Day 4 of Delorean Ownership and Delorean Won't Start!

[leepoffaith]

Today is day 4 of being a Delorean owner and I already have an issue where the car won't start. In all honesty I figured stuff like this would happen so I'm not too upset, but I hope you all can help me troubleshoot. I'm going to give you a little background on the car because I'm not sure if any of this info is relevant. The car was always starting great, although I bought it knowing it had a WUR problem. You had to let the car warm up for roughly 5 minutes or it would die on any constant acceleration. Sometimes if you blipped the throttled you could get it to eventually rev up during the warm up period. After warming up it would run great and didn't have any warm start issues. Yesterday I removed and tried cleaning the screen on the WUR (but in all honesty it wasn't that dirty). I put it back and had the same problem so I figured I'd have to have it rebuilt. Last night I accidentally ran down the battery while playing the radio and working on cleaning the car. I didn't think I had the radio on long enough to kill the battery (maybe 2-3 hours) so maybe there is something else wrong? Anyway, I couldn't get it to start last night, even after jumping the car with another car. It cranks great, but that's it. No attempt to even start. My first thought was fuel pump, so I read up about testing the pump, jumped the RPM relay and heard the fuel pump turn on right away. I'm getting roughly 9 volts from the fuel pump contacts. I can't find exactly how many volts it needs so I'm not sure if this is where it should be or not. I know the fuel pump had been replaced, but it was still the old style pump. The car wouldn't start even with the fuel pump running.

Four other recent observations I had made was that a wire was unplugged in the drivers side rear wheel-well (picture attached). I think this might be a ground? I plugged it back in on Friday night when I adjusted the parking brake and the car still ran fine on Saturday morning so I don't think this was it, but still curious as to why it was unplugged. The second observation I made (just this morning) was that it looks like there is a ground wire that isn't connected to anything that was hanging behind the engine. (Pictures attached) It is possible I bumped this off somewhere when I was tracing the vacuum lines, but it definitely wasn't secured on properly to a bolt. Could this be causing the no start issue? The third observation is that there is also a plug behind the engine that isn't plugged into anything (picture attached). I don't see anywhere that this should be plugged into and I don't think it's ever been plugged in since getting the car so I'm not sure if this is the issue. Lastly, I found a tiny bit of oil on the ground and see that it is coming from a plug on the driver's side rear of the engine block bolt/plug. (picture attached) It looks like that there is a wire going into it. Not sure what this is or if it could be causing my issue either.

Any advice and/or help is greatly appreciated. Thanks!

[jackb]

The plug in your first picture is for your O2 sensor.
The wire in your last picture is for your oil pressure warning light. (The oil pressure guage is on the opposite right side of the motor).
I can’t see anything clearly in the second picture, and I’m not sure off the top of my head what the plug in the third picture is for.

[leepoffaith]

The plug in your first picture is for your O2 sensor.
The wire in your last picture is for your oil pressure warning light. (The oil pressure guage is on the opposite right side of the motor).
I can’t see anything clearly in the second picture, and I’m not sure off the top of my head what the plug in the third picture is for.

Thank you! So I doubt it's the o2 sensor plug or oil warning light that is causing the no start issue. Here is an updated picture of the one that wasn't clear. It looks to be a ground wire coming from the box mounted to the firewall of the engine bay.

[dmcnc]

That grounds to the intake manifold bolt where your idle motor bracket anchors.

58627


Thank you! So I doubt it's the o2 sensor plug or oil warning light that is causing the no start issue. Here is an updated picture of the one that wasn't clear. It looks to be a ground wire coming from the box mounted to the firewall of the engine bay.

[David T]

Get your battery charged up and tested. If it is over 5 years old just replace it. If the car doesn't start you must figure out if it is spark or fuel. A quick shot of Ether can confirm. If the Ether doesn't get it to pop you have an ignition problem. If it does pop and run you have a fuel problem. Fix your known problems so you can continue to diagnose the unknowns meaning replace or rebuild the CPR, take care of the battery and continue your troubleshooting. Looks like you have a lot of stuff to take care of.

[Jonathan]

That grounds to the intake manifold bolt where your idle motor bracket anchors.

58627

This is exactly right. And so are the comments about your other photos of the O2 sensor and oil pressure low light sensor (that oil pressure sender seal is known to leak and likely will only need the seal replaced and not the sensor. Do that the next time you change the oil).

