No start except with starting fluid

[Paulswpc]

I have a no start condition although it starts right up with starting fluid and stays running until I shut it down. Plug swap doesn't work. Jump RPM relay doesn't work, however it runs the pump. Fresh gas. What am I missing?

[Michael]

Check your mixture with a dwell meter. Something may be leaking throwing it off.

If the plug swap doesn't work you may also have a bad cold start valve, but you didn't mention if this was strictly a hot or cold start issue (or both).

Also, just peek under the car and see if by any chance you have a massive fuel leak.

[Paulswpc]

Hot or cold. Doesn't matter. Although it's been over 95 degrees here in Arizona every day. I did check today for a fuel leak. None found.

[Jonathan]

Starts with starting fluid and then stays running? Are you spraying this in through the air metering plate while the air filter housing is removed?

Perhaps something is blocking air flow while the housing is in place? Check the condition of your filter and also comment on what you see with your three-way valve and the air inlet duct. Something could be blocking that too.

[Paulswpc]

Starts with starting fluid and then stays running? Are you spraying this in through the air metering plate while the air filter housing is removed?

Yes and yes.

Perhaps something is blocking air flow while the housing is in place? Check the condition of your filter and also comment on what you see with your three-way valve and the air inlet duct. Something could be blocking that too.
It starts with the housing on or off as long as starting fluid is used.

[Michael]

Like I said you most likely have a vacuum leak throwing off your mixture (unless someone has monkeyed with it recently). Without proper diagnostic you are just guessing. Check your fuel pressure too. Your pump may be running but that doesn't mean it's working, those built in check valves on the old pumps are prone to failure. I would ask about the fuel filter but that normally shows up at higher demands...speaking of,

Once started, take her out and run her hard, does it cut out at higher rpm's? Does it idle correctly?

You have a whole list of probable causes based on just "No start". You need some basic diagnostic work and check known issues..like the distributer O rings, and be sure you know what you are doing. Those springs fly out pretty fast and far.

[Paulswpc]

What are the variables (i.e.: CSV, TTS Coolant Temp Sensor, and others I suppose) that require the coolant temperature/engine temperature to be a certain value before they give the go ahead to start the engine?

I can shut it down and restart it without using starting fluid if the coolant temperature reads 160 degrees Fahrenheit or higher. Once it cools down, it won't start again without the starting fluid.

Can I bypass or jump those devices to take them out of the equation? Keep in mind, the outdoor temperature is in the nineties during testing.

[Bitsyncmaster]

My bet is your CSV is not working. I would think if it was just mixture off the plug swap would get it to fire anyway.

Pull your CSV with the engine cold and put it in a jar and crank the engine for about 10 seconds just to verify it working or not.

If not working, try the hot start jumper and do the same test.

[Michael]

I can shut it down and restart it without using starting fluid if the coolant temperature reads 160 degrees Fahrenheit or higher. Once it cools down, it won't start again without the starting fluid.

You just said earlier this happens hot or cold. Now it's cold only?


Hot or cold. Doesn't matter.

I can't get a straight answer therefore I'm out.

[DMCVegas]

What are the variables (i.e.: CSV, TTS Coolant Temp Sensor, and others I suppose) that require the coolant temperature/engine temperature to be a certain value before they give the go ahead to start the engine?

I can shut it down and restart it without using starting fluid if the coolant temperature reads 160 degrees Fahrenheit or higher. Once it cools down, it won't start again without the starting fluid.

Can I bypass or jump those devices to take them out of the equation? Keep in mind, the outdoor temperature is in the nineties during testing.

You need a Workshop Manual before going any further. This will make it clear as to what "variables" are involved, as well as your temperature variations. If you had that, pretty much most of your questions would already be answered. Including if you could disable them. You can't. This is mechanical, not computer controlled.

A quick overview goes like this:

Once the internal temperatures drop below 54°F or so, the Thermo Time Switch will trip in order to fire the Cold Start Valve. This initiates a rich condition which mimics the Choke on a carb (EFI does this solely by increasing injector flow).
When cranking, you need to keep the gas pedal pressed at about ¼ of the way down.

Typical Problems:

If the car does not start when cold, that means you have an issue with the Cold Start Circuit.
If the car does not start when hot, that means you are not retaining the rest pressure of your fuel system properly.


Please keep in mind however that even for both of the above symptoms, that assumes that everything else is already in proper running order.

So the big question here is: When did this first start happening? Has it ever ran right before this?

The only sure-fire way that I can guarantee that you're going to get this fixed is by returning the engine to stock specification, and to use NOS equivalent parts.

