Hard starting

[TC 2980]

Hello, people of the Honda world. I have a serious problem with my '96 Prelude (H22 with cold air intake, iridium plugs) when running at high rpms I get explosions coming from the exaust each time I change gears (mainly between 2nd & 3rd). The real problem is when stop and shut the engine off and have to go again in another 5mins the car won't start. I have to leave it for another 5mins or so and it starts and drives perfectly normal.

can anyone shed some light on this situation?

[rubix777]

I see you have a misfiring system.

[ludeguy]

what you have is afterfiring, (not to be confused with backfiring, which actually burns back up thru the intake manifold) - it's usually caused by a too rich mixture still burning as it exits your exhaust pipe. It's the air/fuel combination that remains in your exhaust gases getting RELIT off by hot spots in your exhaust system
a number of factors could cause a mixture to be too rich. I imagine it happens between 2nd and 3rd when you let off the gas a bit to switch gears - (ie high rpm, partially closed throttle. It could be due to your injectors, injector resistor or a whole multitude of misinformation given to your ecu by other various sensors. or anything else that allows unburned fuel to enter your exhaust system ie: spark plugs (you mention which ones you have so i assume they are newer), incorrect valve timing, incorrect ignition timing, etc etc...

as far as not starting afterwards perhaps a few more details might help... is your car throwing any engine codes atm?

also have you been running high octane gas?

as shrek always says - better out than in (:, but i'd still try and fix it. or you'll launch your muffler to tokyo, and that shit always scares me in a parkade, like a someone's got a hand cannon or something, and i gotta start ducking behind cars or running like a sissy girl.

cheers

[TC 2980]

Thanks alot, I can rest easy now to know that it would not do any damage to my engine. I'll have entire timing system checked.

Berfore I go Let me just ask a silly question; If I install a MSD ignition, would that help burn the fuel faster in the chamber and reduce the amount of unburnt gas escaping into the exaust.

Thanks again guys.

[ludeguy]

woe woe woe.. i never said you aren't causing damage to your engine - i just said - better out than in (ie: atleast you don't have pre-ignition - that's when your car tries to run even though you've turned the ignition off) but alot of bad things happen (usually over time) from running an engine to rich.

a new coil should give you a higher intensity spark... but i'm not going to say it will solve this problem, in addition to having your timing/ignition checked you should really check the fuel pressure from your fuel pressure regulator (36 - 43 psi) i believe for the h22a, and also with a stethoscope type device someone should have a good listen to the injectors - although if the car isn't throwing codes i'm doubting there is a problem there.

in any case best of luck

[TC 2980]

Okay, I got you.

[ludeguy]

oh yeah, and also - if you haven't recently - clean your filter for your cold air intake (;

could be something simple.

[Gohan Ryu]

I read somewhere that the 4th gen ignition system is good up to about 400 horses - so you won't notice much improvement with an MSD unless you've really built your engine.

[TC 2980]

I was just thinking, maybe it's unburnt fuel remaining in the intake system that causes the occasional hard start when I try to re-start almost immediately after a high rpm run.

[ludeguy]

Originally Posted by TC 2980

I was just thinking, maybe it's unburnt fuel remaining in the intake system that causes the occasional hard start when I try to re-start almost immediately after a high rpm run.

you're car would have to be quite magical to get unburnt fuel back into the intake system...(the injectors are pretty much at the base of the intake manifold (ie: where the intake manifold connects to the cylinders), furthermore they are angled inwards/towards the cylinders.

there is something called "backfiring" caused by running too lean a mixture, that causes the flame propagation to reach into the intake system, but by all the accounts you've given so far - you're hearing explosions from your exhaust which is usually symptoms of afterfiring.

the inability to start is most likely caused by some sensor really not likely what it was told on the previous run, or something needing time to cool etc. you never got back to me on the diagnosis of your hardstarts though - or whether your car is throwing any codes.

[TC 2980]

Got it, thanks. I am yet to find a local mechanic (Tobago W.I) that I'm happy with, as soon as I can get someone that I can trust with my car I would let you know what the source of the problem was.

Just for curiosity sake; did you modify your Honda or are you running stock?

[ludeguy]

my lude was initially a 2.3 si, a connecting rod went (or something harsh in the bottom end), so now I've got a jdm h22a in it, with the h23a's transmission... but as far as all that stuff goes - yeah i'm pretty much stock. I'll prob mod in a bit once i've recouped financially from the swap, but nothing too dramatic, I/H/E, nothing too crazy cuz I want to keep it a daily driver - and i've already had an engine give on me once - don't need it to happen again. I'd like to have a few nicer than stock components that keep a car running well but not necessarily for appreciable performance gains, that being said however i doubt i'll replace much until the stock stuff shows signs of needing to be replaced. honestly I don't need to go much faster (: I think it's great the hobbists that get carried away in this stuff, and I love to see and appreciate really modded vehicles, but at the end of the day it's still a car and gets you from a to b, so as far as sinking a ton of cash into the thing it's not really my bag.

I haven't really had the car that long, but i've learned quite a bit about it because during the swap I was dealing with some idiots, and had to spell everything out for them, and even then they got it back asswards. Optimally i would have done the swap myself, if the car had made it back to the island that i live on.
the shop i used tried to pull a few fast ones on me including not changing the timing belt, using the h23a's injectors!!!, not changing the ecu (from p14 to p13, which made sense to them because the car rejected the p13 ecu with the h23a's injectors! duh!!!), not rigging up the vtec - but I caught them on all of it and finally have the car running well minus a little quirkyness from a leaky EGR valve, and an autotensioner that i've since replaced.

I have a mechanical background myself (helicopters) so I enjoy troubleshooting (although turbine engines are a little different than piston engines), and get my thrills elsewhere (:

[TC 2980]

Like you I haven't done much mods save for the cold air intake, high performannce clutch, and replacing the Auto... with a 5 forward manual Transmission.

But if the finance allow me to I would most likely install the Apex i V-tec/Air flow controller.

[mikester_91]

My H23 was doing the same thing before i got the timing belt replaced because it was so loose the valves weren't even opening. After i got a straight pipe put in with no cat, it would pop and shoot flames when i shifted (pretty cool, but it still ran like shit). I changed it after a couple thousand when i noticd it running bad.(Previous idiots never changed it before 130,000 miles)

[TC 2980]

Thanks Mike, I really do think a change is due.