Spencer

Hello all, New here.
Just bought this Z two days ago as a project. When I drive her (randomly)she will either completely stall, lose ability to accelerate temporarily, or sputter and back fire. The only thing I have tried is fuel injector cleaning. Which didn't noticeably change a thing.

Known issues, probably unrelated..... No muffler, electrical display not functioning.

I know there are a few posts on this site about similar problems, but I haven't found an answer.

Any help in the right direction would be appreciated.

PredatorZ

Have you downloaded the fsm and ran through the troubleshooting steps ?
You need to check out each component of your efi system, the harness, the MAF, sensor connecters, a good ground and solid battery are important. The fsm is in PDF form, you can print out pages, I suggest starting a binder with clear page covers, fill it with pages you need to work on, I have been doing that and it has really helped me stay organized working on an issue. You will need to learn how you car works, and understand the basic principle involved in trouble shooting electrical issues, because these old cars will develop them, mostly because of old corroded connectors. Luckily Fricfrac has a nice kit to replace all the efi type connectors and the maf/map connector too.

http://www.xenonz31.com/

Spencer

Ive downloaded the FSM. Haven't had a chance to look at it yet. Wasn't even aware of the troubleshooting portion of the manual so thank you.

On a side note. I am pretty new to Z's, and my overall automobile knowledge is slim. I do possess common sense, and I am very good at troubleshooting if I know how things are supposed to work/run.

Point is, what is the efi system? I'm assuming electrical?

rogerz

here is some stuff that might help but do it now and prevents stuff down the line:
Get your battery load tested. Be sure you have clean, tight corrosion free terminals on both ends of your battery cables. Be sure the ground (negative) cable goes to a bolt into the frame before going to the starter. grounding through the starter is not a reliable connection. Z's don't like low voltage. causes the electronics to act funny. it is possible to have enough amps to crank but not enough voltage to run the electronics. If you have one size fit all cheapo clamp on terminals they are a problem waiting to happen.

Clean the connectors for the maf or afm, ecu and tps. Deoxit by CAIG is probably the best connector cleaner on the market. spray with CorrosionX after cleaning and before putting together this will help prevent any further corrosion.

efi is electronic fuel injection
you need to get a pressure gage on the fuel ring to find out if you have fuel flow correct.
next thing is timing but since it runs sometimes probably in the electronics (such as they are). probably not that unless the dizzy is shot. Chts and o2 sensor are probably the most common things to make weird running. O2 sensor just reach down there and unplug it. if it then runs normally you have your answer. Chts just replace there is a website with directions on doing this easily. I always cut the wiring at the oval connector on top the engine and throw it away they get fried and just a point of failure. get a new injector connector (volvos in the junk yard are a good place they used really top end connectors) other wise auto parts store. then solder that to the wires you cut. TPS won't do it. Maf you can test from procedure in the fsm. but unless someone stuck a scredriver in there they are pretty simple. I've never found a bad one.

when you specify your car helps to tell us auto or stick, n/a or turbo. you will get better answers.

Get those battery cables in Aone shape. load test the battery and see if that doesn't clear up a lot of stuff. If you start getting schematics printed out of the fsm so them in 11x17 much more readable. there are specific schematics scattered throughout the text so imperative to at least leaf thru the pages in the section you are perusing

Spencer

Alright thanks for that info.

As far as my car make it was in the title. But she is stick.

This is some good info on where to start. I am just looking at not putting in a fortune into her. I am willing to put time and effort, with decent investment. At first it just seems like a big workload!

PredatorZ

Sorry Spencer, its easy to assume that everyone knows the all the acronyms. NP asking questions feel free to pick our brains, ill get back to you asap if I know anything that will help. Sounds like you have an open mind and are willing to jump in and learn how to fix your car, so cheers to you ! Always nice when someone catches the Z bug, once you have owned one, you can't go back, you will always miss them and want another, at least that's how it is for me.

Spencer

Its all good! Yea I had a 350z a few years ago. I loved driving her, but had no desire in doing any work on her. This one is different. I see what this one can become, and it makes me excited! Here is a link to the current state. aflyingcake's uploaded images - Imgur

PredatorZ

I have that exact dash in perfect condition in my shed, my car only had 85K on it when I wrecked it, was always covered and garaged, so its in pretty nice shape, I pulled the entire interior out, sadly the headliner got a black mark on it from me stacking stuff on it.

Spencer

Ill PM you.

