Master thread-top end rebuild questions

[rjd2]

Hi folks, in lieu of a series of threads related to restoration of #5173, I figured I'd put all my questions in one thread. Here's the state of the car:

-6,557 original miles. 1983 5 speed manual, one owner car. Leather and paint a 9/10. headliner and carpet removed for cleaning.

Disassembled and rebuilt/replaced: ALL suspension parts, braking system, hydraulic clutch system, steering rack, fuel system, cooling system.

I have rounded the corner of teardown, and started the re-assembly process, and have a few questions now(and surely a few later).

1-what lubricant should I use for the o-ring where the fuel distributor mates to the MCU?

2-I used silicone grease for the new o-rings at the fuel injectors, after having them sent out for cleaning/testing. I came across some comments about silicone grease potentially clogging fuel injectors. I'm at a stage where I could still reach them to pull them and replace with o-rings with a different lubricant. Am I overthinking this, or should I swap them now?

3-this car has an MCH that never had the hole drilled out for lambda calibration. Should I do this while it's apart?

Thanks for the help folks, that's it for now. I'm getting pretty jazzed about this car. The body is essentially perfect, I'm using all silicone hoses/SS braided everything, and replacing everything that can wear(new GM style fuel pump, new accumulator/filter/charcoal canister). I think when done, it should be about as close to "factory floor" as I will ever see a D.

[David T]

The "O" rings don't require any lubrication to install. Not sure what you are referring to regarding the fuel injectors, they don't have "O" rings, they have seals, copper seals, for the fuel line and a rubber seal for the injector tube. While you have the MCU apart you can press the tamper-proof plug out, you don't have to drill it. In fact, the original plugs are very scarce so it is worth saving it. I would remove it but DO NOT adjust the mixture screw. The vendors sell a nice rubber plug with a metal loop so you can easily remove the plug for adjustment. If the adjustment has never been touched, it should be VERY close to where it should be and unless you have the equipment to properly adjust it, you aren't going to do any better.
As for seeing a "perfect" Delorean, the ones that have been judged in past Concours are about as near perfect as they get. Some even have the original tires. If you are trying to duplicate such a car you should get the Millennium Concours manual to use as a guide. If you are going for reliability (not originality) there are a lot of things to "upgrade" like the plastic header tank, aluminum radiator, relays, circuit breakers, etc. Try to get what would be "correct" for your car. Because it is an '83 it can be challenging to figure out what is "correct". At least make sure all of the recalls have been done.

[rjd2]

Thanks David! Yes, the rubber seals on the injectors are the ones in question. I have those lubricated with silicone grease currently. Should I see how the car runs once done, or pull now and do my best to replace or wipe off?

I have the original Goodyears, I just pulled them off the rims yesterday. The treads are actually great, but the sidewalls are cracking. I think I will plan on keeping all original parts, but for now I will be optimizing for safety and driveability. I don't care much about winning a concourse, but I do care about the car being safe and driveable, and desirable for a potential next owner. I will push out the "plug" in the MCU and save it. I have to say, having a running driving D makes the restoration of this car so much more fun and easy. I have a 3D template to work off of, which is pretty great.

[David T]

[QUOTE=rjd2;273427]Thanks David! Yes, the rubber seals on the injectors are the ones in question. I have those lubricated with silicone grease currently. Should I see how the car runs once done, or pull now and do my best to replace or wipe off?

Try and remove ALL of the silicone from the injector seals. If you can't remove it all, then you should replace them. They are supposed to be dry. Check on the wiper blades. If they are old or cracking you should replace them. If the battery is over 5 years old it should be replaced too. Tires are no good after 7 years so you are WAY overdue on them. Anti-freeze every 5 years. Should check all fluid levels every year. Replace the brake and clutch fluid every other year. As a general rule, if you don't know what kind of fluid is in the car or how old it is, then it should be changed. Filters too. I assume when you did the cooling system you did a tune-up. For the leather I use Leatherique Rejuvinator. You can find it at Leatherique.com. I use it once a year to keep the leather in good shape. It is much easier to keep the car nice then to try to make it nice.

