1985 F150 302 holley problems
 

Hello, I hope by chance someone here can give me a hand.

My truck (1985 F150 302 holley 80457) all at once started idling hard in park, and killing out if put into gear, I thought the choke might have been sticking so I removed the choke thermostat, and installed by instructions a manual choke.

This did not solve the problem, same idling problem and dying in gear.

"I did notice that if I put it in gear while engine was running, used emergency break, I could pull down on the choke and it would smooth en out as the choke neared closing.

So assuming a vacuum problem I decided to pull the carb and rebuild it.

I bought the kit number "37-119" (which is what this carb calls for) and spent some time rebuilding it. Once finished I reinstalled the carb on the engine and hooked up the vacuum lines and throttle cable, as well as fuel line, then turned it over, the engine started right up, but at an rmp that I would consider extreme, and dangerous.

I adjusted the adjustment screw behind the throttle, turned the mixture screws completely in and then reversed 1 and 1/2 turns on both sides. Started the engine again and same thing, very high rpm.

So I unhooked the throttle cable and left it hanging, started the truck and again it started right up, but this time at a very low rpm. I then lifted the throttle to give it gas and it would cut out and then pick up and rev almost like normal, but as soon as I let off the throttle it would go back to very low poor idle.

A little information.....I did not bother the throttle at all during the rebuild, the throttle arm is now where it was b4 the rebuild.

the carb is a 4 barrel, and my 302 is 2 barrel, I have installed a 4 to 2 barrel base plate which is what the truck had when I bought it and at that time it ran great.

I have also used a flashlight to look down into the secondary barrel and they appear to be completely closed.

At this point I am at a complete loss for idea's. any help would be great.

Thanks

Doug

guess i found a problem that even stump the experts, 132 views and zero replies. wow. Thanks anyways, junking the truck tomorrow

Just to make sure, it ran fine before. Correct? It has trouble idling, but can you still drive it down the road?

This could be a fuel pump problem too. Maybe you are not getting enough fuel pressure (5 to 6 psi). Is the fuel good (not 3 months + old)? Also what is the vacuum reading at idle (or as low an rpm close to idle that the engine will stay running)? Does the vacuum gauge remain steady or bounce around? Are you getting at least 17 " vacuum or better at idle?

so your applying choke (meaning richening the fuel mixture) and it starts to run better. But "nearing closing"? Was the engine warmed up when you were doing this? If the engine was cold then this would be expected. If the engine was hot, then that would signify you are running very lean. Could be low fuel pressure or a vacuum leak (I'll assume not a carb issue since the problem is the same before and after the carb rebuild).

Sounds like you put the throttle cable attachments on the wrong spot on the carb linkage - or something was sticking in your throttle cable. You should be able to attach the throttle cable without any movement of the carb linkage/throttle plates. Did you have the throttle return spring installed (some throttle cables has a built in spring)?


So this shows that the problem is with the linkage or how you attached it to the carb. With the cable detached you should adjust the idle speed with the screw.


Be sure to check all the vacuum lines and look around the engine good (maybe a sparkplug wire came off, etc.). Change the fuel filter, and then pump a little fuel into a container and take a good look at it. Is it clear, does it smell right, any signs of water?

I am thinking your original problem may not be carb related and you jumped the gun a little by rebuilding it. We need to get some stats on the engine first.

That's what I was thinking too. When my fuel pump went bad it barely pumped any fuel at idle. It was easy to see with a clear fuel filter between the pump and carb.

Thanks for the replies everyone, Since the original posts I have taken the carb back apart and checked for any problems, found none. I did notice that the secondary throttle plates were just barely opened, called the Holley Tech guyy and he said it should be completely closed and then backed off 3/4 of a turn, so I did this and reinstalled the carb with no change at all.


The engine is a 302 2 brl motor, the carb is 4 brl, but has a 1 inch spacer converting to 2 brl.
As far as vacuum readings I have none, I don't have anything to gauge the vacuum with nor anything to gauge the fuel pressure with. So these two things I don't know.

I did notice that once I closed off the secondary throttle plates, the engine runs at about 2k rpms with the throttle cable unhooked, not sure if this is because of the secondary plates being closed.

The engine has not been run to temp since this problem began, With the throttle cable hooked up it runs far to high to allow it to keep running so I always shut it back off as soon as I hear the high rev, and without the cable i have to keep feeding the carb using the throttle to keep it running.

