Fuel pump does'nt stay primed
10-15-2012, 11:01 AM
#8
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The normal behavior of the MegaSquirt is to prime the fuel system for 2 seconds after key on, then shut off the fuel pump unless there is a valid incoming RPM signal.
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10-15-2012, 01:13 PM
#9
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Yeah, this sounds like a trigger problem to me. The MS may simply not be reading the crank / cam sensors. When you made the swap, did you transfer the CAS from the old engine to the new one, or have you re-wired for the '02 engine's discrete crank and cam sensors?
Why don't I see RPM in that log? I don't mean that it's zero, I mean the column for it is missing.
Also, ignore the fuel pressure indication in MS. Unless you have actually installed a fuel pressure sensor and connected it to the MS, this reading is completely bogus.
Why don't I see RPM in that log? I don't mean that it's zero, I mean the column for it is missing.
Also, ignore the fuel pressure indication in MS. Unless you have actually installed a fuel pressure sensor and connected it to the MS, this reading is completely bogus.
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10-16-2012, 04:36 PM
#11
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Well, on the plus side, it's probably a simple fix then. Most likely a CAS-related wire got cut / broken / squished / not plugged in during the swap.
During cranking, you should read somewhere in the vicinity of 200-300 RPM on the MS, assuming a healthy battery and starter. Until you achieve that, nothing is going to work.
Tip: while you're troubleshooting, remove the spark plugs and disconnect the primary (low-voltage) side of the ignition coils. This will greatly decrease the load on the battery and starter. Also, disconnect the electrical plug for the fuel injectors, so that you're not constantly spraying fuel into the chambers. (The injectors fire once every time you turn on the ECU, regardless of whether the rest of the system is working or not.)
Your dashboard tach may not be working either, but don't worry about that for now. It's the tach in TunerStudio / MegaTune that you need to worry about.
During cranking, you should read somewhere in the vicinity of 200-300 RPM on the MS, assuming a healthy battery and starter. Until you achieve that, nothing is going to work.
Tip: while you're troubleshooting, remove the spark plugs and disconnect the primary (low-voltage) side of the ignition coils. This will greatly decrease the load on the battery and starter. Also, disconnect the electrical plug for the fuel injectors, so that you're not constantly spraying fuel into the chambers. (The injectors fire once every time you turn on the ECU, regardless of whether the rest of the system is working or not.)
Your dashboard tach may not be working either, but don't worry about that for now. It's the tach in TunerStudio / MegaTune that you need to worry about.
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10-20-2012, 02:17 PM
#14
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To rule out an ECU or wiring fault, disconnect the CAS and measure between the white wire and ground at the harness connector where the CAS would normally plug in. You should see +5 here with the key on. If not, it's an ECU or wiring problem. If you do see +5 here with the CAS disconnected, but it goes down to 0v constantly with the CAS connected, it's a bad CAS.
I guess I should try to use the BP-Z3 cam sensor and crank sensor....
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10-21-2012, 03:43 PM
#17
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OTOH, this is only a 4 layer board, and I'm 99% certain that the inner layers are nothing but power and ground planes, so it should be easy to trace visually.
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