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Discussion Starter · #1 ·
Hey everyone, I hopped in the z a couple of days ago, and of course she wont start. Was running perfect two months ago. Now, she'll crank but wont start. My first thought was a fuel problem, because I just got done solving an issue last year where my pump wasn't getting power. So today, I straight-wired the pump to the battery and made sure it was running correctly, which it was. Car still wouldn't start, so I thought okay its the spark. So I started taking out the old plugs, which were pretty well fouled and couple of them actually not sparking, so I thought I had found my problem. After a quick trip to the parts store, and installing 6 new NGK plugs that all sparked, the car still wouldn't start, even with the fuel pump running. I tested to make sure my fuel injectors were getting power, which they were. Tested fuses, they were fine. I removed a plug, and noticed that it wasn't wet with gas, it smelt like it though. Shouldn't it theoretically be wet with gas if fuel was getting to it? Could this be a low fuel pressure issue? However even with starting fluid, she wont start.

Thanks all!
 

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it sat for 2 months? the fact that the plugs were fouled is a clue, how old were they? was ANY thing done to the car from last time it ran perfectly? are there any mods to car? do you have gas in it (no joke it happens). How is the battery?

while cranking see if you can hear the injectors clicking. use a stethoscope while someone is cranking for you.
 

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I second what Dave said - check and make sure all the injectors are firing during cranking. Either grab a stethoscope or use a long screwdriver (put the tip on the injector and bring the handle to your ear - you SHOULD hear them clicking.
 

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Remember to check fuel PRESSURE. Also if it is real cold outside and you have been cranking on the car without starting, you might want to disconnect the cold start injector for a bit. I did my father-in-law a FAVOR by changing the plugs on his 75 (way back in the day when it was new, and before I new ANYTHING about F/I) and was happily cranking it over without plugs then put the plugs in and I FLOODED IT. (Ok, the specifics may be wrong but I remember is was very cold, like mid December, and I was cranking without starting..... but the cold start injector was working REAL well. ......hey it was 1975.......or 6
 

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Discussion Starter · #5 ·
Okay, I think you guys are right. I had someone listen to the injectors and feel them while I tried starting the car, he said he didn’t feel or hear anything. I was wrong about my plugs being wet with gas, because after I took one out today after running the fuel pump and trying to start the engine, the plugs were completely dry. I tested the connectors to the injectors and they’re all saying battery voltage, about 12.5V. So I guess they’re just not pulsing?
 

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time to break out the FSM start checking things.
I would start with Pin 10 of the 35 pin connector. should have 12v with ign on neg to ground.
Its pointless to start throwing out suggestions on what to check or worse start replacing parts until you use the FSM check list.
 

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Not likely and you shouldn't be getting 12v at the injector plugs. That's what the dripping resistor does - drops the voltage. You're skipping around. Get the FSM and go through the tests.
 

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Discussion Starter · #9 ·
Thanks everyone for the suggestions, I’ve been too busy with college to mess with the Z, but I’ve had time to test the pin connector with the fsm. The suggestions here were right, pin 10 is acting strange. First, it won’t ground to the body metal when tested for continuity as it should stated by the fsm. Secondly, when tested for voltage it failed as well. I tested the ecu pin 10 wiring from the ecu to the efi relay, for continuity, just to make sure that section of wiring was good, and it was. Then I removed the relay and performed the tests in the fsm, by connecting 12v to the specified pins and listening for clicks and testing continuity, it passed all the tests. I tested the positive wires that run to the relay for voltage, and they all passed. However, when I plug the positive connectors into the relay, and then test the relay pin that leads to ecu pin 10 for voltage, it doesn’t show any. So either I’m reading that backwards, or am I looking at a broken relay?
 

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Pin 10 ecu harness positive probe of DMM, neg probe to ground (body of car, metal screw) should be 12v ign on. A test light will work as well, better imho since it will load the circuit. Same test, ground clip lead to body, prob of test light to pin 10 of ECU wire harness.

Make sure you are disconnecting the battery when removing ECU from the harness and reconnecting the ECU.
Make sure the battery is connected and IGN is in ON when doing Test.
 

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Discussion Starter · #11 ·
Yeah pin 10 is neither showing continuity when grounded to the body, or showing voltage with ign on. I know the relay it runs to is good, I even swapped it out with another known good relay, and no change. In the fsm wiring diragram, it just shows a black wire running from the relay to the negative pole on the battery, so besides untaping the wiring harness and checking the wires, I’m not really sure what the fsm wants me to check at the battery end.
 
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