Fuel consumption and Hesitation

[doradox]

No I have not, I won't have access to a Volt meter til Wednesday. I will do it then though.

I'm on the UCF campus here and the majority of my tools are about 6 hours away so I have to use what there is at the SAE shop if need be.

However, I highly doubt it to be the wires/plugs. They are less than 6 months old. I hope you prove me wrong though, because I certainly would like this problem to be over.

Well, less than 6 months old might change what I would suspect. Are they stock replacements or high performance?

Steve

[Glliw]

BPR6ES plugs, and I think Magnecore wires? They're Red?

[ConchZ]

You know, I had 77 Celica GT that did the same thing, although that car didn't have a manual choke. It ran fine cold, then would hesitate and buck when warmed up, especially when accelerating up a hill. I went through all the electrical stuff, only to solve the problem by changing the fuel filter. I think it had a dirty fuel tank, as it clogged the filter every once in a while. I just kept a spare filter in the glove box.

That little yellow mini-Mach I was a cool little car. I miss it. A trash truck backed over it while it was parked roughly in line of sight of a dumpster. This was after I had just got it repainted. What a terrible, terrible thing. I also used to have a 64 1/2 Mustang that a tree fell on while it was parked. In college, I had a Dodge Charger that got whacked while parked in a mall parking lot. I am so afraid of parking my Z. I digress...

Edited October 27, 2008 by ConchZ
It had an automatic choke.

[Weasel73240Z]

ConchZ makes a good point, it may not be warming up that causes it to buck and hesitate, it may that it takes a few minutes for enough gunk from the tank to begin clogging a fuel line. Once you shut the car down, and the pressure drops, the gunk drops back into the tank. What type of fuel pump/filter are you using?

[Glliw]

I could've sworn I replied to this earlier, but then again, it is early in the morning.

I will definitely try the fuel filter. I believe the filter is an OEM replacement and the fuel pump is some non-oem unit with no identifiable markings that I saw when I briefly looked it over.

[Friar-Tuck]

You said earlier you adjusted the carbs,

those Three screw S.U.'s might also have the "Last Chance Filter" in the banjo fitting at the carb inlet, that might be worth a peak if the main filter pans out.

Tuck \o/

[clayton 260z]

gillw,

I to have a 260 with three screw su's (Z Therapy) with a European balance tube and had the same problems. What air filter system are you using? I had seperate K&N's and changed back to the factory set up with a cold air duct to a filter in the front grill area, this for some reason help alot. I am no expert but i believe it has something to with the amount of vacuum, but I am not sure.

I do not have to choke, pump the pedal like before and the throttle response is much better. I had tried everything to resolve this, pluges, wires, adjustments to the carbs, fuel filters but nothing really worked. I switched back to the original set up by accident because I wanted a new look and the pay off was a very big surprise.

Again I am not an expert but this helped my problems. Others way in with what you think.

Mike

[Glliw]

You said earlier you adjusted the carbs,

those Three screw S.U.'s might also have the "Last Chance Filter" in the banjo fitting at the carb inlet, that might be worth a peak if the main filter pans out.

Tuck \o/

Thanks, I'll look into that post-other items.

gillw,

I to have a 260 with three screw su's (Z Therapy) with a European balance tube and had the same problems. What air filter system are you using? I had seperate K&N's and changed back to the factory set up with a cold air duct to a filter in the front grill area, this for some reason help alot. I am no expert but i believe it has something to with the amount of vacuum, but I am not sure.

I do not have to choke, pump the pedal like before and the throttle response is much better. I had tried everything to resolve this, pluges, wires, adjustments to the carbs, fuel filters but nothing really worked. I switched back to the original set up by accident because I wanted a new look and the pay off was a very big surprise.

Again I am not an expert but this helped my problems. Others way in with what you think.

Mike

Ya know, I've been wanting to go back to the stock air cleaner since I actually like the look alot more, but I just haven't been able to find one that isn't asking and exorbitantly high price for what it is or is in decent shape. Right now, I just have I think a ram-flo filter on each one.

Will

[Bruce Palmer]

gillw,

I to have a 260 with three screw su's (Z Therapy) with a European balance tube and had the same problems. What air filter system are you using? I had seperate K&N's and changed back to the factory set up with a cold air duct to a filter in the front grill area, this for some reason help alot. I am no expert but i believe it has something to with the amount of vacuum, but I am not sure.

I do not have to choke, pump the pedal like before and the throttle response is much better. I had tried everything to resolve this, pluges, wires, adjustments to the carbs, fuel filters but nothing really worked. I switched back to the original set up by accident because I wanted a new look and the pay off was a very big surprise.

Again I am not an expert but this helped my problems. Others way in with what you think.

Mike

Mike,

One thing you may have stumbled onto are the air horns in the stock can. They really are pretty functional vs the air breaking over a square corner with the aftermarket K&Ns without anything to roll that air into the carbs. Any of you looking for something to help that ugly airflow situation, I run the billet stub stacks from www.aptfast.com.

[Bruce Palmer]

Will,

Two other things have come to mind to check.

A spray around for vacuum leaks might show up something and checking for low float levels would be in order as well.

[Glliw]

Right, I planned to check float levels here shortly actually when I replace the carb needles/nozzles since the front set is worn.

I'll be ordering a new fuel filter and coil today.

One question though, my car appears to be a factory automatic, I have a 5speed from a later model however. When it comes to the coil for the 260z, there are 2 different models. Should I stick with the Auto one or get a manual one instead?

Will

[Glliw]

Update:

Today, I replaced the igntion coil with an Accel one. I chose this one because of it was readily available, and at $2 more than a OEM replacement, there was no reason not to.

At first, I thought the car was doing fine with it, but then again, it was only 65 degrees here today. The car returned back to its old habits. I was really hoping this would be the piece to solve the puzzle.

Anywho, I ordered a fuel filter and it will be here Friday so I will try that out as well.