LQ4 no start
#1
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LQ4 no start
Spent the last 6 months getting a 2002 LQ4 into an S10. Tried to start it this weekend but no joy.
2002 6.0L 24x reluctor wheel
ls2 19005218 heat sink coils
factory motor with addition of 706 casting heads to raise compression
cranking compression is between 185 and 205
Daytona Sensors Smart Spark both LED's blink and flash as they should
coil harness is plugged into the correct side odd-drivers side even-passenger side
laptop reads 150rpm while cranking, sounds as it should
does have spark with spark tester
Battery is in the bed with a big gauge positive and negative going to the starter
plenty of grounds for ignition box and engine block
Have tried several timing maps on dials and programed off laptop
TR6 plugs .025 gap
It doesnt even pop or back fire. Any ideas? I am fresh out and have no clue what to try next....
2002 6.0L 24x reluctor wheel
ls2 19005218 heat sink coils
factory motor with addition of 706 casting heads to raise compression
cranking compression is between 185 and 205
Daytona Sensors Smart Spark both LED's blink and flash as they should
coil harness is plugged into the correct side odd-drivers side even-passenger side
laptop reads 150rpm while cranking, sounds as it should
does have spark with spark tester
Battery is in the bed with a big gauge positive and negative going to the starter
plenty of grounds for ignition box and engine block
Have tried several timing maps on dials and programed off laptop
TR6 plugs .025 gap
It doesnt even pop or back fire. Any ideas? I am fresh out and have no clue what to try next....
#3
10 Second Club
Just for giggles....can you put a battery charger on or use jumper cables on the battery, then try starting ?
Thinking the volts are low for cranking AND the box at the same time.(first starts almost never go perfect)
Thinking the volts are low for cranking AND the box at the same time.(first starts almost never go perfect)
#4
When it doesn't start think gas and fire. You describe the fire part in detail but what about the fuel part?
you do have a carb, correct? Float level correct, good fuel pressure, can see gas come out of the squirters when you pump the throttle?
Try a shot or two of starting fluid in the carb and crank it over. If it doesn't try and start then your problem is with the ignition.
you do have a carb, correct? Float level correct, good fuel pressure, can see gas come out of the squirters when you pump the throttle?
Try a shot or two of starting fluid in the carb and crank it over. If it doesn't try and start then your problem is with the ignition.
#5
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Thanks guys. Fuel is good floats are set squirting fuel. Its fresh 93 octane ethonal free. Voltage goes to 10.5 or so while cranking. May try to jump with car to add some voltage but it sound like its cranking fast enough.
#6
10 Second Club
I don't think it's the cranking rpm, but leaning towards voltage/Amps.
I know you said you have the Daytona box, make sure it's selected to the proper reluctor (wild shot here), but MSD had an issue where some said they needed to turn it faster on the first start and/or had voltage issue on initial start up....but fine after that.
Worth a try, right ?
I know you said you have the Daytona box, make sure it's selected to the proper reluctor (wild shot here), but MSD had an issue where some said they needed to turn it faster on the first start and/or had voltage issue on initial start up....but fine after that.
Worth a try, right ?
#7
He has a Daytona box. Never heard of anyone having trouble with those.
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#9
Being that you have spark and fuel. Really the only thing else it could be is that your reluctor wheel may be installed wrong. You would think it would fart or something though. It does have compression doesn't it?
#10
By the way the new MSD boxes data log input voltage. Would have told you both power and ground are good.
#11
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Put a volt meter on the crank sensor as it came with the motor with unknown past. Has power and ground but the signal is random voltage from 3-7.....not a 10 volt square pattern. So ordered a crank sensor from summit (local parts stores want $70 for it) will be here Tuesday.
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Good news it runs now! Sent the smart spark to Daytona Sensors at there offer to put it on there run stand motor. As I expected it worked fine and as it should. Smart Spark showed up in the mail yesterday. I put in fresh fuel and moved the negative battery cable from a starter bolt to the back of the passenger side head. Fired right up! Very strange I guess heads were not grounded enough???
