Noob fuel pump question

[Trousers]

Hey guys. Just joined, and I have a question (go figure).

 

My friend bought a 75 280 z (2+) a while ago, and we've been slowly replacing bits and pieces. We just resealed the tank, replaced the fuel pump, blew out fuel lines, and have replaced the fuel filters/silicon tubing. However, the new fuel pump almost seems to have too much power, as when the car is on "start", fuel begins to leak/shoot out of nearly every joint held together with clamps. We've tightened down each and every joint further than really needs be, but after a minute or two, leaks start forming. It just occurred to me that we did not blow air through the fuel rails up by the injectors, however I think I once heard that 99% of clogs occur in the hard lines underneath the car. Is that correct?

 

That was part one...

 

Part two of my question is: After replacing spark plug wires, spark plugs, ignition coil, dist. cap/rotor, fuel lines, fuel pump, battery cables, we are still getting 0 combustion. The starter goes for days, but there is no popping/sounds of ignition in the cylinders. What are we missing.

 

(note: I searched for things like "fuel pump leaking joints" and "no combustion in chamber" and found little to help our problems. Sorry to start a new thread)

[Eagle_Adam]

not a bad first post newb, only thing u missed was pics :P - i dont know enough about Z's to help but welcome to the fourm. Someone will be able to help you

[Trousers]

Thank you :)

[Npdavies.]

Do you know what PSI the new pump is working at? I'm not entirely sure for EFI, but what I just read (quick Google search) 31-38 seems right? Seems high to me, as I'm at around 3-3.5 PSI.

 

But, this may sound ridiculously simple but bear with me; is your firing order correct?

That stumped me for at least a full day trying to figure out why my Z wouldn't start. Double, triple check it, especially since you replaced all spark related things.

If you're SURE it's correct, is your ignition coil getting 12v?

[datzenmike]

The 280z used a high pressure (about 40 PSI vs. the 3-3 1/2 PSI pumps for carbs) fuel pump and regular gear clamps and hoses may not be up to the job.

 

"After replacing spark plug wires, spark plugs, ignition coil, dist. cap/rotor, fuel lines, fuel pump, battery cables, we are still getting 0 combustion" This sounds like you are throwing parts at it hoping to fix the problem rather than troubleshooting and discovering what it needs.

 

An engine is more likely to fire up if it has three things. Fuel... Spark... and compression.

 

Fuel: crank the motor over and smell the exhaust pipe. Gas? yes or no??

 

Spark: pull a plig wire off and put anold plug in the end and lay on a grounded surface. Crank motor... Spark?? yes or no???

 

Compression: get a tester and check all cylinders and record your readings. A good motor will have over 150 but even 120 will run fine.

[Trousers]

Well this is very true, we kind of have just been throwing new parts at the car to replace the most visibly destroyed parts, mostly killing time until we got the tank back from the sealing guys. I replaced the spark plug wires in the same order they were when we bought the car, but we bought it from a shady dude who had very, very little automotive knowledge (as is becoming increasingly obvious), I wouldn't be surprised if they were not correct in the first place.

 

Question: What steps would I take to test the ignition coil with a multimeter?

[datzenmike]

 

 

Spark: pull a plig wire off and put anold plug in the end and lay on a grounded surface. Crank motor... Spark?? yes or no???

 

 

 

Does it have spark?????

[NiiChan GT-R]

Does it have spark? :D

 

Coils are cheap, replace it.

 

It would not alarm me if the hard/no starting was due at least in part to a combination of auxiliary air regulator issues, coupled to those existing fuel leaks. I would fix that, before I tried too hard to start the car, or doing much else. What kind pf vacuum are you getting? There is the possibility of leaks in the climate control system. Are you giving the car throttle while trying to start it?

[Trousers]

Well, I feel stupid for not checking this in the first place, but we are getting no spark. How would we go about checking the wiring going to the coil with a multimeter (unfortunately, i'm very unfamiliar with multimeters). I feel sorta bad posting without pictures, so even though i'm pretty sure these wont help, thought i'd throw them in.

[Trousers]

[Busta Nut]

Well, I feel stupid for not checking this in the first place, but we are getting no spark. How would we go about checking the wiring going to the coil with a multimeter (unfortunately, i'm very unfamiliar with multimeters). I feel sorta bad posting without pictures, so even though i'm pretty sure these wont help, thought i'd throw them in.

 

It's actually easier with a basic test light. With the key on you should have 12v at the coil, or a very bright light if you're using a testlight.

 

With the multi meter, switch it to DC volts, (-) side to the battery ground. Check for power at the coil. 12v?

 

If nothing, check fuses. If fuses are good you might need a wiring diagram to check for power from the ignition switch and ballast resistor(ceramic piece next to coil in pic).

 

This is where a testlight is easier.... If you have power at the coil, hook the test light to battery (+). Touch (-) side of coil and crank the engine. Light should blink indicating signal for spark is present. If this is the case, you need a coil. If no signal, then could be a sensor issue.

 

Welcome and Good luck!

[Trousers]

Well after trying the instructions, this is what we got. A light that slowly disappeared..

 

http://s24.photobucket.com/albums/c3/yospoe/?action=view&current=VID-20120522-00001.mp4

[Trousers]

A couple questions (because electrical work and wiring will forever confuse me). When taking a test light to the ignition coil, the bulb lights up when it touches both the positive and negative sides. Is this bad? It seems like one side should be grounded and should therefore not create a complete circuit. I'm not sure if I understand this correctly. We've also tried putting the test light into the short spark plug wire that connects the coil to the distributor, and the light does not light up. I hope this helps to clairify our problem.

[ggzilla]

On an early 280Z, you will not get 12V at the coil while it is running. Maybe you would when it is not running. It uses a Resistor to cut the voltage to the coil lower (even though it has electronic ignition).

