Vexation241

A relatively short summary of my situation is as follows.

I own a 2004 with roughly 128500 miles. I purchased it used with around 119000 miles. As with most older 8's it as its issues, but I come today searching for confirmation/guidance on remedying an issue that has recently surfaced. A week ago today did a bit of housekeeping on my car. Cleaned the MAF, replaced the air filter, cleaned the ESS, and carbon cleaned it. After performing the carbon cleaning on the old ignition system I replaced the coils, plugs, and wires with a new set. Following all of this, none of the issues I was attempting to address (rough idle, poor fuel economy, hard hot starts, reduced power) were solved except for perhaps a slightly smoother idle. Under normal circumstances I would simply attribute these symptoms to a failing engine since they fall directly in line with low compression symptoms, however, a new symptom presented itself post-install. I am now getting very hard cold starts which should not be caused by a low compression engine. Based on my research and knowledge a hard cold start could be attributed (in most cases) to either a weak battery or a bad component of my new ignition system. Once the car starts it runs fine in terms of smoothness and redlines with no misfires, but the gas mileage seems to have suffered even more than it was with what I assumed previously to be failing coils. I was told by the previous owner that they were replaced at about 105000 miles. The car started fine hot or cold when I purchased it at 119000.

My question:

Could these symptoms be caused by a bad plug or would a bad plug cause a misfire while running?

I will repost if I have any other questions and I will be checking periodically so please don't hesitate to ask if you need more information.

Thanks all!

Also, first post.

jasonrxeight

they changed the starter somewhere around 2007 I think so it cranks the engine faster.

Vexation241

That's correct. The S1 starters went from 11 to 13 teeth. I have a new starter, it is unfortunately an older 11 tooth model, but just prior to swapping the ignition system the car did fine on cold starts. I can only imagine that the newfound difficulty in cold starts could be attributed to either a weakened battery from the carbon (zoom zoom) cleaning, or a bad coil/wire/plug though I feel like it should see improved or at least similarly bad mileage from a new ignition system if the hard cold start may be attributed solely to a bad or weakening battery.

Because of my train of thought/logic it leads me to believe that some part of the new ignition system is bad on some way, which is why I wonder if a completely bad plug would throw a misfire. Since I'm not seeing any misfires, if a dead plug would not throw a code then it must either be in the coils or wires, if the ignition system is at fault.

Any other opinions on the matter?

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Williard

iTrader: (18)

https://www.rx8club.com/series-i-tro...t-here-222584/

Vexation241

I've been through that thread several times, though reviewing it briefly reminded me that I forgot to mention that it has a new fuel pump. The main reason I created a new thread was because cold start issues seem to be rare and as such I haven't found much information on them outside of the Symptoms and Causes thread which also points toward ignition based on my experiences with its performance. I haven't yet load tested the battery, though I intend to do that before the day's over.

I promise I've at least attempted to do my fair share of research, though it's very possible that I missed something important and the obvious. I'll continue to try to provide as much information as possible in order to help diagnose the issue.

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dannobre

iTrader: (3)

Low compression will cause cold start issues.......If there isn't enough compression to support combustion it will not start. Poor compression can also lead to easy flooding...and poor starts as well

There are other things that can cause starting problems...if there is insufficient oil from the OMP you will get lower compression..

If you have a leaky injector you can get wash in the chamber and low compression...

I think you need to do a compression test...and see how bad it is before you get too carried away looking for other issues

Vexation241

I suppose that's fair. I don't doubt that I've lower than optimal compression, I was just running on the assumption that the hard starts could be attributed to the coils because it started fine the same day prior to the installation.

Is it possible that the carbon cleaning cleaned out enough junk to cause sudden compression loss to the point that cold start issues would surface?

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Vexation241

I'd also like to apologize for sounding presumptuous earlier. I was in a slight rush typing out my post.

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dannobre

iTrader: (3)

Possible.....it often will wash out all the oil film as well....

If you can start it..take it out for a good run and see how it behaves after. The OMP will output more oil at higher loads and that will re-oil the rotor chamber.

The first few days after a decarb can cause issues with plugs as well....

Vexation241

It's been a week since decarb (and all the other maintenance) as of today. Should I still expect some of the difficulty due to remnants of the decarb? I also injected a fair portion of 2 cycle into the ports after allowing the seafoam to sit for an hour or so in an attempt to help relubricate after the oil was eaten. It also seems that some starts are significantly easier than others from time to time. I'll look into a compression test today and see how soon I can get one scheduled. Any ideas on numbers that might indicate that the cold start issues may be attributed to low compression?

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Vexation241

Had some downtime after work and headed to advance auto to get a quick battery load test. Battery checked out fine, pulling about 10.5 volts while landed and with the fans still running.

