Fuel Injection
Posts about fuel injection systems and related topics.
748 topics in this forum
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- 3 replies
- 2.8k views
I disabled my cold start injector a little while ago by pulling off the electrical connector. Just to see how the car would perform on cold starts without it, and decide if I really needed it or if I could do without. I've not used the car much since I disabled it, but the results are not that dramatic. The cranking times when "Pennsylvania cold" are definitely longer than with it connected, but they are not "objectionable". I'm assuming that if I were in Canada or Wisconsin, I wouldn't be able to get away with this, but here in PA it seems to be OK without. This is a fair weather car for me anyway and I don't expect it will get a lot of winter usage. I'm thinking I may r…
Last reply by Captain Obvious, -
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So if anyone remembers me, I had a car that was jerking and running a bit unsteadily (75 280z), and was able to rectify this by cleaning a bunch of the electrical contacts. I've since done some more homework and determined that the primary culprit was the TPS; my TPS seems to get dirty very easily (and usually fouls a day or do after a rainstorm if I don't clean it immediately after). This will either cause an unsteady idle, or uneven performance at more than 3/4 throttle, so it's easy to diagnose. I have the cover securely on the TPS, so I don't know how it gets fouled, but as long as I spray it with contact cleaner every couple months, the car runs fine as my daily dri…
Last reply by NiiChan GT-R, -
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Hi, 1976 280z. Was starting good and running fine. Lots of vacum hoses replaced on refresh as well as AFM and air regulator. Recently problem started,, would not start on several attempts. Had to do it 3-4 times then would start and run fine. After starting cold engne goes up to about 1100 rpms and as it warms comes down to 800 where set. One thing I do not hear is the relay click when I turn the key one before starting and I don't hear the pump come on. Haven't done fuel presure bleed down test yet, but believe the pump not coming on to bring up presure is the problem. Looked in FSM and didn't see how the system works. Am I correct that the pump should spool up first …
Last reply by FastWoman, -
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I know there have been 48 million posts on this subject but i just need simple answers/opinions. i have a 1977 280z 5 speed all original. after driving and left for 15 ish minutes the car will either start and run at roughly 400 rpm or more recently it will start sputter and die. now iv heard this may be vapor lock or a problem with the cold start injector. either way what can i do to solve this problem? iv heard of wrapping the fuel rail to make sure it doesnt get to hot, and heard about disconnecting the cold start injector. i need help! this is a very embarrassing problem and id love to solve it as soon as possible. thanks!
Last reply by FastWoman, -
- 7 replies
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I have been working on the '77 280z I picked up a few weeks ago and went about removing not 1 but 2 aftermarket radio harnesses. While doing so I saw a previous owner had used 2 wires that were spliced in to the ignition switch at the key to 2 wires going in to the fuse box, a blue w/white stripe wire and a white w/blk stripe wire. I removed the wires and repaired the splices in the wires going in to the fuse box. From what I have read so far this was done either because the fuel pump relay is out or the EFI relay is out. How would I know which relay is out? Due to the cost of the relays is this a safe method of powering the fuel pump and EFI system? My guess is no.…
Last reply by Hardway, -
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The stock engine harness is basically garbage. I have yet to see an original one where the shielding on the Dizzy side is still in good condition but given that it's exposed to the elements it's not fair to expect it too be. There is basically no shielding on anything other than the O2, the fuel pump control (don't care with MS) and the dizzy. An auto engine bay is full of EMI that can cause problems with any electronic fuel injection system. Look at a 240SX wiring diagram and you'll see that the manufacture shields almost all of the sensors. I've been researching a few other after market engine harnesses for other engines to see what the other guys have. The 2JZ, etc hav…
Last reply by FricFrac, -
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A little new to the sight but have posted previously. I have recently purchased a 1976 280Z 2+2 and use it as a daily driver. It runs and starts fine but about once per month it stops running while I am driving. It starts to sputter (if that a word) and acts like it wants to keep going and then dies. Occassionally if I keep pumping the gas pedal it will pull through and run again for several days but others it just dies. If I try and start the car immediately it will try and turn over but not start. If I wait an hour or so it will almost always start. I drive the car 3 miles to work and 3 miles back daily and not much more driving. My original thought was rust in t…
Last reply by Zed Head, -
- 13 replies
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Have 2 injectors leaking on my 77 280. Took a few days of troubleshooting to figure out why my Z seemed like it was loading up on a cold start up. Pulled the plugs yesterday after Z sat over night and found 2 of them wet with fuel. So, I can't decide if I want to just replace them or have a fuel injector service done on the car or pull them and send them in to be rebuilt. Anyone have negative results? One's that you regret? Thanks.
Last reply by 240260280z, -
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I've got a '78 280Z that starts and runs perfect until the temp come up to normal then it stalls or hesitates when coming off a stop. Once I get it up to speed (2000 RPM or better) it seems to run OK. Any ideas??
Last reply by grantf, -
- 13 replies
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I had the "hot start" problem return this fall. The fuel pressure also dissipates over a few hours after shut-off. The PO removed the stock fuel rail "trombone" pipes and replaced them with a single billet rail. There is a Summit Racing pressure guage on the rail. With engine started and running, there is approx. 29-30 psi. Without vacuum to the FPR- approx 36 psi. I knew that the loss of fuel pressure, over time, can be (a) leaking: - check valve in the fuel pump - cold start valve - FPR - injectors The pump is fairly new, so I added a Parker check valve down stream, between filter outlet and rail inlet. No change. The CSV was original, so I replaced it.…
Last reply by Zed Head, -
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Ok, so in my "How weird is this" post Im trying to understand why my fuel pump is energized with the key in the "on" and "start" position. It's a 5/77 280. The fuel pump shut off is different in the 8/77-78 models. I don't have much time to spend on the Z these days so what little free time I have is dedicated to finding this problem. When I test connectors 39 and 36 (AFM still hooked to 7 pin connector) for the fuel cut off I get 7.19ohms with contacts open and closed. I should mention that I am connecting my ohm meter to the 39 and 36 connectors inside the AFM. Just behind the black cover. I should get no reading when the contacts are broken. I even physically made and …
Last reply by rcb280z, -
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I have spent a lot of time researching this issue both on this site and my car. I have a 5/77 280Z. It is running really good. Fuel pressure is correct (just leaks down over several hrs) I can live with that for now. I just prime the pump in the morning (when I do drive it) before starting it. I checked engine vacuum and it's at 19. The issue is after priming fuel lines for about 5 seconds (i have a pressure gauge in line) it doesn't start right away like it used to. It cranks probably 5-7 times and then fires. The idle is around 700 rpm. I have to throttle it around 1300 rpms for a couple of minutes before it will hold there until warmed up. After that it idles at 800. …
Last reply by rotorgoat,
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