521 Stroker Issues

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lduke12

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So im about to pull my hair out. This is my 521 stroker motor (1970 429) Has Edel RPM air gap, Holley 4150 1000cfm, Holley Black fuel pump with Aeromotive regulator. MSD 8580 Pro Billet Ready to run distributor with 6AL Ignition box and Blaster 2 coil. No tach hooked up. So the car fires right up, runs nice and drives but once you get so far down the road or after so long of time, you get what happens in the video at exactly 3:55 minutes. Once it kills itself if you let it sit for a couple minutes it usually starts right back up no issue and will drive down the road again till it kills itself again sitting at a stop light or it will just shut off while driving down the road. At the moment in this video it is open header with 2" Primaries with no collecters. Been trying to get it to run without leaving me stranded so i can get it to the exhaust shop.

Please can someone tell me what they think is causing this, any one else running the 429's with all MSD electronics. Otherwise yes everyone see's and feels me coming down the road and get lots of people stopping to ask "What year is that"

[video=youtube]

 

barnett468

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sounds to me like you could have rust in your tank getting sucked up around the in tank filter stopping the flow . .

might be high float levels too . . the gas level should be near the bottom of the clear windows or just below the inspection holes if you don't have windows.

 
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Finmach

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For me it sounds like your timing is not as it should from the beginning. It pops in the exhaust in the very first seconds. It can be the microphone or my laptop speakers but for my ear its not as it should. When you park the car are you touching the distributor & adjusting the timing? After you pop the hood and wait few secs your timing goes way too retarded and starts to pop in exhaust.

I would start by checking your timing. Hope you got the problem fixed.

 

rocket366

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It's process of elimination.

You are lucky in the fact that it happens reliably.

when the engine dies quickly...

Check for fuel by taking off air cleaner and work the throttle and see if fuel is squirting.

Check for spark by pulling a plug and cranking engine.

From the sound in vid I bet fuel!

The backfiring is not good and maybe a timing issue but not the cause of the engine quiting.

Sounds like you run the carb dry and there is no replenishment like the tank is not venting.

Check those and keep us posted It's not that tough a problem to sort

once you narrow it down.

Paul

 
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BOSS 351

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I would bet that it's the Holley electric pump. I had the same problem with mine (351 ). I called it the 3 mile car. You could drive for just about 3 miles and it would die. Wait 5 minutes or so and run another 3 miles. The holley pump has no suction to get fuel. It will push fuel all day long, but the gravity flow to the pump must be greater than the fuel consumption. I relocated the Holley pump 3 times, each time lowering the pump - no better. Replaced the pump with a Robbmac pump and it ended all my problems.

http://www.robbmcperformance.com/products/ford550.html

The only real difference I see is that I was on the thottle heavy when I was testing mine. I sure like the mechanical pump compaired to the

Holley.

Holley pump for sale. Like new. Less than 25 miles use.

Wade

 

Muswagon

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I had this problem with my roadrunner, kept the mechanical fuel pump and ran a holley in line, and it mostly eliminated it. The problem I was having was the fuel was literally boiling off before it got to the carb. Essentially a really bad case of vapour lock.

I was told running a return line eliminates the issue, have no idea why (I am not very smart lol).

I did however finally and totally eliminate mine before I sold the car with header wraps, which I have heard are bad for the headers but they were summit junk so i didn't care much.

Keep in mind I am a car guy that is still learning so pardon the jargon if I got it wrong!

 
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My first thought was vapor lock as well, just a feeling. Did you reroute the lines since you are not using the mechanical pump?