Now another issue is the tach bounces like a dead cylinder. Worse at idle, does not sound like its missing at all. Tach is a brand new auto gauge shift light 10k rpm. Ideas? Still need to plug in the laptop and see what it reads for rpm.
Thanks for all the previous ideas and suggestions!!
Now another issue is the tach bounces like a dead cylinder. Worse at idle, does not sound like its missing at all. Tach is a brand new auto gauge shift light 10k rpm. Ideas? Still need to plug in the laptop and see what it reads for rpm.
Thanks for all the previous ideas and suggestions!!
#14
TECH Addict
I always put a ground strap from head to block. When I used to have access to a full engine o-scope you could watch the spark quality improve when you opened and closed the extra connection.
FWIW I used to work at a shop that sold Autometer,, between them and MSD not sure which one we did more returns on products for.. They seemed to have a random high infant mortality rate, wed go through a bunch and have no issues then get a cluster of bad ones..
FWIW I used to work at a shop that sold Autometer,, between them and MSD not sure which one we did more returns on products for.. They seemed to have a random high infant mortality rate, wed go through a bunch and have no issues then get a cluster of bad ones..
#15
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That seems strange that the gauges come in bad batches. Smart spark live data shows rpm bouncing between 750 and 1200 so I don't think its a gauge problem. Pulled all the plugs and they all have a very similar light tan coloration from the very short amount of run time so far. May go to each coil with an ohm meter and look for an abnormal one.
#16
If you talk to MSD. They will tell you to run a dedicated ground from the battery straight to one of the heads. Then run a jumper from that head to the other head. Your Daytona box needs to be grounded at the first head as well. Everything else should be grounded to the chassis or cage so there is no interference. Run a main cable to a good heavy spot on the chassis or cage. Then from the chassis or cage to the block. If you get some of those galvanized steel star washers and use them, you will never have to worry if any of the connections are making good or not.
Last edited by TTur1996; 06-11-2017 at 05:38 PM.
#17
Either the better ground fixed it or they did something to the box. Either way it is working, post some burnout videos.
I think the tach just gets one pulse per revolution and not one for each cylinder. So I wouldn't think the bouncing tach is a cylinder not firing. I would suspect a bad signal/dash ground first, maybe need a pull up resistor.
By the way an IR thermometer aimed at each exhaust port is a quick way to find a cylinder that isn't firing.
I think the tach just gets one pulse per revolution and not one for each cylinder. So I wouldn't think the bouncing tach is a cylinder not firing. I would suspect a bad signal/dash ground first, maybe need a pull up resistor.
By the way an IR thermometer aimed at each exhaust port is a quick way to find a cylinder that isn't firing.
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1996, I dont have an MSD this is a Daytona Sensors Smart Spark, have to check if my custom dash fuse panel is grounded to the body or chassis.
Pop n wood, Good point on the tach, I may throw an extra ground in there. I found people putting resistors on the coil with a single coil distributor motor, where would that go in this application? Tach signal wire at the smart spark? Truck has no trans or driveline in it....so burnouts will be a bit difficult. But they will be coming soon hopefully!!
Pop n wood, Good point on the tach, I may throw an extra ground in there. I found people putting resistors on the coil with a single coil distributor motor, where would that go in this application? Tach signal wire at the smart spark? Truck has no trans or driveline in it....so burnouts will be a bit difficult. But they will be coming soon hopefully!!
#19
Sorry about that. I changed it to what it was supposed to say. I was just trying to tell you no matter what box it is, you should probably ground it that way. I have seen too many problems with inadequate grounds.
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The smart spark is grounded to the block. I have a digital tach/speedo wired together with the auto gauge tach. Disconnected the tach sender on the speedo and the bouncing is better. Only 200-300 rpm now. Thought I put enough grounds when I wired the dash and bed mounted battery. I will go over it again and perhaps add a few.