# hard start when engine is warm/hot



## oldsquirrel (Dec 19, 2010)

I have an ongoing problem with a 82 quantum. Car starts every time cold and runs great but if you shut it off after its been driven for awhile you have to crank the crap out of it until it will start. So far 3 mechanics and no luck in fixing problem. I have replaced injector seals/injectors checked fuel pressure and all is good. I am wondering if I should put a button in for the cold start injector and see if it will start easier if I give it a shot of gas? One person mentioned something about a distributor sensor but nobody up here in Canada knows about these cars. I am to the point now of swapping the gas motor for a 1.9 td but thats seems excessive when the motor runs great once going. Any help wouldd be great. Thanks.


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## WaterWheels (Aug 14, 2005)

That you have no cold problem and only when driven for some time kinda throws residual pressure out the window. That more or less leaves a heat soak problem or tune-p/mixture problem. If you let is sit for say half an hour or more after driving does it fire up normal? Heat soak problems happen most often about 3 - 5 minutes after shutting the engine off and then go away after about 20 minutes or more. VW did install a pulse system to fire the cold start valve on some models for hot starts, maybe you can graf on in. You can also re-locate the fuel lines away from any heat source and wrap them to reflect any heat. The idea of wiring a switch for the cold start valve is not a great one but id most likely will work if done correctly. If nothing else it can help determine if it really is heat soak.


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## oldsquirrel (Dec 19, 2010)

*heat sink problem*

Car I will try it today and see about the after 20 minutes or so starting. I will also check and see ifs possible the lines are anywhere near heat. Thing is the car worked great for years then just started doing it. I also have a 82 rabiit caddy that can do the same thing but its very sporadic where as the quantum is every time the car is shut of and tried to restart . If you shut the car off and retry instantly it will start everytime. thanks for your reply. Is heat sink like vapor lock? and what lines would I insulate? I was just going to tap into the 2 wires on the cold star injector. one to a button with power to it and then just the other to ground. Thanks for your answer


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## WaterWheels (Aug 14, 2005)

If as you say it was running fine for years and just started doing it then heat soak may not be the issue. And yes, heat soak is what causes vapor lock. The fuel begins to boil in the line, it does so at a lower temperature than water, and the vapor pockets that are created form a lock of sorts. There are other things which are heat related and could act about the same. The ignition control module can be effected by heat (or by age and heat makes it show), an ignition coil can heat up and more or less die then function again when cool, fuel pumps can do that as can their relay. So I guess you are going to have to do some troubleshooting to come up with the cause if it is not fuel heating up. Try to come up with some times, how long do you need to drive, how long does it take to happen and then work again, even weather or fuel level or dash lights all can be clues if you notice a pattern. Do you have a fuel pressure gauge and a good repair manual?


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## oldsquirrel (Dec 19, 2010)

*hot start problems.*

Hi I do not have a manual as these cars were never imported into Canada.So I have not been able to track one down. I do not see it being coil related as they tend to be sporatic in nature. This is always the same. What I do now to start it is hold the pedal to the floor and crank fires then dies.keep peddle to floor crank till it fires then dies, then on the third attempt it will start and fire and keep running. I checked the fuel pressure and the fuel pump and its relay. hot wired relay direct. one thing nobody here can tell me(in Canada) is where the return line pressure valve is although I do not see that as a problem as we checked for return pressure and it was fine. I am going to put a button inline to the cold start injector today and see if I can make it work better. I am going to swap the gas out for a 1.9 but would like to wear the gas motor out first


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