What mods would make the car more reliable?

[aludden]

I think it would be interesting to list in a sticky the mods that would make for a more reliable car. There are many of us that are not looking for performance or projects - we just enjoy driving the car :-)

[opethmike]

My thoughts:

Updated relays/circuit break kit
Stainless clutch line in case of manual transmission
Tighten down output shaft nut in case of manual transmission (I can't emphasize this enough. Mine backed off, cracked open my transmission end cap. Huge headache.)
Unplug stock door lock module
Starter wiring tech bulletin if applicable and not done

[Ozzie]

Digital RPM relay by Dave/BitSyncmaster.

This is a modern replacement to a high failure part. Many a D owners have had relay failures caused by overheated, or delaminating, original RPM relays on long/highway trips. If your relay goes bad on a trip, you can a) jumper it for a short return trip, b) have and plug in a spare, or c) get this digital one and never think about it again.

I've been running one now for a few years and many miles here (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCUQFjAA&url=http%3A%2F%2Fdelorean2109.blogspot.com%2F2008% 2F05%2Frpm-relay-modern-update.html) is an older review that still applies.

[jawn101]

Replace all flexible fuel lines and any rubber that coolant flows through, to include the short junctions in the pipes under the car. Silicone vacuum lines. Trailing arm bolts!

[JIMJAM]

A few years ago after buying my D I tried to follow the "must do mods" which was rather lenghty. I simplified it and just replaced anything that electricity ran through, gas touches or any part that moves and / or has weight on it.

[aludden]

Replace all flexible fuel lines and any rubber that coolant flows through, to include the short junctions in the pipes under the car. Silicone vacuum lines. Trailing arm bolts!

As far as fuel, you mean all the fuel lines going from the fuel distributor to the injectors? I have been looking at that, but it is a bit pricey, so it may have to wait a bit.

I just finished changing all the coolant hoses, including the heater valve and hoses behind the engine :-) I'm also doing the vacuum hoses.
As far as the trailing arm bolts, I'm pretty sure I got them replaced years ago, but I do have a new set to put in. Mine is more difficult because it's an automatic, but it's on my list.

[jawn101]

As far as fuel, you mean all the fuel lines going from the fuel distributor to the injectors? I have been looking at that, but it is a bit pricey, so it may have to wait a bit.

I just finished changing all the coolant hoses, including the heater valve and hoses behind the engine :-) I'm also doing the vacuum hoses.
As far as the trailing arm bolts, I'm pretty sure I got them replaced years ago, but I do have a new set to put in. Mine is more difficult because it's an automatic, but it's on my list.

Yup, all the flexible lines. From the filter, to the injectors, WUR, CSV, frequency valve, etc.

With coolant, don't forget the side hoses, water pump, and the small collars at the radiator and under the tub.

[Kenny_Z]

The mods I've done or plan to do to increase the reliability of my D:

Relay upgrades (I still have the original RPM installed but I do have a spare)
Plastic coolant tank replacement (I've heard they rupture under pressure, I still have the plastic installed but will be replacing it when I can)
Stainless clutch line (replaced when I replaced my master and slave cylinders)
Upgraded fuel pump with external check valve (came with the car but I just bought a used spare off a local Porsche guy)
Grounding upgrades (can be cheap and easy or not as cheap and extensive, I went extensive)
Coolant hose replacement with silicon hose (planned for Spring)
Coolant active bleeder system (I bought Hervey's but haven't installed it yet)


The ones below are ones I've seen done that just sound like they are a good idea for upgrades:

Stock radiator replacement (I've seen 10 year old plastic ones crack, ours are 30)
Stock radiator fan replacement (lower amp fans take some of the load off your circuits)
Water pump replacement with one with a bolt on pulley
Upgraded alternator (could be just a better DMC unit or an upgrade from another car)


None of the stuff above will get you any extra power out of the engine but they will keep you off the side of the road.

[Kenny_Z]

My thoughts:
Tighten down output shaft nut in case of manual transmission (I can't emphasize this enough. Mine backed off, cracked open my transmission end cap. Huge headache.)
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Is there a document on how to do this? I haven't seen one when I search for it. I'd really like to check this on Red. I drove her a bit with a bad shift link bushing so I don't know how long the previous owner was driving like that.

