73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Neospartan on January 14, 2015, 08:37:29 pm
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1973 C10 350 long bed step side. All original with CA smog and quadrajet carb.
When I try to start it just turns and won't start until I hold the pedal to the floor then it back fires and when I release the pedal it dies.
I replaced the timing chain, problem didn't change
I rebuilt the carb, problem didn't change. I'm out of ideas please help
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How is the ignition system?
Are you getting a good spark as the engine turns over? You can pull a plug, clip a wire to the plug threads and run it to a ground (i.e., the block)
1973 engines came with points ignition.
Does your truck still have the original points distributor? If so, you might inspect and/or replace the points and condenser.
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I have new plugs and wires and new distributor before the problem and I have checked the spark with the spark plug light tool
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Actually I haven't replaced the coil canaster, also I haven't replaced the fuel pump, but when I pour gas down the carb it still doesn't start. It will only start and run rough then back fire and die when I hold the pedal to the floor.
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You have a new distributor. Have you set the timing properly, with a timing light? Do you know that your timing mark is properly located? Did the problem start with the new distributor, or was it running properly for a while after the new distributor? Are you sure the distributor is clamped down properly and hasn't drifted retarded? Did you check the timing with a timing light since the problem started?
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Thank you for the comments.
when I replaced the distributor I set the timing with a light, and after a year of it being a daily driver it started to become hard to start and hard at idle, and now for the last six months it won't start, and when I hold the pedal down it starts but I have to hold the pedal to the floor to keep it running. Then it will back fire through the exhaust and up through the carb and die. The problem didn't get sever until after a year from when I replaced the plugs and wires and distributor and cap, and set the timing with a timing light.
I also can get it to run long enough to get the timing light on it.
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Does the fuel pump have good volume? Fuel filter clean/clear?
HEI or points distributor?
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Points. And I will check the pump when I get home... But I've tried starting by pouring gas down the carb and using starter fuild. Still didn't start. And back fired through the carb.
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Is it possible for the distributor to mess up after a year where It throws off the timing so it won't start? but then why would it start when the pedal is pressed to the floor?
This link is the video of trying to start it
https://vimeo.com/116894792
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Is it possible for the distributor to mess up after a year where It throws off the timing so it won't start? but then why would it start when the pedal is pressed to the floor?
Yes. Points wear out; condensers and points should be replaced as a set. Usually, I'd replace points and condenser at least once a year (every 8k-10k miles). Worn out points/defective condenser can result in hard starting, rough idling, misses, random dying, etc.
Looking at the video, is that fuel puddled on top of the carb?
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Yes, the video was taken right after I pour gas down the carb and it began bubbling back out.
Update: check the fuel pump when I got home, fuel pump is pumping well. Attempting to check the vacuum on the carburetor, gauge says zero vacuum at base of carburetor. Not sure if I'm doing it correctly, or if I have a leak.
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Not sure why anyone would buy a new points style distributor, but I guess you have your reasons. If it was me I would slap a hei in there and be done. Or you can change the points, condenser, check dwell and all of that other stuff that will take more time and money than hei.
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Not sure why anyone would buy a new points style distributor,
I was thinking the same thing. It's almost like, "sorry, we can't begin troubleshooting until you get rid of those points."
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Unless you are preparing to sell your 100% original truck for $1 million dollars ditch that points system yesterday.
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Is it possible for the distributor to mess up after a year where It throws off the timing so it won't start? but then why would it start when the pedal is pressed to the floor?
OP, points are finicky, hard to adjust and notoriously unreliable. And yes, it is possible (and common) for a points distributor to mess up like you describe. Points just magically go bad and cause all kinds of fun. My first Honda had points and it was interesting for the first three months until I realized how bad that setup is and converted.
If it isn't already, an HEI upgrade should be at the top of your to-do list. There is a lot of info out there on converting, and a Google search for HEI conversion brings up many, many hits. Here is one good (possibly overly-detailed) how-to: http://rmcavoy.freeshell.org/HEI.html
Specific to your issue, check your points for pitting on the contact surfaces. Sand or file off any pitting to within tolerance. Make sure that the contact surfaces stay flat for full contact. Then check the gap, adjust, tighten the lock screw, curse when you realize that the gap has changed, wash, rinse, repeat. Cross your fingers and hope. Post #5 here has a very detailed description of point function and adjustment: http://www.hotrodders.com/forum/setting-points-sb-chevy-28120.html
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Yep points system obsolete this day and age.Just leaving the key on with them closed can screw them up
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I think the moral of the story here is, GM stopped using points 40 years ago for a reason. It sucks. Modern ignition coils on new cars now and even back when individual cylinders started getting their own coils, is all based of the reliability and efficiency of HEI ignition.
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Well, just to be the devil's advocate, a points distributor will still work after an EMP attack or a Carrington event. Can't say that for HEI. LOL
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Thank you guys for all the help. Is there a HEI conversation kit you would recommend? I'm looking at HEI distributors and they range from 50-300 dollars, so I'm rather confused with what I need or should get.
