Ka24de bad throttle response. Where to start?

[cheesemounger]

So I'm new to the forums and I just bought my first 240sx Aug. 31st ,2013. I was told it has a bog issue before I bought it. And I wasn't to worried about it I was just planning on buying a new engine ,but since I realized money is tight I want to know what I could do to save my 93' KA24DE( or at least I think its a 93'). The only thing ive noticed so far is that when i rev it up theres is a delay after i hit the pedal and until the engine revs , but it only happens while the rpms are still going down from the previous rev.Oh and its a 91' 240sx hatchback. I'm just looking for some direction on where to star and if anybody is having the same problem .
Thanks

[daemonyk]

First thing every new 240 owner should do is savagely beat it with maintenance Oil & filter, plugs, wires, cap, rotor, air / fuel filters, belts, etc. Shouldn't cost you more than like $200 to do it all - def try to do as much as you can. Also make sure you're running it on premium 93 gas. The KADE is designed so it *can* run on regular 88 w/o knock, but performance suffers if you do. Try doing all that, then see how it feels. Even something as simple as old oil can make a difference in performance

I'd do that first before I go start testing other things

G'luck, and welcome!

[cheesemounger]

Alright thanks. And what about spark plugs what are good for performance

[daemonyk]

I run plain ol' NGK copper plugs in everything. They've never let me down. The times I tried plats or irids, the engines hated them. Multiprong plugs are a gimmick IMHO.

Don't worry about "performance" stuff for now. The fact that the car was sold to you with an unknown bogging problem makes me feel like it wasn't very well taken care of by the previous owner Just replacing old worn janky parts with new fresh properly functioning parts is a performance upgrade for a 240 After that, if you're still having problems, they'll be easier to diagnose because you'll have a long list of new parts that probably aren't part of the problem.

Ya know, while you're doing the plugs, maybe do a compression test too if you can. Just cos the plugs are already out and you just got the car. Can't hurt to know the numbers.

[cheesemounger]

Alright thanks and does any body know or can take a video and show the link of where the front turn signals plug in at because mine are unplugged. ( it's a pig nose if that helps). Thanks

[daemonyk]

I don't *think* the wiring changed between piggy and sharky, and if yours is a 91 it should be a sharky, even if it has a piggy bumper (89-90 = sohc / piggy, 91-94 = dohc / sharky) unless I'm mistaken - if it is the same, it should be pretty difficult to accidentally plug the wrong two connectors together. They should be hanging off the main wiring harness that wraps around down there - just look for matching sets of connectors. If everything else is connected, they should be the only unused connectors down there. If the wiring / connectors are different, still should be the only unused connectors, but not necessarily direct fit.

Also grab the FSM 240sx-factory-service-manuals-t549156.html

[cheesemounger]

Alright I'll go mess with it and see what I can find

[waxdnuggz]

check your fuel pressure. check the injector resistance. if it boggs comming from the previous rpm chances are your starving or gourging the engine with (air or fuel). believe it or not my last ka did that because i had a short in the old harness. make sure your harness isnt chewed anywhere. also check your electronic vitals. (12v at batt when cars off, +12.9v when the cars on, you want as close to zero ohms of resistance as possible anything over i believe 6 or 7 ohms is bad) the short i had caused me to have 38 ohms of resistance at the batt. meaning its starving something of electricity.

if its bogging only on deceleration to accel then chances are its not compression chances are its an air or fuel problem whether its from electrical or mechanical. start with that and let us know

[cheesemounger]

Alright ill check that out hopefully soon. And my plan was to eventually boost my ka but I have no idea where to begin. Looking online for ideas is only confusing me more. Anyone have any ideas? And yes I'm planning to solve the bog problem first. With everybody turning to sr's I would rather stand out and and have a beastly KA

[cheesemounger]

First thing every new 240 owner should do is savagely beat it with maintenance Oil & filter, plugs, wires, cap, rotor, air / fuel filters, belts, etc. Shouldn't cost you more than like $200 to do it all - def try to do as much as you can. Also make sure you're running it on premium 93 gas. The KADE is designed so it *can* run on regular 88 w/o knock, but performance suffers if you do. Try doing all that, then see how it feels. Even something as simple as old oil can make a difference in performance

I'd do that first before I go start testing other things

G'luck, and welcome!