I don't believe that disconnected wire pair with the white plastic connector needs to go anywhere. Although it seems to remain a common source of confusion. There are a couple other connectors that aren't used, either at all or on manual versus automatic transmissions. Perhaps one of us should create a sort of cheat sheet summary with photos of what goes where and what doesn't need to be plugged in. It gets asked enough to make me think that'd be a valuable thing for us to have on the forum here.

That ground wire ring should not be hard to reconnect. Unthread that bolt that was shown for you and put in on with the others. Poor grounds cause a lot of issues on the cars and this may help you in unexpected ways. I don't recall if that ground wire collection also pairs up elsewhere to achieve a good ground overall, but if it doesn't, it could seriously help your ignition problems. There's also an O2 sensor reference ground connection back there and between that and the O2 sensor itself being unplugged, I'd say you're getting much closer to a better starting and idling car. You may need to do a final fuel mixture adjustment once everything else is working again as your car might have seen an adjustment to temporarily handle these pieces of the fuel and idle control system that weren't working.

And definitely take the battery out of the car and charge it back up properly as Dave suggested. A low battery will do nothing but hide the true problems from you and make it harder to figure out.

[Bitsyncmaster]

9 volts on the fuel pump is not good but since you hear the pump run, it's probably not causing the no start issue. After you get it started you should find out why you only have 9 volts.

All the black wires in the engine compartment should be ground. I would bolt that "floating" black wire to the engine block.

Get a can of starter fluid and after a spray of that into the intake (take the air cleaner off) see if it fires. If it does that would tell you the ignition is good and you have a fuel problem.

[DMC-81]

You have solid advice offered so far. +1 on a low battery causing problems. After you get it started, I'll add:

- On the oil pressure sensor, try to determine if it's leaking around the outer seal or around the inner core. The outer seal is a crush washer that I found needed 28 ft/lbs to crush a new seal properly and seal. If it is the inner core try tightening the nuts on the sender electrical spade connector. If that doesn't work you'll need a new sender or you can take it apart and replace the oring seals. I think that PJ Grady offers a rebuilt one.

- Words of encouragement: if you're finding simple things like ground wires off, you'll want to go around the car to see what else is out of place or hacked with crossover parts or "options". But, once you do this, and replace what needs it after 37 years, the car can be as reliable as any other vehicle.

[Rich]

Suggesting you go in David T's direction (first attend to your battery charge or battery condition/age) as well as follow your first inclination:


My first thought was fuel pump, so I read up about testing the pump, jumped the RPM relay and heard the fuel pump turn on right away. I'm getting roughly 9 volts from the fuel pump contacts. I can't find exactly how many volts it needs so I'm not sure if this is where it should be or not.

My recollection is that the pump needs to see at least 11.5V in order for it to generate the threshold injector opening pressure. In other words, while the pump will run at lower voltages you're probably getting zero fuel delivery into the intake with just 9V.

The starting fluid test is a good way to verify fuel/air problem vs ignition, as both David T. and Dave say. But 9V at the pump is out of spec per the K-Jet manual, I think. Anybody out there have one handy to verify this for us?

[Ron]

I'm getting roughly 9 volts from the fuel pump contacts......after taking care of the battery, remove either of the pump's harness wires and then measure across them.

[leepoffaith]

I just wanted to say THANK you to everyone for their suggestions. First thing was I had the battery recharged at Advanced auto parts since I don't have a battery charger (on the Christmas list!). While that was charging I checked all my electrical connections in the engine compartment and I found a corroded connection on the ignition coil and a loose connection on the ignition resistor. I cleaned the coil and secured the resistor connection. I got back home with the charged battery, popped it in and she started right up! I'm thinking I might have bumped the wire on the resistor when I was tracing the lines for the WUR so I think that might have been it. Meanwhile I traced the rest of the ground wires and everything seems to be secured pretty well. Thank you very much for all of your suggestions. I was planning on running through most, if not all of them if my first step didn't work.

~Lee

[DMC5180]

Lee,

Glad you got it going. Just an FYI, the white two wire connector on the back wall harness with Black and Red wires is a radio noise filter. It is the little black cylinder taped to the wire harness. It is unused on your car, mine too, but on some cars there is a mating connector coming out of the engine wire harness that powers the vacuum solenoid. It was a rolling production change to delete it. That Harness never got revised to remove the filter. While the engine harness did get the revision.


