289 4v wont idle more than a couple minutes - Page 2 - MustangForums.com



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Old 11-28-2016, 12:51 AM   #11
Gun Jam
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Okay cool so the carb did work at least at some point.
Again you'll want to make sure the inlet needles are new.

The easiest way to check pressure is to buy a gauge...I Happen to have a vac gauge that also reads fuel pressure...It has a rubber coned fitting that you can simply jam into the fuel line and hold in place while someone cranks the engine over. you'll watch for the highest pressure during pump strokes typically around 6psi
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Old 11-28-2016, 01:06 AM   #12
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yes the carb was working fine. It just seemed a little fat at idle but worked well.
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Old 02-26-2017, 07:43 PM   #13
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Well I spent some more time on it and I have lots of problems!

It has been starting intermittently so I never looked for spark. I did that today and discovered now I have no power to the coil. From what I understand the coil is fed from both the starter solenoid during crank and the ign switch in the run position. I put a meter on it and in the run position I have nothing and during crank I have nothing! Doe this mean both my solenoid and ign switch are broken?

I jumped the coil to the battery and it started but it still struggled to run. Before I could have sworn the accelerator pump was working fine but now when I pump the throttle it just dribbles out. I borrowed a gauge and the fuel pump is making 6psi. The filter is clear so the only thing left is the carb. The carb guy is having a look at it. Third time in a year and about 300 miles!

Anyone have any ideas on the electrical issues? I hope this someday helps someone else.
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Old 02-26-2017, 08:44 PM   #14
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I just checked the ignition terminal on the starter solenoid. It has power on crank but it doesn't make it to the coil.
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Old 02-27-2017, 12:35 AM   #15
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I missed what kind of carb it is. Is this a motorcraft 2bbl carb?
Typically if you have some serious idle issues I always check the float level. The idle mixture screws don't do much for big adjustments, fine tunning only. I rarely have to change them more than a small tweak here or there. When you screw them all the way in, do you crank them tight or just until they seat? Tighten them more than just seating them will crease the needle and cause them to be off. But for now, get that float set right.
On the motorcraft 2bbl carbs I set the float so it hangs level when the bowl is full. Then I start the car, and with the car running pull the top off the carb. Yes, it will run this way. Then adjust the float with the engine idling. I like to leave them set at level, but there are specs on where the float should be set.
When you get the float set put the top back on the carb and run it to operating temp. With it idling at temperature I hold a rag over the carb opening, or close the float. If adjusted right it should increase slightly in rpm's then start to fall. If it increases in rpms and acts like it is running better, but keeps running your running lean and need to raise the float level. If it floods and dies immediately it is too rich and needs the float dropped. If it stays running then your on. Again, don't close the intake air off totally, just close most of the way.
Also, before checking your carb make sure the timing is on. Timing can act like a flooding engine. Make sure it is on, then check the fuel.
I worked on a kids car years ago that thought everything centered around those idle mixture screws. Every time I got it set right, he would mess with the screws to try to get more speed from the car. He thought pouring a lot of fuel in would make it faster, so he would crank them out a couple of turns. Then it would not idle right in cold weather, and would puke black smoke when he started it. So, I would reset the screws, a few days later he did it again. Finally we glued caps on the screws. Those screws don't do as much for the mixture as people think, they will effect the running but the float level is more important to have right.
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Old 03-01-2017, 10:32 PM   #16
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It's an Autolite 4100.
I'm sure the carb has an issue. It's being rebuilt for the third time in a year and about 400 miles.
Steve when I get the carb back I will try to set it up as you suggest.

The only puzzling part is the electrical issues.
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Old 03-03-2017, 03:13 AM   #17
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Electrical problems are a pain to trace! Your on the right track, start at the coil and test back. Check your ignition switch low on the steering column, check the amp gauge to make sure it is connected securely. Also, check your ground wires from the engine to the firewall and frame.
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Old 03-04-2017, 11:05 AM   #18
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Quote:
Originally Posted by SteveL View Post
Electrical problems are a pain to trace! Your on the right track, start at the coil and test back. Check your ignition switch low on the steering column, check the amp gauge to make sure it is connected securely. Also, check your ground wires from the engine to the firewall and frame.
The Ign wire from the solenoid goes right from the solenoid to the coil, stopping at the firewall plug a tee'ing into the one coming from the ign. There must be a break in that wire. I'm going to replace that harness to start with.
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Old 04-02-2017, 07:54 PM   #19
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Well I found a break in the wire hardness in the engine bay. I replaced it. I also found that my carb was very anemic when trying to pump the fuel so I checked the pump pressure and had the carb guy look at it again. He found that someone had monkeyed with the float geometry and it wasn't totally closing when full.

I got it all back together and it's a bitch to start cold but once it's warm it starts like a top. Idles clean and no stumbles. So does this mean my choke is not set right? I have to pump it like mad to get it to start. Once it fires it's good.
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Old 04-06-2017, 05:03 PM   #20
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Choke is not set correctly. It should be almost closed with the engine cold. If its electric, it will open itself, but you still need to set the cold position. Same for a tube fed choke. As it warms it will open up because the coil heats and expands. Loosen the screws on the choke cap and set it so that its nearly closed, when cold. then when the engine is at temp it should be open/vertical.

You should still check your float level with the car running at temperture. This is the only way to really get it dialed correctly. Same with the tune. You can pick up a vacuum gauge at a parts store and adjust the needles to highest vacuum. Then bring your RPM's down to around 750-800 in drive with your tires against a curb using the curb idle screw. You can then monkey around with timing, idle tune, and curb idle to get it all dialed in correctly.

If you adjust your timing without a light, set it a little high, take it for a spin and if you hear pinging (sounds like marbles in a can) back off the timing a little and reset curb idle. Its a big cycle, everything plays off of the other. Idle, timing, curb idle... Dont forget to set your pump shot too so that as soon as you blip the throttle you see a squirt of fuel.
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