intense3123

Here's my problem. After my car has been driven and sits for a while hot, like at least an hour, the first start attempt usually won't turn the engine over. It will crank fine so I know it's not a battery problem or anything.

Second start attempt will be just fine, fires up right away. Even if it's just a second after the first. It's gotten to the point that I'll usually bump the engine over a couple turns, let go of key, and then start it up. It's kinda embarrassing that it doesn't want to start on first attempt.

Seems like it has gotten worse since installing headers. Again, once started it will idle fine and run great, just doesn't like to start or first cycle after sitting hot.

Any ideas?

fleetmgr

Your starter getting cooked maybe?

intense3123

I'm thinking it's something heat related, but the starter turns fast and the engine cranks fast too

jimmyblue

iTrader: (11)

Yeah, once it's freed up - but the heat may be giving the
solenoid a hard time, getting to contact. Does it grunt
and try to turn, just "ka-chunk" (solenoid but no spin)
or click (not even solenoid pull-in)?

intense3123

No, it cranks easily. It just doesn't want to fire. I don't know if it might be a crank sensor problem, but it doesn't make sense why it won't fire on first try but it does on the second.

LS6427

iTrader: (2)

When the engine is cold....it always cranks up on the first hit????

Maybe the heat is doing something to the fuel pressure? I would check the pressure cold, then hot, see if there's a difference.

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intense3123

Thanks, that's what I've started leaning to. I've seen some posts about the check valve in the fuel pump failing and causing pressure to drop off while sitting.

LS6427

iTrader: (2)

I guess just look for a drop of pressure over time. When it primes cold it should hold pressure. Then when hot, if thats the problem, it will not hold pressure after you turn the key on and the fuel pump primes the lines. But engine still off.

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intense3123

So does the fuel pump not prime when the ignition is turned on if the engine is hot?

LS6427

iTrader: (2)

It always primes when you turn the key to on.

Are you not hearing it prime after you drive it somewhere? You should always hear it prime.

.

joshp14

iTrader: (5)

Sounds like your fuel pressure is bleeding down. Possibly a leaking injector or faulty fuel pump. I would put a fuel pressure gauge on it, start it, then turn it off. Watch your fuel pressure...if it bleeds off quickly I would look towards a fuel pump. If it bleeds of slow, then you may have an injector leaking. Pull the railwhile still connected to fuel line, prime the system, and look for drips on the bottom of the injectors.

LS6427

iTrader: (2)

I was thinking leaky injector, but why would it leak only when the engine is hot, and start right up when its cold.

Strange.

Maybe some kind of vapor lock going on.

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joshp14

iTrader: (5)

Sometimes the heat is what induces the fault. Ive had several do this before where it only acts up when hot. Pull the rail and watch the injectors you typically it will sit there a drip a few drips every minute.

intense3123

Put a pressure gauge on it at work today. Turned the key to on, pressure built up to 4 bar right away during priming. Then it dropped off quickly down to 1 bar within 10 seconds. So I'm pretty sure it's the check valve inside the pump.

Also, I was thinking about cutting a door for the fuel pump. I've heard 98s have a different location for cutting then the other f-bodys. Can anyone confirm this, and know where to cut?

Is it the same as the LT1s?

joshp14

iTrader: (5)

The fuel lines are part of the sender so you will have to pull the tank. In other words, you cant disconnect the lines at the sender like you can on the LS cars. Have fun dropping the tank and fighting with the fill neck!

intense3123

Found some write-ups for 98s and you just have to cut back a lil further. Then you can disconnect the lines at the top on the tank.

joshp14

iTrader: (5)

I thought you were working on a LT1...

HAZ-Matt

iTrader: (8)

Interesting. I have a problem like this. I haven't checked my fuel rail pressure but for my car it only happens when it is already warm. It seems like when I am thinking about it and let it prime the entire time that it starts better. If the car is cold I never have the issue and if it has been parked a very short time while warm it doesn't happen. My car has LT's too so the underhood temps are probably hotter (even with the Firehawk heat extractors which probably don't do anything).

I would think that if it was really leaking down through the pump or the injectors then if it sat for a long period it would be hard to start as well since it would have longer to bleed pressure.

MyLS1rx7

iTrader: (1)

Has anybody figured this problem out. My car is having the exact same problem. Any help would be great.

cknoma2005

iTrader: (3)

I am having the same problem. I bought a fuel pressure pulsation damper from the dealer but I haven't put it on yet. My car has been doing this exact same thing for over a year now. I first considered it to be a bad fuel pump after checking the fuel pressure I wasn't so sure. When I turn the key to the on position I can hear the pump priming and the fuel gauge spikes out at 58psi or so and then immediately bleeds off to 10psi. Not holding pressure. When I start the car up the fuel pressure reads normal at 58psi. After reading this thread it seems that the fuel pump has a check valve built into it that helps hold the fuel pressure. This seems like a more plausible source for our problem. I'm just going to buy a new fuel pump.

I will post my results.