Check your fuses & grounds all across the car.
BOSCH Silver Tip Spark Plugs ONLY!
BOSCH, MSD Blaster 2, or Nology Ignition Coils. Never, NEVER use Accel!
Inspect all plugs and correctly gap them.
Verify all wiring from Ignition Leads to your wiring harness are in good order and correctly connected.
Verify all vacuum lines are connected and in good shape.
Verify function & spray patters of all 6 CI injectors and your electronic Cold Start Valve.
Once this is all done, THEN you can play with the timing, and then next check your active and rest fuel pressures and verify they bleed down.
Eventually the Air/Fuel mixture will be a consideration. But until you verify ALL of these problems first, DO NOT TOUCH IT!


Admittedly, your problem could be any one number of things right now. But honestly, all of what I could speculate they are would be automatically eliminated or fixed by you following that list above. There is no magic reset button or single part anyone here could tell you to replace that will just magically fix this. You've got to do some troubleshooting, which is why we're asking the questions we are.

[Paulswpc]

Hot or cold. Doesn't matter. Although it's been over 95 degrees here in Arizona every day. I did check today for a fuel leak. None found.

This is incorrect. It will only start when hot. My apologies as I'm working on another car with similar symptoms.

[David T]

This is incorrect. It will only start when hot. My apologies as I'm working on another car with similar symptoms.

If it starts easily when hot but not cold and giving it some Ether (fuel) starts it right up (cold) the first thing that comes to mind is the Cold Start Valve (CSV). It only operates during cranking when cold and if it isn't working (spraying fuel), you would get this symptom. You say you tried the plug swap and that didn't help. Could be something is also wrong and you are not getting power to the Control Pressure Regulator (CPR). If that is the case, swapping plugs won't get the CSV spraying either. Pull the CSV and see if it sprays when cranking and cold. If it isn't spraying check for power at the Thermo Time Switch (TTS). Refer to D:04:06 in your Workshop Manual for a wiring diagram. You will only see power on the WR wire (White/Red) while cranking. If you do have power during cranking you probably have a bad TTS. The other possibilities include a bad CSV (uncommon), a plugged up hose (again uncommon) or a wiring problem. Make sure the TTS is grounded to the housing. I have seen where it was installed with teflon tape and was isolated from ground preventing the circuit from reaching ground. As for the CPR, same diagram, check for power on the YR (Yellow/Red) wire when the key is on. I would not expect fuse #7 to be bad or the fuel pump won't run. More likely a bad RPM relay.

[Paulswpc]

Thanks to all for the valuable information. I have new plugs, wires and cap & rotor ready to go in. This car has always idled perfectly (even now once it gets started) but under load always was a dog. I've ordered a fuel pressure gauge and plan to replace the relays and vacuum lines. The idle motor pipe is a bit loose so the o-ring will need replacing as well. The fuses are good but may replace them as a whole. I haven't tested the voltages while cranking as I'm partially disabled and do not have a helper, but will do so with a remote starter hookup. The TTS is next to replace and will report back with the results. Thanks again.

[David T]

If you are not getting power to the CPR you may not be getting power to the Lambda relay and that means the frequency valve is not working. That could account for the lack of power. The mixture is set up rich because the Lambda is not functioning. Verify you are getting power out of the RPM relay on the YR wire. Do you hear the frequency valve buzzing? I did not say to replace the TTS, at least not yet. Don't throw parts at the car, do a little testing first. Putting in a new TTS is not going to fix it if there is a problem elsewhere. Besides, the TTS is an expensive part, especially if you don't need it! I suggest fixing this problem before doing anything else. You may cause more problems putting in other parts and make things even more confusing. Those other parts aren't going to fix this problem anyway and you say the car is idling well once it warms up.

[DMCVegas]

This car has always idled perfectly (even now once it gets started) but under load always was a dog.

Ok now, that is something kind of key to know here. As I say, you need to work on every individual thing at a time first. Now, if say your CSV was not firing, yes, you would absolutely have an issue starting when cold. But once the engine warms up, it should purr like a kitten. You've got something else wrong here.

Question: When you get the car running and you press the gas pedal, and the RPMs increase as you try and rev the engine, does it go, "ggggggggvvvvvvvvvvvvvvvvvrrrrrrrrrrrrrrrrrrRRRRRRR OOOOOOOOMMMMMM!" with a slow increase but suddenly shoots up the RPMs at the end? Then when you drive it acts like it's bogged down?

[DMC5180]

For CSV circuit troubleshooting

See this Thread
http://dmctalk.org/showthread.php?14250-High-Idle-no-power-hard-to-start-rough-pfffffff&p=206533&viewfull=1#post206533


Sent from my iPhone using Tapatalk

[Paulswpc]

Ok now, that is something kind of key to know here. As I say, you need to work on every individual thing at a time first. Now, if say your CSV was not firing, yes, you would absolutely have an issue starting when cold. But once the engine warms up, it should purr like a kitten. You've got something else wrong here.

