Cold Start

[alexwolf1216]

Hey everyone. I finally was able to get my car up and running, but it has a hard tme starting when its been sitting. It turns and turns, barely catches, and struggles to start. Purrs like a kitten when it gets up to normal operating range. It will start up perfect after.

I did search the forum, and saw that it may be electrical. Can someone point me to what I should clean/inspect? Please remember, I am a total rookie so answer like you are talking to a 5yr old child :)

[Chris 16409]

Your cold start valve probably isn't firing. Maybe your thermotime switch is bad.

[alexwolf1216]

I found the part on the diagram, but I cant tell if its an easy swap or not? Is it something accessible?


Alex

[DMCMW Dave]

I found the part on the diagram, but I cant tell if its an easy swap or not? Is it something accessible?


Alex

The TTS is screwed into the left side of the water thermostat housing on the water pump. Unplug it. There are two pins.

Set your ohm meter to the lowest scale. When the car is cold, one pin should read grounded (zero ohms) and the other about 30. If either or both read open the switch is bad.

Also pull the blue plug off the cold start injector and inspect the pins in the plug to make sure that they have not backed out of the shell.

[djdogbone]

Could be the fuel accumulator

[kings1527]

Could be the fuel accumulator

That's more related to hot start issues. But for whatever reason, after I replaced my accumulator I started having a weird cold start issue if you'd want to call it that. But it catches perfectly everytime if I depress the accelerator about 1/4-1/2 while cranking on a cold start. The funny thing is, that's exactly the way the owner's manual tells you to start the car so I'll write it off as perfectly fine and by design.

[NightFlyer]

Could be the fuel accumulator

Accumulator wear usually causes hot start problems. That's not to say that it can't also cause a cold start problem, but the only way that would even be possible is if there's a complete failure of the accumulator, which is rare (so rare that only know of 1 example, and it wasn't even on a DeLorean), and would prevent the engine from running normally, if not prevent it from running at all.

As his engine runs fine after he gets it started and warmed up, it's definitely not an accumulator issue. That's not saying that his accumulator isn't due for a change, but if he's not experiencing any hot start problems (which he hasn't reported), then it's probably fine.

As you mentioned it though, there's an easy way to test the accumulator - simply pull the hose coming off the barb on the back of the accumulator when the fuel pump is running. If the accumulator is good, no fuel should be coming out of the barb. A few occasional drops is also normal. As the internal diaphragm and seals wear/deteriorate and as the spring loses its force, you may start to see random pulses of fuel come out of the barb - and as such, it's not going to hold rest pressure very well when the pump is off, which causes the infamous hot start problems. But it usually never gets so bad so as to prevent the engine from starting and running fairly normally. However, if you ever experience a steady pressurized stream of fuel coming out of the barb, then the accumulator has suffered a complete failure, and could very easily cause cold start problems as well as rough running, if not completely prevent the starting/running of the engine. But like I said - that's EXTREMELY rare.

[NightFlyer]

That's more related to hot start issues. But for whatever reason, after I replaced my accumulator I started having a weird cold start issue if you'd want to call it that. But it catches perfectly everytime if I depress the accelerator about 1/4-1/2 while cranking on a cold start. The funny thing is, that's exactly the way the owner's manual tells you to start the car so I'll write it off as perfectly fine and by design.

I'm still baffled by your situation.

But like you said, it does work :thumbup:

[kings1527]

I'm still baffled by your situation.

But like you said, it does work :thumbup:

I know! I have no idea why it's like that but I know it's directly related to my (full sized OEM) accumulator. That was the only thing that was changed when it started happening.

The only thing I can think of is that the diaphragm in the accumulator is brand new and working perfectly. So when I crank, the diaphragm and the spring compress and create extra space for the fuel to travel before they get to the injectors. That extra travel time (slight) causes more cranking time. But if I depress the accelerator, for whatever reason, problem solved. It'll cold start like that in about a 1/4 - 1/2 of a second.

That's the best I can come up with!

[Jonathan]

If it works well hot and not as well cold, perhaps it is something that changes as the temperature increases? Like if a rubber seal or pathway of some kind swells or a fluid gets thinner to allow it to work hot better than when it was cold? Fuel filter plugged to some degree maybe? Or if some swelling in the accumulator when it gets warm holds back the back pressure enough to keep the engine from starving, but doesn't when cold? Grasping at straws here of course... :) (the instructions on the sunvisor thought about it being by design might not be too bad of an idea for the time being until it gets really problematic).

[alexwolf1216]

So I went to grab my multimeter and it died on me. I was unable to test. Time for a new one!

[alexwolf1216]

Time to show my ignorance......


Set your ohm meter to the lowest scale. When the car is cold, one pin should read grounded (zero ohms) and the other about 30. If either or both read open the switch is bad.

