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Discussion Starter · #1 ·
I have an 78 280z. Usually runs great. Sometimes after driving it for a while it just stops running like you turned off the key. In about 20 minutes or so it will start and run fine and in about 20 minutes it will stop again. Is there a temperature sensor some where that tells the engine it is getting hot and tells it to shut off? I put an aluminum radiator in it a couple of years ago. I never gets hot. Could it be a dirty connection some where? Maybe a temperature sensor I can replace? HELP!!!!!
 

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Do you have a stock TIU ignition or ZX distributor?
Either way, carry a can of dusting air. When the engine stalls, hold the can upside down so it sprays out liquid. Spray it on the TIU in the passenger footwell or the ZX matchbox module (whichever you have). Also spray the ignition coil. If the car starts right back up, you have an overheated component in your ignition system.
 

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I have an 78 280z. Usually runs great. Sometimes after driving it for a while it just stops running like you turned off the key. In about 20 minutes or so it will start and run fine and in about 20 minutes it will stop again. Is there a temperature sensor some where that tells the engine it is getting hot and tells it to shut off? I put an aluminum radiator in it a couple of years ago. I never gets hot. Could it be a dirty connection some where? Maybe a temperature sensor I can replace? HELP!!!!!
I had a 77 2+2 with a new NOS EFI harness installed do the exact same thing, long story short I narrowed it down to the Fuel Pump/Main EFI Relay under the instrument panel, drivers side above the hood latch pull handle. To remove it from the car, disconnect the bat (-), demate the two connections. Remove the two 6mm screws securing the Relay. Carefully open the Relay by prying the swagged tabs of the Relay housing to free the phenolic circuit board. Inspect for burnt or loose solder joints. You can also test the Relay for continuity and while biasing the Relay coils using a 9v battery and test leads with alligator clips in accordance with the FSM. If you need to, you can dress up the contact surfaces for both Relays with fine emery cloth or equivalent by pulling a small piece of emery cloth or fine grit sandpaper through the contacts several times to remove oxidation. Clean contacts with electrical cleaner to restore full functionality. Reinstall and secure the circuit board into the Relay housing. Reinstall it in your Z in the reverse order of removal.

Most likely what is happening is that you are loosing your 12V power to either your fuel pump or the ECU is loosing its 12V power source due to worn or oxidized contacts.

ZCarSource.com has a new, modern replacement Relay for our Bosch L-Jetronic EFI used in BMW’s I believe, check it out!

My 0.02 cents
Cheers
 

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I had a 77 2+2 with a new NOS EFI harness installed do the exact same thing, long story short I narrowed it down to the Fuel Pump/Main EFI Relay under the instrument panel, drivers side above the hood latch pull handle. To remove it from the car, disconnect the bat (-), demate the two connections. Remove the two 6mm screws securing the Relay. Carefully open the Relay by prying the swagged tabs of the Relay housing to free the phenolic circuit board. Inspect for burnt or loose solder joints. You can also test the Relay for continuity and while biasing the Relay coils using a 9v battery and test leads with alligator clips in accordance with the FSM. If you need to, you can dress up the contact surfaces for both Relays with fine emery cloth or equivalent by pulling a small piece of emery cloth or fine grit sandpaper through the contacts several times to remove oxidation. Clean contacts with electrical cleaner to restore full functionality. Reinstall and secure the circuit board into the Relay housing. Reinstall it in your Z in the reverse order of removal.

Most likely what is happening is that you are loosing your 12V power to either your fuel pump or the ECU is loosing its 12V power source due to worn or oxidized contacts.

ZCarSource.com has a new, modern replacement Relay for our Bosch L-Jetronic EFI used in BMW’s I believe, check it out!

My 0.02 cents
Cheers
Your solution would only be causing the OP to buy parts that are not used in his car. The fuel pump & EFI relays changed between 77 & 78. Check it out!
 

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1983 280ZX Turbo
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Do you have a stock TIU ignition or ZX distributor?
Either way, carry a can of dusting air. When the engine stalls, hold the can upside down so it sprays out liquid. Spray it on the TIU in the passenger footwell or the ZX matchbox module (whichever you have). Also spray the ignition coil. If the car starts right back up, you have an overheated component in your ignition system.
If the distributor has a module mounted on the outside, this is the answer. They become heat sensitive and fail when the car heats up. I diagnosed mine by carrying a Thermos of icewater, waiting for the engine to fail, then pulled over and poured the icewater on the module. Started it up and drove away.
 