[rjd2]

Ok, thanks David. I'll pull the injectors and clean them thoroughly. All fluids-coolant, brake, clutch, fuel, oil-are naturally being replaced since the systems are all new. The only thing staying on the brakes are the hard lines, booster/MC/rebuilt calipers/SS hoses are in. Since the car sat for 30 years, I am considering doing a "detergent type flush" of the first wave of oil, to try and clean out any old oil, and go in with fresh after 3-6 months... yes, battery and tires are fresh. rims were dropped off for restoration today.

[82DMC12]

I use something called "red rubber grease" for o-rings. Just a thin coating applied with your fingers. It helps keep them from drying out and helps keep them slippery so they don't roll or get pinched when tightening something down over them. Also used on the rubber piston seals inside your calipers.

https://www.amazon.com/GENUINE-Corrosion-Oxidation-Resistant-TS-2-34-04/dp/B01L63SXSU/ref=asc_df_B01L63SXSU/?tag=hyprod-20&linkCode=df0&hvadid=242122067968&hvpos=&hvnetw=g&hvrand=11716547817393367745&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9023250&hvtargid=pla-568759645110&psc=1

[David T]

If you are going to flush out the brake hard lines use Alcohol and compressed air. Repeat till the Alcohol comes out clean. Then you can go ahead and fill with DOT 4 Castrol. As for lubricating the seals on the brake calipers, you should use some clean brake fluid. As a general rule you can lubricate "O" rings with the fluid it is supposed to used with. The logic is if the "O" ring is going to come in contact with the system fluid, it should be compatible with it and not break down.

[rjd2]

Ok, not so much a question, as an observation: I sat the MCU today, and it feels like the bottom of the unit is literally resting on top of the ignition coil wire at the dizzy. is this normal? it's the only way the geometry can make sense to me, I really can't move either one. just checking.

[rjd2]

Next question: I attempted to jumper the fuel pump relay today, and got no sound(new Delorean Industries GM style pump). Either I have an error in the wiring loom, or I'm doing something wrong. Is this how the FP relay should be jumpered to run?69096

[Bitsyncmaster]

Next question: I attempted to jumper the fuel pump relay today, and got no sound(new Delorean Industries GM style pump). Either I have an error in the wiring loom, or I'm doing something wrong. Is this how the FP relay should be jumpered to run?69096

Can't see the wires. You jump the brown to the white/purple wire to run the fuel pump.

[rjd2]

Can't see the wires. You jump the brown to the white/purple wire to run the fuel pump.

Thanks-yes, that is what is being jumpered. Every other time I've jumpered a fuel pump in a car that isnt running, it's audible. I'll check the DI manual for the FP. Thanks

[Bitsyncmaster]

Thanks-yes, that is what is being jumpered. Every other time I've jumpered a fuel pump in a car that isnt running, it's audible. I'll check the DI manual for the FP. Thanks

You should see a spark when you make the jumper connection. If your not inside your garage you may not hear the fuel pump.

[rjd2]

Ok-sadly, my fuel pressure gauge is out on loan, so I can't monitor my fuel delivery that way. I have all my top end connections made, torqued to spec, and electrical connections seated. I got ahold of Delorean Industries and they said the new GM style FP is so quiet I probably won't hear it running.

I have verified that I have +12V across the brown and white/purple pins of the FP relay(this is regardless of key position, but I know 928's do the same thing). I jumpered that connection, and let it "run" for at least 2 minutes. I then cracked the banjo bolts at one injector, and the WUR: totally dry, no fuel. I gave it a few cranks as well, and at least the engine turns over. Is it safe to assume I should see SOME fuel delivery at one of these banjo bolts just through jumpering the FP? Thanks.

