Cold Start Valve

[Silverbullet]

Is there an easy test to see if it is working or not? Last few times I try to start the car when cold it cranks, but does not fire.. takes like 3 times cranking before it wants to fire...
Starts fine warm/hot.
Craig

[David T]

Is there an easy test to see if it is working or not? Last few times I try to start the car when cold it cranks, but does not fire.. takes like 3 times cranking before it wants to fire...
Starts fine warm/hot.
Craig

A quick and "dirty" way is to take it off the pipe, stick it into a cup and crank the motor. It should squirt while cranking for a few seconds.

[Silverbullet]

A quick and "dirty" way is to take it off the pipe, stick it into a cup and crank the motor. It should squirt while cranking for a few seconds.

Cool, my guess is I have to do it while the engine is really cold, first thing in the morning?

Thanks,
Craig

[David T]

Cool, my guess is I have to do it while the engine is really cold, first thing in the morning?

Thanks,
Craig

Yes.

[DMCMW Dave]

It's NEVER the valve. Look for something electrical, even if it doesn't seem to work.

[Rich]

Per Dave's note, look upstream of the CSV.

Cool, my guess is I have to do it while the engine is really cold, first thing in the morning?

Sure, do that. The CSV should actuate any time you crank with coolant temp below 95degF AND not having cranked engine very much in the previous 10min.

See last page of Engine-Will-Not-Start troubleshooting chart in the "thin" factory manual, 4th image of this set - click a second time after it opens to sharpen the text:

LINK: http://dmctalk.org/showthread.php?3142-Factory-Troubleshooting-Charts-Engine-Will-Not-Start (http://dmctalk.org/showthread.php?3142-Factory-Troubleshooting-Charts-Engine-Will-Not-Start)

So first be sure the CSV's getting a voltage signal during a cold crank.

[David T]

Most of the time the problem is the TTS (Thermo Time Switch). Either it's bad, not properly grounded, or the plug is forced on wrong. Another problem can be if the starter was touched and the wires were not put back correctly. It is a VERY simple circuit. Refer to D:01:10

[DMCMW Dave]

BTW if the outer shell of the TTS gets broken, allowing the plug to be plugged in backwards, the TTS will be electrically destroyed the first time you turn the key.

[Silverbullet]

Ok, I checked the CSV and the engine was cold, no gas is being delivered... So I will have to check the electric. I have not done anything with the starter wires of TTC...

Ok, should I get 12 volts across the 2 pins going to the CSV when I crank?

Craig

[Silverbullet]

Ok, this is what I found out...

When I swapped the Gray plug to the CSV, put it in a cup, and started it up, I got gas...

So when it is cold, I should get 12 volts to the Blue plug when I crank, right?

So when cold should the thermmal sensor be open or closed?

Craig

[DMCMW Dave]

Ok, this is what I found out...

When I swapped the Gray plug to the CSV, put it in a cup, and started it up, I got gas...

So when it is cold, I should get 12 volts to the Blue plug when I crank, right?

So when cold should the thermmal sensor be open or closed?

Craig

The thermal time switch is a bit strange in terms of connections. There are two pins on it. One is a heater (other end of the heater is ground). The other is the switch (other end also goes to ground). So if you try to read across the terminals you will read the resistance of the heater if the switch is close and will read nothing if the switch is open (hot). If the TTS has been connected backwards, 12V was put across the switch to ground burning it out.

Your cold start switch is good.

For a good final test of the circuit, go inside the electrical compartment and find the unused connecter that is hanging around in the back of the compartment. Ground the blue/black wire and crank the engine, see if the cold start sprays now (or see if the car starts cold). Don't be tempted just to leave it grounded all the time or you'll flood the engine when starting hot.

[Bitsyncmaster]

Ok, this is what I found out...

When I swapped the Gray plug to the CSV, put it in a cup, and started it up, I got gas...

So when it is cold, I should get 12 volts to the Blue plug when I crank, right?

So when cold should the thermmal sensor be open or closed?

Craig

The CSV will only shoot gas when the starter is cranking. So to test it you need to remove the white/yellow wire on the resistor block so your car will not start.

