cozye

he linked the part number guys. There is no doubt which one it fits.

If you moved the lever on the AFM in the correct direction to open the flap more and it started to die, you are definitely not running lean. I'm assuming that you tried this with a very small amount of movement, like 2mm maybe ? If so, that means that your car is probably running rich. Even when properly tuned, if you move the AFM flap just a little, it will still idle up some I believe before bogging down. IF it bogged down immediately I would think you are definitely not in a lean condition. Can you pull a couple of plugs, take a pic, and post ? If you are running rich, your thermostat or water temp sensor could be the cause of the problem. Have you been able to verify if the temp gauge in the car is correct ?

There is no spoon

Fuel pressure should be about 30psi at idle with the correct vacuum. Not sure what scale you are measuring 3.5 on? You will need a vacuum gauge and a good vacuum measure. You need to rule out any intake and vacuum leaks as well as verify correct operation of fuel supply/pressure before moving on.

What's wrong with just using a direct replacement? I've noticed several owners converting the links to other types of fuses, not sure I understand why really ?

I thought the 77 was the same as the 78 and they deleted the fuel pump cut off switch in the AFM ? If not, yeah my bad. There is that switch in the AFM on the older models. In any case he could jumper it on the AFM connector just as a test.

What year/model car. What is your fuel pressure ? What vacuum are you pulling ? What temp is the motor running? Why did you replace your timing chain? What timing are you running? Have all vacuum lines and intake leaks been inspected and ruled out?

find a PPG dealer in your area. PPG Shop line is reasonable priced, covers well, and is great for the money. A couple quarts of that won't cost you near $400. You should be able to get your base, clear, reducer, hardener, everything for that kind of money.

True that the temp in the radiator could be cooler. My thought is that the water circulates while running, so if you do it as soon as you stop driving it should be fairly close. It shouldn't be any hotter than the water temp sending unit, so if the thermometer says 170, and the water temp gauge says 140, you know that the gauge is wrong. Of course if it reads cooler than the water temp gauge, you haven't proven anything.

Pretty much what Sarah said. I'm thinking you will need to richen up your mixture, but you've got a lot of other troubleshooting and ruling out to do first for sure. The only other thing I will ad is that if you don't want to go pulling our AFM apart, you can pull the throttle valve switch connector off, and take a small piece of wire to jumper the middle pin to the outside pin. If it runs a bunch better, then you are running to lean for sure. You can drive it with the switch jumpered for test. I can't remember which outside pin will be full enrichment. One pin will richen it just a little, the other will richen it quite a bit. This is a good test that only takes 5 minutes. I would take care of that thermostat issue before you do anything else though. If your car won't get up to temp, your FI will richen the mixture up and it's going to get in the way or could even be your problem. Do you have a nice cooking thermometer, or maybe one for steaming milk for espresso ? Go for a drive and get the car hot. Come back and take the radiator cap off very carefully, relieve pressure before unlocking cap all the way. Put the thermometer in and see what it reads, this will rule out your water temp sending switch (since it's just for the gauge and not for the EFI). If it's only 130-140, then replace your thermostat. Also, on the vacuum check, take vacuum reading with motor hot. When cold start is going on or AAR valve partially open, that will lower your vacuum. This also goes back to your motor running cold

I've never owned a 240, but personally I like the styling a bit more. Even the hub caps are more appealing to me. That being said however, I think solid 280's are easier to come by as the 240's seemed to be more susceptible to rust. The 280 will get you .4L more displacement. And if you ditch the big bumpers on the 280, it has that simpler 240 look as well. If you dump the bumpers on the 280 you will be closer in the weight difference as well. I think you should ask yourself two questions. Do you want EFI, or carbs ? Do you want a stock restoration, or customize? It irk's be a bit to see people chop up 240's. I think the solid examples are rare enough that they deserve a stock restoration. I'd say look for either, and when you find the right car whether it's a 240 or 280, then get it! Be willing to pay double for a solid car rather than trying to save money up front on a basket case. You will come out a lot further ahead paying an extra $1500 for a car with little rust, as you probably already know.

What's the fuel pressure ? What vacuum are you pulling ? You need to replace the thermostat it sounds like for sure, sounds like it's stuck open. The EFI is directly affected by water temp and although it may not be the source of your issue, you will have a hard time getting this car tuned right with it running cold all the time.

Are the 240 and 280 masts the same?

What about a used one?

My gauge reads the same cold as it does when it's been running for an hour. I could see that if you installed it right above the exhaust manifold, but installed by the fuel filter it doesn't get that hot. The fresh supply of cold fuel should also keep it from getting too hot. They are made for under hood applications and you will see them directly on the fuel rail of race cars (although I'm sure they aren't using an $18 gauge). In your case it sounds more like a crappy gauge than a liquid vs. non liquid issue. I know there are a ton of Z owners with the same gauge mounted in the same spot. Might not be ideal for tuning a fuel pressure regulator, but for just checking if your fuel pressure is in spec they are fine. I've got an external gauge too, it reads the same.

