no low end power?

[z_boi]

:disappoin I have a stock 78 280. when i drive the car, it feels arse if i dont have much low end power. It seems like the powerband doesnt really kik in until about above 1500rpms, and its even worst when tryin to pull up hill. if im in any other gear besides 1st, i have to be at least at 2000rpms or higher (depending on the steepness of the hill) to get up with out my rpms droping. Is this normal? Is there anything i can do to fix it?

Thanks guys!

[Mudge]

Check your timing, and report back...

Good luck

[z_boi]

Hi Mudge, I dont know all that much about working on cars, im only 17. Anyway, i was wondering if you can tell me how i would go about checking my timing? thanks!

[Mudge]

I am guessing then the car has always been like this? Its not something that occured after some kind of maintenance then...

[z_boi]

:disappoin Then is there anythin i can do to correct this? I've only had the car about 2 months. So im not sure about any kind of maintanace.

[Mudge]

I would recommend getting a Haynes or Chiltons, I got my Haynes for $9 or so off eBay.

If it is the distributor, then you can try to rotate it a small amount clockwise and see if that helps, if you get pinging though then you moved too far. Move it maybe 1/16-1/8" at a time. What RPM does your car idle at?

It could also be fuel related, I dont know much about the SU carbs but there is an oil level that you could check, I will not say what kind of lube they use but I have heard of people making thier own mix instead of buying it. I also have a book on Weber and SU carbs that I could give you for a few bucks if you dont want to hit the web for it, I dont need it, or just ask in the CARB forum for advice on how to check the lube level of the carbs, and what to use to lube them with.

Does the power kind of surge on when it comes, or is it pretty undetectable? You could also check your fuel filter(s) to see how they look.

[z_boi]

my car is set at about 800 rpms but most of the time, it usually idels higher than that, sometimes its over 1000rpms, the highest I've seen it idel at is about 1300rpms. its very unpredictable.

My car is fuel injected. Its not exactly a power surge and its somewhat predictable. Thanks for helping me out Mudge!

Well, Im gonna do a major tune up soon so i'll see what happens after that.

[beandip]

you are asking your engine to produce power with out turning any RPM ! what are you thinking , these engines are good strong LITTLE power plants , but they need help . An engine must be turning more than 1500 rpm to create any ammount of power . You need someone to show you what lugging the engine will do and not do. This engine will not make power in secound or third gear under 2000 and will pull it's hart out up to 5000. Drive an automatic and duplicate the shift vs. RPM shifting pattern in your 280 and you will then see what this car can do. Maby you are used to driveing a desel powered car they make power at low rpm. As far as the post on SUs the oil in the damper is 20wt that is what is recommended by the factory and I find it to work the best . 10w30 will in a pinch. You can find 20wt at a cycle shop it is used in the front forks , it is called fork oil by the 20w , as to the level of oil there is a mark on the dampiner , if you put in too much , no worrys it will just flow down into the carb and be burned with the fuel. By the way the dampiner is the little rod with the black plastic cap in the middle of the dome. On the injected ingine If the idle is vasolating between 800 and 1300 look for vacume leaks, to start with.

[Mudge]

Ok, now that I re-read your first post, its possible that you are expecting too much.

You would need a V8 with around 300# of TQ @ 1500 RPM for you to lug up a hill and not give it more gas, and this is a peaky engine compared to an early 90s TQ puller V8. 4400 RPM is where peak torque is at stock.

What is your gas mileage like? If your in the mid 20s or so, your car is fine. You can also check your plugs for clues.

When you drive a car with a little engine, you are going to rev it more than a V8 with cubes, that is just the facts. This is why Hondas have to rev to 8k or so to make the power that they do, they are NOT torquey engines.

Check your MPG.