Question: When you get the car running and you press the gas pedal, and the RPMs increase as you try and rev the engine, does it go, "ggggggggvvvvvvvvvvvvvvvvvrrrrrrrrrrrrrrrrrrRRRRRRR OOOOOOOOMMMMMM!" with a slow increase but suddenly shoots up the RPMs at the end? Then when you drive it acts like it's bogged down?

It actually purrs like a kitten when just idling whether hot or cold. It has always had an issue with load. When the engine was or is revved, it coughs pretty badly. Bogging, and RPMs eventually go up but it takes some pumping of the pedal to get it there. That's why I have a tuneup kit on hand. Just never got around to installing it. The no start issue is new after sitting for about a month.

[Paulswpc]

Some test results:
CSV: 10 volts when cranking
CPR: 0.06 volts when cranking
T valve: 0.06 volts when cranking
Coil: 6 volts
Coil Spark to ground: big & bright white/yellow spark
Resister Diodes: 12 volts
Jump RPM relay: no start. Humming present
Jump Lambia Relay: no start
Earlier today the CSV did not produce fuel into a jar
TTS: has continuity
Will swap out CSV with known good one tomorrow

Thank you to all for your suggestions. It is now narrowed down quite nicely.

[Paulswpc]

[QUOTE=Paulswpc;206724]Some test results:
CSV: 10 volts when cranking
CPR: 0.06 volts when cranking
*T valve: 0.06 volts when cranking
***Not T valve but Frequency Valve***

[DMCVegas]

It actually purrs like a kitten when just idling whether hot or cold. It has always had an issue with load. When the engine was or is revved, it coughs pretty badly. Bogging, and RPMs eventually go up but it takes some pumping of the pedal to get it there. That's why I have a tuneup kit on hand. Just never got around to installing it. The no start issue is new after sitting for about a month.

It sounds like a problem with combustion. Combustion is a problem with the fuel not burning properly of course. It falls into two distinct categories, but each have their own potential problems.

Ignition

Weak/Bad Coil. Especially prevalent with some aftermarket units.
Bad Cap/Rotor.
Leakage in ignition wires caused by tears that allow the electricity to ground directly to the block without passing through the plug.
Water in the Spark Plug Wells. This allows for leakage as well.
Improperly Gapped, wrong type, or just bad Spark Plugs.
Bad power feed to the Ignition Coil.


Fuel Delivery

Clogged Fuel Injector(s) that restrict flow and interfere with the A/F Mixture.
Clogged Fuel Injector(s) that do not properly atomize fuel so that it cannot be burned properly.
Clogged Cold Start Valve that does not allow for easy Cold Starting, but engine runs fine otherwise.
Incorrect Air/Fuel mixture caused by tampering with CO Screw.
Incorrect Air/Fuel mixture caused by malfunctioning Warm-Up Regulator
Incorrect Air/Fuel mixture caused by malfunctioning Primary Pressure Regulator.
Incorrect Air/Fuel mixture caused by malfunctioning Fuel Distributor which results in unequal fuel flow rates to individual Fuel Injectors.



You already know that you have a problem with your CSV not firing. That raises a couple of questions about the state of the fuel system...

What I believe your next course of action should be is to check the spray patterns, and fuel flow rates of your individual injectors. Start by pulling the spark plugs and see if there is any variances in their appearance to help tell you what area to focus on. Then move on to checking flow rates and spray patterns.

Two quick questions for you:

How old are these injectors, and were they new or "refurbished"?
Other than Techron, have you ever added any sort of fuel system chemicals additives to your gas tank? The kind of stuff that comes in a bottle?

[David T]

Without getting so complicated, what I see is the CSV doesn't work and sounds like the frequency valve is not working. The mixture screw was probably tweaked rich to compensate for the Lambda system malfunction. If it idles smoothly the ignition system is probably OK. I would also verify timing, and vacuum and mechanical advance. Make sure the fuel tank has fresh fuel in it. The plan should be to fix the CSV system and verify the Lambda system is working and if not fix it too. If necessary adjust the mixture screw. Check the timing and advance. That should fix the starting problem and the lack of power.

[Paulswpc]

Two quick questions for you:

How old are these injectors, and were they new or "refurbished"?
Other than Techron, have you ever added any sort of fuel system chemicals additives to your gas tank? The kind of stuff that comes in a bottle?
[/QUOTE]

Thank you for the great informative post!

No idea on the injectors.
The chemical I added suggested by Hervey was B-12 Chemtool.

[DMCVegas]

The chemical I added suggested by Hervey was B-12 Chemtool.

Oh no. :mecry:

Ok, I'm gonna level with you. Unless it is a concentrated bottle of Techron, never EVER run Chemtool, Sea Foam, or other "Mechanic in a Bottle" solutions through your fuel injection system. The only real way to properly clean a fuel injector is to actually isolate treatment to the injector itself. Modern EFI vehicles accomplish this by way of a Schrader Valve on the Fuel Rail that feeds the injectors. You pull power to the fuel pump and make the entire engine run off of just the fuel cleaner alone until the engine dies. The chemicals are not supposed to go back into the tank!

