Delorean wont start

Hi, I am new to the forum. I have had my delorean for quite awhile. I purchased it from my brother's estate when he passed with the intent of getting it going in his honor. The motor had been overheated when he had it and it hadnt been started in a very long time. So I sent the motor out and had it done over, new rings, bearings, valves and guides. The fuel distributor redone. Once I got it back in and tried to get it going had no luck. My other brother suggested it was timing, long story short he was right, it was off 180. Pulled out the distributor found top dead center on comperssion, and it fired. Since then I have painstakingly found, several things that i missed or over looked. Thought I had the o2 sensor hooked up but didnt. Replaced the injectors, then the latest was the seals and clips for the injectors. This has been a long process as I work out of town and cant always work on it. Any way when I would get it running I could never get it to idle down and stay running, likely the unconnected o2 sensor at that time. The fuel pump is new the fuel filter has been changed several times, the acccumulator is new. I even have a new ECU that i recently happened on at an auction. Threw out all this I played with the co. Any way I can pull an injector out hotwire the rpm relay get fuel coming out of the injector. When I try to start it either with the relay jumped or with the relay in, the plugs are still dry. It wants to fire but just wont catch. By the way the dmc in my user name stands foir delorean making me crazy.

Injectors should not spray with the RPM relay jumpered not pressing the air plate. If they do you have your mixture adjusted wrong. You just want to back off the mixture adjustment so they don't spray with no plate pushed. Then you should be able to get it started. Remember a shot of starter fluid should tell you if your getting ignition or if the problem is fuel related.

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Originally Posted by Bitsyncmaster

Injectors should not spray with the RPM relay jumpered not pressing the air plate. If they do you have your mixture adjusted wrong. You just want to back off the mixture adjustment so they don't spray with no plate pushed. Then you should be able to get it started. Remember a shot of starter fluid should tell you if your getting ignition or if the problem is fuel related.

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Thank you for the information, my thoughts were wrong regarding the air plate. Backed it off still wouldnt start, turned the co very little and eventually it would start to fire but not completely start. After several tries, I wound up pressing the accelerator wide open and would eventually catch and run. Still couldnt get it to idle enough to get out and try to adjust. Did this a few times. It would run rough. So i pulled the plugs and they were black, but not what I would consider fouled. Not sure what my next move should be besides taking it to someone.

If you still have the plugs out do a compression test. Dry than wet one cap of oil will do.


Dave B.

Opening the throttle doesn't do anything significant when starting. It sounds like, when you kept trying it, it cleared up and started to run.
Maybe try pressing the plate after it is running rough (it's very touchy even when things are right...like pressing on your eyelid) to help clear it out and get warmed up.
Working the throttle and plate together works best for me. Hold the throttle wide open and press the plate ~1/4" after a helper begins to crank it over. Then drop the throttle down as soon as it fires up...after a few tries, you can baby it while your helper plays with the CO screw to at least get it running on its own (very tiny turns), or wait for it to get warm.

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Originally Posted by Ron

Opening the throttle doesn't do anything significant when starting. It sounds like, when you kept trying it, it cleared up and started to run.
Maybe try pressing the plate after it is running rough (it's very touchy even when things are right...like pressing on your eyelid) to help clear it out and get warmed up.
Working the throttle and plate together works best for me. Hold the throttle wide open and press the plate ~1/4" after a helper begins to crank it over. Then drop the throttle down as soon as it fires up...after a few tries, you can baby it while your helper plays with the CO screw to at least get it running on its own (very tiny turns), or wait for it to get warm.

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Thank you again, my helper most times consists of my 5 year old nephew, he is great but easily distracted. Any way, in starting it a couple times and going back to the shop manual, I was reading about the ECU and how it works with the tachometer so to speak. Only issue/question is my tach doesnt work, did initially, but even then was erratic. Will the tach not working possibly affect the information to the ECU? and could this have anything to do with some of my adjustment headaches?

The tach's only function is to display the RPM. But, yes, it could affect anything connected to it's White/Slate (WS) wire: Coil, IdleSpeed Relay, RPM Relay, and Ignition Control Module. Not a common problem though.
Maybe try a hand held multimeter/tachometer....

Not sure of where you are at with it now. IE it was hard to idle down and dying before adjusting the CO to get the injector opening close...that and changing/cleaning the plugs(?) should of made some noticeable changes??

Forgot to mention before- The O2 sensor shouldn't come into play until after the engine is warm.

I would not think a broken tach would load the ignition signal. All the ignition circuits I've seen have a resistor from the tach signal so only if that resistor shorted would it kill the ignition.

If a good tach does not show some RPM when cranking than something is probably wrong with the ignition.

