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10-27-2023, 05:22 PM | #1 |
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So, I’ve been chasing a cold start issue for 2 years now. Basically the car just cranks got like 6 seconds after sitting for 24+ hours. Then I press the start button a second time and it cranks right up. Only first cold start of the day, rest of the starts are fine no issues
Things I’ve replaced: Fuel sender unit (regulator and filter) All 8 injectors Fuel pressure sensor Any ideas? No codes.
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10-27-2023, 08:46 PM | #3 |
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Not yet - cranks very strong.. can I see the ground in the engine bay?
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10-30-2023, 05:07 AM | #4 |
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you checked the EKP? what kinda voltage is the pump getting on crank? you should also mechanically check the fuel pressure at the rail when the engine is experiencing this delayed crank.
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10-30-2023, 07:58 AM | #5 | |
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Quote:
I have mechanically checked the fuel pressure at the rail, upon prime it’s immediately full pressure, and when I crank it doesn’t drop.
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10-30-2023, 11:44 AM | #6 | |
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Quote:
Lemme see if I can find it...
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10-30-2023, 01:12 PM | #7 |
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What DME sees for fuel pressure?
I can't find it!...ergh. Anyway, if you can easily reproduce the problem I would check the fuel pressure BEFORE priming the pump. See what pressure it sits at "overnight" when the problem happens.
Someone on the forum shared this before, but look at your fuel pressure readings using INPA without priming the fuel pump.
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10-30-2023, 01:21 PM | #8 | |
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Quote:
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10-30-2023, 01:22 PM | #9 |
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Okay. What was your pressure reading?
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10-30-2023, 04:38 PM | #10 |
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I believe around 50-55 psi. Should be plenty to fire right up. When I prime, it just immediately to 75 psi. It actually DOES sound like it’s starving for fuel - but with every component being new, and the pressure being fine..: it’s quite odd (and frustrating lol!)
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11-24-2023, 04:45 PM | #12 |
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So, to update this thread.
I pulled the rear seats back out, and primed the fuel pump. I then clamped the fuel line right after the fuel pump (right side) and the pressure did NOT drop significantly on the gauge. It was about 4 psi over 30 minutes, which is well within spec. Given the sender (left side) is brand new, this tells me the fuel pump is bad.. or the check valve in the fuel pump is. Finally may have figured out the issue. After removing the clamp, the pressure started falling off instantly.
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