I don't know if I did the quote correctly but while I am replacing these I wouldn't mind setting up for a future ka-t setup. By that I mean injectors and mafs because I always see people talking about upgrading or swaping SR injectors /or a300zx mafs those when boosting. So if someone could let me know what to do to prepare for a turbo , or just to beef up the engine .

[daemonyk]

check your fuel pressure. check the injector resistance. if it boggs comming from the previous rpm chances are your starving or gourging the engine with (air or fuel). believe it or not my last ka did that because i had a short in the old harness. make sure your harness isnt chewed anywhere. also check your electronic vitals. (12v at batt when cars off, +12.9v when the cars on, you want as close to zero ohms of resistance as possible anything over i believe 6 or 7 ohms is bad) the short i had caused me to have 38 ohms of resistance at the batt. meaning its starving something of electricity.

if its bogging only on deceleration to accel then chances are its not compression chances are its an air or fuel problem whether its from electrical or mechanical. start with that and let us know

That's the stuff you move on to AFTER you make sure the engine is in decent shape Minimizing potential causes makes troubleshooting easier, and those things are just a good idea anyways Compression test was a "just beause" thing since he would have the plugs out anyway. Especially if he plans to turbo it later, the comp numbers would be nice to know, ya? And if the compression Is low by chance, then he knows not to waste any money on it, or to rebuild it, or w/e. No such thing as knowing too much about your engine

I don't know if I did the quote correctly but while I am replacing these I wouldn't mind setting up for a future ka-t setup. By that I mean injectors and mafs because I always see people talking about upgrading or swaping SR injectors /or a300zx mafs those when boosting. So if someone could let me know what to do to prepare for a turbo , or just to beef up the engine .

Yeah, you got the quoting right The thing about upgrading those things is you'll need a tune to make them work. If you're def gonna go KA-T, start accumulating those parts. Things like maf, injectors, fuel pump, bearings internals w/e you plan to do. Then pull the engine and do it all in one go. My 0.02. Whatever gains you get on the N/A side of things will be peanuts compared to the turbo power. There's plenty of KA-T builds on here s-chassis-build-thread-list-t441933.html - they should give you an idea of what you're looking at and what they entail.

[cheesemounger]

Alright so should I go stock parts now. And in the mean time build a collection of future performance parts ? And speaking of performance parts there Is currently a spectre( I think it's spelled that way) cold air intake and I was planning to replace to do the todo list that I quoted and its a funnel intake. Good or bad idea? I don't know if it will mess with the a/f ratio or not.

[daemonyk]

I have a Spectre cone filter on the end of my MAF lol. Intakes are fun to spend money on, but I wouldn't bother. Given how little gains they actually offer, they're almost more of a dress up mod than a performance mod As a dress up mod, have at it, they do look alot slicker than that stock plastic intake tube IMO, that's for sure.

If you keep the stock compression ratio, you can do all manner of things to the bottom end to build it up for low boost. The only thing is stock CR isn't too good for high boost IIRC - it's like 9.5:1 - turbo cars are usually more like 8.5:1 (?) RB25DET runs 9:1, and that's thought to be oddly high. If you put lower compression pistons in, in prep for turbo, I think the engine needs a tune to adjust for the change in CR. Someone more experienced than I when it comes to KA-T setups should be able to better answer questions on that front.

All things to consider. If you can wait, It'll pay off in the long run if you save up parts, buy the right parts, and don't skimp on important stuff. If you find a cheap KA somewhere, you can always build that up at whatever pace you want, and when it's done, drop it in. In the meantime there's a ton of other mods that can be done to make it run and ride better. Suspension, for instance.

[cheesemounger]

Good point in saying I should get a spare engine to build and I think I'll do that. Anybody know where to get a cheap ka24de. I live in Arizona so somewhere in state would be best?

[daemonyk]

Check craigslist, and check the NICO classifieds classifieds.html . I know we've definitely got more than a few AZ members on here

[cheesemounger]

So I just bought some copper NGk spark plugs, fuel filter, so I'm getting closeish. But anyways I looked and there are spare connectors near my turn signals to connect so I have no idea where they plug in at

[cheesemounger]

I meant not spare connectors

[daemonyk]

Dunno Try looking in the FSM. Google images is also handy for finding random images of stuff to reference. I don't plan on having my bumper off any time soon, and mine's a mess of wires cos HID's and extra wiring for silvia lights. Otherwise I'd snap a pic.

[cheesemounger]

Alright ill check it again