Just rebuilt a 93 Mustang G.T, hatchback. we put a 351 Windsor motor in it brand new, everything is brand new. Transmission TKX. It has an Aces EFI fuel injection on it. Got car running it was over heating so got a new radiator (3 row aluminum)and had it tooned. Seems to have fixed the heating issue while sitting at ideal. The only issue I'm facing now is car after idling does not want to fire right back up. It turnes over but want run as if the motor needs to cool Down. But its not running hot on the guage. I'm at a losse right now and can't figure it out. Has anyone ran into this and or what steps would you take.
Fox Car want crank back up after idling.
- Thread starter kimscales
- Start date
89ripper
Founding Member
Ive never heard of "Aces" efi. Would have to know more about that to maybe troubleshoot. Is it a slow crank or regular just wont fire up?
The car cranks and will run and drive fine. But soon as it is turned off from motor being warmed up it will not fire back up will just turn over only. So yes a slow crank. I have to wait and let the car cool down for it to crank. I can let it set a couple of hourse and it will fire right back up. As far as the ACE'S E.F.I, it's called the KILL SHOT it is just like the Holly Sniper fuel injection. It's a newer brand of EFI that has not been on the market to long.
89ripper
Founding Member
I had a problem with a "slow crank" it was my starter getting heat soaked id have to let it cool down before it would start. Did this problem only start after the tuning of your car?
Killshot 4-bbl EFI Master Kits (Black)
Aces EFI Killshot EZ Tune EFI system is one of the most powerful 4-bbl TBI systems on the market! Each Master Kit includes the following: (1) A Black Killshot EZ Tune EFI System (2) Black Jack Pro Series Distributor (choose engine configuration) (3) Black Jack Pro Series Ignition Coil (4) Fuel...
acesefi.com
I am wondering if this system has the same problem as the Holley Sniper where an RF shield was needed.
No. Been an ongoing sronlem for everything else fixed only issue is now the hot start. I will try wrapping it and see what happins.
What's the rf shield do?Killshot 4-bbl EFI Master Kits (Black)
Aces EFI Killshot EZ Tune EFI system is one of the most powerful 4-bbl TBI systems on the market! Each Master Kit includes the following: (1) A Black Killshot EZ Tune EFI System (2) Black Jack Pro Series Distributor (choose engine configuration) (3) Black Jack Pro Series Ignition Coil (4) Fuel...
I am wondering if this system has the same problem as the Holley Sniper where an RF shield was needed.
Being I don’t have a Sniper setup I cannot talk in depth about the issue but I did read about it on here:
Also a quick Google search got this:
Said I'd do a review on the Holley Sniper, so here it is.
First off, I picked up a 1984 GT350 a couple of years ago that had most of the original parts in it yet, including the dial snorkel air cleaner. Since I had that, I just had to use it.
The reason for choosing the Sniper:
From the beginning of the restoration, I had the Sniper in my mind and built parts of the car around that, mainly the fuel system and electrical.
The kit I bought:
Also for timing control, this distributor...
First off, I picked up a 1984 GT350 a couple of years ago that had most of the original parts in it yet, including the dial snorkel air cleaner. Since I had that, I just had to use it.
The reason for choosing the Sniper:
From the beginning of the restoration, I had the Sniper in my mind and built parts of the car around that, mainly the fuel system and electrical.
The kit I bought:
Also for timing control, this distributor...
Also a quick Google search got this:
89ripper
Founding Member
Have you replaced the starter/battery cables?, old, barely big enough cables that are 30 year old will cause slow hot cranking issues. A voltage drop test will confirm this.
All cables and wires are brand new and are the correct size needed. Voltage test came back good.
Uhoh.... I've been called out!! 
I have the Killshot on my Cobra II as well, but haven't driven it more than probably 20 miles since. I've had to do a lot of supporting mods to get it to a point where it should be reliable. But, reading the problems you're having, I'm curious about your battery and charging system. From what I recall, these aftermarket fuel injection systems are sensitive to voltage input. It could be a combination of a few different things that have already been mentioned. So you'll want to be sure that that's all up to snuff.
What I did was a 3G alternator swap, installed a power lug that runs straight from the battery to tap into for a few different accessories that includes the Aces system, and ensured that all of my cables and associated connections were in good shape. And if your starter is heat soaked, as was mentioned, it's going to require more amperage which could potentially cause issues with the system as well.
Now, if all of that is up to snuff - which you said it all should be - it may be a fuel issue for some reason. What pressure are you running? I've got mine set to 50 pounds. I don't remember off the top of my head what they suggested for fuel per hour, but I've got an Aeromotive 18638 Stealth 340 Fuel Pump plumbed to 3/8" lines with a 5/16" return.
As far as an RFI issue, Aces recommended using their coil to eliminate that as a possibility. I was having issues with it after the intial install which turned out to be my own error, but I did go ahead and swap out my MSD Blaster for an MSD 6EFI 86415 Ignition Coil which looks exactly like the Aces unit for a bit cheaper. So if that's a concern, I'd recommend this coil just because it's cheaper than theirs.
But like I said to begin with, it honestly sounds like a voltage drop or insufficient amperage when warm. If it's cranking slower it's probably not feeding the FI system the appropriate voltage to operate properly.
Gratuitous pic of my engine for reference.
