Hard start...stumped!
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Joined: Dec 2007
Posts: 56
Hard start...stumped!
Hey guys, I just want to say that first off, I have been mostly a lurker on this board but it is one of my favorites...full of people extremely knowledgeable with anything Z28 and willing to help. Anyways, Im hoping someone can help me here...I have had no problems until yesterday out of the blue, went to start my 94 Z and it took about 10 seconds to start. When it did start, it threw a code but continued to run as normal. Ever since, it has done the same thing, taking quite a while to start.
Well, I did some troubleshooting today...I suspected leaky injector and dropping FP, so tried starting in "clear flood mood" (pedal to the floor) and it will NOT start like that, at all. I also tried priming multiple times, KOEO, before starting, to "test" fuel pump, and no luck. I then replaced the fuel filter suspecting a clog causing a hard time building pressure, same thing. I then threw on a fuel pressure gauge (which I should have done in the first place) and it primes and holds pressure just fine, albeit a bit low at 38 PSI. I then figured ignition, and threw on a new coil, no luck. Before anyone asks, the opti is GM OEM and has ~11k on it, and the plugs/wires have ~5k. Old coil tested fine, anyways. I may have forgotten a few things I did, and will add if I remember...
So, before anyone asks, I tried getting the code scanned at AZ, they can only do OBD2, and I couldnt even BUY a scanner in my area that would work, so I ordered one online, but it will be over a week at least. I just want to get a jump start on this, especially if the code I end up getting doesnt lead me directly to the issue. I am suspecting the coolant temp sensor on the WP housing, but not too too sure of the symptoms...
Sorry for the novel and any and all input is greatly appreciated! TIA!
Well, I did some troubleshooting today...I suspected leaky injector and dropping FP, so tried starting in "clear flood mood" (pedal to the floor) and it will NOT start like that, at all. I also tried priming multiple times, KOEO, before starting, to "test" fuel pump, and no luck. I then replaced the fuel filter suspecting a clog causing a hard time building pressure, same thing. I then threw on a fuel pressure gauge (which I should have done in the first place) and it primes and holds pressure just fine, albeit a bit low at 38 PSI. I then figured ignition, and threw on a new coil, no luck. Before anyone asks, the opti is GM OEM and has ~11k on it, and the plugs/wires have ~5k. Old coil tested fine, anyways. I may have forgotten a few things I did, and will add if I remember...
So, before anyone asks, I tried getting the code scanned at AZ, they can only do OBD2, and I couldnt even BUY a scanner in my area that would work, so I ordered one online, but it will be over a week at least. I just want to get a jump start on this, especially if the code I end up getting doesnt lead me directly to the issue. I am suspecting the coolant temp sensor on the WP housing, but not too too sure of the symptoms...
Sorry for the novel and any and all input is greatly appreciated! TIA!
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Joined: Oct 2006
Posts: 2,731
From: Post Falls, Idaho
Re: Hard start...stumped!
Could be low battery, starter going out or battery terminal corroded. Does it crank strong? Try turning the key to the run position, but don't try & start it. Pump should prime to about 40 PSI and stop. When it stops, pressure should not drop off quickly. Start the engine, then pull the vacuum line off the FPR. Correct pressure should be around 43. Anything within 41-47psi is OK. Reconnect vacuum line, pressure should drop proportional to intake manifold vacuum. About an 8psi drop on a stock engine is normal.
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