Zed Head

In other words - yes, we'd like to hear back. We love to see a win. If you can, give this link to your tech. He can download the book and use it to troubleshoot, it covers all years through 1980. There's a whole complete section on electrical tests.

The red wires at the battery have fooled many people. Nissan did that, not a previous owner. I must have looked inside the plug for populated terminals when i was working on my relay. I thought that they could only plug in one way. Having two plugs right at the same spot that can be swapped just seems way too illogical, especially for a part that highly engineered and complex. If I had a car here I'd run out and check, just to be sure it was true. Seems unbelievable, but, apparently it is so. Keep going....

I don't recall any problems getting the right plugs on the right terminals on mine. I think that they are "keyed" somehow. SteveJ, is that a suitable replacement for the Nissan combined relays? Is it available? I think that you were involved in the past in writing up a way to use two Bosch relays to replace the Nissan NLA relay. Maybe? https://www.amazon.com/Bosch-0-332-514-120-Injection-Combo-Relay/dp/B005JCN1M8 The plugs might not be right but they could be made to fit.

The electronic ignition modules (where SteveJ said) degrade over time and overheat as they start to fail. One big clue is the tachometer needle. It will either get erratic, jumping around and not reading right, as the module starts "over-sparking" or it will just drop to zero even though the engine is still turning over, if you have a manual transmission. The distributors are not optical, they are magnetic, variable reluctor triggers. The pickup coils can also degrade and fail. The ECU's will also fail like you described. They usually run really rich, gassy smell, before they conk out. The short answer is that there's a bunch of things that can fail and cause sudden engine stoppage. SteveJ's link is a good cheap upgrade if you decide it's the module.

This might be the super spreader event of the whole pandemic. All a person can really do on the big scale is watch and hope. https://thehill.com/homenews/state-watch/510470-south-dakota-expecting-250000-people-for-sturgis-motorcycle-rally

One easy thing you can do is to apply power to pin 74 at the relay plug. You can jump wires right at the plug to do this. This will test the wiring all the way back to the pump. If you apply power to pin 74 but the pump doesn't run then nothing you do at the relay will help. Run the power through a light or a fuse in case the circuit it shorted. I like to break the big circuits in to small pieces. There is a plug beside the passenger seat that the pump power runs through. You can also apply power there is you get nothing at pin 74.

Chicago is going all remote in their school system. Of course this means that the poorer families will be disadvantaged. https://www.cnn.com/2020/08/05/us/chicago-schools-virtual-coronavirus/index.html

https://www.mdmetrix.com/covid-19-projections

Schools are opening as we sit. Some are already quarantining teachers and students after positive test results. As a bunch of rational thinkers here on our car forum, it's easy to see that it's just not going to work. You can't put a bunch of snot-nosed kids together, or even teenagers, and expect disease to not spread. Schools will be the new nursing homes, disease spreading centers. We won't have to wait for Fall to see the case numbers start rising again. They'll probably be rising again before the end of August, if they don't just keep rising from now.

Just for easy reference.

I didn't mean that in a bad way. Dave WM and SteveJ are both engineers. And, actually, if I had your problems I probably would go through all of the tests shown in the FSM, and probably take the top off of the relays to examine the coils. If I had the time and the work space. I've already done that once with a combined relay and had a switch jumpered on to my working relay in the car so that I could run the pump with a switch or run it normally or turn it off completely for theft prevention. I was just offering the shorter path.

We're contradicting each other here. Oh well. It all depends on what your end goal is. Everyone has their own way of doing things. Having the engine running will keep the battery charged.

It's very common to hot wire the pump for troubleshooting. Wire it to a circuit that is powered by the key or have a switch handy though so that you can turn it off quickly.

I would focus on the fuel pump relay. You have a lot of other stuff going on at the same time. Very distracting. Break the circuit down in to parts. Confirm power to the fuel pump relay. Confirm power on the circuit that is supposed to trigger the relay. If the trigger circuit doesn't energize the relay then you know where to focus. 77 has the combined relay. The FSM procedure is very complex and overdone I think. Like an engineer wrote it! I would just identify the couple of important pins in the plug and measure voltage there.

oops

Does the engine run now? You haven't really described what you're trying to do. Just your incorrect (no offense) thoughts about the fuel pump.

Since orange is a combination of red and yellow it might be that the red pigment is fading over time. Red BMW's and other old cars have that problem in a big way. I've seen red cars that had a cover over them but with parts exposed and the sun will just bleach the red out over the years. Makes for a patchy look, like it's had body work. Maybe it's just old paint versus new.

Take off one of the cowl access covers and take it to Home Depot's color matching machine. Today's tech is pretty powerful, you'll get numbers to compare against. I've found that the internet doesn't really transfer colors well, besides the quality of the phone or camera taking the picture. Who knows what color those really are.

As everyone is saying, this is correct. The pump does not get power when the key is on. Here's the pump test from the FSM.

Isn't the connection made in the seat belt latch itself? Latch it the buzzer turns off, open it the buzzer turns on.

30,000 person experiment. I'm so glad I don't have to make today's decisions. I just needed to watch my bank account and avoid getting sick since I had no insurance. Big university classrooms are packed. This can't end well. https://www.wdrb.com/news/university-of-kentucky-begins-performing-covid-19-tests-on-30-000-students/article_ccd25f62-d5a5-11ea-8cda-e76d7ab72ba4.html https://covidactnow.org/us/ky/county/fayette_county?s=819151

It's getting closer. 52 year old athletic type with some mental skills. Let's see how he does. https://www.espn.com/nfl/story/_/id/29589969/eagles-doug-pederson-extremely-optimistic-season-positive-coronavirus-test-result https://en.wikipedia.org/wiki/Doug_Pederson

This is why someone like me would just go to the wrecking yard and get some 1995 Pathfinder thermistors. http://www.sfu.ca/phys/231/archived, 041-061/061/data_sheets/thermistor.pdf

I would bet that zcardepot sourced that thermistor from a modern vehicle. Maybe one with resistance in line. Probably gave it a short time frame test and went to market with it. Might be fun to go to the wrecking yard and tear up some fuel tanks.

Has to have been posted already but just in case...