There is a black probe and a red probe. Do I ground the black to the car, and touch the pin with the red? I really have no idea what I am doing here :(

How do I know if its open? Will the screen say open, or is there another reading?

[Rich]

Time to show my ignorance......
There is a black probe and a red probe. Do I ground the black to the car, and touch the pin with the red? I really have no idea what I am doing here :(
How do I know if its open? Will the screen say open, or is there another reading?

How to use a VOM: http://www.youtube.com/watch?v=Ftc3EQGZowk (http://www.youtube.com/watch?v=Ftc3EQGZowk)

For Resistance (Ohms):
Open is open-circuit = high or infinite resistance
Closed is short-circuit = low or zero resistance
Dave's values were in Ohms. My reading of his instructions is to put one probe on a good ground, other probe to either pin.

And for resistance readings the black-red orientation of the leads is unimportant unless you are looking at a diode, which is not the case here

[alexwolf1216]

Thanks Rich.....Im learning as I go along....:banghead:

[Jonathan]

Your multimeter may have more than one place to plug the meter end of the red probe into. It will have little icons indicating which socket is used for which sort of test. If testing Ohms, look for the socket with the Ohm symbol (upside down horseshoe sort of) as well as having the selector on the same symbol.

Resistance is one of the easier things to learn to test for. Or simply whether it is a closed loop or not. To familiarize yourself with what the display will say, test it on a screwdriver or one of your panels or a tape measure even. Anything that's just one piece of metal. Once you place both red and black tips of the probes on the metal, the circuit or loop is completed or closed. That will tell you what the multimeter display will show for a closed loop and when you lift off one or both of the leads from the metal surface, it will now show you what an open loop/circuit message looks like. Some multimeters are able to give an audible beep when you get a completed circuit (or continuity).

If you are just trying to see if the circuit of wires and switches has any breaks in it as opposed to continuous all the way through, this sort of resistance or continuity check is easy and the numbers on the display aren't that important. If you actually want to see what the resistance is as compared to a known proper valve (like inside some sort of electrical component or switch) then you start to need to know what the Ohm value is. That's probably more advanced than you need it to be right now and can be saved for the guys trying to figure out why a shift computer doesn't work or something like that.

Many switches on our cars work by completing a circuit in the same way you are trying to test for with the meter. Even something as simple as the trunk light switch or the parking brake switch. Something physical happens to the switch and then it needs to give that information to the warning light bulb (in the case of the parking brake for example). When you move the brake handle, the plunger on the switch moves and completes the circuit, sending electrical power to the warning light bulb. (It actually might be the opposite in this example and moving the brake handle opens the circuit and the bulb comes on possibly, but you get the idea. Sometimes these loops are designed so they fail in the alarming condition. Remove power and light comes on as opposed to on our cars where if the wire is cut, you get no light telling you anything.)

Long and the short of it is, testing to see if the circuit is at least complete or not is a pretty handy first step in troubleshooting to find out where your problem is.

[David T]

Thanks Rich.....Im learning as I go along....:banghead:

Pull the CSV and stick it in a cup. Start the motor. While cranking it should spray. If it doesn't you have a wiring problem or a bad TTS.

[Jonathan]

So I went to grab my multimeter and it died on me. I was unable to test. Time for a new one!

Just one other note... many mutlimeters have a fuse inside them to protect the internals from getting zapped if they are hooked up the wrong way (probe in wrong socket or testing in a mode that exceeds that particular test rating). You might not need a new meter, just a new fuse, or battery even maybe.

[alexwolf1216]

Was a 9v battery. I used my own multimeter to check it, my tongue ;)

[alexwolf1216]

I'm assuming this is th part.http://img.tapatalk.com/d/14/07/04/buqepady.jpg
http://img.tapatalk.com/d/14/07/04/a6a3ugej.jpg

Multi meter set like this
http://img.tapatalk.com/d/14/07/04/yseqe9u3.jpg

If I ground the black one to the car, touch the red to either connector nothing happens.

[Rich]

I'm assuming this is the part.

That's the part Dave refers to in post #4. Shown here in the DMCH catalog to confirm:

http://store.delorean.com/p-6265-switch-thermotime.aspx

[Rich]

If I ground the black one to the car, touch the red to either connector nothing happens.

See post 20 about the part ID being correct.

Meter is set and connected correctly for the reading you want.

Question/clarification: You say you grounded the black probe "to the car" and you meant to say "to the engine" or to some other known ground, correct? The stainless panels are not always a good ground.

[alexwolf1216]

Yes I grounded to the engine

[DMCMW Dave]

That means the switch is either bad, or those green looking terminals are so corroded that you can't get contact.

Here's another trick.