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[leepoffaith]

- On the oil pressure sensor, try to determine if it's leaking around the outer seal or around the inner core. The outer seal is a crush washer that I found needed 28 ft/lbs to crush a new seal properly and seal. If it is the inner core try tightening the nuts on the sender electrical spade connector. If that doesn't work you'll need a new sender or you can take it apart and replace the oring seals. I think that PJ Grady offers a rebuilt one.

So I looked at this more closely and it definitely is the small middle washer that seals the bolt that the sensor wire clamps to. It just spins when I try and tighten it. Is there any way to replace/tighten the center bolt on these? I think the washer actually might be just fine, but it just needs to be tightened. Thanks!

~Lee

[DMC-81]

So I looked at this more closely and it definitely is the small middle washer that seals the bolt that the sensor wire clamps to. It just spins when I try and tighten it. Is there any way to replace/tighten the center bolt on these? I think the washer actually might be just fine, but it just needs to be tightened. Thanks!

~Lee

Sure, you can tighten it up some. Be careful as its only a small shaft. Here are a couple pictures to illustrate:

This is an OEM Oil Pressure Sender-light ( 102462 ) with the electrical connector disassembled and the second nut loosened. Notice how the sender cylinder is spring loaded and is moving away from the hub. (You don't want to completely remove this nut as the sender will fall apart in the engine.)
http://dmctalk.org/attachment.php?attachmentid=58662&d=1542848618

Here it is with the electrical connector disassembled, and the second nut tightened all the way. When tightening,after the threaded shaft spins, you can carefully grab the shaft with pliers ( without damaging the threads) while snugging up the nut a little bit more. By the way, the nut is 7 mm.
http://dmctalk.org/attachment.php?attachmentid=58663&d=1542848723

When you are finished, you can install the electrical spade connector, shaker washer, and nut:
http://dmctalk.org/attachment.php?attachmentid=58661&d=1542848492

[leepoffaith]

Sure, you can tighten it up some. Be careful as its only a small shaft. Here are a couple pictures to illustrate:


Thank you very much for all these great pictures! That explains why it was spinning. I"ll try grabbing the end gently with a long nose pliers and use a very small 7mm wrench to tighten the nut. I'll be sure to let you know how it goes! :)

~Lee

[David T]

Tightening it up usually won't stop the leaking. I take it all apart, wipe the parts down with alcohol, and reassemble with small dabs of silicone sealer on the sealing washers. Or you can just get a new one, they aren't expensive. The wire going to the sender is usually all burnt up. Either splice in a piece of high temp wire or cover the burnt up wire with a fire sleeve.

[DMC-81]

Thank you very much for all these great pictures! That explains why it was spinning. I"ll try grabbing the end gently with a long nose pliers and use a very small 7mm wrench to tighten the nut. I'll be sure to let you know how it goes! :)

~Lee

You're welcome.


Tightening it up usually won't stop the leaking. I take it all apart, wipe the parts down with alcohol, and reassemble with small dabs of silicone sealer on the sealing washers. Or you can just get a new one, they aren't expensive. The wire going to the sender is usually all burnt up. Either splice in a piece of high temp wire or cover the burnt up wire with a fire sleeve.

Well, it stopped mine from leaking. This is the logical first step to try. If it doesn't work, then removing the sender is required to repair or replace ( see post #8 ). This requires a new crush washer.

Also, I don't recommend using just any silicone to repair anything engine related. Using proper oil rated o-rings is ideal, but if you want to try a FIP gasket, you will want to find a product that is rated for engine oils...for example, Permatex gray RTV gasket maker.

[David T]

You are right, you can't use just any silicone sealer. It must say "Sensor Safe" or you run the risk of fouling your O2 sensor. While tightening it up will slow the leak down considerably, it will still be moist. There is a LOT of pressure on that switch. I reuse the large crush washer, again, with a dab of silicone and really tighten it up tight.

[DMC5180]

These are New O-rings I installed on my switch assembly. The originals were completely hard and square profiled and had lost all resilience to effectively seal.

https://uploads.tapatalk-cdn.com/20181123/4e0ed9d090056e8b1d2f460413eaa768.jpg


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