Funky-P

I was wondering if that might be a possibility, I had to do that for my rx7 to get the wipers running. I'm going to check to see if I'm even getting power to the relay first, I don't think I did that yet for some reason.

It looks like the relay has been replaced before (written on it in sharpe is '78 fuel pump relay) making me more skeptical that it is the problem.

Today was the first day I had to get to check out the relay due to school, work and the weather. We tested the relay based off of the 280z fuel injection book. What we found was that the relay did not click when ignition is turned to start, so we checked the circuit between ECU pin 4 and ground for battery voltage when the starter solenoid and cold start valve were disconnected, and ignition was turned to start. We did not get the twelve volts, more like .7 to .01 volts. The fusible links appear to be okay. So it looks like the power relay/fuel injector relay is not working, this relay is surprisingly expensive as well, I'm wondering if there is anything else we should be checking before buying one esp as it looks like it has been replaced before. The relay has 78 fuel pump relay written in sharpe on it is why I assume it has been changed before.

Hmm I'll take a look its definitely possible with all the rewiring that has been done. Probably wont have time though until Friday.

So some more information on what I've been doing/how I've been testing: Based on page EF-22 I checked the Electronic Fuel Injection Relay: Fuel Pump Relay, by checking continuity between ECU pin 20 and grounded body metal. This checked out fine. From the same page I checked the Air Regulator and Fuel Pump circuit by checking continuity between pin 34 and body metal. Again this was fine. Based off of page EF-46 I checked the continuity of the circuit from fuel pump to air regulator to the ECU harness, connector 34. This circuit also checked out fine. The fuel pump itself works when connected straight to voltage, so I'm at a bit of a loss as to why it doesn't come on at the START position. Unless the relay is bad, but the only test I see for that in the FSM is the ecu harness point test. Is there a good way to actually test this relay on its own? I tested the injector pulse using the steps outlined on EF-52, where it describes connecting a small lamp to the harness of injectors 1 & 4 (not simultaneously) and cranking the engine to see if the light pulses. The light did not come on at all, and I tested to make sure the light functioned. Is there any other reason than a bad ECU for this issue? A previous owner has messed with the wiring, there's a new ignition wired in and the connectors to the battery are rewired as well as some various other things, so its a bit more convoluted than it should be to try to get things tested individually. I think it would be a bit more of addictive car if I could get it started, thanks for the suggestions though guys.

The continuity for to the fuel pump checked out, so we went to check the ECU. Using the lamp to injector harness method it appears that the ECU is not functioning properly as we got no pulse. The car came with two ECU's, both of which gave the same result. Is there any other situation that would prevent the injectors from getting pulsed? It seems a little unlikely that both ECU's are bad, but I wouldn't be all that surprised.

Okay so we finally had some time to get some more work done today. We found that the spark plugs were no good so we replaced and now we are getting spark. We replaced the water temperature sensor and the continuity check for that circuit is now good. We did the sound check for the fuel pump, didn't get any sound. We removed the fuel pump and checked it by just running it directly off the battery and it worked. So it seems the circuit to the fuel pump is disrupted, tomorrow we are going to try to trace the circuit and hopefully find out what the problem is. I think the cold start valve may be no good as well, when I ran it off the battery before disconnecting the fuel pump I didn't notice any sound or anything. I'll look into that further as well I guess. I think we're getting closer to getting this thing started, or at least I hope so.

I'm checking the continuity based on the continuity check setting on the multimeter, so it doesn't give number values. What I figured today was that the afm may be bad, but not likely to be the main problem. I did not recheck the connectors directly on the afm, but the various connectors on the harness to the ECU. Yes I've been referencing the wiring diagram as well. It smells very strongly of fuel in the components. Could not check the spark yet, I needed to get a tool first, so its next up. I'm not sure what the process is for checking the actual fuel pressure is, but I will check as to whether the pump itself works. I've been going over the issues in the order specified in the FSM, hence checking the continuity circuits before the pump itself, which was my original thought to do. I probably wont have time to do any more checks over the next few days.

Today we went back over and tested all of the connections listed in the engine fuel section of the fsm. While I don't it still seems like the afm is not showing the right resistances I don't think it is preventing the car from starting as all the pins to the ECU (6&8,7&8,8&9) all show continuity as well as those to the fuel pump contact points (10&20). All the circuits checked out for continuity for the Fuel pump relay, the air regulator and fuel pump, the ground circuit and the throttle valve switch. The problem appears to be the water temperature sensor whose circuit does not have continuity. I guess we will try to replace that and hope it is the sensor itself rather than a wiring issue. The troubling thing is that after further investigation it still appears the negative terminal of the battery goes solely to the body to ground without connecting to the harness at all. There has been some rewiring of the harness and connections in various places, likely having to do with the alternate ignition wired in.

OK, I'm going to start over with the testing from the beginning and taking notes as to what all the readings are and try to check everything you've suggested. Then I'll post up my findings.

Thanks for the info guys. We went in and plugged it back in and checked the flap action which was good, but didn't recheck the resistance. It sounds like you are saying that it has to be plugged in to be getting the right resistance readings then? When I measured it originally I had it disconnected, which is how it is shown on EF-52. I went through though and checked the water temp sensor, the fuel pump contact points, the EFI relay, the ground circuit. The fuel pump contact points were okay, but everything else was showing an open circuit. We noticed something that seems to be wrong, the negative terminal of the battery looks to just be connected to the starter and then to the body. Two grounds and no harness connection, which struck me as odd and clearly is not what the wiring diagram shows. So I guess tomorrow hopefully with some daylight we can try to figure out whats going on, there is a lot of rewiring done by the PO which may be the root of the problems. I haven't had to deal with this sort of electrical issue before so I definitely appreciate the help.

I'll have to check the tps and temp sensor, I just was checking in the order the fsm has to check and stopped at the afm as it was giving bad readings. One thing is the engine will crank fine, but not start and it smells real strongly of gas almost as if it were flooded even though that doesn't seem like the issue.

Hey all, I just picked up a 77 280z a couple of weeks back which doesn't start. In trying to determine why I've found that the AFM failed almost all of the testing specs. I'm not sure whether this is due to tester error or not, but its an expensive part so I'd rather be sure that its the problem before trying to replace it. I was wondering if anyone had any advice or a functioning one that we could borrow to make sure that it is the issue. Thanks, hopefully we can get this thing running soon.