[David T]

Ok-sadly, my fuel pressure gauge is out on loan, so I can't monitor my fuel delivery that way. I have all my top end connections made, torqued to spec, and electrical connections seated. I got ahold of Delorean Industries and they said the new GM style FP is so quiet I probably won't hear it running.

I have verified that I have +12V across the brown and white/purple pins of the FP relay(this is regardless of key position, but I know 928's do the same thing). I jumpered that connection, and let it "run" for at least 2 minutes. I then cracked the banjo bolts at one injector, and the WUR: totally dry, no fuel. I gave it a few cranks as well, and at least the engine turns over. Is it safe to assume I should see SOME fuel delivery at one of these banjo bolts just through jumpering the FP? Thanks.

Is it possible you mixed up the 2 hoses to the fuel pump?

[rjd2]

yes, that is something I may have done. the new kit has a backflow valve.

[rjd2]

Ok, I still have no fuel supply at the engine. Here's my updated specs:


1-tested the electrical harness at the FP. I have 5V and 12V on the middle two pins when jumpered. elec seems right.

2-I had the return line from the FD connected to the "fender side" hard fuel line, which was apparently wrong. I switched this to the "inner side" hard line, and the supply line is now connected to the "fender side" hard supply line. When I disconnected the fittings, both lines were bone dry.

I still have no fuel delivery at the engine. I cracked the line at the cold start valve, and it was dry. My only theory now is that the backflow valve that comes installed in the supply line for the FP was in backwards-it was finger tight, I just secured it as it came with wrenches and continued on.

Any thoughts?

[David T]

Ok, I still have no fuel supply at the engine. Here's my updated specs:


1-tested the electrical harness at the FP. I have 5V and 12V on the middle two pins when jumpered. elec seems right.

2-I had the return line from the FD connected to the "fender side" hard fuel line, which was apparently wrong. I switched this to the "inner side" hard line, and the supply line is now connected to the "fender side" hard supply line. When I disconnected the fittings, both lines were bone dry.

I still have no fuel delivery at the engine. I cracked the line at the cold start valve, and it was dry. My only theory now is that the backflow valve that comes installed in the supply line for the FP was in backwards-it was finger tight, I just secured it as it came with wrenches and continued on.

Any thoughts?

You must have 12 volts AND a good ground at the fuel pump. Make sure you have a good, solid ground. The inertia switch opens the ground circuit.

[rjd2]

I swapped the inertia switch with a known working one-same behavior. No fuel delivery. The only other ground I know of is for the level sensor, which connects at the radiator mount.

I'm a bit stumped at this point. My next guess is the backflow valve in the new supply line being installed backwards. Maybe I should remove it, connect a hose from it to a fuel canister, and see if the pump runs?

[Rich]

My next guess is the backflow valve in the new supply line being installed backwards. Maybe I should remove it, connect a hose from it to a fuel canister, and see if the pump runs?

There may be one more simple test to run before you disconnect the fuel line to check flow or worry about the check valve.

Set up your VOM to test current through the pump circuit. The current should indicate the pump motor is using the voltage you think it's getting. Looked at the other way if the current is zero when the pump has voltage/ground at the terminals on top of the tank then you know there's a pump motor/connection problem. In the tank.

Connect your meter in series with either the + or - wire at the pump, assuming your meter can handle something like a 20 amp load. Be sure one probe lead is connected to the "20A" current plug and set the selector for the highest DC current. Then apply the 12V/ground signal the way you've done it before and see how many amps are flowing in the circuit.

You want to see the pump motor is running (using power) which is beyond verifying there's correct voltage at its terminals. No current means no power consumed - no power used means no fuel flows regardless of the check valve.

The fact that you can't hear it running when it should be is the biggest hint so far...Presumably you can't feel it vibrating from the tank top cap, either?

[rjd2]

Thanks Rich! I have a few DVM's around, hopefully one can handle 20A. So, + lead at the input pin of my jumper for the FP relay, - lead at the output TO the FP, connect and measure amps? Yes, I can't hear it running, but the rep at D.I. did say it's so quiet that I shouldnt expect to hear it. I'll give this a shot. I agree, Occam's razor would imply the pump is not running.