With K-Jetronic you actually have to remove the injectors and hand-pump cleaner through them until you get a proper spray pattern. And of course if you aren't able to clean them, if the procedure fails, you have to throw the injector away and get a new one. Be very skeptical of "refurbished" injectors.

Berryman's B-12 Chemtool is a HARSH chemical! It's less detergent and more nasty petroleum distillates. Even on Berryman's own website they warn people to be very careful around rubber with it. On a stock DeLorean, there are two particularly sensitive pieces of rubber that are very sensitive:

The Fuel Pump Boot.
The O-Rings on the Primary Pressure Regulator.


I've used Chemtool before of a couple of vehicles, and I paid the price severely. On an old '95 Dakota the stuff just gummed up an entire fuel pump and caused it to seize. On my DeLorean it made the Fuel Pump Boot down in the tank all mushy as it started to break it down. But my favorite part was when it damaged those rubber O-Rings in the Primary Pressure Regulator.

If you're familiar with K-Jetronic, you'll know that the injectors are controlled by Diaphragm Valves. The diaphragms split the chambers inside of the Fuel Distributor into Upper and Lower sections. As pressure is reduced in the Lower chamber, the diaphragm pulls away from the inlet tube that feeds the individual fuel injectors in the Upper Chamber, it increases fuel flow. When pressure increases and starts to balance out with the Upper chamber, the diaphragm bends back and starts to reduce flow into those tubes and thus the Injectors themselves.

So as the Air Flow Plate gets pulled down when you crack the throttle, the plate moves the Plunger inside of the Fuel Distributor to reduce pressures in the Lower Chambers so that the Injectors can feed the engine the fuel it needs. It accomplishes this by dumping excess fuel back into the return line. The default fuel maps were already calculated by BOSCH a long time ago to match the engine, and the Primary Pressure Regulator on the back of the Fuel Distributor is what maintains that map in conjunction with the engineering specs of the rest of the fuel system components. The other two external devices, the Warm Up Regulator & the Frequency valve are specifically plumbed in to also modify those lower pressures as needed by bypassing the PPR when needed. The WUR helps maintain a richer fuel mixture on a cold engine as well as fuel boosts during Wide Open Throttle to prevent the mixture from leaning out too much. And the FV is controlled by the LAMBDA system to simply fine-tune the fuel mixture even further for emissions concerns.

The PPR doesn't let fuel return to the tank until the minimum system pressure is achieved to ensure that the injectors get enough fuel pressure to crack open. But it also has a spring inside to act as a pressure relief. So as voltage increases to the Fuel Pump and it increases the Supply Line pressures, the PPR will slide open to let the excess fuel return back to the tank. Otherwise the excess pressures would alter the pressures in the Upper & Lower Chambers of the Distributor and thus throw the entire mixture off.

Make sense?

So what happens when those O-Rings get damaged? Well, as it happened to me, aside from the mushy fuel pump boot, I discovered that both of my O-Rings were damaged, with one of them split.

46402

So what happens if the O-Ring is bad and starts leaking fuel back into the return line? The entire engine runs too rich! The fuel mixture is permanently thrown off with the LAMBDA system trying to fight to get it back into it's narrow range of operation. Which is what David is describing.

It also fails to maintain rest pressure, and will cause a Hot Start Issue where you can't restart until you cool down or jump the CSV manually.

Is this your car's problem? I don't know. But with my experience when suddenly I had a chugging engine and power that got worse and worse along with more difficulty with starting, I just replaced those two little rubber O-Rings and suddenly the car correctly again. But that only was able to happen because I had the same Injectors & WUR from the previous time when the car was tuned, and had NEVER tampered with the Air/Fuel ratio. So I literally had just brought the car back to the same spec it was since all the other components and their variable values that could have affected operation remained unchanged.

If I were you, I would start by replacing the Cold Start Valve and those Rubber O-Rings. That however is assuming that no one has messed with your CO screw. Do that, and then you can move on to Ignition Timing, and then the Spray Patterns and Flow Rates of the Injectors. You *technically* should verify a failure with the PPR first with a fuel pressure gauge, but it's so cheap to repair, and you've run that Chemtool stuff though, you might as well just do it.

BUT FOR THE LOVE OF GOD DO NOT REUSE THE COPPER CRUSH WASHERS! THEY ARE ONE-TIME USE ONLY AND WILL LEAK IF YOU TRY AND REUSE THEM. EVEN IF YOU DIDN'T TORQUE THE HOLLOW BOLTS ALL THE WAY DOWN, THE WASHERS ARE NOW NO GOOD! PLEASE DO NOT RISK AN ENGINE FIRE BY REUSING THEM!!!!