new cam, new carb, new dist. wont start
#1
new cam, new carb, new dist. wont start
350 v8 with a fresh cam, intake and carburator. distributor is installed at 0* base timing. wires are routed correctly. the car will crank and crank and not fire. if i give it a little gas then crank it the car will fire up and immediately die. I bottomed out my min idle screws then backed them out 1 1/2 turns (thats where the min idle is currelty set) any ideas? Is my min idle set to low?
Last edited by thegoon1969; 08-14-2012 at 06:21 PM.
#2
Supreme Member
Re: new cam, new carb, new dist. wont start
Open the idle screws a little more and try moving the distributor around a little.
#4
Re: new cam, new carb, new dist. wont start
i went out another 1 1/2 turns on the idle screws (now 3 turns out total). car started ran for 8 seconds at low low idle then died. now it wont restart and my battery is dieing
#5
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Car: 1990 IROC
Engine: Rebuilt L98 with H/C/I/Carb
Transmission: TH350 with ATI Treemaster
Axle/Gears: 7.5 with 4.10's
Re: new cam, new carb, new dist. wont start
Get a battery or charger. Put your base timing closer to 15 degrees advanced. Verify spark. Verify fuel. Then crank away.
#6
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Car: '85 iroc-'13 powerstroke H&S tuned
Engine: 406 sbc full roller
Transmission: t5 soon to be t56
Axle/Gears: stock
Re: new cam, new carb, new dist. wont start
Are your floats set correctly ? Do you get any fuel out the squirters when you hit the throttle. Sounds like more of a fuel issue, like above verify fuel and try moving the dizzy a bit when cranking
#7
Re: new cam, new carb, new dist. wont start
before i drained my battery i lost spark to the plugs (i verified this with my little Lisile tools "spark tool". I was watching the spark when i was cranking but the last time i put the key in turned it to crank it, the spark fired once and then that was it. the car kept cranking (labored cranking due to the discharged battery) but no more spark. whats up with that? dizzy is brand new, cap, coil brand new all MSD. whats up with that?
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#8
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Re: new cam, new carb, new dist. wont start
You'd be surprised what some of those performance ignition parts are good for... which is nothing.
Primarily I've had TERRIBLE luck with Accel ignition modules. I finally went to a stock Borg Warner one for $20 and it's been fine ever since. But Ive heard the same complaints about MSD. The dizzy, wires, coil, etc are most likely fine, but the modules were always the parts that gave me fits. So do you have another stock one around you can swap in? If not just ignore that for a while and keep it in your back pocket. It's PROBABLY fine, but you just never know. Its all made in china these days anyway.
Also, I assume the plugs are new? I used some old plugs in one of my builds and they caused a ton of issues. I had an engine I put together and had issues with a cracked block, finally got it back together around a year later when my heart was back in it again and it wouldnt fire. Got some fresh plugs and it was fine. The old plugs looked okay, just sat out in the garage for a while and I guess they just got a little oxidized and/or dirty.
The last thing is, I used some "build em yerself" plug wires once, and maybe even with new already made wires, make sure the contact in the plug boot is snapping or at least fitting agaisnt the plug tip well. With mine I had to squeeze the contacts around each plug tip with some channellocks to get them to make good consistent contact.
You may be losing spark because you're draining the battery.
Whenever it doesnt start, spray some carb cleaner in it and see if that fixes it. Also I would advance the timing a tad. I could never quite get my setup to run with zero base timing. It may like between 10-20 base timing. Higher base timing will make the engine idle higher too, so if the carb is baselined, the choke is off, and you're just trying to get it to kick over and its gurgling at a really, really low idle for a second, kick up the timing a tad and it will build more cylinder pressure and keep it running.
And lastly, if this is a cold engine with new parts... dont expect it to idle right off the bat. You'll need to hold the throttle open to keep it running. Just let it run a few minutes and then set hte curb idle screw to the lowest RPM you can make it run at. Then start tweaking things from there. Get your timing right, get your idle mixture screws right... etc etc.
Sounds to me like it's really, really close to running right.
Primarily I've had TERRIBLE luck with Accel ignition modules. I finally went to a stock Borg Warner one for $20 and it's been fine ever since. But Ive heard the same complaints about MSD. The dizzy, wires, coil, etc are most likely fine, but the modules were always the parts that gave me fits. So do you have another stock one around you can swap in? If not just ignore that for a while and keep it in your back pocket. It's PROBABLY fine, but you just never know. Its all made in china these days anyway.
