marcuspoccia

What if i said the fuel pump was replaced last summer, because the old one was completely dead?

After 20+ years of sitting, got the z running last summer. After driving a few times, the car began cutting/stalling when giving it a heavy throttle press while driving. The cutting has no relation to speed or rpm, but more the load/stress the engine is under (acceleration/hills). Last fall, we found the car would drop about 10 psi of fuel pressure before cutting out. After this past winter, we have started by replacing all of the rubber fuel lines from the tank to the engine, along with replacing the fuel filter. We cut open the filter and did not find any noticeable contaminants. We had one more successful small drive where we could really get on it, only for a small skip really high in the rpm's, but it would take a full throttle pull or two. After that ride, we took the car out the next weekend for a much longer, more strenuous ride, and the cutting slowly came back. We drove a couple back roads normally where it ran decent, then took it one exit up the highway which is where it really began to struggle. We had the car running at about 3500 rpm in 4th for 5 or so minutes there. We struggled to get the car back home after that highway ride. Tonight we took the car once again, and it ran better than after the highway ride, but not well. I am looking for some advice on what you guys would do. I think it has something to do with a blockage or something in the fuel system. Thoughts?

Looks like I got lucky. After cleaning many electrical connections, along with fiddling with vacuum hose line connections, i have got the car running pretty good. over the last three days, ive put a few hours of driving around the neighborhood and cant get it to die. Still experiencing a slight skip under heavy heavy acceleration, but i am glad it is much better than it was. Now its time to pack up and head to college, returning to the project over winter break. thank you all for the help

Hi again. Since my last update, I received and replaced the afm-throttle body boot, and tested vacuum/ fuel pressure. The boot did not fix the problem, and the testing showed no signs of an issue there. I have spent time cleaning connections, like grounds, and the connections to the sensors on the thermostat housing. let the car idle for a long time the other night, and could rev it out with no stumble or hesitation. Last night took it back out onto my road, and proceeded to become undrivable once again once it warmed up. Im not sure what to do

wow. good call, THANK YOU! I had noticed that inside there, but would not have thought to switch it over. Thanks to everyone here, this was really helpful and learned a ton.

haha. as you were typing this i took off the afm boot. theres a pretty good hole in it at the bend that i can stick my finger through. this wasnt there when I replaced the AFM itself, so I figured i would deal with it later if it broke since it was not in great shape. Going to order a new one. Should I continue to diagnose or should this be the fix? I really hope this does it. Got a week and a half before I go back to college!

fuel tank has been drained, brand new filter, lines were blown through with compressed air when the tank was emptied, along with again today. all connections in the engine bay have been cleaned. Working on renting a kit to test fuel pressure and vacuum from the parts store. I have gone through every test starting on page 45 of the fuel injection bible, but was unable to complete the test on p53. Pin 20 does not have a connection, does the 1978 have a different circuit? It is the air flow meter fuel pump contact circuit. As far as removing the black cover on the AFM, it is newly refurbished from thezstore.com, and looks like its glued on. Do I just pry it off? I really dont want to break it. And what should I use to glue it back on? Finally, according to the tests I did from the bible, the water temp sensor works fine. Probably could use a new afm-throttle body boot, its got a big crack but I didn't see any that went fully through.

After sitting for about 20 yrs in a no-start condition, we have finally gotten our z running once again. In terms of the fuel injection system, the fuel pump(dead) and air flow meter(glue holding it together let go and let in lots of unmeasured air) have been replaced so far. After getting it started and letting it run well a few times, we decided to take it up and down our flat road, with less than a mile of driving. As the engine comes to operating temp, it loses power under load. In neutral/with the clutch in, it seems to healthily rev without stalling out. However, in gear, if more than about a quarter throttle is applied, the engine gives out, eventually coming to a point where it has no power to drive the car back in the garage, but still revs out fairly normal. After cooling, it can be taken out the next day to do the same, and progressively lose power as the engine warms. From pulling the plugs, it seems the engine runs lean. I have seen that it could possibly be the water temp sensor? How can I test this(does anyone have a link to a step by step guide? I can't seem to find it in the manuals that I have)? Does the new air flow meter need to be adjusted? Also, I have not gotten a fuel pressure reading yet, but it is a new pump. In summary, runs great while parked, has no power to drive after coming up to temp. I am a beginner, so I am struggling with diagnosing this, looking for some guidance! Thanks!