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red $45
http://www.ebay.com/itm/HEI-One-Wire-Distributor-Red-for-Pontiac-301-326-389-400-421-428-455-V8-E-Z-/191425368132?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c91d75044&vxp=mtr
(http://i.ebayimg.com/00/s/ODAwWDgwMA==/z/nIEAAOSwj0NUc8JZ/$_12.JPG)
Clear $47
http://www.ebay.com/itm/Chevy-SBC-350-BBC-454-65K-Coil-HEI-Electronic-Distributor-Clear-Cap-/181567616389?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a4645f585&vxp=mtr
(http://i.ebayimg.com/00/s/MTYwMFgxNjAw/z/CSUAAOSw6aVUoOPY/$_12.JPG)
Nother clear $49
http://www.ebay.com/itm/SBC-BBC-Chevy-v8-HEI-Distributor-50-000-Volt-SUPER-COIL-w-Clear-Cap-50k-Volt-/201205002428?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ed8c0b0bc&vxp=mtr
(http://i.ebayimg.com/00/s/OTAwWDcwOA==/z/p~wAAOSwU9xUT9tf/$_12.JPG)
Black 46.95
http://www.ebay.com/itm/New-305-327-350-400-454-Chevy-HEI-Distributor-Complete-w-Black-Cap-SBC-BBC-V8-/111547761514?pt=Motors_Car_Truck_Parts_Accessories&hash=item19f8c3c36a&vxp=mtr
(http://i.ebayimg.com/00/s/MTEwNVgxNjAw/z/H8AAAOSwnDxUmCxv/$_12.JPG)
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I've had a $45 ebay HEI for two years now with not a single issue. Not sure on the changeover procedure casue mine had HEI already, and especially if you need to keep the smog system.
You should also check on your choke to be sure it is operating properly
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one thing about the hei is all you need a hot with the key on both "on" and "start"12v to the distributor and she will work lol
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An HEI swap will also require different plug wires.
The original power wire to the + side of the coil "can" work for an HEI, but it is a resistor wire and should be replaced or bypassed with a non-resistance power supply wire.
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the 12v on a points system should be coming off the starter solenoid to the coil
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the 12v on a points system should be coming off the starter solenoid to the coil
This only supplies whatever available voltage the system has during cranking. Once the key is released from the cranking position the resistance voltage is applied. A fused key on & crank B+ source to the coil is required for an HEI retrofit
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tanks vile :-[
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Okay so I purchased the second clear HEI I got it in the mail yesterday, now what wires should I get?
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HEI distributor is in, I connected the red wire from the distributor bat side to my existing yellow wire that was connected to the positive side of the original coil. I checked the wire for volts and it read 11-12. I spliced my red wire to the yellow and when I tried to start I heard a pop and everything went dead and nothing works. Checked the fuses under the dash they are all good. Dont know what's wrong now.
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You cannot use the resistance wire on the HEI
You need to run a fused 12V 12 gauge wire from a Key On source at the fuse panel to the distributor. Clip the resistance wire back and tape it up good same with the wire that goes to the R terminal on the starter. Check to see if you blew a fusible link.
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Okay now what about my tachometer wire? I don't have a tachometer.
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It plugs into the HEI cap next to the supply wire. Look at the square part of the HEI. It should have TACH written on the top. You will need a spade connector on the end of your tach wire to make it work.
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Okay now what about my tachometer wire? I don't have a tachometer.
If you don't have a tachometer then why do you have a tachometer wire? ???
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Not explaining myself well enough, the HEI came with two connection wires. One that plugs to the BAT side and one that plugs into TACH side. I don't have a tach, so should I just unplug the wire from the cap?
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Okay now what about my tachometer wire? I don't have a tachometer.
???Since you do not have a Tach, there should be no wire hooked up to that terminal. If you decide to buy a Tach, then that terminal is where it is plugged in at.
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Not explaining myself well enough, the HEI came with two connection wires. One that plugs to the BAT side and one that plugs into TACH side. I don't have a tach, so should I just unplug the wire from the cap?
Are you saying you received the distributor with two pigtails and the distributor harness connector? Post a pic
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I replaced the the two fusible link wires off the starter, no change on the power issue. Everything still doesn't work. Any ideas?
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ITS ALIVE!!!! Thanks for the help guys!
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OK, you can't leave it at that! What worked to get 'er going?
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I got the new HEI distributor in, there was a red wire an a brown wire in the connection. The brown wire is for the tachometer the Redwire is for the battery. I connected the red wire to the existing yellow wire that went originally to the coil for the points distributor. Well that was my mistake because I thought the yellow wire was getting 12 V it would do but I ended up blowing the fusible links. So I went to the auto parts store bought some fusible link wire replaced the two that were on the starter and then the one that was on the firewall. And then ran a wire from the fuse box to the distributor. So now it starts and runs and so far I haven't gotten any problems but I haven't taken it on a long test drive yet.
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HEI distributor needs constant 12v. Points wire only provides 12v at crank and 7.5v during running.