conedodger

LJet which is the system on the early EFI Z and many other cars of that period were 'batch fired' in other words, the injectors fired at the same time in groups irregardless of what position the piston was in. It really didn't matter that much because the real magic happens when the spark comes and the spark fires individually for each cylinder. What Zed Head is saying is that if the problem is the injector harness, you obviously have some injector wires that are good. If you switch the leads between the cylinders you will fire the injector that wasn't previously firing. It really comes down to checking the resistance of each lead. There is a sequence for this in the FSM. It will tell you to touch one end of the multimeter to a numbered position at the ECU plug and at the plug end of a particular sensor or injector. It will tell you a range of resistance that the factory considers 'serviceable'. You can put a set of plug wires on if you wish. They are as you said, cheap.

Your compression numbers aren't all that bad. Check the resistance of your spark plug wires. What are their condition? Just from some of the things you're saying it sounds like you're using a rather expensive method of fixing a problem. One that eventually works but costs lots of necessary money. Figure out what's wrong, then buy the parts. Don't throw parts at it until something works. I am also a bit worried about your mechanics. A valve adjustment comes before any tuning. Otherwise, you are tuning out the problems caused by the poor valve adjustment. And spending money you will have to spend again once they are adjusted. I suspect you have an electrical problem. Someone above mentioned pulling plug wires one at a time and listening to the engine. No change? Probably no spark. Another way is to check with a multimeter to see what the resistance on the plug wires are. If you're feeling frisky, there are resistance readings in the manual for all portions of the EFI harness. Check all that before you spend more money.

It can be done. I suspect though that you are going to have to source another AFM without the switch. My recollection may be faulty but I thought that the fuel pump switch came on later AFM in the 280Z series. If I am right, you may not have the correct one in the first place. I had a 'how to' on doing this modification on a website I had in the 1990's called PlanetZ. You should be able to unscrew the existing circuit board and install the NA one. Now, having said this, I just want to say that you should prepare yourself to figure some other method of operating this engine. There is not enough flexibility in the LJet system to make it run well under load in all circumstances. This is particularly important given the expense of your engine. There is someone selling a set of Extrudabody throttle bodies with manifolds and fuel rail in the classified section. Not cheap, but probably cheaper than what you might do to that engine trying to cobble together an old LJet system to run it. I would run it with SDS + closed loop O2 sensor. Good luck though! I have seen stroker motors in Z cars at the autocross events and they are amazing!

I agree with cozye. Adjust your valves and do a compression and leak down test.

Ok, after reading your other thread I have a bit more to work with. You state you have the FSM. Good. In there you will find a proceedure for troubleshooting and tuning. You must follow the procedure in the order they prescribe. One thing effects the next. Don't follow the path of least resistance. Some people will check the fuel pressure because they don't know how or don't have a feeler gauge for the valve adjustment. Don't get caught in that trap. Very little about this LJet system has adjustment. Mostly it requires service on vacuum and injectors. If you want to continue your fuel system refresh (I would from what you described) I would pull the injectors and send them out for a rebuild and calibration. Sticky injectors will increase your HC and CO especially at idle. This gives you an opportunity to replace those 33 year old high pressure fuel lines. Be sure to use hose rated for EFI! Marren and RC engineering come to mind for injector rebuilding. Next, I would find and fix any and all vacuum leaks. Any and all adjustments are pointless with a vacuum leak. EFI hates vacuum leaks. Adjust your valves. Did I mention that you should adjust your valves? If all the sensors are sensing, and the vacuum leaks have been conquered and the injectors are in good service, EFI requires very little adjustment. My bottom line point is that any adjustment without these things taken care of is pointless and costs you money. There was a guy who used to have an EFI video he sold, I think his name was Scott Bruening? Anyway, he owned Z Therapy before the current owners. If I can paraphrase him - most fuel injection problems are not fuel injection problems at all.

I am wondering why you are focusing on the AFM? Your rich part throttle numbers lead me to believe your problem is elsewhere. The AFM is approximating how much air is coming in. TPS, WTS, CHT and injectors are effecting fuel.

After all these years, I think our harnesses are finally giving up the ghost. If someone has a 280Z harness that they can send me, I will give it to my electrical engineer friend who builds Porsche harnesses and have him make new Z car harnesses. If they are anything like 914 harnesses they would be about $350 + core and shipping. But here is the big upside, When we plug his 914 harnesses in, we almost always have instant happiness. As for the OP, all it would take is a broken wire in your CHT or WTS harness and resistance would go to infinity telling the ECU that you're running really hot. The ECU would 'protect' the engine by increasing injection time and making the engine full rich.