 

If you replace the coil, get rid of that MSD Blaster coil and put a genuine 280Z coil on there (Hitachi or Hanshin). The specs are a little different from other Datsun coils.

 

In your photo, it looks like the coil high tension lead is loose. Do a double-check. Push it firmly into the coil, pull the other end out of the distributor cap, put an old spark plug in the end and lay on a grounded surface. Crank motor... Spark?? yes or no???

 

If no, inspect the coil lead carefully for cracks or burns. Especially check the metal ends of the lead inside the boots. If they are corroded, the lead may be bad. It should have no more than 12,000 ohms per foot resistance. Replace it if it is bad. Or temporarily swap one from another car on there as a test

 

If the lead is good, but still no spark, replace the coil.

[Busta Nut]

A couple questions (because electrical work and wiring will forever confuse me). When taking a test light to the ignition coil, the bulb lights up when it touches both the positive and negative sides. Is this bad? It seems like one side should be grounded and should therefore not create a complete circuit. I'm not sure if I understand this correctly. We've also tried putting the test light into the short spark plug wire that connects the coil to the distributor, and the light does not light up. I hope this helps to clairify our problem.

 

I'm assuming that you do NOT have spark. Do you have power at the coil?

 

Hard to see if you were on the coil or resistor in the video....and it's really short. Is the light blinking and just goes out?

 

If one side of the test light is on the (-) and the other on the (+) of the coil, then yes, it's normal. The ground completes the circuit. Signal from your distributor grounds the coil which then emits a spark. This would also indicate that you do have power at the coil.

[Trousers]

On an early 280Z, you will not get 12V at the coil while it is running. Maybe you would when it is not running. It uses a Resistor to cut the voltage to the coil lower (even though it has electronic ignition).

 

If you replace the coil, get rid of that MSD Blaster coil and put a genuine 280Z coil on there (Hitachi or Hanshin). The specs are a little different from other Datsun coils.

 

In your photo, it looks like the coil high tension lead is loose. Do a double-check. Push it firmly into the coil, pull the other end out of the distributor cap, put an old spark plug in the end and lay on a grounded surface. Crank motor... Spark?? yes or no???

 

If no, inspect the coil lead carefully for cracks or burns. Especially check the metal ends of the lead inside the boots. If they are corroded, the lead may be bad. It should have no more than 12,000 ohms per foot resistance. Replace it if it is bad. Or temporarily swap one from another car on there as a test

 

If the lead is good, but still no spark, replace the coil.

 

 

(Quick note: the spark plug wires/ignition coil are brand new) So I just tried putting the high tension lead (I think thats the short spark plug wire, right?) to an old spark plug and laid it on the valve cover and got no spark. Because I wasnt totally sure if the valve cover is grounded, I also tried it on the intake manifold and then on part of the engine bay frame by the intake and still got not spark.

 

I'm assuming that you do NOT have spark. Do you have power at the coil?

 

Hard to see if you were on the coil or resistor in the video....and it's really short. Is the light blinking and just goes out?

 

If one side of the test light is on the (-) and the other on the (+) of the coil, then yes, it's normal. The ground completes the circuit. Signal from your distributor grounds the coil which then emits a spark. This would also indicate that you do have power at the coil.

 

In the video, the test light was hooked up to the (-) and was put on the (+) side of the coil, and the light would remain on, until we tried cranking the car over, and then after 4 or 5 seconds, the light would slowly go out. I hope this all helps.

[ggzilla]

At this point, I'd swap a different coil in there, to see if it fixes the problem.

 

Btw, Pick-n-Pull in SLC has a 1977 280Z right now. I think the coil is the same (1978 coils are different).

[Trousers]

hmmmm. Well, we just tried the old coil, only now we get one tiny little spark right as we stop cranking the motor over (however, this is only when we run a plug straight from the coil via the high tension lead. We tried hooking the coil to the distributor and then leaving a grounded plug out and we got no spark). I suppose this is progress?

[ggzilla]

Yes. Temporarily run a jumper wire from Bat + to the coil + and see if the engine will fire up. Don't connect it for more than a minute like this as the coil will get too hot.

[Trousers]

So I was hoping my friend would respond with our results (as he was the only one there when it happened), but I will try and describe what he described to me. He hooked the cable from Bat + to Coil + and quickly ran to start the car (with both of them connected) and apparently heard it crank for a moment, then what I've heard described as a "Pop" and/or a "Fizzle", and then the motor stopped, and then there was no power to be had for the radio, headlights, interior, nothing. Any idea what happened? I haven't been back to look personally since it happened (friday I believe).

[ggzilla]

Sounds like a fuse blew. Check the fuses under the dash.

[Busta Nut]

Fuse dude.

 

 

 

Actually.....fuses!

[Trousers]

Thats what I thought, but after scanning the fuse panel and the two fusable links near the battery, I see nothing blown. Are there other fuses that could have been fried?

[Trousers]

hmmmmm, now an unusual thing has happened. We thought that a fuse had blown. Then my friend took the battery off, cleaned the terminals, hooked it back up, and we got accessory power. The radio came on, the fuel pump turned on (and stayed on consistantly, which was weird. Isn't it supposed to shut off after being on for about 30 seconds on acc?). Then we tried to turn it over, and everything shut down. The car would not come back on until jeff took the cables off the battery, and put them back on. Everything would also shut down when I tried turning on the headlights. What on earth?

 

(side note: at the moment, with things being weird as they are, we tested to see how much power was getting to the coil, and we are getting 7V to the positive. 5V to the negative.)

[ggzilla]

This is very common, not weird at all. This is the number #1 with cars, even new cars. Clean the battery cables.