While fooling around I have come to the conclusion that it wont start at all unless I give it gas first (pushing throttle 2 times) and once its running it will die in about 25 seconds unless i hit the throttle again. If I play the throttle and slow pump it, it will keep running but only so long as the throttle is active.

Yes, b4 I rebuilt the carb it would start up at a slightly slugish idle, and when put into gear hesitated and would try to die. after rebuild it dont idle at all on its own.

The fuel in the tank is right now about 5 weeks old, I put gas in it on my way home the last day it ran.

The throttle cable seems a bit to short, I know its not, but the linkage would have to be pulled about 1/2 inch to reach the cable. During the rebuild I didnt remove the linkage or anything that had to do with the throttle outside of the adjustment i did on the secondary after talking to tech support.

I can hook the throttle cable to the linkage using different holes on the linkage, but even at the setting where the throttle is relaxed, the engine will not idle even when I raise the throttle using the screw, it revs for a sec then peters back out.

Fuel looks clear/blueish, as it always does..

Hope this helps you better see my situation :)

With a 2 barrel to 4 barrel adapter there are at least two gaskets involved, one under the carb. and one between adapter and manifold. Any chance one or the other of these gaskets is causing a large air leak?

Any chance that some part of the carb. linkage is hanging up on the adapter?

Not that I have been able to find, I sprayed ether around the carb while running but didnt get any change at all.

The carb linkage arm is supposed to sit on the idle speed adjustment screw on the side of the carb. If you take the linkage off, it should spring back and sit on this screw, and that's how you adjust your idle. If you are pulling the carb arm off the idle screw to get the linkage hooked up, and it does not come back and rest on the screw, then that is not right.

I know you said it ran ok with this adapter, but they are nothing but trouble. It would not surprise me if you could loosen all the bolts on the bottom and top of the adapter, and move the carb around to make the linkage work better. They are pretty much a rig. I know a intake can be expensive, but I would put that on your priority list to get the proper 4bbl intake.

While installing the carb several times I have noticed that a lot of play can be found once bolts are in place but not tightened. This could be part of the problem with the throttle linkage. Thanks for bringing that up.

I am somewhat leaning toward changing the fuel pump out as it is only around 25 bucks or so. So it may be worth trying, wondering if pounding on the tank would help give an idea if the pump is going bad, I know it works with the starter but not sure about the fuel pump.

Completely off subject, but if I am going to change the fuel pump, Ive never been a fan of removing the tank in a truck and I always lean toward raising the bed, wondering if I can install heavy hinges near the tailgate of the bed and making it a kinda light duty dumper.

Would have to raise it by hand and that would be fine, I at some point plan on building a flat bed on it anyways as the wells are rusted out in a bad way.

I am going to try the fuel pump and see if it makes any difference at all, hope it does, if not, does anyone on here have a decent carb they would sale at a cheap price?

Thanks again and I will update tomorrow when I install the new pump and let everyone know how it went :)

The bed construction is not strong enough to support hinges and tilting. You would need to make a frame (like 2x2 square tube) for the bed to rest on and to attach the hinges.They make kits for this, Check out Northern Tools.

Unless the truck was EFI you shouldn't have to pull the tank. The $25 pump would be a lift pump that bolts to the block.

yes your right, it mounted straight to the motor, but after installed, still the same problem. I loosened the carb and pushed it back, now the linkage lines up as it should.

Started the truck....started up just as always does, still at an rpm that is dangerous.. i now have no other options....

At this point I have spent more than the truck is worth and have been over a month trying to figure this out. any more ideas?

Is the linkage arm on the side of the carb resting on the idle set screw?

The problem started suddenly... you've done an awful lot of messing with the fuel system with no real change... which tells me the cause of the problem is most likely not in the fuel system.

Sudden changes in behavior are often caused by something electrical having failed.

A 1985 302 would have been computer-controlled... I am assuming you removed all of that and are now using something like a Duraspark (or other) electronic, non-computer-controlled ignition?

If Chris is right, do you have manifold vacuum hooked to the distributor? That will cause a very high idle in some cases. Pull and plug the vacuum hose to see what happens.

Also, be sure to check the "high (cold) idle speed" setting. Maybe your starting the engine cold so the choke is closed and therefore idle cam is on the "high speed" lobe/setting. This adjustment screw is on the opposite of the carb from the idle speed screw.

Although that should not be such a high speed as to concern you (under correct adjustment) but if the high speed screw was run all the way in it would have the engine running very fast.