I would leave the evap canister. You don't what fuel vapors in your engine compartment and your gas tank needs to vent. The distributor vacuum advance was designed to run off ported vacuum on the TB and it's no problem to have this T fitted in with the evap canister as designed. Your water temp gauge should be connected to a separate temp sensor (with one barrel connector). Some years might have used the same sensor with FI, not sure what year yours is but the 77-78 is using a different sensor for the dash gauge. The temp sensor for the FI has a two terminal connector on it just like the injectors. If your problem is intermittent, I'm not sure I would add the resistor just yet until you understand what's going on for certain. Mine and Sarah's problem was not intermittent. If you do have a faulty tstat, it could cause some issues but I wouldn't rely on your dash gauge to prove that. For the fuel pressure gauge, I would install a more permanent gauge so that you can leave in and drive. This way if it's running good you can see what's going on without stopping the car, and the same if it's running poorly. A lot of people (including myself) installed this gauge right between the fuel filter and fuel rail: http://www.summitracing.com/parts/SUM-800160/ you will need this T fitting http://www.summitracing.com/parts/SUM-G1710/ The fuel line is supposed to be 7mm. However, no fittings are made in 7mm. What I did was use 5/16" fuel hose, which is just a tad larger than 7mm and a tad smaller than the 3/8 fitting. You can get it on and clamp it.

I understand. I tried to convince myself it had character, embraces the late 70's, and that I wanted to keep it. I couldn't get over it though. I decided to cave

Not sure on the 75 mounts. They just look smaller to me and I thought I'd read that the 77-78 bumpers were increased in size over the previous 280. You don't think the 240 bumper with the rubber and extra bumps removed, holes filled in and chromed look good? That single clean chrome line of a cleaned up 240 bumper is the cats meow to my eyes!

I've got a pair of 240 bumpers that I'm going to use. I prefer that look. You might want to look into a 75 bumper though, or even a 260 bumper. The bumpers got larger each year. The 75's are a little smoother on the rubber and look to me to be a bit shorter. They will probably bolt right up too, although you might need some bodywork to smooth out the quarter panels.

I've got the same exhaust on the way.

What Fastwoman said. You have to be absolutely certain that you fix all your vacuum leaks and other issues first though. You will want your distributor advance connected to the throttle body, it wasn't designed for manifold advance source. After doing more research and searching forums on "resistor water temp sensor" i've found several credible Z mechanics refering to this as a known issue with old ECU's drifting and the fix is to put resistor inline with water temp circuit.

Definitely one of the nicest I've seen. Very good job. I'm a bit envious as I haven't had any time to do the cosmetic stuff yet. I'll start with cosmetic stuff on mine in a week when my suspension parts arrive, i"m going to clean and refresh the undercoat while I go through the suspension. I wish my engine bay looked as good as yours!

Thanks for posting your results as well. Your post above about the fast idle got me thinking about mine being too rich. I'd already suspected I might have gone too far, but you got me on a train of thought to take another look at it. I'd had 850 ohms dialed in to my potentiometer on the water temp circuit, but my AFM was still rich by 4 teeth. I went on and back out my AFM to the stock setting, and took another drive. The last time I drove it with the AFM at stock yesterday, the pot was set at 1150 ohms. Today at 850 ohms the car was much smoother and had good power. Also, the idle was smoother as well. I lost .5hg of vacuum, but thats not that important since the car is still at 18 and runs better. I'll try this for a bit, and see if it helps my cold start once it cools down.

On my cold start up, I'm getting a really slow idle. Before I would not get any fast idle, it just idled around 800-900. My air bypass is working so something is still not quite right on my cold start ups. I might be a bit to rich still. I need to dig into it further. I hadn't put a lot of effort into it yet since it started cold quite well before, but now with the richer mix I've got to hold the gas a bit. Like you, I've found that a 900 rpm idle is much smoother than 800. Looks like your compression numbers are great. Mine were about 150-155, but I will check again after I've run a richer mix for a while. It will be a bit before I try a megasquirt setup. It's not on the top of my list, suspension is next. I'll be sure to post up when I do though. Until then there is plenty of reading and info I need to do about the subject.

Yeah, I do not think it is that difficult though. Just get rid of the AFM all together and all you need is an IAT and MAP sensor. From my initial research it looks to be a much more modern type EFI, will reuse everything except the AFM, and can be configured for closed loop with a wide band o2. I really like the idea of a wideband. I've used them on my motorcycles for tuning on the race track and it's extremely reliable and easy to use. Personally I think I would do fuel only with it, not spark. I'm going to go this route I think, but will stick with my temporary work around for a while and work on other repairs. (suspension, paint, etc..). One of the main things I don't like about the current EFI setup, with work around is that the changes affect every rpm under every throttle setting. A system like MS you could configure for a particular air fuel ratio on a much more granular scale, and have it calculate the changes necessary to hit your target. Much more efficient.