eg d15 flat spot in acceleration

[tottitomo]

I have a 94 eg with a d15b7 manual,

When taking off first is fine then second acceleration stops and has flat spot I would say it’s around 2500-3000rpm with your foot flat to the floor nothing then all of the sudden it will rocket off... or you change in to third its usually fine too, it’s been like this since I got it and it doesn’t happen all the time.

I’ve changed:
Spark plugs
Leads
coil
Fuel pump
Fuel filter
Earth straps off gear box and rocker cover
Air filter
timing belt
Changed injectors
Reset ecu
Cleaned throttle body
Checked ignition timing

Is there anything else anyone can think of and does anyone have the same problem

thanks Rhys

[Flippit]

sounds like VTEC is kicking in lol!

On serious note, You said you changed fuel pump, how about fuel filter?

[tottitomo]

Sorry yea changed the filter too I'm seriously stumped

[brad]

O2 Sensor..? I know there's usually a CEL associated with it, but it's worth a try if you've done everything you've listed.

[Daveho1]

check the calibration on the tps befor replacing more parts.

[hoaanguyen]

i have this problem as well, started happening after i changed my headers and extended my o2 sensor to fit the new headers i bought on my d16y4.

[tottitomo]

Thanks for the ideas how do I check the tps

[Super-DA9]

Thanks for the ideas how do I check the tps

Searching usually helps: http://www.ozhonda.com/forum/showthread.php?120191-Calibrating-the-Voltage-on-the-TPS

I'd check the O2 sensor, do you have a friend with a D series honda? swap there O2 into your car and see if it fixes the problem.

[tottitomo]

Thanks I'm using a phone to look at this I did a quick search didn't come up with anything ill test my tps when I get home and if its good ill put a new o2 sensor in as I don't know anyone with a Honda...

[VTURBO]

blocked Cat .... checked the timing on the dizzy ...

[Daveho1]

honerstly could be a number of things and random guesses arnt gonna get you there. stop replacing parts for a bit and go through all the sensors that control air and fuel delivery peramiters. have a loom at ecu-mans pgmfi diagnostics threads as per each sensor that could effect it and test accordingly.
for all sensors there is a way to test em. just gotta figure out how and its free so nothing to lose

**from what i recal changing the o2 sensor is recomended every 100,000 or so anyway regardless of if its faulty or not, gets colged up or somethin

[zhong]

Check that your fuel pump sock is mounted in the right direction (down, not up). Sounds like fuel starvation problem to me.. Check injectors after that.

Peace.

[tottitomo]

thanks for all the ideas I think the cat is fine as it doesn't happen all the time,
and the fuel pump pre filter can only go on one way
im going to check my tps and o2 as soon as i get back home

[zhong]

That's true - but is your fuel pump OEM? I'd check injectors too, other than that maybe a kinked throttle cable?

Stumped.

[Super-DA9]

That's true - but is your fuel pump OEM? I'd check injectors too, other than that maybe a kinked throttle cable?

Stumped.

I don't think there's a way to really "check" your injectors. Pretty sure if they aren't working well they just tick really loudly.

It's also pretty much impossible for the throttle cable to get kinked as pretty much the entire thing is sheathed.

[zhong]

I don't think there's a way to really "check" your injectors. Pretty sure if they aren't working well they just tick really loudly.

It's also pretty much impossible for the throttle cable to get kinked as pretty much the entire thing is sheathed.

It's not to check that they're "not working" it's to check whether it has a flow issue that may potentially cause inconsistent flow. And how do you diagnose an injectors' health by listening to its ticks? @_@ Doesn't hurt to check, they're worth peanuts - heck I have a spare set you can take for $10. My throttle cable was kinked and started to tear up like a brush - which caused me to have "flat spots" - like it will just jump, replaced it and it was gravy. This was all on my mighty D15 also.

Just speaking from experience.

Peace.

[Super-DA9]

It's not to check that they're "not working" it's to check whether it has a flow issue that may potentially cause inconsistent flow. And how do you diagnose an injectors' health by listening to its ticks? @_@ Doesn't hurt to check, they're worth peanuts - heck I have a spare set you can take for $10. My throttle cable was kinked and started to tear up like a brush - which caused me to have "flat spots" - like it will just jump, replaced it and it was gravy. This was all on my mighty D15 also.

Just speaking from experience.

Peace.

Fair enough about the throttle cable, I guess all it takes is a single look at the exposed section at the throttle anyway. But on the subject of injectors I didn't say "not working" I said "aren't working well"... If the injectors have any sort of blockage they usually tick louder.

So how would you actually check them for consistent flow?

I guess replacing is an option, or you could have them properly cleaned but I wouldn't really class that as checking them.

[zhong]

Fair enough about the throttle cable, I guess all it takes is a single look at the exposed section at the throttle anyway. But on the subject of injectors I didn't say "not working" I said "aren't working well"... If the injectors have any sort of blockage they usually tick louder.

So how would you actually check them for consistent flow?

I guess replacing is an option, or you could have them properly cleaned but I wouldn't really class that as checking them.

"Check" them by seeing if your replacement set of injector removes the 'flat spot' whilst driving I guess? I wasn't trying to be technical, I was just trying to help. Plus, you can get them flow tested to "check" also. lol

Peace.

[Daveho1]

seems like guess work to me.besides injectors eather have restriceted flow or they dont, injector problems in older engines such as this will cause a constant problem rather then an intermitant one such as this, however most injectors would benifet from a cleaning.
it sounds electrical, as you may know some sensors are variable resistors in one way or another and when they are faulty they somtimes function normaly untill a spacific resistance and then can be erratic or unresponsive.

[zhong]

LOL I love ozhonda.

Goodluck with it all OP!

[~Sp33~]

So how would you actually check them for consistent flow?

It's called flow testing. Injector flow testing + clean will set you back about 150$.

[Super-DA9]

It's called flow testing. Injector flow testing + clean will set you back about 150$.

Yeah I know, I've had mine cleaned on the machine before too, but it's not really something you can do yourself to find out if it's an issue before spending the money, which is what I was getting at. It's pretty much just doing it hoping that it fixes the problem.

Not that getting it done is a bad thing though, but it may not be a necessary $150 to spend.

[tottitomo]

My mate has an injector machine could get it done for free...

[Super-DA9]

My mate has an injector machine could get it done for free...

Hah! Well there you go! Lucky!

[Daveho1]

makes it easy. i doubt thats the issue though but ive been wrong befor

[tottitomo]

So I just calibrated my tps it was out by a tiny bit its now bang on, went for a short drive no problem. but I've been driving all day (before calibrating the tps) on the old pacific highway and trough Sydney and haven't had the problem so I'll give it a few days to see if the flat spot has gone

[tottitomo]

Nope still has the flat spot... Ill check more stuff as soon as I can