NismoPick

Wow... so you downgraded from a 2.8L to a 2.4L motor?

It is most likely that sensor.

lukypetr

Tried searching posts but can't get a straight answer. Finally got the car started after letting it sit for 2 years. It is hard to start at cold. I have to hold the throttle down and then it starts. If I push on the peddle within the first minute of starting the rpm's drop and it feels like it is going to cut off. After the first minute it revs really well with no smoke.I started to inspect the cold start injector, so I pulled it off of the manifold. It would not spray so I figured that the connectors for the AAR was switched by accident ( I rebuilt this engine). Once I switched them around the cold start injector started spraying with the ignition on, but it was a constant spray. Is it supposed to pulse like the regular injectors? The AAR seems to be open when cold because I pulled it and checked. Once I put the cold start injector back in the car would not start. I disconnected it and it starts. While the car is running, if I connect the cold start injector it cuts off. When the car finally heats up the rpm needle goes up and down betwen 1000 and 800. Once it is warm and I try to start it again the rpm's are really low than after a few seconds it goes back up. One other thing I have to mention is that I had to relocate the CHTS to the thermostat housing. The new engine I dropped in does not have a port for it on the head. Please help me out with any info.

NismoPick

Merged post w/ your previous starting issue thread so we can continue the same discussion...


The cold start valve & AAR are independent of each other. The cold start valve receives it's signal from the thermotime switch (which you have replaced w/ the CHTS). Maybe you can split the signal?

The easiest solution would be to use the correct ecu for your new motor.

lukypetr

I didn't replace it. I had an extra fitting on the thermostat housing so I screwed in the CHTS and extended the plug.

NismoPick

So the thermotime switch is still plugged in? Have you checked it?

JPerkins

i'm gonna be a synical pric here and say for your particular block/head combo, you'd prolly be better off ditching the EFI/ECU and replacing it with a 4-barrel carb set up.

the ECU's were only set up for the 2.8Liter engines. Not the 2.4liter engine that was in the 240z. all the sensors and ecu fuel mapping is set up for a larger engine, so of course you're going to run rich. and to my knowledge there is no way to reprogram the stock ECU's. They're the equivilant of a texas instruments calculator. Take into account also that your sensors are not in thier proper place and pulling the wrong reading, which is throwing the ECU even further off and you've got a recipe for an engine that runs bad.

get you a 4-barrel carb manifold from arizona z-car, and go buy a holley 4 barrel carb. you can tune that carburator down to the propper fuel supply where you cannot with the ECU.

Now before you do any of that, go change your oil. when you drain it, check to see if the oil has a milky color to it. If it does, you've got a coolant leak into the combustion chamber. Takes all of 30 minutes tops and can save you alot of headache.

lukypetr

The car does not smoke at all, just when I connect the cold start injector then it dies in 2 seconds( maybe less). The oil looks fine, no water. Checked the pressure in the cooling system and holds pressure. I have to check on the thermo switch.

lukypetr

Ok....I had a chance to work on the car. It still has a hard time starting. I have to crank it a couple of times and when it's started, if I hit the gas pedal the rpm's drop and it feels like it's going to die. After a minute it revs perfect. It is not smoking one bit but I would like to solve the starting issue. It seems that I am missing two sensors on my thermostat housing. I have one wire that has no plug on the end (just the stripped wire) and I have another single wirw that has a flat connector on the other end. I believe that one of them was hooked to a sensor for the FI fan but I removed the fan. I currently have three sensors on the thermostat housing and only two are connected. I also hooked up a vacuum gauge and I am only getting about 9 lbs. The rpm guage goes up and down between 1000 and 900 at idle. I have checked all my hoses and they seem fine. I have tried to use the fsm to make sure they are connected correctly but I am having a hard time understanding it. I attached some pics in hopes that someone can tell me if I have something hooked up incorrectly. Also, when I unplug the vacuum hose going to the egr, the rpm's increase and when I pull up on the egr valve the rpm's drop.