Forgot to add, when driving, the first 1/4 throttle feels the best. Struggles a little under load, but well enough. Past that, it just bogs. No power, doesn't stall, just doesn't want to go. It sounds like it's being choked with fuel

 

I think I know what's causing the issue I talked about earlier in my car and it could be the problem with your car since it sounds like our cars are doing the same thing. Today my car was sputtering at low rpm and died at a light. I missed a whole light cycle (stuck at the front of the line, I'm sure the people loved me) and then it finally barely started. Went through the turn with zero power and no revs to give, then it just backfired crazy loud and spit a cloud of smoke out the exhaust and instantly got its power back. Like something an uncle would be driving in an 80's movie. Is this similar to what you're experiencing? My friends brought some ice to cool down my fuel rail and it got me home with no problems. I guess I'll be making or buying a fuel rail LOL

 

check the plugs, if fouled and black smoke coming out. prob rich, check the CHTS, make sure it matches the resistance/temp curve in the FSM, check it at the ECU connector. Make sure you disconnect the battery and the key switch is off before disconnecting the ECU connector. Do not mess up the connector by pressing too hard to get a reading, use a thin wire that is just tight enough to fit.

if resistance values are wrong, you will need to start by checking the sensor and then the wiring. Look for corrosion.


Whenever disconnecting or connecting the 35 pin connector, ign off, battery disconnected.

 

other things to check, pinch off the CSV line or just pull it and see if its leaking. I did not see a vacuum line on the aftermarket fuel pressure regulator. It needs it so the fuel pressure tracks with the vacuum. the FSM explains all this.

 

Your fuel pressure is low. It should be 30 at idle. The PCV hose on the valve cover is cracked and is probably leaking. If you have vacuum leak (you mentioned) it will run lean plus low fuel pressure will make it leaner'er. The missing vacuum hose in the second to last picture should have a hose that is "T"ed into the small hose on the right side of the intake manifold near the EGR.
That tank by the light in photo 3 is a vacuum reservoir. The two solenoids, one if for supplying vacuum to the HVAC system in your dash when you turn it on (missing hose, this is a vacuum leak). The other is for the device that increases the engine RPM when you turn on the A/C. That is the hose that is still hooked up to the intake manifold. (the other small hose in second photo).
I see you have a high performance paint job on the valve cover !

 

With that vacuum tank, is it needed if the car doesn't have ac anymore?
Yes! If im going to spend this muvh time in there, id need something cleaner to look at on the engine

 

Thanks guys! I'll check into them and see how that does

 

Ok, so I pulled the spark plugs and are covered in carbon. Checks out so far. My car doesn't have a CHTS, but I did check the thermotine and that seems to be well. I didn't check too much on the CVS tonight, but will get to it when I can.
The vacuum lines to the tank didn't do much when moving them around, so I took them out and plugged the two ports. it idles a bit better now, but it still runs rich. I now have it set to 28-30 psi fuel pressure at the regulator, but bogs heavily and runs around 300 when set to 36. Wot in neutral only revs up to 5000 rpm now and my idle is starting to sound like a rotary now. So some improvements with more questions now lol

 

check compression in each cylinder and coolant temp sensor. you can use carb cleaner spray while the engines running to find vacuum leaks. Try under the injectors mine was leaking at the injector seals and replacing them helped my idle

 

Why don't you have a CHTS on the car? No wonder it is running rich. The ECU goes crazy rich if it has a reading of infinity for the CHTS. I don't care what you find on the internet............don't F with the AFM! Don't even take the cover off.

 

I think the CHTS was used starting 80/81. It has a coolant temp sensor instead, but works the same. The CHTS is just a more accurate reading

 

Ok, with work, I didn't get as much time to work, but I have replaced the pcv(?) Hose that was cracked from the valve cover as well as both hoses to the air regulator (which was also checked for function). New silicone hose for afm to air intake. Temporary air filter will be bought tomorrow as well.

I have the FPR vacuum hooked to the intake, and the dizzy and the part that touches the throttle linkage (can't remember the name) next to dizzy is all hooked together into the throttle body. The hvac vacuum lines I've left as is now. And I guess my checks weren't good enough, as one of the sensors at the thermostat was disconnected and missing its retaining clip. I've got new sensor connectors ready to be installed for tomorrow, so that won't be an issue again.