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Montoyarx8

Hi everyone im new here so if i ask anything stupid im really sorry!

I just bought a 2004 AT rx8 and im having a problem with starting it,
the car will start when cold but it'll take about 5-8 seconds but now
when is hot it will not start it'll take a few tries, it cranks but does not
turn over then when it does it slowly turns over. i had a 6speed b4 and same
thing was happening so i changed the starter because i know it had a recall on it and that solved my problem but is it the same with the AT? according to the guy that i bought it from, he said that the spark plugs were changed and so the coils, i took a quick look at the cables and they look pretty new to me. so the things i tried to get this solved was sea foam it but didnt help with the hot start problem i also clean the MAF sensor and the throttle body, this did help with the idle but thats all. also the car was making a weird noise when i would shift it from 1st to second at 6.5 RPMs it would rattle but then i read that i needed to red line it more so i did, i took it to almost 8,000 RPMs and hasnt done it again so im not sure what that could be.

its a 2004, 85,xxx miles, AT

please someone help me im scared that my engine is going bad
i dont have much money to spent on that so im really hoping is not my engine :'( though i dont think is the case because i have red line it and never felt a los of power.. so please some help me on what i can do next..

Khurram

Get a compression test. Hot start issue is one of the major indicators for low compression..
I could be wrong..

an upgraded starter may only mask the problem for sometime.
Start off with a compression and an starter.

Montoyarx8

so there is nothing else i could do other than get a compression test? anything i can do to try and fix it b4 paying for that because i hear a lot of stories about ppl taking their cars to Mazda and not getting anything answered and its all a waste of money.

niteshade247

To the OP with all the cleaning you did I didn't see where you reset the memory as I'm led to believe you should reset the memory after cleaning the ESS and MAF. I wonder if this old stored data from you dirty components is causing you to have problems with the new data the clean components are now feeding.

04Green

iTrader: (1)

@ Vex,
I did not see where you reset the ECU after your work. Messing with the starter might have done it but it shoulds like you did all the right things.

I suggest doing the 20 brake stomp reset, then starting the car and just letting it idle until the idle drops down in the 850 range. Then drive gently for a bit to let the ECU re-learn. You changed a lot (all good) but the ECU is still trying to start the engine with the old parts, not this one.

Given the age of the car, I suggest the $100 thread in my sig. You have done many of the hard things, but there are some easy ones that will help as well.

Montoyarx8

hi guys so I'm sad to report that the starter did not change anything... :'( i feel like killing my self because i have a feeling that mazda is gonna tell me i need a new engine i don't have all that money
from you guys experience with rx8's what do you guys think is wrong with it?
im gonna take it to mazda this week but I'm so scared...

Montoyarx8

Hi everyone so I took the car to mazda and get it tested and they said that it has a bad engine.. 😭and is about 7k to put a new one... I'm really sad idk what to do if anybody knows anyone that does rebuilts or can install a new one for less I would love to know or can I upgrade to a new starter to hide the problem for now while I get money to fix it? Pls someone answer me on what I could do?

Williard

iTrader: (18)

Montoyarx8, Im assuming that you had a compression test done. Can we see the chart?

2stroke

Also if you make a trip to your local dealer and pull a VIN report and see if any TSB's have been performed more specifically the N3Z1 starter I believe


Things to remember too: warm up fully before turning off, latent fuel may stress an already underpowered ignition ( but I know your stuff is new so probably not any of that) also you make want to be prepared for a new fuel pump as well (I've got an extra). They don't do so well and yours probably is really old, maybe check and clean the filter (search DIY in tank sock filter).

dannobre

iTrader: (3)

That seems very high.....shop around. The dealer price for a reman is about $3400 or less and there shouldn't be more than 12-16hrs labor.....So about 5K would be more likely...

Montoyarx8

@ Williard
i will post them alter today im at work but from what i read they said that two of my
coils are failing that my #2 & 4 coils are failing that rotor 1 has 0 compression and that rotor 2 has very small compression but i dont understand how that can be if i dont lose any power when i drive it like crazy on the freeway.

Montoyarx8

@ 2stroke

How do i do the vin report thing sorry im stupid at this..
and where are you located and do you think the fuel pump could be causing the problem as well?

Montoyarx8

@ dannobre

i asked around and i can get an engine with 66k on it for $1,900
but i dont know how much labor would be and at this point im almost out of
money. i want to sell it instead but i fell like i wont even get $6,000 for the car is so
clean like 10/10 interior, 10/10 body is just this damn problem! even if i would get like $5,000 for it i would probably sell it.

hoosier1104

iTrader: (2)

I had mine replaced for $2k but I knew the guy.