isays

Hi, sorry if this is just flogging the dead horse. I did a bit of searching around the forums, but I want to make sure I have everything right.
As you may have guessed, I have some engine trouble.

It all started yesterday. I was accelerating hard up a shallow hill and around 6500 the engine hesitated for a split second. I didn't see anything light up, but I noticed the engine wasnt totally warmed up yet so I thought that might be the cause.

Then last night I was again accelerating hard up a shallow hill and around the same RPM the engine hesitated for a split second. This time a bunch of lights flashed up and went out (before I could read them) but the CEL stayed on solid.

Other than that, it drove just fine, no issues, but I nursed it home to be safe.

This morning I took it into the dealer. They found a p0302, so they checked the coils and plugs, found nothing. They also inspected the coolant for leaks and didnt see anything. They removed the warning and said to keep an eye out, and if it comes back, they'll have to take it in overnight to pressure test the cooling system to see if it leaks into the engine.

Everything was fine, so just before I got home (with the engine warm) I gunned it up another shallow hill. Around 8000-8500 there was the split second hesitation again, and the CEL blinked for about 10 seconds and went away.

The car is a 2004 GT, stock. I've had it for 15 months, I got it with 25000 KM on it and since i've put on another 30000 KM. The owner before me took care of it (wouldnt drive it in winter, etc) and I've tried to take care of it pretty well myself. I take it to the same dealer as she did.

I only have my underground parking space to do work, and my only DIY expierence is fixing the cold solder problem in the heating control... so I'm not really able to perform any complicated DIY diagnosis.

So far on the forums, common causes seem to be plugs, coils and the fuel pump.

I'm looking for simple tests I can peform to check stuff myself, as well as what you guys think the likely culprit is. Basically, I want to know enough to not get hosed by the dealer.


Thanks

Jedi54

iTrader: (7)

P0302 Rear rotor misfire detected Flash/ON 1 or 2 Misfire
taken from our awesome sticky thread with all the CEL codes https://www.rx8club.com/series-i-tech-garage-22/rx-8-technical-info-cel-codes-pcm-pin-list-collision-guide-26291/

flashing light / hesitation is typically a sign of a misfire which is confirmed by that code.
likely suspects are coils, plugs, wires.
In the 30,000 kms since you've had it have you replaced any of those?
The previous owner took good care of it but did she replace those parts?

If not, I would start there and consider it a 'tune up' for your RX-8. I usually replace my spark plugs every 20,000 miles so and ignition coils can last anywhere between 10,000 and 50,000 it really is luck of the draw.
both of those are very easy to do if you consult our DIY subforum. Either that or maybe a fellow member in your area can help you out with them.

ShinkaEvo

iTrader: (3)

Keep it under 3k rpm before warm up, unless you want a new motor...

isays

The plugs were replaced by the previous owner (it happened a few weeks before I met her, I didn't get the receipt... so who knows for sure). The guys at the dealer checked the plugs and coils and said it was OK (not that they right 100% of the time, or anything).

I might give a look at replacing those myself, though. I don't know when the coils were last replaced, let alone the wires. Probably haven't been any time recently.

What do you think of the dealer's suggestion to pressure test for coolant leaks into the working chamber of the engine? is that something worthwhile getting, or are they just blowing smoke?



it wasn't cold, but it hadn't reached its resting place right smack in the middle of the temp meter either.

anyways, that isn't really the point of this thread.

ShinkaEvo

iTrader: (3)

It's about your 8...

Keep gunning it before it's warm as you wish then...

Jedi54

iTrader: (7)

isays: no pressure test needed.

scremn8

Replace the coils and wires. Then go from there.
Dealer will tell you coils are good cause they have no clue

isays

Thanks for your help Jedi and scremn8. I'll start looking around the forums on how to inspect the coils and wiring myself. I was looking at the BHR page yesterday too to get some pricing on new stuff. Good to know that the pressure test is probably just a shot in the dark. I thought it was kind of a strange test to perform... but I'm not an expert.

thanks for all your help, ShinkaEvo. You've helped me so much with the problem that I've had.
Out of the 3 times I gunned it that I discussed in this thread, twice were warm and the other was on the way to the hospital because my roomate just broke his arm. And that time was almost warm. Quit being douche-sauce.

