Hot start issue with faulty CSV / TTS

[Magnus86]

Hello there!

So my first post in this Forum after i got my Delorean for some days and i already have an issue with starting the car up when it‘s hot

My Delorean has a problem while starting it when the engine is warm or hot. The problem occurs immediately after i turn of the warm/hot engine. I checked this after about 10 seconds i turned the engine off and tried to start it again..it was really hard to get the engine running again. If i floor the gas pedal it (sometimes) starts up after a few seconds.
So the first thing i did was checking for fuel pressure. I removed the air box and slightly pushed against the flap of the air intake. When the engine hasn‘t been running for a while there is no resistance at all. After a short time of running, i can feel a resistance for quite a long time. So i think fuel pressure is not my issue. After that i tried something different and did the plug swap when the engine was hot..but that didn‘t help except some fuel smell from the exhaust.
So then i thought maybe my CSV is activated even with a hot engine and this may cause some flooding of the engine. Thats where i just unplugged the CSV and tried to start it up again. The engine started just fine with the CSV disconnected. It seems like every time i plugged in the CSV again a hot start was really bad, without the CSV there was no problem at all.

As the cold start with plugged in CSV works just fine, i would suggest there is something wrong with the TTS itself? When the TTS is „dead“, will it always fire up the CSV, no matter if the engine is cold or hot? Is there some way how i can check if the TTS works correctly when the engine is hot? I searched in the forum for this issue with a faulty tts. But all those topics seem to refer to a cold start issue, not a hot start issue like i have.

Thanks a lot in advance for your help!

[Bitsyncmaster]

Check if your "hot start relay" socket has a jumper or relay installed in it. That relay socket is at the back of your relay compartment with the socket just hanging off the harness. It has only 3 pins in that socket.

[Magnus86]

Hey Dave,

thanks for your reply. I already read about your hot start relay etc. when i was searching for solutions regarding my hot start issue

So i checked the compartment today, but it seems like there is nothing jumpered on this socket:
8531174F-F21A-4CC7-8EAE-2D7C596E1435.jpg

I also tried to start the engine today with really cold engine (car has been sitting for 24 hours) with the CSV still dieconnected and it just started fine. The temperature here is currently at about 6-7 degrees. Is the cold start valve and the tts designed for even lower temperatures?

Only thing i noticed is that right after the cold start the engine i reving up and down between 800-200rpm till it get?s a little warmer. But that was also the case with the csv connected as far as i remember.

So i think i should check the TTS?

[Bitsyncmaster]

My car only seems to need the CSV after it sits for a week or more without running. I can tell when it needs it because it has to crank for one second and that is when my hot start relay activates the CSV.

[Magnus86]

Okay i understand.
So is there anything to check if the TTS is damaged? I read something about that i can check for voltage on the blue plug for the csv? When the engine is warm there shouldn?t be any voltage on that blue plug?

Otherwise i?d just keep the csv just disconnected for now, as the tts is quite expensive

[Bitsyncmaster]

Okay i understand.
So is there anything to check if the TTS is damaged? I read something about that i can check for voltage on the blue plug for the csv? When the engine is warm there shouldn?t be any voltage on that blue plug?

Otherwise i?d just keep the csv just disconnected for now, as the tts is quite expensive

I think the TTS just will not provide the required ground to the CSV when cranking the engine above a certain temp or after cranking exceeding the built in time out. I think the fact you fixed it disconnecting the CSV proves something is grounding that circuit all the time. The white/red wire on the CSV only gets 12 volts when cranking.

You may be able to test zero ohms to ground on the cold engine and open circuit on the hot engine with the CSV unplugged.

[David T]

I have seen where the plug to the TTS gets damaged and it gets plugged into the TTS incorrectly. That immediately burns out the TTS and can cause this problem. The CSV is only supposed to operate on a cold motor (like a choke to enrich the mixture so it can start easily) and only for a short time. The TTS senses engine temperature to only operate the CSV on a cold engine and times out the CSV so you don't flood the it. Also make sure you are putting the correct plug on the CSV and the CPR. If you do the "plug swap" you must quickly switch the plugs back once the motor is running. The plug with power all the time (with the motor running) is the one going to the CPR.