[jawn101]

I spent a TON of time chasing this problem too and found the issue to be the pins at the bulkhead connector. I believe Dave (Bitsyncmaster) had the same issue on his car. The connections were marginal and carried voltage but not amperage. It took weeks to track it down.

[Silverbullet]

The CSV will only shoot gas when the starter is cranking. So to test it you need to remove the white/yellow wire on the resistor block so your car will not start.

Ok, I disconnected the White/Yellow wire, and cranked, got to power to CSV.... So where on the bulkhead plugs should I look...what color wires...

PS. It did not want to start, I reversed the Blue Plug for the Gray plug, she fired right up... so I need to figure out this power thing.

Craig

[Silverbullet]

The thermal time switch is a bit strange in terms of connections. There are two pins on it. One is a heater (other end of the heater is ground). The other is the switch (other end also goes to ground). So if you try to read across the terminals you will read the resistance of the heater if the switch is close and will read nothing if the switch is open (hot). If the TTS has been connected backwards, 12V was put across the switch to ground burning it out.

Your cold start switch is good.

For a good final test of the circuit, go inside the electrical compartment and find the unused connecter that is hanging around in the back of the compartment. Ground the blue/black wire and crank the engine, see if the cold start sprays now (or see if the car starts cold). Don't be tempted just to leave it grounded all the time or you'll flood the engine when starting hot.

If I ground the Blue/Black Wire and it pumps gas, what does it tell me?

[DMCMW Dave]

If I ground the Blue/Black Wire and it pumps gas, what does it tell me?

That everything is good other than the TTS.

[Bitsyncmaster]

I spent a TON of time chasing this problem too and found the issue to be the pins at the bulkhead connector. I believe Dave (Bitsyncmaster) had the same issue on his car. The connections were marginal and carried voltage but not amperage. It took weeks to track it down.

Yes I had the same problem with the bulkhead connections. Took a long time since the schematic did not match what my harness really is. There is a jumper on back side of two bulkhead connectors that was my problem, it read about 50 ohms pin to pin.

[Silverbullet]

Ok, I found the plug on the TTC had pulled out, put it back... but Now... I got no power to the fuel pump... I checked the plug and it was dead... I hot wired the fuel pump and it starts up... the 20 amp #7 fuse is good...
So after it started... I connected the fuel pump back up... and It starts and runs fine...WTF...
And... Thanks

Craig

[David T]

Ok, I found the plug on the TTC had pulled out, put it back... but Now... I got no power to the fuel pump... I checked the plug and it was dead... I hot wired the fuel pump and it starts up... the 20 amp #7 fuse is good...
So after it started... I connected the fuel pump back up... and It starts and runs fine...WTF...
And... Thanks

Craig

I hate it when you seem to "fix" a problem like that. Everything seems fine till it bites you again because you never really found and fixed the root cause. It could just be a dirty connection in a plug. It could also be a connector that backed out and now instead of being inserted into it's twin it is just touching. Go over EVERYTHING that you touched. Visually inspect it again till you feel certain you are not overlooking anything. Look for corrosion and signs of overheating.

[jawn101]

I hate it when you seem to "fix" a problem like that. Everything seems fine till it bites you again because you never really found and fixed the root cause. It could just be a dirty connection in a plug. It could also be a connector that backed out and now instead of being inserted into it's twin it is just touching. Go over EVERYTHING that you touched. Visually inspect it again till you feel certain you are not overlooking anything. Look for corrosion and signs of overheating.

Agreed - what you've found is not a fix, it's just a guarantee that you'll have the problem again down the line - probably after you've forgotten everything said in this thread and need to start over. Electrical problems don't just go away...

[Silverbullet]

I Agree... It was so weird... the pump did not run. the plug had no pewer... I just hot wired the pump to my battery charger (on Start mode) I could hear it run... got pressure and it started... then, still pressurized. and pluged in... It works now.. just like it re-set something that stopped the power to the fuel pump...

Craig

[DMCMW Dave]

Often just unplugging and reconnecting things cleans the connection enough to work.