Anyways, thanks to everyone else.

Jedi54

iTrader: (7)

isays: over revving a cold rotary engine is a BIG no-no. don't think shinka was trying to be a douche, it really can cause lots of issues. I understand you only did it once, we're just letting you know.
Moving on now..


the BHR coils are a great upgrade! Both scremn8 and I have had issues in the past with OEM coils failing prematurely where as the BHR coils seem to withstand anything and everything I can throw at them, including 115°F heat in vegas which usually cooks up OEM's.
If you want to test the OEM's, I can provide you with instructions but you'll need a multi-meter.

http://www.finishlineperformance.com...16-07-1793.pdf

MazdaManiac

iTrader: (3)

The PCM has a cold rev limiter, so "gunning" it when it is cold isn't really a problem. I wouldn't race it until it was warm, but the PCM will keep the revs below 5500, anyway.
ShinkaEvo's advice isn't really valid.

The fuel pump can also be an issue, but that generally doesn't manifest itself until the engine is warm.
Bad plugs are amazingly difficult to diagnose.
When in doubt, simply replace them.

isays

ah, sorry I got so defensive. I come from posting on tech blogs where people flame eachother for no reason and are generally douchy. Maybe I need more sugar :p

If I replace my coils, I'll probably replace the plugs too, just to get em all at once. Is inspecting the coils as hard as the plugs? I've never done it before... I'm just going to follow Jedi's instructions (I do have all kinds of small tools and a multimeter, just no big tools or a way to lift my car).

How do you inspect the wires? or is it obvious when they're in poor condition? ... or I suppose I could just use the multimeter for that, too... lol.

For the most part, the car still seems ok as a daily driver. Is it going to cause issues or damage if I keep driving around and keep the RPM down, until I get everything fixed?

isays

What makes diagnosing plugs difficult? Is diagnosing the coils also difficult, or just the plugs themselves?

Two of the times that I had this problem, the engine was warm. (the other time it was fairly warm). It wasn't hot like from being on a track or anything, but it had been driven for 15 min or more. How would I go about testing the fuel pump?

Hopefully I'll get to testing it tomorrow.

Mazurfer

If you aren't limited by funds, then do the coils, wires, and plugs.
Look at it this way..................if you do these yourself and buy them from a vendor on this site, you will save a ton of cash that you might have otherwise spent at the dealer or any local shop in buying them and paying to have it done.
Plus..........you get to learn about and be more "in tune" with your car. It ain't rocket science.
People will pipe in with the best price on coils, plugs, and wires...............or you can simply go the BHR ingition route which will get them all and be far, far better than stock!

http://blackhaloracing.com/products-...nition-system/


Oh...and we are douche's and ain't gonna stop for you! That much you can rest assured.

isays

hahaa, thanks mazurfer.
At some point I do want to do my ignition system and replace my fuel pump anyways... but I'm my bank account is still recovering from christmas, so if I don't need them I'd like to hold off until I'm ready to do other work as well :p

I don't realy trust my dealer that much anymore. they're nice, but i've been a bit suspicious after they wanted 500$ to fix my heater that turned out to be the cold-solder problem lol. I'm trying to do as much as I can myself now.

Is there a good way to test my fuel pump without much equipment? If the fuel pump is causing misfires, does that problem manifest itself in other ways? is it related to the fuel starvation problem that the pumps have?

Mazurfer

I gotta be honest here, I highly doubt at this time it is the fuel pump.
As I know it(and I could be wrong), these USUALLY start to fail because the fuel is used to cool them and the problem starts with less than 1/4 tank of gas on a warm or hot engine. In other words, it won't have any issue when tank is say 3/4 full, but when low on gas, it will. See if you can see verify that.
In terms of checking the pump, I'm sure if you do a search(advanced seach) on here, you will see how it can be tested.

What say Jorge and Jeff? Did I get it halfway right?

Oh...............and I don't think fuel pump issues cause misfires(per say). I'm still betting coils, plugs, and wires at this point, but I better go read your initial symptoms again.