Fashion a 3 inch male-male spade jumper. Go into the electrical compartment behind the driver seat. Find the empty socket at the back of the compartment. The connector is either black or white, usually white. It will have 3 wires going to it. Jumper the black and black/blue together. Now see if the car starts easier. If so, it's a bad TTS. If you leave the jumper in place the car will tend to flood especially when hot, so this is not a permanent fix.

CAUTION - do not connect the white/red wire on that plug to anything else. If you do, major damage will occur as this is the start line from the ignition switch.

[alexwolf1216]

Interesting. I took off that connector last night and.forgot to reconnect this morning. Started right up. I was afraid that I could mess something up, so I reconnected and let it sit for a couple of hours. Started right up again. Maybe cleaning those connectors helped? I'll try again tomorrow morning

[DMCMW Dave]

Interesting. I took off that connector last night and.forgot to reconnect this morning. Started right up. I was afraid that I could mess something up, so I reconnected and let it sit for a couple of hours. Started right up again. Maybe cleaning those connectors helped? I'll try again tomorrow morning

It is not unusual that unplugging and re-plugging connectors cleans corrosion from terminals and they start working again. This applies to every connector on the car. For some reason the folks that engineered this electrical system didn't think the car would ever be wet (pretty strange for a car engineered where it rains all the time). Look at the connectors in any car built in the past 20 years for a comparison, now everything is completely waterproof especially if in a part of the car that gets wet.

The only caveat with doing this all over the car is that sometimes you'll push a connector out of a terminal and cause a new problem! So go carefully.

[alexwolf1216]

Update. Its having trouble starting cold and even sometimes hot. I also noticed that the idle is rough, and my AC blower wouldnt start tonight unless the car was running...Any thoughts?

[Jonathan]

How old is your battery? Could be that it's dead and you need a new one. Any of the problems you described could be from a bad battery, or none of them could be from a bad battery. If the battery is more than 5 years old or you don't know how old it is, you might consider replacing it.

[bluscreen]

Pull the CSV and stick it in a cup. Start the motor. While cranking it should spray. If it doesn't you have a wiring problem or a bad TTS.

Sorry to resurrect, but any ideas what might be going on if it doesn't spray when you crank the car, but there is voltage going to it when it should be spraying? Mine doesn't even drip. =|

[Bitsyncmaster]

Sorry to resurrect, but any ideas what might be going on if it doesn't spray when you crank the car, but there is voltage going to it when it should be spraying? Mine doesn't even drip. =|

For the CSV to open, you need 12 volts on one pin and 0 volts on the other pin. The 12 volts come from the starter during cranking. The ground comes from the thermal time switch (or hot start relay).

[bluscreen]

For the CSV to open, you need 12 volts on one pin and 0 volts on the other pin. The 12 volts come from the starter during cranking. The ground comes from the thermal time switch (or hot start relay).

I understand. I'll.. check the pins to a common ground individually? I was getting just about 12 volts across the two of them during cranking-- but no gas. Thanks for your help!

[David T]

I understand. I'll.. check the pins to a common ground individually? I was getting just about 12 volts across the two of them during cranking-- but no gas. Thanks for your help!

Be careful with the TTS. It is polarity sensitive meaning if you manage to get the plug on the wrong way you will damage it. It also needs to be grounded so if it was put in with teflon tape you must remove it and get rid of the teflon. You only get 12 volts during cranking and if you crank too long the TTS will time out and open the ground connection stopping the CSV. Refer to D:04:06 in the Workshop Manual for the wiring diagram. Another way to test the CSV is to do the plug swap with the CPR to see if it will spray.

[bluscreen]

Be careful with the TTS. It is polarity sensitive meaning if you manage to get the plug on the wrong way you will damage it. It also needs to be grounded so if it was put in with teflon tape you must remove it and get rid of the teflon. You only get 12 volts during cranking and if you crank too long the TTS will time out and open the ground connection stopping the CSV. Refer to D:04:06 in the Workshop Manual for the wiring diagram. Another way to test the CSV is to do the plug swap with the CPR to see if it will spray.

Thanks David-- I saw in another thread that those connectors could be swapped out to see if the CSV even works, I'll give it a shot! I appreciate your references, too.

Didn't mean to hijack the thread, just thought that no power at the CSV upon testing would be helpful here. =]

[PJ Grady Inc.]

It's hard to see in the picture but the little round hole on the flat of the hex area on the switch should be filled with a smooth brown epoxy. If that is gone and there is rust present than the switch is/will go bad soon. Just a visual reference until you get your multimeter going again. It looks to me like rust in the picture?
Rob Grady


I'm assuming this is th part.http://img.tapatalk.com/d/14/07/04/buqepady.jpg
http://img.tapatalk.com/d/14/07/04/a6a3ugej.jpg

Multi meter set like this
http://img.tapatalk.com/d/14/07/04/yseqe9u3.jpg

If I ground the black one to the car, touch the red to either connector nothing happens.