I have the Killshot on my Cobra II as well, but haven't driven it more than probably 20 miles since. I've had to do a lot of supporting mods to get it to a point where it should be reliable. But, reading the problems you're having, I'm curious about your battery and charging system. From what I recall, these aftermarket fuel injection systems are sensitive to voltage input. It could be a combination of a few different things that have already been mentioned. So you'll want to be sure that that's all up to snuff.
What I did was a 3G alternator swap, installed a power lug that runs straight from the battery to tap into for a few different accessories that includes the Aces system, and ensured that all of my cables and associated connections were in good shape. And if your starter is heat soaked, as was mentioned, it's going to require more amperage which could potentially cause issues with the system as well.
Now, if all of that is up to snuff - which you said it all should be - it may be a fuel issue for some reason. What pressure are you running? I've got mine set to 50 pounds. I don't remember off the top of my head what they suggested for fuel per hour, but I've got an Aeromotive 18638 Stealth 340 Fuel Pump plumbed to 3/8" lines with a 5/16" return.
As far as an RFI issue, Aces recommended using their coil to eliminate that as a possibility. I was having issues with it after the intial install which turned out to be my own error, but I did go ahead and swap out my MSD Blaster for an MSD 6EFI 86415 Ignition Coil which looks exactly like the Aces unit for a bit cheaper. So if that's a concern, I'd recommend this coil just because it's cheaper than theirs.
But like I said to begin with, it honestly sounds like a voltage drop or insufficient amperage when warm. If it's cranking slower it's probably not feeding the FI system the appropriate voltage to operate properly.
Gratuitous pic of my engine for reference.
Here's my thread on my installation. It probably won't help you much as you've already gotten it installed, but you can look through and see if there's something there that might help in some unforeseen way. 
And I think I misspoke last night - I was intending to run 5/16 return lines, but I ended up going with the same 3/8 lines all around.
As I said in my "progress" thread:
So as I sit here and do whole lot of nothing - I went ahead and ordered the remainder of what I think I'll need to complete the install of the fuel injection system I bought. Unfortunately I don't have any kind of ETA for when I'll get started - not being very mobile kind of puts a damper on actually working on projects.....
3 more days until my follow-up and hopefully having this cast removed. I'm hoping that I'll be able to start bearing weight again. If I'm ok'd I'm planning on getting a jump on this, I kind of figure the house projects will be...
And I think I misspoke last night - I was intending to run 5/16 return lines, but I ended up going with the same 3/8 lines all around.
OK I have a 140 amp alternator ,from CVR the entire serpentine kit is ..after five or idle and heated turns slow as in drag like no power .put heat shield on starter and same problem... Engine is to hot to touch water pump, alt, everything is hot hot...I also have the 340 lph fuel pump(in tank). From radiator to driveshaft is all new..I'm running around 46psi on the fuel pressure.I'm going to check battery its a diehard.. Would a ground cause this issue I have 2 grounds on engine to firewall and chassis 1 and 1..battery is located in trunk , do it need a ground from engine block straight to battery..battery is grounded to chassis..
How would I stop heat soaked if that's the problem ,running bbk longtubes and starter is right there tight.would radiator cause this problem its a 3 row aluminum, didn't kno if was big enough only bout 3" thick.
How would I stop heat soaked if that's the problem ,running bbk longtubes and starter is right there tight.would radiator cause this problem its a 3 row aluminum, didn't kno if was big enough only bout 3" thick.
Mcmahst
5 Year Member
I think you need to get more basic. Run it, get it hot. Then, pull the center coil wire and with your assistant’s help, crank it to see if you’re getting a hot spark. If so, stop. Reinstall, and give it a shot of starter fluid. See if it starts. If it does, you’ve isolated the issue. If it doesn’t start, IDK. I think it is voltage related as well. Hot cranking, what is the voltage reading at the positive lug that feeds the FI system? Good luck.
I'm going to throw this out there too, since it wasn't mentioned - have you confirmed timing? Long story short, I had gotten my 302 back together and running but it would overheat unless the car continued moving. I did a lot of upgrades to the cooling system chasing an overheating issue, but it ultimately came back to bad timing - it was timed right at 0*. 
It ran exceptionally well like that which is why I overlooked it for so damned long! But once I put a timing light on it to confirm then readjusted, I had no more overheating issues. In fact, the car barely breaks the 200* mark.
From everything you've said so far, it all looks like a heat related issue. Heat can ruin a lot of things here.... Some other ideas to look at would be to check your battery cables again after it's ran - are they hot? If so, you've got power running through them and extra resistance somewhere that will need to be remedied. Like I said, if it's timed incorrectly you'll end up with a hot engine/engine bay which can wreak havoc on different things like your starter, ignition coil, and fuel system. So I'd suggest looking at those 2 things to start and go from there. It doesn't sound like it's a problem with the EFI system at this point - which I think is good news!
It ran exceptionally well like that which is why I overlooked it for so damned long! But once I put a timing light on it to confirm then readjusted, I had no more overheating issues. In fact, the car barely breaks the 200* mark.From everything you've said so far, it all looks like a heat related issue. Heat can ruin a lot of things here.... Some other ideas to look at would be to check your battery cables again after it's ran - are they hot? If so, you've got power running through them and extra resistance somewhere that will need to be remedied. Like I said, if it's timed incorrectly you'll end up with a hot engine/engine bay which can wreak havoc on different things like your starter, ignition coil, and fuel system. So I'd suggest looking at those 2 things to start and go from there. It doesn't sound like it's a problem with the EFI system at this point - which I think is good news!
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