OG Z Posted January 25, 2011 Share Posted January 25, 2011 So I was driving (1973 240z with N42 L28) back from LA and I decided to enjoy some spirited driving before state line, I was in 3rd gear at around 6k when all of a sudden my headlights turned bright into what seemed like 12k HIDs along with the gauges for a slight moment and then all power shuts off. As I pull over the car still idles for a minute, bogs and shuts of as well. The smell of burnt plastic began coming from the passenger side. The car was not able to start up again. I towed it home and since then... Ive checked oil, spark plugs,wires, distributor, coil blaster, alternator, replaced rotten terminals, found out my battery only had a 2% charge and my fuel lines are not getting any fuel.. so i borrowed a battery, poured some gas into the carbs manually, started the car and SHAMWOW the car turns on like magic! The previous owner of the car told me he had upgraded the fuel pump recently. So Im thinking relays or fuses because all my lights work as well except for the headlights and the rear corners, which would also explain the burnt smell coming from the passenger side after I had made the fuel pump work harder. So I am not too familiar with these cars and was wondering if someone could help with this as to whether I might be right about what could be the problem. I want to get out and drive it to some meets already. Also where the hell is the relay or which one is which because my passenger side looks like a bowl of spaghetti. Thanks Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted January 25, 2011 Administrators Share Posted January 25, 2011 Just a reminder if you haven't read the forum rules linked in the upper right corner of the page yet; HybridZ rules and guidelines ... 3. Please make a good effort to post a topic "subject" title that is pertinent and descriptive of the subject that you want to convey. When you post a thread with a title like “I need help†this makes it harder for the next guy to find what he is looking for when they try to search the database. It is impossible to know what that thread is about so it must either be skipped over or opened to check the content. The title of your post is not the place to be VAGUE!!! ... As for your issue, first thing that comes to mind is possible battery shorting to the hood or fender stiffener if the battery is not tided down. The bright lights after 6k rpm, that indicates possible alternator and/or voltage regulator issue. Hope that helps, Paul Quote Link to comment Share on other sites More sharing options...
OG Z Posted January 26, 2011 Author Share Posted January 26, 2011 Well I took the alternator to autozone to get it checked out. They told me that it was fine along with my battery. All my bulbs got burnt out by the voltage spike. My main issue at the moment is fuel, there is no fuel getting to the lines. So I bypassed the fuel pump and hooked it up to a battery, the result.. fuel pump did not work. So Im going to the junkyard to get one off a 280zx tomorrow. Can the fuel pump get fried in a voltage spike such as the one in my case? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted January 26, 2011 Administrators Share Posted January 26, 2011 Excessive voltage spikes can damage anything electrical if high enough and long enough. If your car is still using the pre '78 external voltage regulator, that most likely is the culprit for allowing the alternator to pass more than 14 volts to the cars electrical system, I think that is probably the only way more than 14 volts could get out of the alternator, locked/malfunctioning voltage regulator. Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 26, 2011 Share Posted January 26, 2011 (edited) If you're running carbs the ZX fuel pump will be overkill and might cause problems, unless you a have the right fuel pressure regulator. ZX's have fuel injection,using a high pressure pump. You need a low pressure pump or high pressure with a regulator, for carbs. It might be hard to find something suitable in the junkyard since most carbed engines use mechanical pumps. To BRAAP's point - When you had your alternator tested, did they tell you if it was internally regulated or not, or mention if it was a stock 1973 alternator? Converting to internally regulated modern alternators is pretty common. 6K on an L28 is very spirited driving! Mine runs out of steam at about 4800. I wonder if yours has some performance mods. Edited January 26, 2011 by NewZed Quote Link to comment Share on other sites More sharing options...
OG Z Posted January 26, 2011 Author Share Posted January 26, 2011 (edited) Well they did not tell me anything about the alternator. I am guessing it is a 280zx alternator because I looked at a few engine bay photos of other 240zs and they seem to have the voltage regulator inside a black box by the battery correct?. I looked in my engine bay and i do not have that box. By the way my L28 is using 71 SUs, and I already have a fuel pressure regulator dial which looks kind of old school to me because its just a simple chrome dial. It is currently set at 3.5 Edited January 26, 2011 by OG Z Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 26, 2011 Share Posted January 26, 2011 Waiting for the fog to burn off (Oregon)... Do you mean that you bypassed the fuel pump relay (you said fuel pump)? Connected proper terminals, + and -, right at the pump and nothing happened? It's possible to hook them up backwards. You might have a burned relay and not a burned pump. I have read on this forum of people using a high pressure pump with a regulator so your regulator might be okay with a ZX pump. Not sure. But you don't need the high pressure capability. Sounds like you were looking at a fuel pressure gauge. Did it show 3.5 when the engine was running, now it shows zero? Some low pressure pumps are set at a constant low pressure. Unless you've actually seen the FPR and know you have one, you might end up putting 60 psi through your carbs. Sounds like you have an interesting, modified old 240Z. I would spend some time figuring out what you actually have before swapping parts. If you put a 73 alternator on and the car has been modified for a new alt, you'll have problems. Same with putting a ZX pump on a carbed car. Your car is no longer a 1973 240Z. Quote Link to comment Share on other sites More sharing options...
OG Z Posted January 26, 2011 Author Share Posted January 26, 2011 Yes i hooked up the battery directly to the fuel pump properly and nothing occurred. As far as fuel pump relay, I have been wondering where or what it looks like exactly because I honestly don't have a idea of which one it is.? If someone can give me a link, photo or advice on which relays are which and where the fuel pump relay would be it very helpful. I checked the fuel pump fuse link and that is fine. As far a the 3.5 setting, I did not read it off a gauge, it is a dial that lets me adjust fuel pressure and is set for 3.5. The fuel pump I have on right now is a small universal fuel pump. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.