Very true. Could easily be the problem. And the fast idle doesn't go off until you blip the throttle.

yes the linkage is lined up and setting good on the screw

Then turn the screw back to reduce the idle speed. Does it respond to this or does the screw just back up and leave the throttle? If it does, take the gas pedal linkage off. Does it fall back to the screw and reduce the idle with the gas pedal linkage off?

Sorry, been a fews days since I could get to the truck, been pouring the rain, anyways, truck is still in same condition but i have a few small updates.


I checked the fast idle which is behind the choke, the screw is at about halfway in, or out.... the linkage lines up nice with the throttle cable but when attached it still runs at a high rpm, not as high as b4 but around 2500 rpms,

if started without the throttle cable it still runs under idle and dies, I noticed that I have a small fuel leak at the pump where the line from tank comes into the pump, it was raining so i didnt want to get into pulling the power steering pump back off to tighten the fuel line. will update more on that asap.

now the fast idle screw behind the choke, should i turn that all the way out or in? I noticed that when the choke is closed/cold the cam is not touching the FIS at all, and when the choke opens it seems to do very little, the cam looks to be in good shape, no sighs of being wore down or broken.

The carb still seems to be getting to much fuel at times, and not enough at other times

When the throttle cable is hooked up, and the engine is started i can let it run at high idle and it seems to be getting enough gas to keep it runing, but without the cable attached it seems to be getting to little fuel. Again I have not found any vacuum leaks at all.

The floats are both just under the sight hole, when I puch the linkage it squirts 2 nice shots of fuel into the chambers, the idle screw on the linkage is all the way out, and the FIS on the choke side is a halfway in.

Am I missing anything else that could cause this?

I called Holley support and he said the secondary plates should be compleatly closed, is that right?

I am reallly confused because I have never had a problem like this one b4 and I cant make sense of it at all lol Thanks in advance again guys.

You are not getting it yet. Leave the fast idle screw on the choke side alone for now. It does nothing until the choke is activated. That's the only time you adjust it, when the choke is activated.

Before you get it going again, look on the driver's side of the carb. There should be a screw there that the throttle rests against. This is the screw you want to adjust.

TAKE THE THROTTLE LINKAGE OFF. From what you are describing, this will let the throttle fall back till it hits the screw on the driver's side, and then engine will stall. LEAVE THE THROTTLE LINKAGE OFF. Turn this screw in till the throttle lever on the carb starts moving open. Go around and re-start the truck. If it quits and is idling too slow let it die, go out and turn the screw on the driver's side in some more. Try it again. You should be able to turn this screw till the engine will run by itself.

Once it runs by itself, go out and tweak the idle speed to what you want it to be. Turn it down fairly slow and then you can tweak the idle mixture screws. If you have it running too fast, the idle screws won't work.

Once you get it running smoothly and at a decent rpm, turn the truck off and figure out what you are going to do about the throttle linkage. If you try to hook it back up, you will probably be idling at 2500 rpm again. You need to fix that.

OK, thanks,

Today, I tightened the small fuel leak at the pump intake, the throttle cable is disconnected, and the fast idle screw on the passenger side has not been touched at this point.

with the throttle cable removed and the engine cold, I started the truck, started up as expected, idle was around 1800 to 2200, the linkage idle screw is backed out as far as it will go, engine remained running.

the electric choke began to open and at about 1/4 way open the engine began to idle down to about 1200, then sputters and dies. I turned the driver side idle screw in until the linkage began to move and started it again, it started up just fine at maybe 800 to 1100 rpm and died

Turned the drivers side idle screw about 1/4 turn raising the linkage a bit more with same results after starting, once more turned the idle screw about 1/4 turn and the engine started at about 1500 rpm and died.

Still have not touched the fast idle screw on the passengers side, mixture screws are at 1 1/2 out,

If the engine is idling at 1500rpm and is dying, you have another problem. When it's right, the engine should idle comfortably at 800 rpm or so.

Double check for a vacuum leak somewhere. Just for a experiment, how far out are the idle mixture screws? They are the ones on the front on each side of the square part of the carb if you have a holley.

The idle mixture screws are at 1 1/2 turns out , Where could I find vacuum leaks? their is no vacuum to the distributor, its electronic,

Can I upload a video to here or link a youtube video of my truck on cold start?

Wait a minute. What do you mean by the dist is electronic? What is controlling the dist? Where is the timing set at?

I asked about that in Post #15 but he never responded....

Now you see why I'm sitting on the sidelines. We aren't getting answers to important questions. (Plus, I can't use my laptop on FTE at present, and the iPhone makes it painful.)

