Car stalls at idle....
Just purchased a 04 Mazda rx8 and everything seemed fine until a month or so ago. I started to experience problems starting the vehicle it would just turn over and just keep cranking until it started to turn over faster then it would start, but the real problem is getting it to stay on without stalling. Every stop a light and things drop lol the rpms drop to about 800 and it's hit or miss if it recovers or just stalls. So far I have had the intake manifold taken apart and cleaned out the intake valve, had a compression test with a result of 70 50 I don't know if that could be and underlining issue and what should be done to fix it, I'm not exactly a mechanic. The spark plugs and wires where changed as well as the ignition coils so if you narrow it down, I'm really not to sure what is causing it to still take so long to start and keep it from stalling at lights. Any help at all would be greatly appreciated. Thank you....
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Any help???
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I would start by getting a rotary specific compression test. I am not sure what 70 50 is, but is not the results of a proper compression test.
You should have gotten numbers in a format something like this: Rotor 1: 7.5, 7.6, 7.5 Rotor 2: 7.2, 7.3, 7.3 250 RPM |
It could of been 7.0 and 5.0. I'm not too sure. Is there anyway to go about fixing the compression numbers dropping so low before it's unrepairable or is that still a safe number.
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I believe that that compression test was measured in psi
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OP have you read through the new owner thread ->https://www.rx8club.com/new-member-f...t-here-202454/
check the battery terminals regardless of rpms 7's are borderline falling comp http://www.rx8help.com/img/compression_chart.png Edit: more info will help us interwebz diagnose |
50 psi is not even on the chart...could it possibly be an apex seal that needs replacing?
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It could possibly be any number of things. But if you have low compression you will need an engine rebuild.
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I'm gonna have another compression test and get back to ya
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Hey, guys I just found this Conversation, mine is doing the same thing. What ended up happing with your car? Did you need an engine rebuild? I have already had one engine rebuild. I am not keen for another.
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Originally Posted by nvsrx8
(Post 4811896)
Hey, guys I just found this Conversation, mine is doing the same thing. What ended up happing with your car? Did you need an engine rebuild? I have already had one engine rebuild. I am not keen for another.
https://www.rx8club.com/new-member-f...t-here-202454/ https://www.rx8club.com/series-i-tro...t-here-222584/ |
You guys need to get some actual data. It could be any number of things from a vacuum leak to a worn out engine. Get hold of a Bluetooth OBD adapter that lets you read the engine data on your smartphone. Look at engine codes if any, fuel trims and air flow reading at idle. And a compression test. Report back with numbers :)
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I have the same issue and I am at high altitude. my car was not doing it at lower altitudes when I drove it up here.
My compression was measured in PSI and one rotor was at 105PSI and one at 85PSI all faces the same. we used my buddies rotary compression tester. I did a water treatment and I am trying to get the compression of the first rotor higher. it seems to be working with time and slowly as the idle is getting better over time and the car seems to feel like it has more power, we'll see when the temps get hotter here. still doing more testing. My idle has a little over 5 G/S from the mass air flow sensor and I don't think its a vacuum leak. at lower altitude the compression is 106PSI and 131PSI. I have replaced a lot of things already as the car was throwing cods every where. so new spark plugs, new coils, new and flow tested fuel injectors (only 3 are new, 3 could be reused), new SSV solenoid, new MAF sensor, etc. I watch my AFR's at idle and they are going to 17AFR when the car is hot. mine only has issues when the entire engine is heat soaked. It does not do it till 30 minutes warmed up and if the engine bay is hot. If I keep the engine below 82C or so the engine seems to idle fine, when the engine gets above 95C and with the fan off (the inside cabin fan, not the radiator fan) the engine idle fluctuates sometimes and sometimes mine dies. If I get the engine and bay super hot the engine wants to shut off every time. super hot being over 100C temps. I recently ducted my radiator and its keeping temps a lot lower. I also had my fan on inside and the idle AFR was 14.7AFR and the car was idling much stronger and fine. really weird. I also notice the voltage fluctuates before it dies (when fan is off). It seems like something is drawing power and messing up the engine or shutting it off. It fluctuates down to 12.5V (I think the voltage is causing the shut off, not the voltage fluctuating because of the shut off, but its tough to tell). so I am going to dielectric grease and make some good grounds to ensure this is covered. I do think the rotor compression difference might be a contributor so I am driving the piss out of the engine and trying to get the compression back up in rotor 1. I will probably do a couple more water treatments to the engine as well over time to loosen up any carbon inside the engine if that is the root cause of the lower compression. Thoughts: Could the difference in rotor compression cause an issue? Is the issue that one rotor is spinning at a faster rate so to speak than the other which then throws off the timing for one of the rotors? Could this be a fuel pump going out? or is the resistor at idle going bad to the fuel pump causing low fuel pump pressure and voltage fluctuations? |
Problem: Car runs great when cold, when car is driven for20-30 minutes continuously the car will sometimes die at idle. I canimmediately turn the car back on with no issues and the car may or may not haveidle issues. Idle fluctuates beforedying most of the time. Typically the car will die after being driven andcoming to a stop, it will slowly bring the idle down and either die orfluctuate for a while then die. Only happens when the car is heat soaked hot,won’t if the car is warmed up but not heat soaked. Car is new to me andpurchased dirt cheap, 130K miles on it. Keep in mind that I don’t have abaseline for some of the cars capabilities and I am unsure if the car isrunning at 100% at WOT. I am also 6,300FT above sea level car was purchased atsea level. Seems like car developed this issue at altitude. The car had badspark plugs and ignition coils before I got it. It also had a failed SSVsolenoid, bad MAF sensor and dirty fuel injectors. These are all fixed. I havethrown codes at one point in time for P2096, P0171, P300, P301, P302, P661,P101,
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Jeez, your forum name is spot on. Start your own thread please, troubleshootinf 3 different cars in 1 thread is not going to be effective.