Sent from phone

[mike123]

For a good final test of the circuit, go inside the electrical compartment and find the unused connecter that is hanging around in the back of the compartment. Ground the blue/black wire and crank the engine, see if the cold start sprays now (or see if the car starts cold). Don't be tempted just to leave it grounded all the time or you'll flood the engine when starting hot.

When cold, my car takes a long time to start. It was 3-4 seconds with the original Paris Rhone starter, it's like 10 seconds now with the Eagle Premier starter. (It was my mistake to replace the starter, and I regret it, but that is beside the point). If I depress the gas pedal a bit when turning the key, it starts in about 1.5 seconds with the Rhone and 3 seconds with the Eagle Premier, but it takes so much pedal that the RPMs rev up to 4000 or 5000 briefly, which I am assuming is not a good thing to do.

The car starts very quickly when hot, in less than a half second with the Paris, and about 1 second with the Eagle Premier.

When I grounded the blue/black wire in the unused connector, I observed no change in the cold starting behavior. Is it right to assume this means either:
(a) I didn't ground it properly (picture attached in case I am doing something silly and not realizing)
or
(b) the thermo time switch may be OK but the cold start valve isn't spraying well?

Sorry to raise this thread from the dead but figured I'd ask here since this is where I saw the previous helpful advice. Thanks!

70178

[AugustneverEnds]

Have you observed the cold start valve in action? It's easy, unscrew the two hex head screws, put the CSV in a jar, turn the ignition to position 2, unplug the connector on the WUR and plug it into the CSV and see if it's spraying.

[Bitsyncmaster]

Have you observed the cold start valve in action? It's easy, unscrew the two hex head screws, put the CSV in a jar, turn the ignition to position 2, unplug the connector on the WUR and plug it into the CSV and see if it's spraying.

That test is good for checking the CSV but for testing the full cold start system you need to let it power normally into the jar on a cold cranking. You can just pull the white/yellow wire off the resistor block to prevent engine start.

[AugustneverEnds]

That test is good for checking the CSV but for testing the full cold start system you need to let it power normally into the jar on a cold cranking. You can just pull the white/yellow wire off the resistor block to prevent engine start.

I'm under the impression that mike123 was trying to determine if his CSV was firing well/at all. I figured it's hard to beat actually seeing the CSV spray.

On electrical matters I will always defer to the (Bitsync)master :smile:

[mike123]

Have you observed the cold start valve

I have not :-) I am new to all of this, but thanks to the manual I think I can pick it out of a lineup now. I've only ever done simple and purely-electrical stuff so far. This will be my first step into the wonderful world of ICE fluids.


That test is good for checking the CSV but for testing the full cold start system you need to let it power normally into the jar on a cold cranking. You can just pull the white/yellow wire off the resistor block to prevent engine start.

OK! Putting two and two together, it sounds like this is the recommendation, attached. My car is hot right now so I will try it in a few hours.

70182

[David T]

Typically the problems in the CSV system are electrical in nature. A bad connection, wiring mods, a bad TT switch, the plug on the TT switch forced on incorrectly, that kind of thing. The polarity to the TTS is VERY important. If it is reversed you burn up the switch inside. It is rare to have a non-functioning cold start injector. Sometimes I have seen the tiny "O" ring missing though so be careful and don't lose it when you remove the injector. BTW, you don't have to actually remove it. Just do the plug swap thing and if it starts easier then you know the injector is working. Hard cold starts can be caused by a lot of things. There are several systems that function when the motor is cold to get it started and warmed up quickly. Since you mentioned you changed the starter there is a possibility you did not install it correctly. Two small wires go to it, one is the power to the solenoid and the other sends power to the CSV system during cranking. Make sure you have power to the CSV system ONLY during cranking. Get out your Workshop Manual and go to D:01:10 fig 9.

[mike123]

Test scenario:
- Jumpered the Blue/Black to the Black on the otherwise empty Hot Start Relay.
- Disconnected the white/yellow wire on the ballast resistor.

Nothing comes out of the Cold Start Valve when turning the key.

The right contact in the wires leading to the Cold Start Valve (see pic) was showing 10V when turning the key. When not turning the key, both of those female connectors were grounded.

70183

David T, I think I can rule out a bad thermo time switch as a potential culprit due to jumping the hot start relay. And the new starter is installed properly, it eventually gets things going when cold and immediately gets the car started when hot.