And know this..........even if you use the pdf to check the resistance of the coils, they can still be bad! While that test is good, it's not a catch all. If plugs were replaced recently as you stated, I would go for coils, but to be honest..........I would do plugs and coils. That's just me..............then I would have my own baseline. You can do those both in under an hour...........even if a noob! That's why I said one hour.......it's actually much quicker if experienced or have done on this car before.

isays

ok, sounds good. I'll do a quick search on how to do fuel pump too. Mostly because I'm still curious.

I'll probably end up doing what you guys suggest and replacing the whole thing with the BHR ignition setup. I'm waiting to get a quote on shipping:p

isays

i figured i'd update here:
still haven't gotten around to replacing my coils (i wanted to be more certain before i sunk 600$ into a solution).

my friend and I were looking at it and the wires that go from the coils to the plugs need to be replaced badly. So I'm going to do that soon. the lead that attached to one of the plugs (presumably the one acting up) was all messed up and wasn't making contact properly. also there were signs of damage to the wires themselves.

but i've noticed some other behaviour, which has given me pause:
just over 4000 RPM (presumably when the other ports open up) the engine hesitates for a split second. It still misfires up around 8500 as usual... but this is different.
first of all, it always happens at the exact same RPM. Secondly it will happen every time if i've got my foot down. thirdly, no CEL flash or anything.
its like it misses a step... just a sudden loss of power for like 1/8 second... then it works fine until it misfires around 8500.

could this also be attributed to the wires? or would this point to something else? I have to replace the wires anyways, but i dont want to spend money on the coils if this is a sign that something else needs to be fixed instead.

ganseg

iTrader: (5)

This is more about the random misfire - check to see if you have oil in your intake. Loosen the crosspoint screw on the front of the accordian hose. Pull the hose back and look in it and look in the hard plastic cylinder it connects too.

Oil getting sucked in this way can cause misfire by the oil fouling a plug or more. If you have oil in there, lower the oil level in your engine. (I can't run my oil at the full line.) I am going to add a catch can to prevent oil getting in the intake.

isays

I've checked the sparkplugs and they're not fouled up at all, they seem nice and clean. I'll check the intake anyways just to be safe. thanks.

akruger

I'm reading this thread because I'm having a very similar problem... my CEL is flashing though. Happens very similarly to how you've described and usually when pushing the car and between 3rd and 4th at about 8000 rpms. Doesn't happen every time, seems to happen after driving for about 15-20 minutes and engine's probably hot. I changed the plugs, coils, and wires with the BHR ignition system ( just for the record - i don't blame any of my problems on the BHR product - it is great and the people behind the company really know their business) I think that there were weaknesses down the line in the system and once the spark/coil issue was resolved it may have exposed the bigger problem. I will admit, I don't know engines so most of this is Greek to me but I have done my research and have been very diligent about taking proper care of this unique car. Any advice as to where to go from here would be great! My thoughts are to take it to a shop (not feeling great about the dealer) and see if they can pull codes and go from there based on their findings. The whole thing saddens me - love my car, just want to drive! Autocross season is short and don't want to spend the season with it in the shop but am concerned that I might be doing damage if I keep driving it even if the flashing light doesn't come on. Any thoughts on carbon build up in cats? help.

isays

I'm just about to order the BHR ignition system myself, so I hope someone can shed some light on the problem, since perhaps it isn't the coils/plugs/wires after all.

are you getting the hesitation around 4200RPM without the CEL, in addition to the misfire with CEL at 8000+? or is that just me?

akruger

The kit has a great track record - I think it's my car and the fact that the plugs and coils needed changing was one of the problems... not getting the hesitation at 4200 rpm. - I spent a lot of time reading on here and bottom line is that I need to take it in to a shop or dealer and pay to figure it out. I was just wondering if you got to the bottom of your issue yet - might shed some light on mine. keep me posted.

akruger

AGREED,worth investing in

isays

Figured I'd update:
problems fixed.
I cleaned my SSV and seafoamed. I also made sure my plug wires (which were in terrible condition) were on firmly.

This fixed the misfiring and engine hesitation at 4300rpm.

The engine still felt a bit groggy and lacking in power.
When I installed the BHR coils, wires and sparks... voila, its way more responsive and pulling much better.
I've only had the coils in for a few hundred KM, but they're working great so far.

(note: the SSV was pretty dirty, but the seafoam hardly made any smoke. I don't know if that means my engine was clean or what, but i thought I'd make a note of that)