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I was hoping that my problem and the thread starters are the same.
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just a little encouragement while we are all trying to sort out our problems lol
https://cimg2.ibsrv.net/gimg/www.rx8...1096c0ec83.jpg |
I guess that wasn't the finest of j0kes
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Did you find what's at fault?
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I have a 2005 RX 8 that had a first engine replaced at only 20K back in 07, then 2nd engine replaced in 2013 due to storm water taken into engine on a flooded road. All has been great for the last 4 years except the car just out of nowhere decided to crank fine but runs rough idle for about 20 to 30 seconds, then calms and runs fine but after a few minutes will drop below 1000 rpms and shuts off. Always cranks back up easy and smooth after first time. Runs great on road but once at red light is starts dropping below 1000rpms and does same thing. Had taken to Mazda Dealer and after cleaning and replace Maf sensor and 3 days or returning with same problem they changes spark plugs and wires. $1100 later it's still doing the same thing. Any help here what to try next? They are saying could be engine needs replaces AGAIN! Why would it run so great otherwise with no sputtering at all?
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Originally Posted by TerryG
(Post 4818444)
I have a 2005 RX 8 that had a first engine replaced at only 20K back in 07, then 2nd engine replaced in 2013 due to storm water taken into engine on a flooded road. All has been great for the last 4 years except the car just out of nowhere decided to crank fine but runs rough idle for about 20 to 30 seconds, then calms and runs fine but after a few minutes will drop below 1000 rpms and shuts off. Always cranks back up easy and smooth after first time. Runs great on road but once at red light is starts dropping below 1000rpms and does same thing. Had taken to Mazda Dealer and after cleaning and replace Maf sensor and 3 days or returning with same problem they changes spark plugs and wires. $1100 later it's still doing the same thing. Any help here what to try next? They are saying could be engine needs replaces AGAIN! Why would it run so great otherwise with no sputtering at all?
Is the check engine light on? Are there any codes? Have the ignition coils been tested/changed? That's a VERY common failure point, which again a Mazda dealer should be familiar with. Is there any smoke or smell from the exhaust? Are you losing oil or coolant? Can you start your own thread in the New Member section, rather than bombing someone else's? |
I know was a waste but I don't trust them now. Went to autozone to try computer reading..no lights, no codes. Sorry first time on here wasn't sure how to post. No engine lights,...they say it might need engine but it runs so good otherwise and cranks up everytime. This only has 50k at the most on a new engine. No leaks or oil loss to my knowledge. Only has smells when idle is going crazy but smooths out quickly after cold start. Then cranks up fine once warm. 2nd mechanic says might be engine starting to fail but when I replace the other engine it never did this. Just never stayed cranked and was shaking like crazy. Totally different feel than then. They didn't replace coils but at this point do not want to put more money into...just want to sell and buy another larger vehicle anyway at this time. Had Autozone put on computer again just for another option and there was no codes coming up.
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Originally Posted by TerryG
(Post 4818455)
I know was a waste but I don't trust them now. Went to autozone to try computer reading..no lights, no codes. Sorry first time on here wasn't sure how to post. No engine lights,...they say it might need engine but it runs so good otherwise and cranks up everytime. This only has 50k at the most on a new engine. No leaks or oil loss to my knowledge. Only has smells when idle is going crazy but smooths out quickly after cold start. Then cranks up fine once warm. 2nd mechanic says might be engine starting to fail but when I replace the other engine it never did this. Just never stayed cranked and was shaking like crazy. Totally different feel than then. They didn't replace coils but at this point do not want to put more money into...just want to sell and buy another larger vehicle anyway at this time. Had Autozone put on computer again just for another option and there was no codes coming up.
Ok well if the coils are older than 35k, you're risking the engine by not changing them. This will be an important point for whomever you sell it to, or they'll be on here the day after purchasing asking why the need a new engine. This should have been the first thing the dealer called out and tested. Seriously, I would go back to them to get money back. $1100 for a MAF, 4 spark plugs and 4 wires is INSANE. You can get new coils at Autozone for about $200 and if you're at all handy, you can replace them yourself, it's easy. |
Originally Posted by stucky22
(Post 4817680)
Did you find what's at fault?
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SO I recently started having this problem on my 2004 RX8 6 speed. I've had my car for a little over a year now and it was running fine with no issues. Almost a week ago, on my way back from the store, my car died on me at a stop light. There was no sputtering, or jerking just a smooth drop in RPM until it stalled. I was able to get it home by keeping the RPMs at 1k. My car has 133960 miles on it. The car would only stall after it was warm but when I first started it, I had no issues until it reached normal operating temperature. I was able to fix my issue today. I changed my coils, plugs, wires and air filter. I also cleaned my throttle body and mass air flow sensor. After I did all of this, not only did it stop stalling but I had much better throttle response and it felt like it was running much smoother in the higher RPMs.
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