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Discussion Starter · #6 ·
Do you have a stock TIU ignition or ZX distributor?
Either way, carry a can of dusting air. When the engine stalls, hold the can upside down so it sprays out liquid. Spray it on the TIU in the passenger footwell or the ZX matchbox module (whichever you have). Also spray the ignition coil. If the car starts right back up, you have an overheated component in your ignition system.
Thanks for your suggestion. Where is the TIU on a 78 ? Thanks
 

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Discussion Starter · #7 ·
I had a 77 2+2 with a new NOS EFI harness installed do the exact same thing, long story short I narrowed it down to the Fuel Pump/Main EFI Relay under the instrument panel, drivers side above the hood latch pull handle. To remove it from the car, disconnect the bat (-), demate the two connections. Remove the two 6mm screws securing the Relay. Carefully open the Relay by prying the swagged tabs of the Relay housing to free the phenolic circuit board. Inspect for burnt or loose solder joints. You can also test the Relay for continuity and while biasing the Relay coils using a 9v battery and test leads with alligator clips in accordance with the FSM. If you need to, you can dress up the contact surfaces for both Relays with fine emery cloth or equivalent by pulling a small piece of emery cloth or fine grit sandpaper through the contacts several times to remove oxidation. Clean contacts with electrical cleaner to restore full functionality. Reinstall and secure the circuit board into the Relay housing. Reinstall it in your Z in the reverse order of removal.

Most likely what is happening is that you are loosing your 12V power to either your fuel pump or the ECU is loosing its 12V power source due to worn or oxidized contacts.

ZCarSource.com has a new, modern replacement Relay for our Bosch L-Jetronic EFI used in BMW’s I believe, check it out!

My 0.02 cents
Cheers
Thank you for the writeup- I appreciate your help. How would I find the Fuel Pump/Main EFI on a 78?
 

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Thanks for your suggestion. Where is the TIU on a 78 ? Thanks
The TIU is in the passenger footwell, near the fuse box. If you look in the BE section of the FSM, you will see the layout.
It is a box that should look like this:
Circuit component Rectangle Electronic component Electronics accessory Metal


The first thing you need to do is verify what distributor you have since many people have modified their cars.
This is a ZX distributor. It has an ignition module on the side of the distributor. The stock distributor will not have a black box mounted on the side like this.
Auto part Machine Engineering Metal Nozzle



Thank you for the writeup- I appreciate your help. How would I find the Fuel Pump/Main EFI on a 78?
You won't find one. It doesn't have it. The 78 is wired differently. You can read about it in the EF section of the FSM.

You should download a copy of the factory service manual. You can find it in the Xenonzcar link in my signature.
Also download a copy of the wiring diagram from Blues Tech Tips. You'll find it in the electrical section.
 

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Discussion Starter · #9 ·
The TIU is in the passenger footwell, near the fuse box. If you look in the BE section of the FSM, you will see the layout.
It is a box that should look like this:
View attachment 110902

The first thing you need to do is verify what distributor you have since many people have modified their cars.
This is a ZX distributor. It has an ignition module on the side of the distributor. The stock distributor will not have a black box mounted on the side like this.
View attachment 110901



You won't find one. It doesn't have it. The 78 is wired differently. You can read about it in the EF section of the FSM.

You should download a copy of the factory service manual. You can find it in the Xenonzcar link in my signature.
Also download a copy of the wiring diagram from Blues Tech Tips. You'll find it in the electrical section.
Thank you for the response-I appreciate your help.I am now an owner of the FSM. When you were saying I wouldn't find one I guess you meant the black part of the side of the distributor not the fuel injection relay. I guess the relay tells the fuel pump to turn on? When my car stops running it doesn't stumble or act like it is out of gas, it is just like you turned the key off. Is there a component somewhere that senses a high temp and shuts everything off?
 

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1983 280ZX Turbo
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That component could be the module on the distributor, IF it's present. When it fails, your tach will drop to zero and the engine will indeed shut down like you turned the key off.
 

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Thank you for the response-I appreciate your help.I am now an owner of the FSM. When you were saying I wouldn't find one I guess you meant the black part of the side of the distributor not the fuel injection relay. I guess the relay tells the fuel pump to turn on? When my car stops running it doesn't stumble or act like it is out of gas, it is just like you turned the key off. Is there a component somewhere that senses a high temp and shuts everything off?
No. You won't find the EFI relay described by Kevin T.
 

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No. You won't find the EFI relay described by Kevin T.
Steve is correct in that I described the JECS EFI Main/Fuel Pump Relay (P/N: A13-000 001) installed on a 75 - and on late 77 (7/77) Calif and Non-Calif US models.

My apologies I should have read the OP more carefully. Just wanting to help a fellow owner, I gave the wrong advice which wasn’t exactly useful or applicable. Hey, the information is out there now in the ether for anyone else to read (search for) so they can remove, and repair their own OEM EFI Main/Fuel Pump Relay to get or keep another S30 going down the road or at least another possible method for troubleshooting a driveability issue.