I am sorry if I have missed the important questions you have asked. I am not ignoring them, just overlooked them.

The distributor has no vacuum lines running to or from it, so I assumed it would be considered an electronic distributor because it has no vacuum lines.

I hope the video will shed a little light on what I am dealing with, if not, please let me know what I can do....pictures or more video. I really appreciate all your help and taking the time to look over my problem with me.

On another note, guy at Advance auto ran the engine number and said the motor was dated around 1975, so around 10 years older than the truck. I dont know if that will make a difference, but i bought the fuel pump for the truck, and it looked just like the one i removed from the truck, but the in and out on it were reversed, took it back and thats when he told me the motor was older than the truck, so it needed a different fuel pump, once he grabbed it from the back, it was exactly like the one I took off, so it made a difference with the fuel pump, maybe that helps a little to diagnose the problem.

Thanks again

Thanks again, I am sorry if I missed your questions, I try to get on here as much as possible but being these not so smart phones are such a pain to try to do anything with, and working I just haven't been on here as much as I should be.

I said the distributor was electronic because it has no vacuum lines that I can find, so I assumed that if not vacuum then it must be electronic. Sorry about that.

If this video does not help, please let me know, I would be happy to take more video or pictures if it will help. Please let me know and thanks again for all your input so far.

I really appreciate you guys taking your time out to help me with this problem and anything I can do to make it easier please just let me know.

Sorry I sort of took over the thread for a bit, but now I have caught up with everyone else, we need to get this timing thing sorted out.

Truth be known, it will probably run with the timing locked, but you do need to know where you are at. If the timing is way off it's not going to idle. If you do not have a light, you could get the truck running as slow as it will go, then loosen the dist and turn it a little bit and see if you can make it run better.

This will be sort of a experiment, not a permanent fix. You have a mess going on here, and this truck is never going to run correctly from the sounds of the equipment it has on it.

Thanks, I assume you have watched the video?, where and how to I turn the distributor? I know the cap is held on by 2 metel clips on the top, but do I need to loosen something to turn the base or the top?

I know that when this truck was running, it ran smooth and great, never a single miss or sputter, drove to gas station on my break at work one day and when I came out to leave that day it was acting this way.

I get off work around 3pm tomorrow and as soon as I get home I will check this page again, and then head out to the truck to see what I can do with the distributor,

when I start the truck cold right now, it will run at high idle (about 2500rpm) and will keep running until the choke begin to open or I push the linkage. Once the choke opens it acts like to much air or not enough gas. I cant tell between the two.

Also when it is running cold at this higher idle it seems to have a thud like sound, not loud or deep sounding, just a noticeable difference in the way it sounds from b4.

Until I see pictures, I wouldn't trust anything said by a person working at a parts store. Pictures will help this thread move in the right direction.

If the truck starts and runs, then the truck should be easily tuned given time and patience.

Perfect, tomorrow I will take pictures of everything under the hook in hope it will help you guys to see a direction to the problem, it will run until the choke opens then it acts like it has problems. Thanks, is there any pictures in particular i should be sure to take?

I don't want to sidetrack things, but once the timing gets sorted don't forget the vacuum leaks. I think it is leaking like a sieve and the only reason it has enough fuel to run is the choke. Once the choke opens it dies.

Ignition is not the problem because it runs good slow and runs good fast.


Yeah, the video was nice. Seems extremely likely air leak. There is a massive air leak somewhere. It explains why it runs with choke, and why it runs very fast with choke. I would blame the 2/4 barrel converter plate.



If you can get it to idle, and video shows you can. Block all air from the top of the carb. with a cloth. I don't know about 4 barrel carbs, but block the secondaries with cloth, then block the primaries one by one. If you can block all 4 and it still runs massive air leak somewhere.

Use either a propane torch with a small tube connected and small amount of propane gas leaking out ( DO NOT LIGHT THE PROPANE TORCH), or starter fluid spray at base of carb, if it changes rpm then you found the leak.

It also might need a bit longer to warm up give it 10 mins or so to heat up fully and please..

SAFETY FIRST WEAR GLOVES AND ALSO FIRE EXTINGUISHER VERY CLOSE BY. I have MANY huge fire extingishers 1 in each car and several in the house, I hope I never use them.

Thanks, i will update tomorrow after work, as well as take some pics and more video, I will let it warm up to running temp and cover the secondary's and then the primary's one by one on video.

I forgot to say

you must have vacuum gauge
you must get/check fuel pressure gauge

without these two you're flying blind