PredatorZ

There is a bad spot, something made a grease mark, tried to clean it up, should be ok, worst case a little matching dye will cover it. I have so many parts you could use, any chance you will be vacationing in Idaho soon ? I could load You up with parts, we could even take a cutting wheel to the body and get you all the patch panels you might need, the under carriage looks new, no rust

PredatorZ

Steve has a lot of parts for our cars

300zx Parts For You webpage

When he has dashes, he is selling for 195 plus 100 shipping

Spencer

The dash looks great! Nothing that a little cover up cant fix. Now... If you could figure out how much it would cost for you to ship it, we may have a deal. I'm assuming around the same price range... Which I'm not sure is worth it. A trip to Idaho is not likely, but I wont completely take it off the board.

Spencer

Update on the status.

On a hunch I looked at my ECU in regards to my fuel injection. Had weird glue/silicon stuff all over the chip. Decided to just buy a replacement, which will arrive early next week. Soon I want to replace the spark plugs, and then clean all the connectors for the EFI.

I purchased a replacement cluster for my dash, as mine is faulty. I checked everything I could, it appears the entire cluster just failed. It will arrive early next week as well.

Headlights. I wanted HIDs so I bought them. Current headlights are fine....mostly. On my left Headlight, only high beam will work. That means its probably wiring?

Found a guy that is selling me seats, mirrors, a muffler, and a windshield(mine cracked) for 300. So that will be around next paycheck, as I need to drive 3 hours to go get them. As far as mufflers go, do you have any recommendations? How do some of the aftermarket mufflers sound on the Z31s?

Tomorrow is probably going to be the bath day for her, she desperately needs a cleaning. Both outside as well as the engine.

PredatorZ

Cool that you found some parts near you, texas has a lot of Junked cars just waiting to be picked over. Sounds like you are making progress, keep us posted.

Spencer

Oh I forgot. I wrote down the codes my ECU was saying when it was plugged in.
1. fuel temperature sensor circuit
2. throttle valve switch(idle switch)circuit
3. load signal circuit

Do you think these could have anything to do with my stall/stuttering problem?

PredatorZ

A throttle sensor possibly on the fritz could confuse the computer getting bad input and messing with how it runs. Worth at least proving wrong, its a good place to start.

Check out the TPS, do the trouble shooting steps to test and set it, the fuel temp can be ignored, from what I have read it does not effect performance, I got my tps wet and my car would barely move, so it can seriously screw your car up if not working properly.

"The TPS is checked by Checking for continuity with the throttle closed and then opening the throttle and the continuity should break. If it does those 2 things it is good. The computer uses those 2 signals to determine whether to be in idle mode or run mode. " (quote from AWG on Zcar)

Spencer

Hmmm. How much will that cost me. Ebay here I come.

PredatorZ

try testing and adjusting it, it could have water in it, a corroded connector or just out of adjustment, if you replace it you will still need to know how to set it. Just don't buy parts ***** nilly, unless you are rich or have your mom's credit card.. hehe because if thats what your mom want's well lets keep her happy, but seriously, you can spend a small fortune replacing everything, but sometimes parts do need replacing, just do the trouble shooting and adjusting, it will be educational, you need to learn your engine, become one with it and seek a Zen moment when it runs perfect

Spencer

Small update..

Tried going without O2 sensor. No noticeable improvement. Continued sputtering, however.....I didn't stall while driving this time, or fall on my face so to speak. It is of note I only drove her for 10-15 minutes, and she did stall when I first started her.

Going to check the throttle sensor tommorrow morning. Connections and what not. I need to consult my Haynes or FSM.

"Just don't buy parts ***** nilly, unless you are rich or have your mom's credit card."

Haha, well I'm not rich. However my wallet has a real steady income. Wish my mother would pay for it ;p but she hasnt gave me a dime since I moved out 4 years ago.

Spencer

Correction. I did not in fact unplug the O2 sensor yesterday. I unplugged the TPS. I forgot to mention I started her up, and didn't notice an improvement, then I plugged it back in and drove around.

Today I unplugged the O2 sensor hahaha. Unfortunately it made my issue worse. I couldn't even drive her at all. She didn't want to get above 1 mph.

Thoughts???????

PredatorZ

So are you saying it ran the same with the tps plugged in and with it disconnected ? Then your tps is the issue, if the tps isn't working correctly your computer has no idea if you are at idle or full throttle, it cannot tell.

Spencer

Without the TPS it ran.... worse.. I suppose. It took a few tries to start, then it caught and it felt choppy. I turned off the engine. Plugged the TPS back in, started her, no choppiness.

I was asking if you had thoughts with the O2 sensor. Why would unplugging it, make my car inoperable essentially?