Edelbrock 650 with electric choke will be fine for your set up.

[JGrono]

Here's the simple answer: Get at least a carb with at least 600 cfms. Choose what style choke you want, and after that there are only a few models to choose from. If you really want adjustable secondaries, then go with Thunder series, if not Performer series will be fine.

There are a lot of haters on both the Edelbrock and Holley sides. I think they both have advantages, but if you have it set up and tuned right either one will work well. That being said... I think you are making a good choice! There are so many less things that can go wrong with an Edelbrock.

[Johnate0]

That is basically why am going with the Eddy over the holley. Less fine tuning needed. Plus I baby my car and it'll never be raced so I don't need track performance out of it. I already have a wood fiber spacer in place so that will be used with the Eddy as well. I now need to figure out where to run the fuel lines and what type of pressure regulator to get. Fuel pump is stock mechanical. Do I need to go so far as to get insulated fuel lines? I hear one tricky thing about Eddy's is that they boil fuel a lot more often than a holley due to the position of the bowl.

[JGrono]

You definitely don't need to worry about insulated fuel lines. If you already have a wood spacer, you probably won't have to worry about heat soak anyway - just make sure the fuel lines (and filter) aren't near anything hot. Those big metal can filters can transfer a lot of heat to the fuel. For the fuel line, most people go back towards the drivers' seat, and then around the rear of the engine.

This is just my opinion, but even though heat soak is a real thing, many people are running too lean and instead of richening the mix, they blame it on heat soak and add a spacer and then can continue to run lean but don't fix the root of the problem. 14.7 is leftover from leaded (not unleaded) gas and calculations from the 1950's.

The Summit cheapo regulator will work, you might as well get the gauge too. Heat soak WILL CAUSE YOUR FUEL PRESSURE GAUGE to read low even with small temperature changes. If you set the regulator when the gauge is cold you will be fine.

[JGrono]

That is basically why am going with the Eddy over the holley. Less fine tuning needed. Plus I baby my car and it'll never be raced so I don't need track performance out of it. I already have a wood fiber spacer in place so that will be used with the Eddy as well. I now need to figure out where to run the fuel lines and what type of pressure regulator to get. Fuel pump is stock mechanical. Do I need to go so far as to get insulated fuel lines? I hear one tricky thing about Eddy's is that they boil fuel a lot more often than a holley due to the position of the bowl.

I can't believe you are even thinking about carb heat soak right now.... aren't you buried in snow?

[brian84foxbody]

Thanks everyone, I rebuilt my 1406 to 1405 used orange springs and wow what a difference. At first I couldn't get the rpm's to drop when setting the screws in. Double checked the timing and it was way off. Set it to 13 deg since I'm using 93 Oct and the rpm's dropped when I retried it. Now it has a slight idle, steady throttle miss I gotta check into.

[JGrono]

Thanks everyone, I rebuilt my 1406 to 1405 used orange springs and wow what a difference. At first I couldn't get the rpm's to drop when setting the screws in. Double checked the timing and it was way off. Set it to 13 deg since I'm using 93 Oct and the rpm's dropped when I retried it. Now it has a slight idle, steady throttle miss I gotta check into.

A 1406 with 1405 jets, rods, and springs is not the same as a 1405.

A 1406 is very lean at idle, but goes "way rich" during transition to compensate and that richness can stick around for awhile.

A 1405 is already rich enough at idle so it doesn't richen up as much as a 1406 during transition to the secondaries.

A 1406 with 1405 jets and rods STILL WILL GO "WAY RICH" during transition to the secondaries, that is why so many people have trouble with the 1406. This will still happen regardless of what springs you use. If you ever wondered why 1405 jets aren't in a 1406 calibration kit...

A 1406 and 1405 run EXACTLY THE SAME ONLY DURING POWER MODE (low vacuum) with the same springs. It's the idle, cruise, and transition where they are different. Since you have to idle, cruise, and transition, I think this is how Edelbrocks get a bad reputation. If you know this about the 1406, you can actually use it to your advantage to get a faster response than you could get with the 1405 when slamming the gas pedal.

The Thunder Series carbs aren't like this... the only difference between their "same" carbs is the chokes. The 1406 and 1405 differences are unique, but that's why they are marketed economy or performance.

Since your timing was off, it adds another variable, but if the rpms would drop with your old calibration, and won't drop with 1405 rods and jets, when you are leaning out the screws... it's too rich. It makes it worse if you are constantly transitioning, like when you are starting and stopping at stoplights because it is constantly "overcompensating."

[Johnate0]

I can't believe you are even thinking about carb heat soak right now.... aren't you buried in snow?

Yes we were pretty much knee-deep in it for all of February and most of this month. It's finally melting away now and i'm getting ready to put the Mustang back on the road. I'm ordering the 1406 now and just need to figure out which fuel pressure regulator I should get.

ETA: So here is my Summit cart. About an hour of researching other threads here tells me this setup should work fine for my car. Everything look good? I will have to buy more fuel lines and fittings too I guess.

[JGrono]

John,

You might have already bought that list, and all those parts will work. This is just my opinion, but If I were you I wouldn't spend that much on a regulator. You could buy about 5 Summit brand regulators for the price of that one Edelbrock.

[brianj]

Skip the regulator, skip the gage, just buy the Edelbrock performer mechanical pump. It comes with the correct pressure and flow right out of the box, will require less fittings and chances for leaks, and is a good quality piece. What you have listed will work, but it is kind of an expensive and complicated way to get there.