Also, I assume the plugs are new? I used some old plugs in one of my builds and they caused a ton of issues. I had an engine I put together and had issues with a cracked block, finally got it back together around a year later when my heart was back in it again and it wouldnt fire. Got some fresh plugs and it was fine. The old plugs looked okay, just sat out in the garage for a while and I guess they just got a little oxidized and/or dirty.
The last thing is, I used some "build em yerself" plug wires once, and maybe even with new already made wires, make sure the contact in the plug boot is snapping or at least fitting agaisnt the plug tip well. With mine I had to squeeze the contacts around each plug tip with some channellocks to get them to make good consistent contact.
You may be losing spark because you're draining the battery.
Whenever it doesnt start, spray some carb cleaner in it and see if that fixes it. Also I would advance the timing a tad. I could never quite get my setup to run with zero base timing. It may like between 10-20 base timing. Higher base timing will make the engine idle higher too, so if the carb is baselined, the choke is off, and you're just trying to get it to kick over and its gurgling at a really, really low idle for a second, kick up the timing a tad and it will build more cylinder pressure and keep it running.
And lastly, if this is a cold engine with new parts... dont expect it to idle right off the bat. You'll need to hold the throttle open to keep it running. Just let it run a few minutes and then set hte curb idle screw to the lowest RPM you can make it run at. Then start tweaking things from there. Get your timing right, get your idle mixture screws right... etc etc.
Sounds to me like it's really, really close to running right.
Last edited by InfernalVortex; 08-15-2012 at 03:48 AM.
#9
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Car: '85 iroc-'13 powerstroke H&S tuned
Engine: 406 sbc full roller
Transmission: t5 soon to be t56
Axle/Gears: stock
Re: new cam, new carb, new dist. wont start
also if its a fresh cam i wouldnt worry about it idling i would get it to 2000 or whatever the cam card has for break in on it for whatever time usually around 20 min so you dont wipe the lobes off it, if using a roller cam then disregard
#11
Re: new cam, new carb, new dist. wont start
I got it a little bit more figured out. its not a fuel issue its a spark issue. when i plug my spark plug light tool inline with the number 1 plug wire and turn the key to crank the motor. The light on the tool only lights up once then it doesnt light up anymore durring that cranking cycle. Pull the key out and try again it does the same thing. lights up once then no more spark. the distributor is new and i just swapped in a new coil to no avail
#12
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Car: '85 iroc-'13 powerstroke H&S tuned
Engine: 406 sbc full roller
Transmission: t5 soon to be t56
Axle/Gears: stock
Re: new cam, new carb, new dist. wont start
Check the wires going into the dizzy and make sure its hot with the key on and while cranking if I remember right it the pink wire but not positive on that
#13
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
I haven't seen any details regarding the new parts, like the brand/type of distributor.
Remember how an ignition coil works: A magnetic field is created by electrical voltage on the primary windings. When the voltage is removed, the magnetic field collapses, and imparts a much higher voltage on the secondary windings. It's the removal of the voltage on the primary windings that causes the spark. What I would suspect is happening is the voltage is on when you turn on the key, then when you go to start, you aren't getting the voltage cycling anymore. That could be either a fault in the power to the coil, or a fault in the triggering system in the distributor.
Remember how an ignition coil works: A magnetic field is created by electrical voltage on the primary windings. When the voltage is removed, the magnetic field collapses, and imparts a much higher voltage on the secondary windings. It's the removal of the voltage on the primary windings that causes the spark. What I would suspect is happening is the voltage is on when you turn on the key, then when you go to start, you aren't getting the voltage cycling anymore. That could be either a fault in the power to the coil, or a fault in the triggering system in the distributor.
#14
Supreme Member
Re: new cam, new carb, new dist. wont start
Well how is this project going?
#15
Re: new cam, new carb, new dist. wont start
got it started. problem was that i was that during cranking my voltage at the distributor was droping to 8 volts. I ran a wire strait from battery to distributor and it fired right up. now it wont turn off unless i pull the distributor wire from battery. weird though becasue i have an electric fuel pump that turn on and off with the key on and off so i would think lack of fuel pressure would shut the motor down but nope it still runs like a champ.
#16
Re: new cam, new carb, new dist. wont start
could try running that hot wire that you have going to your battery to your ignition harness for switched 12v power with the key, I beleive it is also a pink wire in the ignition harness you can just use a test light to find it. that way it goes on and off with the key.
#17
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Car: 88 Z28 Sport
Engine: 350 TBI
Transmission: T-5
Axle/Gears: 3.73
Re: new cam, new carb, new dist. wont start
My old 85 did the same thing. I actually found out that my ignition control module was bad too it into autozone they tested it and gave me a new one for like 40 bucks. Hope it helps
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