Idling way to fast |
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moose0211
Senior Member Joined: 23-September-2009 Location: Baltimore Status: Offline Points: 456 |
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Posted: 12-June-2010 at 6:25AM |
I just did a four barrel conversion on my 351 2v. Edelbrock intake, holley 600cfm and full msd ignition. Started it up today and it was idling way to fast. I tried to mess with the carb idle crew but nothing happened. What do I do next? It wont kick down into low idle and just runs fast. I have been trying to drive for about a month but something always happens. ???
Thanks
Lou
Edit: she is also backfireing through the carb Edited by moose0211 - 12-June-2010 at 6:29AM |
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Skinnys Garage
Senior Member Joined: 26-February-2010 Location: South Dakota Status: Offline Points: 277 |
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The fast idle could be a number of things.
1st thing I'd check is the factory throttle cable. When switching to a Holley the ball may not sit in the exact place of the 2 barrel. If the cable bracket on the intake isn't adjusted ahead a little it or modified it can hold the throttle open. Pop off the linkage off and see if the idle drops back, if it does adjust the cable bracket. 2nd thing would be a vacuum leak. Some aluminum intakes should use a gasket-steel plate-gasket set-up between the intake and carb for a more positive seal. Some intakes don't have enough material at the carb flange to seal a base plate well without a support plate of some kind. Also could be a vacuum line, booster line or the intake gaskets didn't seal to the heads properly. 3rd thing would be to check the fast idle screw on the right side of the carb. If the choke cam is engaged or the screw is just turned in too far, that could cause a high idle also. The screw is hard to see but you should be able to find it. 4th thing is the small secondary screw adjustment in the base plate on the right side. It is adjusted from the bottom with the carb off, but the metal tang can be bent on the top side, to check if that's the problem. If no one has messed with it, it's probably ok, but it's something to check. There could be internal problems with the carb, incorrect vacuum advance source, timing set way too high, sticky cable etc., so all you can do is eliminate the basics and go from there. Good luck with the diagnosis. Edit for the backfiring: Could be a flat cam lobe, bent push rod, mixture way off, bad vacuum leak, incorrect plug wire location, timing or ignition problems etc. Back firing through the carb isn't a good thing, I hope it's nothing serious. Did it do this before the intake swap? Edited by Skinnys Garage - 12-June-2010 at 7:36AM |
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lynchster
Senior Member Joined: 07-January-2006 Location: Pennsylvania Status: Offline Points: 2150 |
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Have tryed starting it with the throttle linkage disconnected to eliminate the linkage as the problem?
Chuck
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Chuck
72 Gran Torino Sport 13 Taurus SHO "Mr Pig" |
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moose0211
Senior Member Joined: 23-September-2009 Location: Baltimore Status: Offline Points: 456 |
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I will try disconecting the throttle linkage tomorrow but I think thats the problem because I had to pull it back to make it hook up to the carb. As far as the backfiring, I hope it isnt too bad. I hope its the timing because when I did the MSD distributor the directions said i may need to advance the timing. If it is something serious, just another excuse for a 460 LOL
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moose0211
Senior Member Joined: 23-September-2009 Location: Baltimore Status: Offline Points: 456 |
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Today, I tried messing with the timing and I also played with the fast idle screw. It wont slow down! Also, when I hit it real fast the engine acts like it is gasping and she still backfires! It did not do this before I did the carb and intake swap, so whats up?
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lynchster
Senior Member Joined: 07-January-2006 Location: Pennsylvania Status: Offline Points: 2150 |
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Check for a vacuum leak. Possibly at the base or an unplugged fitting.
PVC plugged in? Just a thought.
Chuck
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Chuck
72 Gran Torino Sport 13 Taurus SHO "Mr Pig" |
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Skinnys Garage
Senior Member Joined: 26-February-2010 Location: South Dakota Status: Offline Points: 277 |
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Is the intake you're using for 2V heads? If not, I would say you have major vacuum leak problems in the port mismatch. If your intake is for 2V heads and you're confident the side gaskets stayed in place, that wouldn't be it.
Was the intake and carb new? If not, was the intake checked for straightness? Was the carb in good shape and not have a cracked base plate, was it clean and adjustments base lined etc? Could be many things, if you checked all the basics I mentioned, we'll need a little more info to help you narrow it down. |
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moose0211
Senior Member Joined: 23-September-2009 Location: Baltimore Status: Offline Points: 456 |
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The intake is new and the carb is like new. It was originally on picon3's car but a mechanic tried to tune it and messed it up. So, he sent it to Holley and they rebuilt it. I am confident the manifold is for a 2v because it has 351C 2V etched in the side. A NASCAR friend said that if there was a major vacuum leak, then we would hear it. My grandfather gave me a "Motor Monitor" recently that tests the vacuum. When I hooked it up, the gauge was saying that it is giving enough vacuum pressure for me to be driving, while I am at idle. Is there an adjustment on the vacuum pump that I could play with?
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moose0211
Senior Member Joined: 23-September-2009 Location: Baltimore Status: Offline Points: 456 |
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Any ideas?? I am sorry to be a pain but I need to get the car running so I can drive it to the body shop
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antlerfiend
Senior Member Joined: 14-June-2010 Location: Louisville,KY Status: Offline Points: 3023 |
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I talked to my dad, showed him the whole thread. He was a Master Ford mechanic for years. He suggested to me to tell you to take the intake and carb back off and reinstall them. He feels for sure that it is a vacuum leak causing all your problems. I myself ask him questions all the time and he has never led me down the wrong path. Hope that helps.
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Alex
72 GTS (Morgan's Baby) 68 CJ Drag Car Clone 65 Mustang (first car) 77 LTD II (Drag Car) 78 Mustang II V6 4 speed |
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lynchster
Senior Member Joined: 07-January-2006 Location: Pennsylvania Status: Offline Points: 2150 |
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I haven't given up, just thinking.
Have you pulled the plugs? I'm just wondering if it is running rich. Seven out of eight might indicate a leak somewhere.
Have you checked the float level to see if they might be too high?
Chuck
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Chuck
72 Gran Torino Sport 13 Taurus SHO "Mr Pig" |
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moose0211
Senior Member Joined: 23-September-2009 Location: Baltimore Status: Offline Points: 456 |
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today, I hooked up the choke and tightened some vacuum lines, after doing this,she started right up and purred like a kitten! But, when I was doing a test drive, she backfired through the carburetor again. Tomorrow, I am going to re-time it as it was difficult to start, and I am going to adjust the richness. Thanks for the help guys.
Lou |
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moose0211
Senior Member Joined: 23-September-2009 Location: Baltimore Status: Offline Points: 456 |
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Update, I solved the problem. With my MSD distributor, had to advance the timing and I was still timing the car to 6* BTDC. Now, at 26* BTDC she runs great. Thanks for the help, it is much appreciated. |
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GranTorinoSport
Admin Group Admin of "The Org" Joined: 20-May-2003 Location: Seattle Status: Offline Points: 2287 |
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26 degrees BTDC of initial advance? (without vacuum or centifugal advance)
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Scott Eklund
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moose0211
Senior Member Joined: 23-September-2009 Location: Baltimore Status: Offline Points: 456 |
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Yupp, 26 degrees of initial advance. I think that is very high, but it starts and runs great. I never realized how loud these cars are stock, I floored it and guys in corvettes were staring. This also fixed my backfiring problem and basically makes the engine run better. Is anyone else running the MSD distributor on their 351?
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