Strange Starting Problem
Thread Starter
2nd Gear
Joined: Sep 2001
Posts: 2
Likes: 0
From: Grand Junction CO
Strange Starting Problem
My 85 has a strange problem I can't figure out. When the engine is cold it will start almost instantaneously. However, if I have run it for awhile the engine will spin for a few seconds before starting. On occasion after running for awhile it will not start...won't hit at all. If I wait for about a half hour to 45 mins it will start again. Any Ideas?
Dave
Dave
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: Strange Starting Problem (Dhccasey)
coil? something in the ignition is over heated or over heating...
could also be vapor lock... or a variation.
next time, turn on the key, count to 10, THEN try and start... see what happens.
could also be vapor lock... or a variation.
next time, turn on the key, count to 10, THEN try and start... see what happens.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Strange Starting Problem (Dhccasey)
The time to diagnose is when it won't start. Measure the fuel pressure at the shrader valve on the fuel rail. If normal, see how long it takes to lose 1 psi. GM says if it takes less than 30 minutes, you have leaky injectors. Check for spark. Use your timing light to check for spark and see if it is timed right. I have seen spark modules that quit when they get hot. Engines need air, fuel, spark to run, you are missing one or more when it won't start.
Burning Brakes
Joined: Feb 2000
Posts: 824
Likes: 2
From: Camden SC
Re: Strange Starting Problem (jfb)
As jfb states, you will have to attack this problem when it hits. You may consider buying an "in line spark check" tools. This little gadget, under $15, connects between the spark plug and plug wire. You have someone turn the engine over and see if the little light pulses. You can determine secondary spark by other means but this little device will keep 20000 volts away from computer stuff. This device will help determine if you have SOME some level of secondary spark. The second tool I would carry is a fuel pressure test gauge. This will help tell us if we have fuel pressure. One other helpful test item would be an inexpensive noid light. This would hook up to the injector and tell us if the injectors are being pulsed. So far your total investment is around $60-75US. Intermittant conditions suggest ready access to test equipment. Spark, gas, correct timed compression, and it should go. Good luck. Let us know.
dlmeyers 90 coupe zf6 3 speed shocks
dlmeyers 90 coupe zf6 3 speed shocks
Instructor
Joined: Jun 2002
Posts: 231
Likes: 0
From: 80/680 junction Ca.
Re: Strange Starting Problem (Dhccasey)
My 87 has some strange starting probs too. When cold, same as yours, fires right up when warm it takes a good few cranking revs to fire, but if I just bump it on the first try then crank it again right after, it fires right up every time. No error codes from the system, runs fine besides that. Just seems strange that it will fire up instantly ever time on that second try, I just automaticly give it a quick bump and then a second now, always works! :confused:
Le Mans Master
Joined: Jan 2002
Posts: 5,320
Likes: 4
From: Kyle TX (Because Mojo Made me fill it in)
Re: Strange Starting Problem (Dhccasey)
I think it is leaking injectors. You can try this little test to see if that might be the case.
Copied from the TechTip section - https://www.corvetteforum.com/techti...D=97&TopicID=2
"Say your L98 starts right up after sitting for a long while, such as overnight, but is hard to start after sitting for a little while. Before trying to start it, hold the accelerator to the floor for a brief period and release it.
If the engine then starts right up it's a sign that an injector may be leaking, causing a flooding condition. Holding the throttle plates open allows some of the excess fuel vapors to escape, which removes some of the accumulated excess fuel and makes the engine easier to start."
Copied from the TechTip section - https://www.corvetteforum.com/techti...D=97&TopicID=2
"Say your L98 starts right up after sitting for a long while, such as overnight, but is hard to start after sitting for a little while. Before trying to start it, hold the accelerator to the floor for a brief period and release it.
If the engine then starts right up it's a sign that an injector may be leaking, causing a flooding condition. Holding the throttle plates open allows some of the excess fuel vapors to escape, which removes some of the accumulated excess fuel and makes the engine easier to start."