[jawn101]

The mods I've done or plan to do to increase the reliability of my D:

Relay upgrades (I still have the original RPM installed but I do have a spare)
Plastic coolant tank replacement (I've heard they rupture under pressure, I still have the plastic installed but will be replacing it when I can)
Stainless clutch line (replaced when I replaced my master and slave cylinders)
Upgraded fuel pump with external check valve (came with the car but I just bought a used spare off a local Porsche guy)
Grounding upgrades (can be cheap and easy or not as cheap and extensive, I went extensive)
Coolant hose replacement with silicon hose (planned for Spring)
Coolant active bleeder system (I bought Hervey's but haven't installed it yet)


The ones below are ones I've seen done that just sound like they are a good idea for upgrades:

Stock radiator replacement (I've seen 10 year old plastic ones crack, ours are 30)
Stock radiator fan replacement (lower amp fans take some of the load off your circuits)
Water pump replacement with one with a bolt on pulley
Upgraded alternator (could be just a better DMC unit or an upgrade from another car)


None of the stuff above will get you any extra power out of the engine but they will keep you off the side of the road.

Big +1 to the grounds, radiator, water pump, coolant tank, alternator and cooling fan updates. The grounds, alternator and fan updates will make a huge difference in the car's behavior (at least they did in mine). Hervey's ground cables alone made an immediate and enormous difference - best 40 bucks and 40 minutes you'll spend. The other updates are great for long term reliability and safety.

[jawn101]

Is there a document on how to do this? I haven't seen one when I search for it. I'd really like to check this on Red. I drove her a bit with a bad shift link bushing so I don't know how long the previous owner was driving like that.

From my understanding you pretty much just have to drop the transmission, remove the end cap and torque the nuts. Not easy or pretty but easier than repairing it if something goes wrong. It is my big planned winter project this year.

[robvanderveer]

The best mod for a making the car more reliable would be an owner that maintains and drives it at a regular basis.

[jawn101]

The best mod for a making the car more reliable would be an owner that maintains and drives it at a regular basis.

That's not a mod, that's a prerequisite! :)

[Kenny_Z]

From my understanding you pretty much just have to drop the transmission, remove the end cap and torque the nuts. Not easy or pretty but easier than repairing it if something goes wrong. It is my big planned winter project this year.

Thanks, I was afraid you were going to say drop the transmission. I planned on replacing the clutch within the next year so I'll probably take care of that and the second gear roll pin all in one swoop.


Big +1 to the grounds, radiator, water pump, coolant tank, alternator and cooling fan updates. The grounds, alternator and fan updates will make a huge difference in the car's behavior (at least they did in mine). Hervey's ground cables alone made an immediate and enormous difference - best 40 bucks and 40 minutes you'll spend. The other updates are great for long term reliability and safety.

Not that I would not want Hervey to have business because he's an awesome guy but I bought a couple of 15 dollar cables from Autozone that did the same thing. I grounded the battery to the transmission (skipping that torsion bar bolt completely) and then grounded the engine to the frame on the passenger side ground point. It was the cheapest and best upgrade I ever did on Red. The one other ground I did that I felt had a drastic impact was the grounding on the fuel pump. Without it I was getting about 10 volts to the pump if I was lucky but after the grounding I got a steady 12+ volts.

[jawn101]

Fair enough, but what matters for the sake of this thread is that ground improvements are a critical mod for reliability :)

And yes, the second gear roll pin is another big one for M/T cars. Output shaft seals and flange maintenance are another one while the trans is being worked on. Help keep all that oil inside where it belongs :)

[DMCMW Dave]

From my understanding you pretty much just have to drop the transmission, remove the end cap and torque the nuts. Not easy or pretty but easier than repairing it if something goes wrong. It is my big planned winter project this year.

This can be done with the trans in the car. The only part you need is the paper gasket. Just don't lose the 5th gear detent ball, make sure you understand exactly how it comes apart or you'll see parts escaping across the garage floor.

[jawn101]

Well shoot Dave... Where have you been all my life? :) While we're on that topic, is it even possible for a home tinkerer to get the trans out without a lift and without pulling the engine? I've been putting all this stuff off as I just don't know where to start.

[opethmike]

Well shoot Dave... Where have you been all my life? :) While we're on that topic, is it even possible for a home tinkerer to get the trans out without a lift and without pulling the engine? I've been putting all this stuff off as I just don't know where to start.

Yes. The biggest issue is safely elevating the car the two feet or so you'll need to get the transmission out. You can lower the transmission with a floor jack and some wood planks, but I STROOOONGLY recommend getting a transmission jack.