 

lduke12

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Thanks for all the replies guys. To answer your question 71mach1lady yes all the original fuel lines were removed from the car and brand new 1/2" line was routes along the passenger side of the car. There is no return line and the tank just has the stock vent hose on the top. For Finmach when we park at the has station and PPP the hood we are not touching anything under the hood except we start to rev it a bit and it starts the rough idle and dies. And yes at the beginning of the video it is popping and backfiring bad, but we were thinking it was because of left over fuel sitting in the headers from the last time it crapped out. As mentioned I am using ceramic coated Crites headers and only the 2" primaries are installed during this video, the collectors are not even on yet. At first we thought my fuel pump was over pressuring my regulator and flooding the carb, and after 2 regulators not being able to lower the pressure below 14 pounds my buddy's Aeromotive is finally keeping the pressure right at 7 steadily. When the car starts to run rough and shut off the pressure doesn't change at all and we have two different pressure gauges one at the regulator and one on the fuel log on the carb. I am going to have the car towed to the exhaust shop today to get the pipes on because my buddies neighbors have been chewing him out every time we start the car, and then I we can fiddle around some more to figure out the problem.

 

71coupe

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first...why is neighbor chewing him out ever time he starts the car? because its loud! Nothing like the sound of good 'ol american muscle!!!!

My car was stalling...would be driving, make a turn then bam..dead! just dead!!! turned out to be float levels to high. your doesn't sound like float level, but you never know. Give them a check.

 

MotoArts

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It's process of elimination.

You are lucky in the fact that it happens reliably.

when the engine dies quickly...

Check for fuel by taking off air cleaner and work the throttle and see if fuel is squirting.

Check for spark by pulling a plug and cranking engine.

From the sound in vid I bet fuel!

The backfiring is not good and maybe a timing issue but not the cause of the engine quiting.

Sounds like you run the carb dry and there is no replenishment like the tank is not venting.

Check those and keep us posted It's not that tough a problem to sort

once you narrow it down.
X2!

Try clamping on some glass packs temporarily to the collectors, if you can scrounge any up.

Definitely work with one, and ONLY one, potential problem at a time.

Sounds like a fuel issue to me, too. I had a vapor lock issue with a stock 258 powered CJ7 Jeep that sounded just like that when it died. Got lucky one day, and actually heard the fuel line "refill" while my head was under the hood looking for clues on the side of the road. The bad tank venting issue mentioned falls into this same category. Try loosening the gas cap to eliminate that issue while driving. It's a cost free test.

If it still does it, move on to the next potential problem.

The backfiring may or may not be related. Make sure you don't have any potential crossfire between the wires. Separate each one of them with whatever non flammable insulator you can find, again just to test and eliminate a potential fault.

Or, better yet, just ship that lump to me here in Pittsburgh. I'll trade you a freshly Krylon'd 302 to fill the hole, and I promise to return it just a soon as it's sorted! (yeah RIGHT! ;) hehehe)

 
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Qcode351mach

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I think vapor lock too..Had the same problem with my 521 stroker one of the issues with running a big block & headers the amount of heat generated under the hood & manifold area

 

Finmach

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Ok, I hope you got the problem sorted out. Electric fuel pumps really needs to mount lower than the fuel cell&tank. Inline pumps are thick IMO, so I've been using "canister" style like this:

$T2eC16d,!)sE9swm,vL1BRTOHzmVEg~~60_12.JPG


Mainly because the inlet & outlet of the pump is located to the lowest possible point - it makes it easy to install it so that inlet of the pump is lower than the outlet of the fuel cell&tank. I'm in the middle of converting my Mach1 to EFI and going to use twin Bosch 044's. They are nearly famous of that they don't create any suction, so the positioning will be under the tank with two existing AN8 lines or even two AN10 lines will be feeding the pumps. Fuel problems can be tricky, but if you've got the fuel pressure gauge installed after the regulator it should give you the answers to the fuel problem.

 

lduke12

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Thanks all. I got the Mustang home last night from the exhaust shop with my entire new 3 1/2" system. Me and my buddy were in the garage afterwards till late and went over everything checking the rocker arms, carb everything. I wont go into detail about what we discovered but i happened to look at something we had taken off the car and "DING" light bulb oh crap this simple tiny little thing wasn't done just right. So a quick adjustment and throw everything back together and she is running like a bat out of hell.

Thanks again all for all your replies and words of help but she is running excellent now.