[David T]

Test scenario:
- Jumpered the Blue/Black to the Black on the otherwise empty Hot Start Relay.
- Disconnected the white/yellow wire on the ballast resistor.

Nothing comes out of the Cold Start Valve when turning the key.

The right contact in the wires leading to the Cold Start Valve (see pic) was showing 10V when turning the key. When not turning the key, both of those female connectors were grounded.

70183

David T, I think I can rule out a bad thermo time switch as a potential culprit due to jumping the hot start relay. And the new starter is installed properly, it eventually gets things going when cold and immediately gets the car started when hot.

Apply 12 volts directly to the CSV when the motor is running and the fuel pump has gotten full pressure. Rare for a CSV to not function with a full 12 volts. Easiest way to do it is the plug swap but verify you have 12 volts on the plug to the CPR (Control Pressure Regulator) first. You cannot rule out a bad TTS until you see it working. If you have to, you must "ring out" (test) each wire in the CSV circuit. It is one of the circuits that you see a lot of "creative" mods. That and the fuel pump wiring and the cooling fans. Remember, not only must you see 12 volts on the CSV, you have to see that it also has a good, low resistance path to ground.

[82DMC12]

This is a 2-man job, but try this:


confirm you have continuity to ground on one of the two pins for the female cold start plug
When a second person cranks the engine (with coil wire removed and inertia switch plunger up), check DC volts on the other cold start plug pin, you will probably 9 to 10 volts. That's good enough.
Now plug the cold start valve plug in and place the injector into a jar. Put the plunger back down on the inertia switch and crank the engine. The CSV should fire into the jar. If it does, you've confirmed it's oK.
If it doesn't, try pinching the terminals together on the blue cold start plug, very common for them to get spread apart too far and not make contact with the male pins.


If you know the CSV is working but it still takes a few turns of the starter to get the car to start cold, you are probably very slowly bleeding off fuel through one or more leaky injectors into the cylinders. Can be confirmed by removing all injectors and placing them in glass jars too. Pressurize the system, push down on the meter plate to make them sing, then watch each injector and make sure it doesn't drip afterwards.

You might not see the dripping on a fuel pressure gauge because it happens too slowly. Give it a day or two and you could have a couple of bone-dry injector lines.

[sweetp01569]

The thermal time switch is a bit strange in terms of connections. There are two pins on it. One is a heater (other end of the heater is ground). The other is the switch (other end also goes to ground). So if you try to read across the terminals you will read the resistance of the heater if the switch is close and will read nothing if the switch is open (hot). If the TTS has been connected backwards, 12V was put across the switch to ground burning it out.

Your cold start switch is good.

For a good final test of the circuit, go inside the electrical compartment and find the unused connecter that is hanging around in the back of the compartment. Ground the blue/black wire and crank the engine, see if the cold start sprays now (or see if the car starts cold). Don't be tempted just to leave it grounded all the time or you'll flood the engine when starting hot.


I also have a cold start problem, after getting my car serviced for new water pump, plugs, etc. The CSV will spray with the gray WUR plug plugged in, or jumping the blue/back wires on the electrical compartment plug. Otherwise, the CSV will not spray during normal use. I also attached a picture of a stray unconnected connector that I can't figure out where it connect to. Could CSV not spraying be related? Thanks!

[WHO1DMC]

I also have a cold start problem, after getting my car serviced for new water pump, plugs, etc. The CSV will spray with the gray WUR plug plugged in, or jumping the blue/back wires on the electrical compartment plug. Otherwise, the CSV will not spray during normal use. I also attached a picture of a stray unconnected connector that I can't figure out where it connect to. Could CSV not spraying be related? Thanks!

If you're car is a manual? That connector is for the automatic kick down switch. Un used in a manual of course.



Dave B.

[sweetp01569]

If you're car is a manual? That connector is for the automatic kick down switch. Un used in a manual of course.



Dave B.

