87 Vert--cold starting
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Joined: May 2011
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87 Vert--cold starting
Engine has run well for nearly a year following a rebuild--that is, once I discovered fuel pressure problems and replaced the fuel pump. Lately, engine hesitates to start on first crank after setting for a few days or/and when cold [ambient temps in 50s], but then starts immediately upon recrank. Engine starts fine when warm. Thought it might be fuel pressure leak down or something but letting fuel pump run the full 5-7 secs before initial crank doesnt help. Thoughts?????
Team Owner
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Have you checked fuel pressure before attempting to start the engine? The fuel pump should only run for 2-3 seconds once you turn the ignition key to the ON position then it will shut off. At that point, there should be something like 35-45 psi of fuel pressure. When you try to start the engine, do you let it crank until it starts or just engage the starter for a couple seconds or so?
When you turn the key to ON, do you hear a short buzzing noise at the rear? That will be the FP running to create enough fuel pressure so the engine will (should) start.
When you turn the key to ON, do you hear a short buzzing noise at the rear? That will be the FP running to create enough fuel pressure so the engine will (should) start.
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Havent re-checked fuel pressure since installing new fuel pump. Yes, fuel pump engages for 3-5 seconds when key is turned to on position--as indicated, I've let the pump run until timeout before first crank but doesnt impact/improve starting. Again, engine starts immediately upon second/subsequent cranks. I've let the initial crank go for awhile but with no effect. Since I hear the fuel pump engage when key goes to on position, I've not been trying to activate the oil pressure override with persistant first cranks as a primary means of starting the car--instead, I just go to the second crank which works everytime......
Last edited by dsandmire; Apr 21, 2013 at 11:56 AM.
Burning Brakes
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Pro
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2021 C4 of the Year - Unmodified Finalist
CS injector
If you are running the stock intake you have a ninth injector, the Cold Start injector.
Either the injector has died OR you have high resistance at the electrical terminals (maybe corroded wires) .
Drove me nuts. Went through three mechanics before one found the corroded wires INSIDE the coated wire near the injector connection.
Either the injector has died OR you have high resistance at the electrical terminals (maybe corroded wires) .
Drove me nuts. Went through three mechanics before one found the corroded wires INSIDE the coated wire near the injector connection.
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Appreciate the input--especially the part about being "driven nuts." This was my first re-build of a Corvette and I still "marvel" at how temperamental the fuel and ingition systems are. I found this issue to be particularly vexing as the hesitation to start is always and only on the first crank attempt, and only after the car has set for a day or two. Second and subsequent cranks always result in immediate engine start--too weird.
Pro
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2021 C4 of the Year - Unmodified Finalist
first start
I hear you goin' nutz man! Once the engine starts you're screwed for diagnosing the problem because the CSI in no longer in ECM loop so you can't troubleshoot it.
I'm pretty sure you'll find resistance at the wires is the problem.
I'm pretty sure you'll find resistance at the wires is the problem.
Safety Car
Joined: Jan 2004
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It is only a thermal switch that only gets power when the engine is being cranked over and is closed below 85F (? )
It supplies power for a timed period to the CSI
Simple enough to put a DVM on the switch when the engine is cold and see if it is working ( closed ) , also to check for power into the switch when engine is cranked over
Ditto to put DVM between the switch and the CSI to check the wiring
Factor in $150 to replace the CS switch
Last edited by vetteoz; Apr 23, 2013 at 06:58 PM.
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