[Ed]

Since you are new to this and if you still feel that there is something wrong with your car my advice would be to take it to a shop. Go to someone that has experience working on Z's. Some shop's will let you go with your car and see what the mechanic is doing. I usually never ask and just walk back there as the mechanic is getting ready to tinker on my car. Then I stay out of his way and start asking questions. You could learn so much in twenty minutes. If there is nothing wrong then you pay a little. Usually just a diagnostic check. If he does a little work on it, it's usually about $50 an hour. It's well worth the education.

[z_boi]

when i say no power i mean its like, even if i floor it, it doesnt pic up any more speed untill it gets to a certain point. I've drivin 4 cylenders(manual) b4 and have never experienced any thing like the way my car perfporms. Or maybe im jus used to drive automatics. I dunnoe guys, even when im goin in 2nd or 3rd gear at about 1800 rpms or so, my rpms would drop even if i floor the pedal ( that is goin up hill). I dunno guys, U tell me.

My mpg doesnt seem all that great. i think its under 15 mpg. Not quite sure. Again, i have a 78' fuel injected 280z. no carbs.

Well, ima try to replace all my vacume hoses and egr unit soon and then i'll see wat happens.

thanks guys for helping me.

[Mudge]

You should have a 13 gallon tank, fill it up and watch your mileage the next time you fill it up. If you went 200 miles and you used 10 gallons to refill the tank, you got 20 MPG.

[Ben]

Hi Z_boi,

If you have next-to-no power at any rpm's then you have issues.

Task #1 get a manual, & get familliar with the diagnostic proceedures for both the engine & EFI system.

Based on that you will find out that for something like lack of power the following could be the cause (taken from Engine-Fuel section of the L24E FSM):

Improper ignition system

Malfunctioning throttle valve

Malfunctioning air flow meter

Clogged air cleaner filter (now _that's_ easy to check)

Improper fuel line

Improper fuel pressure

Problems in the following circuits:

* Ignition coil trigger input circuit

* Control unit power input circuit

* Injection circuit

* Air flow meter potentiometer

* Throttle valve switch, idle contact & full throttle contact

* Air temperature sensor

* Water temperature sensor

* Air regulator & fuel pump circuit

I know that's pretty much everything, but fixing these problems is a process of elimination. The L-jet system is relatively simple & a proper diagnostic process _will_ solve the problem.

Keep us posted & get ready to enjoy heaps more power from your car!

[Mudge]

Dont expect to gun it at 1500 RPM and have it fly, unless you are in first or second gear. If you had a V8 or V10 built for torque that would be different, small engines are built for higher powerbands.

[beandip]

It appears that you are inexperienced in the driving and handeling of the car. What you could do here is to take the car out to a stright road with no traffic and dry pavement . start out form a stop like normal in first gear and take the car up to 2000 rpm and level out on the speed and dont shift. Now as you are crusing along do nothing with the clutch just floor the gas and take the engine up to 3000 . Now that you should have felt some power . go ahead and shift . Now if you have the room do the same thing from 2000 only this time take it to 4000 but do it in secound gear , you should be getting the picture. Just make sure you are on dry clean pavement . As for the mileage if you are not shifting at the right speeds and lugging the engine the mileage will be crap, and the enging will be getting loaded up with carbon. Be careful here when doing this test as the car should respond unless it is so loaded up and running bad . How ever this should blow it out and clean things up . I have seen this before with people that are not use to driving a manual shift car, trying to pull hills with a load in the wrong gear . This is good that you are asking these questions because y ou can knock out the lower end of the engine by lugging it. The lower end is the crankshaft and main bearings not to mention blowing holes in the tops of the pistons. Get back to us on this . Gary

[Ed]

Z-boi, The "power band" on your car should be between 2500-6000 rpm. Look at your rpm guage before you shift.

Atleast take it to 5000 rpm.

[beandip]

If he is getting used to handeling this car 4k should be plenty , unless you need a parts car, only kidding. I was just trying to get him to get into the power band of the engine with out loosing controll , he will be doing plenty of that on his own. By the way ed did you mail Phred.