Most of the time the tach is not the problem, it is a connection to it. There is a flexible printed circuit board inside the binnacle that connects all of the instruments and is often the source of the bad connections. As for the hard starting, maybe it's time for a tune-up. Fresh spark plugs and finding and fixing all of he vacuum leaks will make a big difference. Maybe some fresh fuel too?

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Originally Posted by Bitsyncmaster

I would not think a broken tach would load the ignition signal. All the ignition circuits I've seen have a resistor from the tach signal so only if that resistor shorted would it kill the ignition.

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Yeah, since it runs and a short would kill it, the tach is probably not getting a good connection.
Curious- Are you talking about the precision resistor (or some other resistor) mounted on the tach's board? If not where is it?

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Since it has all been apart since running good, I'd suggest going through all of the basic settings, which means investing in a fuel pressure gauge setup capable of looking at the Primary and Control pressures -- Gonna' need it sooner or later.

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Originally Posted by Ron

Yeah, since it runs and a short would kill it, the tach is probably not getting a good connection.
Curious- Are you talking about the precision resistor (or some other resistor) mounted on the tach's board? If not where is it?

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Since it has all been apart since running good, I'd suggest going through all of the basic settings, which means investing in a fuel pressure gauge setup capable of looking at the Primary and Control pressures -- Gonna' need it sooner or later.

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The RPM relay and idle ECU feed the ignition signal into a pin which feeds a resistor and capacitor couples into the circuit. These components are inside the units. I assume the tach does the same but I have not looked at that circuit yet. My units also use a resistor but DC couple into an optical isolator.

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Originally Posted by David T

Most of the time the tach is not the problem, it is a connection to it. There is a flexible printed circuit board inside the binnacle that connects all of the instruments and is often the source of the bad connections. As for the hard starting, maybe it's time for a tune-up. Fresh spark plugs and finding and fixing all of he vacuum leaks will make a big difference. Maybe some fresh fuel too?

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How hard is it to get to the printed circuit board, for 32 dollars plus shipping I would get the new flexible printed circuit board, I have bought an after market tach to sit in the engine bay to compare to the timing light I have on hand. the timing light actually has the RPM display as well. My concern is the ECU getting the rpm signal from the tach, and how that might effect the running. I will get more plugs, any specific plug that has been found to be better in the deloreans? And I have all new vacuum hoses, still doesnt mean there isnt a leak. I have read about spraying starter fluid around the areas of concern once it is running to find a leak. Would there be a better option? Once I get the plugs and my teenage son to help I will update where I am at with the running. Thank you all for the input, wish I joined a long time ago might have saved a lot of bad words and aggrivation.

You can put in a new board but if you are really careful with the old one, with a bit if Scotch-Brite and some patience, you can fix up your old one. Puling the binnacle and the gauge cluster isn't too bad. Replace all of the bulbs while you are in there. If you decide to convert to LED do NOT convert the bulb for the alternator. Also a good time to lubricate the speedometer cable. As for finding vacuum leaks, the best way is to use a smoke machine. It makes the invisible visible. Using it I have found leaks you just would never find any other way.

Where in the Northeast are you located? I'm in Northern NY.

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Originally Posted by northeast dmc

My concern is the ECU getting the rpm signal from the tach, and how that might effect the running.

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It doesn't work that way.Sorry I wasn't clearer earlier- The Ignition Control Unit (ICU) monitors the distributors speed and outputs the signal on the WS wire. It is a grounding signal that makes the Coil fire. The RPM Relay looks at the signal to know when to turn the pump on/off. The Idle Speed Motor's control unit looks at the signal to adjust the idle. The tach looks at the signal to display the RPM. The engine does not use the tach for running. The tach would only affect the running if it had a short (to ground or power) -- If an external tach reads correctly, I'd forget about it for now and get it running.

Bosch HR6DS spark plugs.

Smoke is better and safer to find vacuum leaks...

Thanks for that explanation! ,it makes understanding the systems and how they're wired and work clearer :thinkin:
Very interesting

Cheers
Shane

Yes the tach, RPM relay, idle ECU and ignition coil all connect to the ignition ECU output. The ignition coil has power on the plus side provided my the ignition resistors and the negative side is driven to ground by the ignition ECU. So normally you will see 12 volts and 1 volt (switching) on the white/slate circuit but when the ignition ECU switches to open you get about a 400 volt spike. Most of the stock circuits capacitor couple that signal through a voltage divider to drive each units circuitry. So components and wire attached to the white/slate circuit really should be rated above 400 volts. Makes me wonder it the binnacle flex board has that rating.

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Originally Posted by Rich_NYS

Where in the Northeast are you located? I'm in Northern NY.

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West of Albany, and just South of Amsterdam NY.

