Hello all,

I have a 1987 Z52 Vette and here's my issue:
Car starts up fine when the engine is cold. However when the engine is already hot and I shut it off the car the car will start and then stall/die when I try to turn it back on. Either it just cranks forever, or sometimes it will start weakly and then die within seconds. I've read a bit on this forum about similar situations with causes listed as fuel pump, MAF sensor, bad injectors, vacuum issues, and more! However my scenario does not match others' exactly and here's why- if the engine is hot and it's only been off for 5-10 minutes it will start up again fine- such is the case when I get gas or make a short stop etc. It is only when the engine has been off for over ~10 minutes, all the way until it cools down again hours later, when it has the stalling problem. Here's the kicker- if I give it some gas and rev it up while I'm starting, instead of stalling it will start and and stays on! Why do you think that is? Incredibly the idea of giving it gas while starting was suggested to me by a coworker who had an old car that you needed to prime the pedal before starting.. totally different situation, but by God his advice led me to try giving it gas when I start it hot, and instead of stalling it starts every time! This trick has been a good short term fix to get me through last summer, but I'd really like to get to the root of this problem. I know it's not an overheating problem, once it's started the car runs totally fine and can be pushed hard, and offers plenty of speed and TORQUE!

Does anyone have any insight into this situation? I am hopeful that it might be obvious what I should repair, given the specifics that the engine does start when hot, but not if it's been turned off for more than 10 minutes, and that giving it gas/revving the engine while starting overcomes the stalling issue entirely. My technical and conceptual knowledge is pretty limited to diagnose this but my mechanic is a friend and he will do the repair for me. We were hopeful spark plugs and tune-up kit would fix this issue but sadly it persists. I figure it is time to ask the experts!


Some more backstory on the car and my incredible luck and blessing to find it- I picked up my Vette for $1500 last summer and have put some money into it since then.. new window actuator, brake pads, battery, water pump, spark plugs, tune-up kit, and an injector or two. It was a single owner car, my mechanic's uncle sold it to me on behalf of the owner's widow.. I hit the lottery, it runs great! Put over 4000 miles on it last summer including trips to Maine, Boston, even Manhattan! From what I can tell it was a very well-maintained car in its day that probably sat 5-10 years before I rescued it. The type of deal you only get in a small town from good people, and it's totally changed my life! It has a known coolant leak which will be addressed soon and I suspect is unrelated to the stalling issue when hot. Other than that, everything is great and I absolutely love the car.

Thanks so much to all you guys who make up this forum, and I really appreciate any help or suggestions that you experienced members may be willing to offer!

-Lucky87

The beautiful Vette on an adventure to Maine last summer

 

I just picked up a LT4 car and it does the same thing. I was thinking bad gas at it sat unregistered for over a year before I bought it.

 

Interesting, I have driven it a lot and filled up the tank countless times with this issue, but that doesn't rule out sediment or something in the bottom of the tank.. anyway, try giving it gas when you start it! I crank it first with my foot off the pedal and then start giving it gas as it continues to crank and it will start and run strong. Let's see what else we can find out!

 

That part where you say opening the throttle plate w the pedal sounds to me like your Cold Start injector is leaking. But It's just a guess.

The LT4 doesn't have that.