[jawn101]

Yes. The biggest issue is safely elevating the car the two feet or so you'll need to get the transmission out. You can lower the transmission with a floor jack and some wood planks, but I STROOOONGLY recommend getting a transmission jack.

Sounds like a conversation that needs to be had, lol. I don't want to hijack the thread so I'll take it outside.

[DMCVegas]

Digital RPM relay by Dave/BitSyncmaster.

This is a modern replacement to a high failure part. Many a D owners have had relay failures caused by overheated, or delaminating, original RPM relays on long/highway trips. If your relay goes bad on a trip, you can a) jumper it for a short return trip, b) have and plug in a spare, or c) get this digital one and never think about it again.

I've been running one now for a few years and many miles here (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCUQFjAA&url=http%3A%2F%2Fdelorean2109.blogspot.com%2F2008% 2F05%2Frpm-relay-modern-update.html) is an older review that still applies.

http://upload.wikimedia.org/wikipedia/commons/1/18/%22Citation_needed%22.jpg

Since when as the RPM relay been any sort of a "High Failure" Part? Even if it did fail, a jumper from the brown wire in the corner to the other wire diagonally across from it on the other end of the harness will get the fuel pump flowing again. Something you do anyway while testing the fuel system.

[Ozzie]

Since when as the RPM relay been any sort of a "High Failure" Part? Even if it did fail, a jumper from the brown wire in the corner to the other wire diagonally across from it on the other end of the harness will get the fuel pump flowing again. Something you do anyway while testing the fuel system.

That is fails: I only write what I have discussed and observed with other owners with original RPM relays who this happened to, and to me after a 3 hour drive (fuel just cut off, came back on after original RPM relay cooled - I know owners who advise/give the original relay a whack to get it going again). The OEM relay heats up with use (touch it after a drive) as it is a mechanical relay in motion in continuous use, and as they are now 30 years old, they are having board delamination and solder failures and that's only going to get worse with time and usage. So, age + usage/heat (heat = premature death for electronics) + history tend indicate that it is a high failure rate part, as reliability is assessed in industry.
Once I put Dave's solid state version, you can feel after the same type of drive his version puts out much, much, less heat, and I have made that same 3+ hour trip (and back) w/o any RPM related issues.

That there is a work around, yes I agree with you I mentioned two others (jumpers and a spare). As you know, but others may not, jumpering the RPM relay's socket should be a temporary event only. The fact that a spare is a backup, again indicates to a part with a high potential for failure.

BTW: I have no interest in plugging Dave's product other than spreading the word that it is a great modern upgrade for our cars.

[DMCMW Dave]

Since when as the RPM relay been any sort of a "High Failure" Part?

Probably since about 1985. We see lots of bad ones, from just dead to intermittent.

[aludden]

Thank you all! I had read about most of these in various threads, but it's nice to get them all in one place. Let's keep adding to it! :driving1:

[Farrar]

Install low-amp cooling fans and/or Dave McKeen's "Fan Fail Module" replacement; and replace incandescent bulbs with LEDs. Less strain on the car's electrical system, IMHO.

Farrar

[Chris Burns]

Those low amp fans are nice for sure. I was in a Delorean that overheated in a traffic jam once when the 30 yr old fans gave out. My mechanic did the work on the car and after a new set of fans and a radiator the car never overheated again (even on the hottest days!) One quick fix remedy I have been told is just to unplug one fan until you can do the major fix.

[jawn101]

Those low amp fans are nice for sure. I was in a Delorean that overheated in a traffic jam once when the 30 yr old fans gave out. My mechanic did the work on the car and after a new set of fans and a radiator the car never overheated again (even on the hottest days!) One quick fix remedy I have been told is just to unplug one fan until you can do the major fix.

With Dave's solid state fan fail box you can do that from inside the car - just pull one of the fuses. It's a nice little unit for a lot of reasons.

[Rich]

Two more items for the list of mods for reliability improvement. One is an adjustment, not a modification. Both have to do with the doors.

1. Mod: Reduce the probability of eventual door torsion bar failure by checking for contact between either of the torsion bars and the respective rear door hinges. If the torsion bar rubs against the hinge then insert some rubber or thick vinyl between them as a separator to prevent further rubbing and wear of the bar. Check it annually to be sure it's still there and isn't wearing thin.
2. Adjustment: Make sure the door torsion bars are not over-torqued. Many PO's mistakenly compensated for tired door struts by upping the door torque.