Never starts on first try
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Never starts on first try I've put an LS2 from a 2006 GTO into a Miata. It runs great, but it never starts on the first attempt. It just cranks and cranks. It always starts right up on the 2nd, or subsequent attempts. It doesn't matter if it's hot or cold, recently started/run or not. Fuel pressure is fine. Injectors/coils have power. We've even tried giving them direct power from the battery. VATS have been tuned out. No OBD codes are being thrown. Yet something is preventing it from initially starting. I feel that it's a computer related issue, like something isn't wired correctly. Any ideas?
Thanks,
Jon
Thanks,
Jon
Thread Starter
Teching In
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The cam sensor pigtail was never cut from the harness, so it has to be in the correct location. It could be that the sensor is bad, or perhaps the crank sensor, but I'm hoping that's not it.
Thanks,
Jon
Thanks,
Jon
Thread Starter
Teching In
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Yes. We've turned the ignition on and can hear the pump run. We've run it until it stops, because the computer stops it after a few seconds, and then tried starting. No change.
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Teching In
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Thread Starter
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10 Second Club
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Do you have your fuel system setup like the stock GTO--no return? Does your fuel pump have a residual pressure valve?
The prime on the stock setup is 2 seconds. If you do not have a residual valve, set the prime to about 6 seconds, turn the key to the on position, count to 3 and then start it. I don't have a valve in mine and I have to do this. If I just turn the key to start it, it just cranks. Even tho the regulator says it has 58# immediately, I guess the fuel rails are not full pressure. Regulator is before the fuel rails on mine. Maybe this will work?
The prime on the stock setup is 2 seconds. If you do not have a residual valve, set the prime to about 6 seconds, turn the key to the on position, count to 3 and then start it. I don't have a valve in mine and I have to do this. If I just turn the key to start it, it just cranks. Even tho the regulator says it has 58# immediately, I guess the fuel rails are not full pressure. Regulator is before the fuel rails on mine. Maybe this will work?
Thread Starter
Teching In
Joined: Mar 2017
Posts: 22
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Do you have your fuel system setup like the stock GTO--no return? Does your fuel pump have a residual pressure valve?
The prime on the stock setup is 2 seconds. If you do not have a residual valve, set the prime to about 6 seconds, turn the key to the on position, count to 3 and then start it. I don't have a valve in mine and I have to do this. If I just turn the key to start it, it just cranks. Even tho the regulator says it has 58# immediately, I guess the fuel rails are not full pressure. Regulator is before the fuel rails on mine. Maybe this will work?
The prime on the stock setup is 2 seconds. If you do not have a residual valve, set the prime to about 6 seconds, turn the key to the on position, count to 3 and then start it. I don't have a valve in mine and I have to do this. If I just turn the key to start it, it just cranks. Even tho the regulator says it has 58# immediately, I guess the fuel rails are not full pressure. Regulator is before the fuel rails on mine. Maybe this will work?
No starts on first try are commonly caused by not enough fuel on startup.
If you fuel system is OK and you already checked fuel pressure at startup, filter, pump and everything checks good, then modify the tune and give it more fuel to the cranking VE and/or cranking fuel tables.
Start with small increments of 5-10% and test.
If you fuel system is OK and you already checked fuel pressure at startup, filter, pump and everything checks good, then modify the tune and give it more fuel to the cranking VE and/or cranking fuel tables.
Start with small increments of 5-10% and test.
Thread Starter
Teching In
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No starts on first try are commonly caused by not enough fuel on startup.
If you fuel system is OK and you already checked fuel pressure at startup, filter, pump and everything checks good, then modify the tune and give it more fuel to the cranking VE and/or cranking fuel tables.
Start with small increments of 5-10% and test.
If you fuel system is OK and you already checked fuel pressure at startup, filter, pump and everything checks good, then modify the tune and give it more fuel to the cranking VE and/or cranking fuel tables.
Start with small increments of 5-10% and test.
Another interesting point about the failed first starts is that there is no firing. It's not even trying. Whether it cranks for a second or 20, it never attempts to fire. No stuttering. It's just cranks and cranks. Then on second attempt it fires immediately. We tested for current at the coils/injectors and they seem to have it. Maybe we need to run that check gain. So I feel that it's something computer or sensor related. Anyway, we'll keep trying every idea that is suggested. Thanks!
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I had that problem with my LS3, I ended up putting a check valve on the fuel pressure hose close to the tank and replaced the regulator to hold the pressure in the line. Now when I turn the key without starting it the pressure still reads 60 psi. Sometimes the fuel pump valve or regulator leaks and drives us nuts.