Hard starting.....what to check??
Thread Starter
Heel & Toe
Joined: Apr 2004
Posts: 15
Likes: 0
From: Shelburne MA
Hard starting.....what to check??
Over the weekend my 94 developed starting issues. It now takes 5-10 seconds of cranking to fire it up. Once it does start, it seems to run fine. Where should I start looking.....is there a common failure on these LT-1's that would cause this issue?? The car has 107,000 miles on it and except for plugs, wires, etc, I believe everything is original.
Thanks! :cheers:
Thanks! :cheers:
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: Hard starting.....what to check?? (slowryd)
check fuel.
try this:
turn on the key, count to 2. turn off the key. Turn the key back on, count to 2, then start. If all is well, the fuel pump is weak, or, you have a leak.
try this:
turn on the key, count to 2. turn off the key. Turn the key back on, count to 2, then start. If all is well, the fuel pump is weak, or, you have a leak.
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: Hard starting.....what to check?? (slowryd)
Yeah the fuel pump should prime itself when you first turn the key on for about 2 seconds. After that the fuel pump doesn't turn on until I believe it sees oil pressure?
If your fuel pump is weak and not priming the system you could be having to crank it for a long time until it builds enough fuel pressure to start. A quick way to test is to put a fuel pressure gauge on the fuel rail and just watch it's behavior. If you turn the key on it should go up to about 40 PSI and it should hold good pressure for several hours.
If the pressure goes up but then falls off it could be leaking back into the tank or you could have a leaking injector. If the pressure never builds really high to start with it could be a bad fuel pump. Another thing to check is fuel pressure while it's running. At idle it should hold at around 38 PSI. Blip the throttle to wide open and it should go up to about 46 PSI. Of course it will vary with vacuum at any point in between.
If fuel pressure falls at all when you give it throttle then something is wrong. :cheers:
If your fuel pump is weak and not priming the system you could be having to crank it for a long time until it builds enough fuel pressure to start. A quick way to test is to put a fuel pressure gauge on the fuel rail and just watch it's behavior. If you turn the key on it should go up to about 40 PSI and it should hold good pressure for several hours.
If the pressure goes up but then falls off it could be leaking back into the tank or you could have a leaking injector. If the pressure never builds really high to start with it could be a bad fuel pump. Another thing to check is fuel pressure while it's running. At idle it should hold at around 38 PSI. Blip the throttle to wide open and it should go up to about 46 PSI. Of course it will vary with vacuum at any point in between.
If fuel pressure falls at all when you give it throttle then something is wrong. :cheers:
Racer
Joined: Mar 2000
Posts: 262
Likes: 0
From: Tulsa OK
Re: Hard starting.....what to check?? (Nathan Plemons)
I had a problem similar to this, it didn't have to crank for 10 seconds but it cranked for 4 or 5, and it was a bad battery. Not a dead battery just a bad cell. I didn't realize it at first because I had also raised my compression and thought it might just be that I needed a higher torque starter. It really didn't crank that much slower and did this for about 6 months without getting better or worse before I had a wild hair and checked the battery. It always started fine, it just had to crank a few seconds. New battery and it fires right up. I doubt this is your problem but if the fuel pressure is fine and it is cranking slower it might be worth checking. It's always nice when it is something simple.
Josh
Josh
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: Hard starting.....what to check?? (NOS6SPEED)
That's certainly strange, but I've seen stranger. My dad has an old 46 pickup, 6 volt system of course. When it's hot you can crank it and cranks a LOT slower than when it's cold, I feel like it's just heat soak in the starter. The funny thing is that you can crank on it forever until it drains the battery, OR...
Hit the starter for a just a second or two and turn the motor over. Then let off, let it stop and then immediately hit it again and it fires almost every time. Makes no sense whatsoever, just one of those little "tricks" to driving that truck.
Hit the starter for a just a second or two and turn the motor over. Then let off, let it stop and then immediately hit it again and it fires almost every time. Makes no sense whatsoever, just one of those little "tricks" to driving that truck.
Thread Starter
Heel & Toe
Joined: Apr 2004
Posts: 15
Likes: 0
From: Shelburne MA
Re: Hard starting.....what to check?? (edsalinas)
Thanks for all the help everybody! This forum is awsome!! I'll try some things and post back if I'm still having problems. :cheers:
