Engine Turning but not Starting

[lazabby]

There is probably an easy answer to this. I can't get my car started. The engine cranks but it won't fire up. It's been about 1-1/2 weeks since I drove it. What could be the problem? Water in the gas? Bad starter? Bad fuel pump (it sounds like it's working)?

Perplexed in Texas

[sean]

If it cranks then you can rule out the starter. Be a good idea to check for spark and makes sure you have fuel pressure at the mixture plate. You can also jump the rpm relay sock to power the pump and attempt a start.

[TTait]

There is probably an easy answer to this. I can't get my car started. The engine cranks but it won't fire up. It's been about 1-1/2 weeks since I drove it. What could be the problem? Water in the gas? Bad starter? Bad fuel pump (it sounds like it's working)?

Perplexed in Texas

Run out to the garage and hop in, with the door open turn the key to run, not start, and you should be able to hear the fuel pump hum in the front trunk area hum for about 3/4 of a second - if not tell us that. Turn the key several times and make sure it hums or fails consistently.

Then open up the back. Find the cold start valve (csv), blue device just left of the air filter, and the warm up regulator (wur) about 10 inches forward of the csv. CSV has a blue plug on the top, the wur plug is grey. Unplug both.

Plug the grey one onto the top of the csv, leave the blue plug unconnected, and try starting the car - then come back and tell us if it worked and we'll try the next step.

Tom

[DMCMW Dave]

Wiggle the plugs on top of the coil and on the two white resistors mounted just above the engine at the back of the compartment.

[David T]

If it is cranking at a good speed and not starting the 2 most common problems are:
A) An electrical problem in the fuel pump circuit
B) a bad connection on the ballast resistor on the firewall.

Try to see if you can hear the fuel pump running.
David Teitelbaum

[WelmoedJ]

Wiggle the plugs on top of the coil and on the two white resistors mounted just above the engine at the back of the compartment.

+
Also check the wire connector under the whiteish/yellowish cover below the resistor pack if you don't have spark. That connector seems occasionally to disconnect by itself (not visible though) and cause the same symptoms.

[lazabby]

Thanks for all the suggestions. I plan to work on it tonight. I'll let you know what happens.

[dn010]

Check your bulkhead connectors as well... That's whats keeping my D from starting currently...

[lazabby]

Ok we're closer to the solution. I checked the various plugs such as the ballast connectors. I also checked the connection to the coil. That might have been a little bit loose. Fuel pressure plate had good pressure. There is a question as to whether the fuel pump was buzzing every time but we could always smell gas. I also found the wire going to the spark advance thing-a-ma-jig by the distributor next to the firewall was unplugged. I plugged that back in. We have spark.

It appears to be something wrong with the cold start valve (CSV). We would get the same symptoms where the engine would crank but not start UNTIL we unplugged the(CSV). Then the car started like a champ every time and ran smooth. What's going on that it is keeping the engine from starting? Since there is a strong smell of gas, even though I'm not pressing the gas pedal, it leads us to believe that the CSV is somehow stuck open. What's going on?

[DMCMW Dave]

Could be stuck open, more likely the themotime switch is stuck closed. Try unplugging it.

Either condition will flood the engine.

[Bitsyncmaster]

Leave the CSV unplugged. I found my car starts better with the CSV not active. But I have seen a thermal time switch fail that caused the CSV to always fire.

[David T]

Check to see if there is anything plugged into the hot start relay plug by the fuseblock. If there is, remove it.
David Teitelbaum

[lazabby]

Check to see if there is anything plugged into the hot start relay plug by the fuseblock. If there is, remove it.
David Teitelbaum

I assume this is the same as the "Start Inhibit" as described in the workshop manual (#28 on page M:07:01). Yes that relay is in the socket. What happens if I unplug it and should I then replug the cold start valve?

[Bitsyncmaster]

I assume this is the same as the "Start Inhibit" as described in the workshop manual (#28 on page M:07:01). Yes that relay is in the socket. What happens if I unplug it and should I then replug the cold start valve?

No. The hot start relay in a white relay socket at the back of the relay compartment wired into the harness.

[lazabby]

It appears that my CSV or thermotime switch is bad. How do I test to see which one is bad?

[DMCMW Dave]

It appears that my CSV or thermotime switch is bad. How do I test to see which one is bad?

With the car cold put a test light across the pins of the CSV. If the light goes on while cranking, the TTS is good. If the light does not come on, the TTS is bad, OR it's too warm, OR the connection from the starter to that circuit (blue wire on the starter) is dirty. The blue wire connection is a double hit - it is also the coil resistor bypass feed, and if it's dirty enough not to fire the CSV you are also getting a bad spark.

Careful - in hot weather (like you are having in Texas now) it my not be "cold" enough to engage the TTS, even after overnight, it if the garage temperature is warm.

[lazabby]

Still having problems with the car not wanting to start. Can't quite figure it out. Once it start it runs like a champ. Very little hunting. Idles smooth. I replaced the thermotime switch thinking that was it but it still won't start at the first turn of the key. Generally have to crank the car for 20 seconds before it kicks in.

[David T]

You have a problem in the CSV circuit. See if it is active during cold start cranking. If it is not you will have to go through the wiring and find the problem. Start at the starter and follow the wiring up to the TT switch and then to the CSV.
David Teitelbaum

[Bitsyncmaster]

You check you CSV by disconnecting the coil wire (at the resistor block), remove the CSV and put it in a jar. Then crank the engine over on a cold day. Crank it for about 5 seconds and you should see gas in that jar.

[lazabby]

You have a problem in the CSV circuit. See if it is active during cold start cranking. If it is not you will have to go through the wiring and find the problem. Start at the starter and follow the wiring up to the TT switch and then to the CSV.
David Teitelbaum

I forgot to add that I unplugges the CSV and I'm still having a problem with the hard start. I will add one thing but I don't think this has anything to do with it. A couple of months ago when this first started, a fellow Delorean owner felt it was bad gas. He said to add a bottle of Seafoam (in case there was water), a can of Chevron's Techoline (fuel injector cleaner) and put in premium gas. I'm still running on that same tank of gas with the mixture as I haven't used it all up. I don't think that's the issue since it seems to run fine once started.