It is starting to run better now, but when fuel is set to 36 psi, idle drops to 3-400 and idle adjustement screw won't help. I'm pretty sure now a large amount is due to lack of air filter which I haven't been able to find oem replacements or similar for a ridiculous amount, but the temporary should get me closer

 

Air filter should not cause this issue. Yes the coolant temp sensor and the CHTS are basically the same thing. You made it sound like you had nothing hooked up.
Have you done ALL the checks from the 35 pin connector at the ECU? That is VERY important as it checks the sensor/device and the wire to and from the ECU to said sensors/devices.
So you have turned the idle adjustment screw all the way and your engine idle doesn't change?

 

Yeah, I read another post of you discussing nearly this exact stuff lol.

I will be tonight as I have a few dedicated hours for this without interruptions. The values for the pins are found in the fsm, right?

Yeah, pretty much. It'll adjust below 650 but not any higher

 

Engine Fuel System, page 34 is where the ECU pin testing starts. Remember to disconnect the battery before disconnecting the 35 pin.
If you lived in North Dakota I would let you barrow my Kent Moore J25400 EFI tester!

 

Man, if only! That would be so helpful lol. Thank you though, for helping me in the right track. Time for my after work break and back to the car!

 

Ok, quite a bit to deal with on this. All of the blue marks are what read wrong/ didn't read (water temp sensor and air temp sensor didn't read, so didn't do a full check, steps 8, 9, and 12) so if I'm understanding right, there's either a short or a ground is hooked up where it shouldn't be? I didn't have time to check other things, only got the ecu checked

Would it be simpler if I removed the engine wiring harness, checked over wires, and reinstall it? (If other ways aren't the best option)

 

Some of your issues may be badly corroded electrical connectors. You need to check/clean/replace anything related to anything on the engine to ensure you have good connection between the device and the ECU.
I have removed an entire electrical harness from a 1983 to look for issue. I unwrapped the entire harness. I used tie wraps to mark where wires split off the main harness so I could wrap it correctly. The most difficult part is reinstall and getting the main harness back where it belongs where it goes thru the firewall. FYI I found no issues with the harness. my issue was bad connectors and a bad ECU. It took me 5 weeks of checking and re-checking to figure it out.
Finish the checks from the 35 pin. It is had to believe that you would have more than a coupe of bad readings. If the device/sensor checks out then I would trust the wires and be suspect of the electrical connectors unless you have evidence of mouse munching! They are evil little critters.

 

Hmm, alright. Good thing I bought new injector/sensor/afm connections last week! As far as I can tell, there aren't any damage from rodents, thankfully. It would be nice to go that in depth, but that sounds like a winter project lol.

I think today I'll recheck the ecu, then attach new connectors, clean male end to those connectors, check ecu again. And hopefully fix most of the issues. Will stay posted!

 

It only took me about 20 minutes to remove the entire harness. About an hour to unwrap and inspect and an hour to re-wrap. A couple of hours to re-install.

 

Ok well I decided to just take it out for ease. Rechecked the ecu, everything read the same as before. Went through and soldered on new connections, checked that each were wired properly, rechecked the pins and nothing has changed. I've removed some of the coating and checked wires, but haven't found anything yet.

The WTS is showing continuity through pins 14 and 15, instead of 14 and 49 as my wiring diagram shows. I'm thinking my thermotine and WTS are bad (if that wiring is correct), as I'm still reading 0 at both of them. There's no reading for the heater coil now, when there was on my first check

There's still power being found in grounds 15, 19, 20, and 22 ranging from .8-1.6 which I haven't found any reason for either.

I'll get back to it later tomorrow

 

Here's a stock 79' engine.

Your engine has a vacuum hose going that valve on the throttle-body that should have nothing connected to it.

Have you checked the distributor vacuum-advance to see if it's leaking? Due to the age of these engines the inside-diaphragm cracks and leaks. A hand-held vacuum-pump will be needed to find out if it's bad.

If no A/C or heater disconnect the hose going to the vacuum-tank and plug it.

Also if you have not steering, how do you turn the car?

 

Thanks man, it's been a wreck trying to undo the po work from all of this.

I haven't messed with the internals of the distributor, just a bit weary on working with it lol, but will defintley be the next thing to check.

The last person I discussed about the ac vacuum really skirted around answering that question from me. That makes much more sense now

And as for steering, I just crank it hard in low speeds. There were the 280zxr that had a limited release that didn't include power steering, just gotta find it if mine was I've if then lol

 

Possible the egr has carbon holding it open. Apply vacuum while running. You should notice a change in running