Without some data about where you are at, it doesn't make sense to change anything. What are your numbers? The bypass screws are more about idle than anything else. I wouldn't stress over them.

Exactly. Be sure you understand this. Stated value just means 'you say that your car is worth X.' You will get paid what they say it's worth plus whatever you manage to negotiate out of them using "comps, appraisals, valuations etc..." What this means is that they will say your car is worth X. This number will almost certainly be disturbingly lower than your stated value. You refuse to settle, and go out and find a few cars similar to yours that are for sale or have recently sold. If you can prove that your car was worth more in this way, you nudge them in the direction of your stated value. Appraisal is just that, you get an expert to look at your car and state what it is worth. Costs something, in my experience, about $300 but it is solid evidence that your car is worth more than their X value. A valuation is something an expert writer might do. I am not aware of anyone doing this for the Z car but in the case of Porsche, Bruce Anderson does valuations on each Porsche model annually. He looks at sales of cars and comes up with a range of value with the added 'low mileage excellent examples can be worth 10% or more above these values.' You want an agreed value policy. No haggle. You suffer a complete loss, they pay you that amount. You have to keep on top of that amount though. If you think your car is worth X and they agree to that, then 10 years down the line the car is worth double that, and you suffer that loss - you agreed to X. Sorry about that... My wife is an insurance broker... I ask questions.

Think of it this way with just about any of the Classic Car insurers: They drew a sharp black line. They said 'no driving the car for daily commuting to work, no driving the car in speed contests.' You're trying to blur their sharp black line by saying 'well what if I drive it occasionally to work to see clients and such?' Insurers work off of statistics. They can tell pretty accurately what their risk of having to pay out is based on number crunching for particular types of driving. If you stray across their sharp black line, you increase their risk of having to pay out. Not going to happen. Your honesty is commendable but statisticians speak numbers not English.

Last Call!!! The April Sacramento Z Car Reunion is just an hour and a half off... Come on up even if you didn't shine yours up! The more the merrier!

Don't make me beg!!!! 8(

The Sacramento Z Car Reunion is just a day away! Tell your wife it's her birthday party and come on down! See you there with your shiny Z!

Bring your wife and tell her it is for her birthday!! Yah! That's it. That's the ticket! 8-D

Just two days! See you at the Sacramento Z Car Reunion!

The guy who originally owned ZTherapy (USAF guy) used to build convertibles in the PNW. What was his name? I think he was at Mountain Home AFB when he decided to get out of the Z business or something... But I recall that he built convertibles.

Who dat gonna come on down? Who dat? The April Sacramento Z Car Reunion is Sunday at 10am! Are you going to join the gang? See you there!

Cool! Hope you can come. I just talked to Bill and he is in Oregon that weekend (probably for a dog thing:stupid:) and then the next weekend, there is a double SoloII at Mather and he has dog things both days! I think I am going to drive out tomorrow and pick up his car so it doesn't feel 'dog envy'...

Less than a week before the gang gets together to get our donuts ON!! The weather is amazing and we should all get out and enjoy it! Leave the dogs at home. They have no sense of time anyway. They don't know they have been in the kennel for a week. They think it's an hour!

I agree and that is all true enough unless he is needing to write checks for 300 hours of rust repair.:classic:

Time to get 'em out and shine 'em up guys! Spring is finally here. The April Sacramento Z Car Reunion is Sunday April 10th, 10am to 1pmish... Usual place, Family Donuts and Deli at 9045 Fair Oaks Blvd. at the corner of Fair Oaks Blvd. and San Juan Avenue. I changed the usual day from Saturday to Sunday in case someone has some lame-assed dog agility trial or something

My apologies. I didn't read that you are looking for NOS. The reproduction was plenty good enough for me... :classic:

Excellence Magazine which is of course, a Porsche magazine did an article where they took an abused and rusted beyond belief 356 that was found in some woods and restored it. They proved that with insane effort, you can make a concours car out of a POS. My grandparents generation used to call that making a silk purse out of a sow's ear. I say this because you can fix that car. It might take 'insane' effort though, meaning you will spend much more in money, blood, sweat, tears than you can ever hope to get out of it. There are some exceptions. Did the car belong to some famous person? Is there documented evidence that this car has very low mileage? Is it one of the first 100 cars made? A little introspection will tell you if you have the time, money, skills, patience to take on such a project. If you find you don't, $1000 might be even a bit high...

Used is always cheaper. Classic Datsun Motorsports is always my first choice. MSA is always a close second...