 

Muswagon

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Oh I really think you need to go into detail, I am not the only one that is curious :)

 

lduke12

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Well thought everything was good after last nights run. We noticed after removing the spark plugs that cylinder 5 & 6 were perfectly clean when all the others looked pretty normal, so it was misfiring those two cylinders. Turned and looked at the distributor cap with the wires attached and realized we had wire 5 plugged into 6, and wire 6 plugged into 5.

But today i took my brother for a ride in her and she died while driving down the road again. Waited a couple minutes then fired right up and made it to my neighbor hood where started to stumble and run real crappy before dying again just like in my video. Going to replace the ignition switch tomorrow, and if that don't work i got to find a reputable shop that knows how to work on a highly modified car to figure out the problem because im about done with it. Because now im going to miss 2 more nights of awesome Central California cruising in Bakersfield with my buddies due to a car that decides when it wants to run.

In the meantime i got my hood badges on and my Halo's wired up.

1znlutv.jpg


 
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Qcode351mach

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I'm really leaning towards vapor lock how do you have the electric fuel pump plumbed ? as soon as it stalls pull off the air cleaner move the throttle arm look to see if the carb is squirting fuel in ....Need to know that..if not it tells you it's a fuel problem possible the fuel is boiling off in the carb bowels....If good then it's a electrical problem. Believe it or not it could be the ground wire to your msd control box..where do you have it grounded ?

 
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If you have a MSD control box, I would be looking at it very closely as the potential cause of your problem. It almost sounds like something that is overheating in the electronics ie., a module that requires a heat sink and was assembled without adequate paste or not tightened properly.

A coil that is failing can cause intermittent problems but usually takes longer to recover.

A brand new MSD box is no guarantee that it is working properly.

 

lduke12

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I'm really leaning towards vapor lock how do you have the electric fuel pump plumbed ? as soon as it stalls pull off the air cleaner move the throttle arm look to see if the carb is squirting fuel in ....Need to know that..if not it tells you it's a fuel problem possible the fuel is boiling off in the carb bowels....If good then it's a electrical problem. Believe it or not it could be the ground wire to your msd control box..where do you have it grounded ?
Hey Qcode351mach, yes when the car is idling and its stumbling, when you pull the linkage to give it more gas the carb still spits fuel down the carbs throat just fine, and when you remove the bowl sites the fuel is right at the bottom of the holes. And also as stated no matter what there is always 7 psi on the system whether its stumbling and shutting off or dead.

As far as where the fuel pump is, Pump is on passenger side, the 100 micron filter is right off the tank on the driver side using 1/2" tubing all the way up to the front.

23sxgco.jpg


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At the front of the car the 1/2" line runs up the passenger side of the car through a bulkhead in the firewall to a Aeromotive pressure regulator. Then it runs straight around the valve cover and into the carb fuel log.

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As far as the MSD box, as pictured its mounted to the radiator support in between the grill and the A/C condenser.

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And the 1 black wire connected to the negative terminal of my battery is the direct ground for the MSD Box.

15rjm2q.jpg


 
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turtle5353

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If you have a MSD control box, I would be looking at it very closely as the potential cause of your problem. It almost sounds like something that is overheating in the electronics ie., a module that requires a heat sink and was assembled without adequate paste or not tightened properly.

A coil that is failing can cause intermittent problems but usually takes longer to recover.

A brand new MSD box is no guarantee that it is working properly.
+1 I had a brand new MSD 6al box that was bad right out of the box when I first got my 408C in my car. Messed with it over and over. It would die, shut off driving down the road, had a miss...ect ect. Could not figure it out and EVERYTHING, I mean EVERTHING was brand new!!! Finally got fed up and un hooked the msd and dug up an old duraspark box off my old derby car and hooked it up to my MSD dizzy and it ran GREAT!!!! drove it around a few days like that just temporarily wired in and not one bit of trouble. Got another new MSD 6al box and it was good to go. I have heard of a lot of 6Al's being bad out of the box. Also the new 6AL box was about 7 degrees off on the timing from the first one???? Weird! Just my experience with it. Hope you figure it out!!!

 
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