I’m not exactly sure when the new add-on EFI/ FP Relay circuit configuration was incorporated. Datsun part date coding to the nearest month notwithstanding. Although a fun factiod; there were actually qty (4) S30 260Zs shipped in late 74 w/ EFI! Yup a 260Z w/o the flattop boat anchors, go figure? Mr K doing his marketing survey I suppose?

And yes the aforementioned BOSCH EFI Main/ Fuel Pump Relay (P/N: 0 332 514 120) is a direct replacement that’s readily available for the early 75-77 JECS Relay noted above if your Relay is Inop and or contacts fried beyond the point of refurbishment due to arcing.

Cheers
Kevin
 

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Your problem sounds the same as the one my stock 1978 has been having. Mine has been dying suddenly, no sputtering, no engine hesitancy before, with tach dropping like a stone to zero (no winddown), and no tach movement when I tried to start immediately after. Restarts right up after it sits for 5-10 minutes, like nothing happened.

I got some advice from an expert based upon my symptoms, and I may have fixed it yesterday by replacing the pickup coil located in the distributor. (I really replaced the original distributor with a rebuilt one I had already purchased because of a faulty vacuum advance, and the rebuild included a new pickup coil.) After swapping the distributor, my car sat and ran 30+ minutes twice yesterday with hood shut and outside temp in the high 80s without any problem, when it wasn't making more than 20 minutes before. Tomorrow morning I'll be roadtesting, and will update results.
 

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Do you have a stock TIU ignition or ZX distributor?
Either way, carry a can of dusting air. When the engine stalls, hold the can upside down so it sprays out liquid. Spray it on the TIU in the passenger footwell or the ZX matchbox module (whichever you have). Also spray the ignition coil. If the car starts right back up, you have an overheated component in your ignition system.
In my 78 Maxima, There was an ignition module on the distributor cap that fails at high temperature. After a minute it came back working until one day it didn't. Check it our if that may be the problem. The cooling spray would help that also. But when your car shuts off in a busy intersection and another vehicle is bearing down on you because they are not paying attention and you have your kids in the car...you will want to get it fixed!
 

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The new pickup coil/distributor seems to have solved my very similar problem. Problem did not re-occur this morning. Drove my '78 stock Z to gas station - 2 or 3 miles away - stopping and starting 4 times until I left there, and no problems. I then drove it for 40+ minutes, at speeds up to 55 mph, without me turning the ignition off, and car performed without a hitch - no dying like I'd been getting after 20 minutes. Then I made a quick grocery stop, Z sat for 10 or so minutes and then restarted and drove 10 more minutes home. No problems at all.

I'm going to declare the problem solved.

For your comparison, I've attached pictures of the distributor I removed, and which show the pickup coil (with its red and green wiring) that seems to have been the source of my problem.

Good luck.

Crankset Automotive tire Bicycle part Vehicle brake Rim
Gas Wood Machine Nut Auto part
 

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I have an 1982 280zx which has exact same symptoms. When driving it randomly shuts off, exactly like key is turned off. It does start back up after 10 mins or so no issues. This happens at highway speeds or in town after 5 mins or 20 mins of driving. It's so dangerous to have it randomly die that I have not driven it in 2 years now which is very sad. I'm not a mechanical car person but I was wondering if anyone that posted about Fury Pilot's '78 z would comment on if any of the fixes may also apply to a 1982. More importantly, if anyone knows a superb z repair specialist in southern/mid Minnesota or Northern Iowa, I would appreciate any leads. I've tried 2 repair experts in Rochester, MN with no luck on this issue. Meanwhile my z sits in the garage unused with only ~90K miles on it.
 

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I have an 1982 280zx which has exact same symptoms. When driving it randomly shuts off, exactly like key is turned off. It does start back up after 10 mins or so no issues. This happens at highway speeds or in town after 5 mins or 20 mins of driving. It's so dangerous to have it randomly die that I have not driven it in 2 years now which is very sad. I'm not a mechanical car person but I was wondering if anyone that posted about Fury Pilot's '78 z would comment on if any of the fixes may also apply to a 1982. More importantly, if anyone knows a superb z repair specialist in southern/mid Minnesota or Northern Iowa, I would appreciate any leads. I've tried 2 repair experts in Rochester, MN with no luck on this issue. Meanwhile my z sits in the garage unused with only ~90K miles on it.
The probable fix has been mentioned many times. Search for "ignition module 280ZX" and you'll find all the info you need. Your ignition module is most likely failing when heat builds up. It's on the distributor and an easy fix.

If no one has figured this out yet, they may be experts on newer cars, but they don't know squat about Datsun Z-cars.
 
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