[rjd2]

Ok, as confirmed, the FP is not drawing any current, as measured across the jumpered brown and white/purple lines of the relay harness. So I'm not sure exactly where to check now; how do I verify the ground for the fuel pump? I swapped out the inertia switch for a known working one, and I got the same behavior. Is there a wiring location I can check? Thanks for any tips.

[David T]

Ok, as confirmed, the FP is not drawing any current, as measured across the jumpered brown and white/purple lines of the relay harness. So I'm not sure exactly where to check now; how do I verify the ground for the fuel pump? I swapped out the inertia switch for a known working one, and I got the same behavior. Is there a wiring location I can check? Thanks for any tips.

If you think you do not have a good ground just wire up a temporary one.

[Rich]

If you think you do not have a good ground just wire up a temporary one.

+1

And that temp test ground wire can go directly to the ground side (blk/purple) of the FP plug near the tank (the plug attached to the FP). Other end can go to any convenient engine bolt or to the (-) batt terminal.

For testing you can do the same thing to the (+) side of the FP plug (wht/purple) between the pump side of the plug and any live 12V terminal, including the battery.

When you complete these connections the pump should operate.

Safety notes on test wires
- Be careful with unfused test wires. A short circuit melts wire insulation fast.
- Make the last test connection at a wire end away from fuel tank. There will be a small spark at the last connection point and first disconnection points unless you add an optional switch to the test circuit or use the existing FP (+) wire at the plug instead of an always-on (+) source for that test wire.

[82DMC12]

Safety notes on test wires
- Be careful with unfused test wires. A short circuit melts wire insulation fast.
- Make the last test connection at a wire end away from fuel tank. There will be a small spark at the last connection point and first disconnection points unless you add an optional switch to the test circuit or use the existing FP (+) wire at the plug instead of an always-on (+) source for that test wire.


For this reason, when I tested my fuel system during my frame-off, I used a 20 amp fused connection close to the battery and a simple on/off switch so I could cut the power fast if needed.

69155

[rjd2]

Thanks for the help, folks. I took apart the new wiring harnesses that came with the D.I. pump wiring, and found that the ground pin harness was just a mm or 2 short of making contact with the male side. After reseating, I now have the FP working, and can verify fuel at the distributor.

Next up: I charged the system with fuel, let it saturate, and then attempted to start the car. It stumbles as the engine cranks, and sounds like combustion is periodically happening, but it never starts and holds an idle. I have new plugs, wires, distributor cap, and coil. I am assuming my next step should be to verify spark? I have not confirmed compression, but have no reason to believe there isnt compression. I recently bought a compression tester, so I could make those my next steps?

[Rich]

Next up: I charged the system with fuel, let it saturate, and then attempted to start the car. It stumbles as the engine cranks, and sounds like combustion is periodically happening, but it never starts and holds an idle. I have new plugs, wires, distributor cap, and coil. I am assuming my next step should be to verify spark? I have not confirmed compression, but have no reason to believe there isnt compression. I recently bought a compression tester, so I could make those my next steps?

Following from the partial work list you shared I'd first suggest:

A. Verify all 6 new plugs are tight/torqued.
B. Verify spark, as you say. Any convenient plug wire can be used for that. You can disconnect the FP for this test if you like.*
C. If there's spark at any wire then double-check each of the new plug wires is connected to the correct post on the dist. cap.

* as you crank the non-fueled engine also listen to the cranking noise/pattern - this may give you a free hint about uniformity of cylinder compression

[David T]

Recheck the firing order and make sure the rotor and cap are properly fitted. Check for spark but that only tells you you have it, not if you have it going to the correct cylinder at the correct time. Anything you touched is suspect including new parts which, as you found out, aren't always good parts.

[Ron]

With so many failed starts, the plugs could be fuel fowled by now.