[z_boi]

I was normally shifting at about 2000rpms. is that bad?

But when i go up hill i shift maybe around 3000 or so. Now im sifting at about 2200-2500 rpms.

Ed, when you say at least 5000 Your not talkin about normal driving are you?.

Guys. when im talkin no low end power. im not talkin about pushin the car. im talin about normal driving. I have no problems when driving the car hard expept when i shift fast and pop the clutch, it seems to get a lilttle jerky and doesnt quite accelerate for a few seconds.

[Zedrally]

Can't help myself here!

z_boi, you have a vehicle that has a high revving engine. It's not a Ford or GM.

You will have to get used to it and once you do you'll never regret it.:stupid:

As much as you might hate the thought, L series engines purr between 3 & 5K

Just try shifting through the gears at those rpms and enjoy!!!!!!!

LOL

[2ManyZs]

Look at it this way, torque is what gets you off the line and gets the vehicle moving. The L-series does not have the torque that a low revving domestic straigth six has because it has a small displacement.

If you look at one of the hottest sports cars to come from Japan in the last 10 years you will see the similarities with your Z. The Honda S2000 has very impressive HP numbers from a very small displacement engine, yet it lacks torque. If you read all the tests of the S2000, they all say the same thing, lack of low end torque. Get that little Honday revving in the 4K and up to its 9K rev limit and it does fine, below that and it is a bit of a slug.

Your Z is in the same dilema, it has good power, but it will always be a bit low power in the lower revs, unless you do something to improve it. Two things that will help it significantly are a light weight flywheel so the engine will spin up to higher revs quickly and a lower rear end gear ratio.

[z_boi]

Ok. I'm talkin about normal driving. When you talk about shifting within 3000-5000, are you guys talking about driving it hard or normal driving?

when i drive my car hard, i dont shift untill at least 4000rpms or above.

when i drive normally. speed limit, normal stop and go, I USED TO

shift at about jus under 2000 becuzz i thought it saved more gas that way, and at about a loittle over 2000rpms for hills. but what im getting from you guys is that it is not good on the engine.

So now when i drive NORMALY, i shift at about a little over 2000 to 2500rpms. it seems to be driving fine.

So im jus wondering now if you guys are talking about PUSHING IT

or jus NORMAL DRIVING?

[Zedrally]

Pushing It....Gear Change 5/6K

Normal Driving 3/4K

[z_boi]

humm.. I guess its jus cuzz my car is loud and when i drive it up to 3k normally it jus seems like im reving high. Guess i'm more used to driveing quite little four bangers.

Thanks guys.

I needa get sum electric fans, any recomendations?

[Mudge]

Originally posted by z_boi

Ed, when you say at least 5000 Your not talkin about normal driving are you?.

Powerband, not shift points! Depending on how fast I'm accelerating, I shift from 2000-4000, if I'm on the track I shift from 5000-6000 depending (road track, not drag).

I also skip gears ALOT, but I have a 3.90 rear, I do 1-3-5, or 1-3-4-5, or 1-2-4, yada yada, sometimes even 1-4-5.

Straight 6/8 engines are usually considered torquey low revvers (for the old days), because long cranks dont typically like to be wound out (even the Viper has a low peak HP RPM). However with 168 cubes for the 2.8L we dont exactly have a tow truck

I have so much friggin rear gear, that I am shifting to 4th by 28-35 MPH and that is not at a low RPM either, that is one big reason why I skip shift alot. I can take off from second without hardly slipping the clutch at all. I can't wait to put in a 3.36 or 3.54, the 3.90 is ridiculous without it being a full on race car, or at LEAST a later model 5 speed.

As for the electric fan, just make sure you do the wiring yourself if you want to save money. MSA sells a kit for a very high price, I bought a Saturn fan for not even $30 (you could find a fan for $5 if you wanted) and then buy a relay/temperature sensor that you like at Jegs.com or Summitracing.com from $20-$50 depending what you want.