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Originally Posted by Ron

It doesn't work that way.Sorry I wasn't clearer earlier- The Ignition Control Unit (ICU) monitors the distributors speed and outputs the signal on the WS wire. It is a grounding signal that makes the Coil fire. The RPM Relay looks at the signal to know when to turn the pump on/off. The Idle Speed Motor's control unit looks at the signal to adjust the idle. The tach looks at the signal to display the RPM. The engine does not use the tach for running. The tach would only affect the running if it had a short (to ground or power) -- If an external tach reads correctly, I'd forget about it for now and get it running.

Bosch HR6DS spark plugs.

Smoke is better and safer to find vacuum leaks...

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Thank you for clearing that up, so for the time being dont worry about the Tach, and that is the first time I have seen or heard of using smoke.

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Originally Posted by northeast dmc

West of Albany, and just South of Amsterdam NY.

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I'm highly familiar with the area. I drove through Amsterdam last week, enroute to Niagara Falls. PM'ing you..

Sent from my LGL164VL using Tapatalk

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Originally Posted by Ron

It doesn't work that way.Sorry I wasn't clearer earlier- The Ignition Control Unit (ICU) monitors the distributors speed and outputs the signal on the WS wire. It is a grounding signal that makes the Coil fire. The RPM Relay looks at the signal to know when to turn the pump on/off. The Idle Speed Motor's control unit looks at the signal to adjust the idle. The tach looks at the signal to display the RPM. The engine does not use the tach for running. The tach would only affect the running if it had a short (to ground or power) -- If an external tach reads correctly, I'd forget about it for now and get it running.

Bosch HR6DS spark plugs.

Smoke is better and safer to find vacuum leaks...

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Thanks again to all the responses, I did put in a set of plugs I had on hand they werent new but when I put them in it startes right up on high idle then idled down, so I was happy with that. I was able to check the timing and the rpm with the timing light and it was actully had to increase the idle slightly, it was around 500, adjusted the idle up to around 780. Put the wheels on and the airfilter, and drove it around the yard, has a pretty good hesitation when I try to accelerate in drive. In reverse it goes pretty good, but in drive need to work the throttle to get it to move.

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Originally Posted by northeast dmc

Thanks again to all the responses, I did put in a set of plugs I had on hand they werent new but when I put them in it startes right up on high idle then idled down, so I was happy with that.

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:thumbup:

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Originally Posted by northeast dmc

I was able to check the timing and the rpm with the timing light and it was actully had to increase the idle slightly, it was around 500, adjusted the idle up to around 780.
Put the wheels on and the airfilter, and drove it around the yard, has a pretty good hesitation when I try to accelerate in drive. In reverse it goes pretty good, but in drive need to work the throttle to get it to move.

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If you used the 3 brass screws (or other method) to adjust the idle, you should know that it should be 'automatically set' by the Idle Speed Control Unit. Checking the fuel pressures and items listed in section D:05:XX in the manual would be a good next step.
Forward and reverse should basically act/feel the same pulling off...Note that the transmission is shifted electrically, using two solenoids. If there is an electrical problem, it may blow fuse #13. This puts it in 3rd gear (Not 2nd for a "limp mode" as some do.) which is extremely hard on the clutch pack(s)...they are only about as big as a fist and just a few "abuses" will toast them!
I'd finish tweaking out the engine (idle system, confirm all basic settings etc.) W/O driving it. Then address the transmission. If needed, making some shift test light can be found HERE.

Well its been a little while since I have posted, being out of town makes it tough. Any way I have had some success, last go round I was able to get it to actually idle where it should or close to it, which I see and read verying numbers related to idle rpm. What is the correct idle for an automatic that is warmed up to temperature? Second what is the thoughts on using the Eagle premier starter? The casualty of my extended attempts at startinbg and getting it running, has taken its tole. Starter works but but the bendix/relay has a bad spot. Some time s need to cycle the key several times before it wil engage. The next step is to do the front brake system, and get new rubber on the wheels. What is the thoughts regarding powder coating the wheels?

The stock idle ECU for both auto and manual is 775 RPM which is fixed if your engine is adjusted correctly.

I have the small Eagle starter and it works fine and gives you a lot more room and less weight.

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Originally Posted by Bitsyncmaster

The stock idle ECU for both auto and manual is 775 RPM which is fixed if your engine is adjusted correctly.

I have the small Eagle starter and it works fine and gives you a lot more room and less weight.

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Thank you for the response, I did see a post regarding the wiring can you tell me what the difference is and what I will need to do, sounded like there might be one less post on the eagle versus the dmc starter.

Check out the pic HERE. Or you could tie the Blue/Yellow to the White/Red.

If you VIN is <2547 you might want to check out the service bulletin HERE>

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Originally Posted by Ron

Check out the pic HERE. Or you could tie the Blue/Yellow to the White/Red.

If you VIN is <2547 you might want to check out the service bulletin HERE>

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I just came across this pic, looks like the same pic with labeling:

Attachment 61899