My car is a manual. Thanks for confirming that the connector is not needed. I am not sure what to check next regarding the CSV not spraying. The thermo-time switch is new, and is plugged in the correct way. Also, one pin is grounded, and the other looks like 40 or 50 ohms resistance to ground. I thought I read that the TTS can time out if cranking too much? I disconnected the resistor connecto to prevent it from starting. Do I need to wait to try CSV again? Thanks.

[Bitsyncmaster]

My car is a manual. Thanks for confirming that the connector is not needed. I am not sure what to check next regarding the CSV not spraying. The thermo-time switch is new, and is plugged in the correct way. Also, one pin is grounded, and the other looks like 40 or 50 ohms resistance to ground. I thought I read that the TTS can time out if cranking too much? I disconnected the resistor connecto to prevent it from starting. Do I need to wait to try CSV again? Thanks.

The thermal time switch has a heater so it should only work the CSV for 10 to 15 seconds of cranking. On a cold engine it should cool off quickly.

[sweetp01569]

The thermal time switch has a heater so it should only work the CSV for 10 to 15 seconds of cranking. On a cold engine it should cool off quickly.

Thanks, Dave. I'll try it again tomorrow, anyway.

[sweetp01569]

Back at it fresh today, and made some measurements on the TTS installed in the car, and a few spares I had on hand. For the one in the car, one pin read about 50 ohms to ground and the other about 4 ohms, not quite reaching zero. On my three spares, one pin read about 30 ohms to the case, and the other pin grounded out to zero, consistently for all the spares. Thus, I expected the TTS in the car is not right. I switched it out with one of the spares, and the CSV now sprayed properly, and car starts right up when cold. Thanks, again, Dave for your valuable feedback and expertise on this site!
Regards, Paul

[Bitsyncmaster]

Back at it fresh today, and made some measurements on the TTS installed in the car, and a few spares I had on hand. For the one in the car, one pin read about 50 ohms to ground and the other about 4 ohms, not quite reaching zero. On my three spares, one pin read about 30 ohms to the case, and the other pin grounded out to zero, consistently for all the spares. Thus, I expected the TTS in the car is not right. I switched it out with one of the spares, and the CSV now sprayed properly, and car starts right up when cold. Thanks, again, Dave for your valuable feedback and expertise on this site!
Regards, Paul

Glad you got it working. Testing with a meter does not always show the problem. Your 4 ohms with the meter is probably worse when the one amp of CSV current is flowing through that connection.

[David T]

Glad you got it working. Testing with a meter does not always show the problem. Your 4 ohms with the meter is probably worse when the one amp of CSV current is flowing through that connection.

Another thing to note, do NOT use teflon tape on the TTS. It MUST be grounded to work and teflon tape can isolate the switch from ground. As I said in earlier posts, the most common reason for the CSV to malfunction is electrical, usually the TTS but modifications to the wiring of the circuit is also common. The plug swap should have worked to verify the CSV does operate.

[sweetp01569]

I did verify previously that the CSV does work properly, with the plug switch. Also, there was no pipe dope on the TTS threads. I did figure out that there was an electrical problem, but wasn't sure if wiring or TTS (which was purchased new from DMC). Since I had the good fortune of having three spare TTSs from over the years, comparing measurement of each pin to ground (or TTS body) quickly demonstrated that the unit in the car had different resistance readings than the spares (which all had the same readings). It was easy to swap it out with one of the spares. The CSV immediately sprayed and worked fine. Now I need to see if I can get a refund for the faulty TTS from DMC.

[82DMC12]

I did verify previously that the CSV does work properly, with the plug switch. Also, there was no pipe dope on the TTS threads. I did figure out that there was an electrical problem, but wasn't sure if wiring or TTS (which was purchased new from DMC). Since I had the good fortune of having three spare TTSs from over the years, comparing measurement of each pin to ground (or TTS body) quickly demonstrated that the unit in the car had different resistance readings than the spares (which all had the same readings). It was easy to swap it out with one of the spares. The CSV immediately sprayed and worked fine. Now I need to see if I can get a refund for the faulty TTS from DMC.

Was the faulty one made by VDO? That would be the OEM part. I've heard the newer cross reference ones (not VDO) have a high failure rate. You can usually find a good used VDO thermotime switch on Ebay from a Volvo for about $40 or so.