Since it's getting cooler here in TX, my Z doesn't like starting up. This morning was the worst. It was 59F and she sputtered like I was trading her in for a Honda. She finnally settled down before I took off for work, but... winter's not here yet and I don't want to have to find alternate ways to work.

Cold start valve is what I'm thinking, but any opinions would help!

 

haha cold in texa I WISH! i was there for a visit christmas time it was peachy!
come up here to canada where it gets to -50 to -60 C...i have NO chance driving MY Z lol!


anyways yes check the cold start. easy way to do it is take it out and connect it to a battry see if it squirts any gas out i took mine off since i dont drive it winters

 

Yeah...I know. My Z has been in texas all of it's life and likes it warm. Today was rather rough though. I have a feeling that there's something else up as well. I got a huge drop in power after trying to race on the way to work....not good. It did this three years ago and it sat for a long time after it wouldn't turn over again. I don't want to go through a dismal winter again!

 

I had the same problem that started about a month ago, rough start, bad idle and noticble power loss. The Z's getting a new fuel pump and filter. I was stranded 300 miles from home for two days before I could get into another ride. Seems parts for a 21 yr old car are hard to come by. Go figure? I guess it's my punishment for the 14" rim thing.

 

ahh...the 14" rim thing is old news.

Anyway, the fuel pump is new, hardly has 1,000 miles on it and it was replaced after I dropped the tank and cleaned it out. Same with the fuel filter, but I'm not opposed to changing that again. The plugs have low miles on them, but have been in for about 11 months...I'll look at those and see what I can find.

What really bothers me is that this seemed to be progressive in nature. First it started rough and would run fine when warmed up. Second came some acceleration lag in third gear that progressed to the point that I can't even push the gas pedal down to get rolling without the motor sputtering. I get some fuel smells under the hood, but no signs of leaking anywhere. I need to look at the AFM and see what's up there, but nothing looks wrong on the surface, including the hose. I know my, water pump is going out, but that shouldn't have anything to do with the way the motor runs, right?

I'm just at a loss. This is what happened 6 years ago and why it sat for those 6 years. I'm NOT doing that again.

Any ideas? Anyone?

 

manually advance the ignition timing. If that seems to fix the problem a little, then your vaccume advance "stuff" is going out. It happened on my car. After replacing the distributor, I had easier starts, better acceleration, and an additional 2 horsepower!

 

Is that with rotating the distrubitor, or all that TDC stuff that's on another post? BTW, cap and rotor are only 11 months old. I'll look at the cap and rotor too.
I've got two more days 'till I can get some time to do some wrench bending, but I'll let you know what I come up with.

 

just losen the little bolt on the base of the distributor and rotate it. That's how you advance or retard the ignition timing a little.

 

Just double checking. Thanks, I'll hit this tomorrow and hope for the best!!

 

What Temp spark plugs are you running? I was told that it makes a large difference to the performance and stability of the engine at extremes of temps.

 

I don't remember exatcly what temp they are, it's been awhile since the purchace. They are NGK copper...that I do know. I don't think that's really the issue though. It had been running just fine for 11 months.

 

NGK model numbers can tell you whether it is a hot or cold plug. I think from memory they range from 4 to 10. My mate's brother has a beastie mini. He runs hot plugs for hill climbing and cold ones for racing circuit because of the difference in race distance. Day to Day driving he has an in between plug for winter and summer. He is a systems engineer and has a few race cars he maintains himself.

As for the L28 motor, I have found that my starting problem is more to do with the ambient temperature then just a Carb problem. My plugs atm need to be swapped for hotter plugs because I notice more carbon build up and that is due to the fire not being the right temp. Ask a performance car engineer about the importance of the plug temperature to the smoothness of the engine.

Here in Brisbane, temps can range from 0-3°C in the dead of winter mornings and 40°C in the summer.

 

Thanks, I'll look at what I have. I still didn't get to work on the car...friends in this weekend... It's just a daily driver right now (or was...driving the truck at the moment ). I just want to get it running again so I will be able to modify at a later date.

 

Ok...Had a chance to put the Z under the wrench this past weekend. This time, it wouldn't even turn over. The starter would turn the motor (nicely, even) but no crank. Spark plugs are oily looking and smell like gas...all 6. I cleaned them off, re-gapped and put 'em back... same thing.

What is baffleing me is that it was running nice, then it bogged down when I'd hit the gas...sorta like it was either flooding out or starving for fuel. Now I know it was flooding out. WTF?!?!?!? I haven't touched anything that even relates to fuel flow under the hood for nearly a year!!!! Then the rough starting happened.....ugh.......

Vac lines look good, haven't tried another CSV (cold start valve) yet.... The only thing I haven't done is drop the gas tank and clean it (again...did that 11 months ago, no rust or anything!) and change the fuel filter.

Now what?

 

are ur injectors any good? (maybe a few stuck wide open?)

 

Maybe you have no spark. Spark plugs can go bad. Try replacing them if you've got $10 to spend.

Ok, another free test you can do. Take out all the spark plugs again and clean them. Leave them all out for a while to let the cylinders "air out" and dry some of the excess fuel. Then put them back in. Remove the intake boot off the throttle body. Hold the throttle shaft down to open the butterfly valve in the throttle body and spray a good amount of starting fluid in there. Connect the boot (don't bother tightening it yet) and crank the engine over. It should fire up if you have any spark at all. Even if it starts and dies again, at least this test will let you know your ignition is working somewhat.

 

Yeah....sounds like last time. I'll give it another shot. If this works, how can I prevent this from happening again (besides rebuilding the whole top end of the motor and getting the rings done)?

 

Maybe your battery is weak and giving your coil too little voltage. Maybe new spark plugs will fix it. I can't say for sure. These are all just guesses.

If it is just weak spark, you might have been running slightly rich. Maybe the fuel pressure regulator was going out slowly over time and increasing the fuel pressure. That kinda makes sense. Then it would run but have less power and eventually start missing out... the rich condition will cause the spark plugs to foul up.

 

Have you tried cleaning out the throttle body with carbie cleaner?

Another possibility, When you partially hold the accelerator down do you hear a puttputting noise from the exhaust? If so, your valve timing might need to be adjusted. If that doesn't fix the putt, your valve springs might need to be replaced.

 

Well....tonite she ran. ....and ran good! New plugs, fuel filter, 5 gallons of 93 octane with a 1/2 bottle of B-12 Chemtool (for carbon build-up) was all I spent money on. Now, last night I left the spark plugs out of the block in order to dry out the cilinders, and put 'em back in when I got off work. It fired up, sputtered at me, stalled twice, and then just ran.

There was some gurgeling going on back at the exhaust, along with LOTS of black smoke...but it seemed to work it out. Kind of hard to put into words....sorta like a cat hacking up a hairball. You think it's gunna die, and then everything's fine. Now--it doesn't like a full push on the throttle 'till it's warmed up, it bogs down. Air/fuel mix maybe???

Anyway, I took her out for a spin and even burned some rubber at a stop sign. I just don't get it.

 

Well (if any of you are interested...), I pulled out the ECU and cleaned the contacts with one of my wife's emory boards......runs like a champ!

 

That is a good thing to know.