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Hey guys I'm new to the Forum. Learning a lot! My 2007 Acura RDX (85,000 miles) started misfiring under load. we were driving to Portland and the car started heating up. Made it all the way there with a lot of stops and struggle, but did not get the car to redline (luckily).
Barely found a thermostat replaced it in Portland drove at home performance was totally fine.
A month later what started to have a random misfire, no check engine light. I automatically thought ignition coils so I bought new ones replace them there was no difference. So I went on and change the spark plugs as well the misfire went away! Drove it for another month and it came back just as bad? I thought maybe my head cracked when it was heating up on the drive to Portland. But there is no smoke out of the exhaust and my compression is about 142-151 throughout four cylinders.
I
s there any suggestions? Has anybody had any electrical issues with the connectors to the coil packs or anything you can suggest. Thanks
What plugs did you use? There are several that fit the car, but some are not the correct gap and should not be used (even though some websites may still tell you they are correct). Aside from that, assuming you're already validated there is no fluid leaking into the combustion chamber(s), I'd also recommend checking o2 sensor, air filter, possible boost leak...really, anything that involves air that you haven't already looked at. With new coils and plugs (again assuming correct plugs), spark should definitely not be an issue. Also doubt it's fuel - usually your pump and/or injectors either work or they don't. I wouldn't expect fuel to result in the intermittent issue you're seeing. Good luck and hopefully it's nothing too serious.
I used NGK lazer iridium plugs I got online.. I thought one may have been gapped wrong but I was also told that you cannot grab those because you can damage the tip of them.
if there was antifreeze in the combustion chamber wouldn't that cause white smoke? And when I did the pressure test it would lose pressure after it's sat for a minute or so from what I understand and would have to escape somewhere.
Also how can I check the O2 sensor? There's no code or anything like that and I first I thought maybe it was my cats but they are running at about 500 degrees Fahrenheit idle and then they go up to about 1200 when I drive
You need a scan tool too, plug into your obd2 port. It will get you all the diagnostics on your truck. Those are the spark plugs the dealership used too. What ignition coils did you use?
I used NGK lazer iridium plugs I got online.. I thought one may have been gapped wrong but I was also told that you cannot grab those because you can damage the tip of them.
if there was antifreeze in the combustion chamber wouldn't that cause white smoke? And when I did the pressure test it would lose pressure after it's sat for a minute or so from what I understand and would have to escape somewhere.
It depends on how much coolant is getting out. If it was a somewhat slow leak into the cylinders, the cat is hot enough to evaporate the coolant and there wouldn't be any smoke at all.
Does the vehicle struggle to start first thing in the morning (after sitting 6, 8 hours+)? Otherwise, it's extremely hard to tell what may be going on. As Tom mentioned above, if spark is there, it's either related to fuel (doubtful), air (restrictions of some sort), or compression. You said compression is decent (spec says 135 minimum so you're ok), but that really only is half the story of the mechanical bits. Technically when I have to diag something like this, I'll start with a compression test, but immediately follow it with a leakdown test. This will 100% pinpoint if there is a leak from either intake valves, exhaust valves, through the piston rings, or a headgasket/between the cylinders issue. Sometimes compression can be good but a leakdown will show something else.
Otherwise the only thing that concerns me is that you said you kept it out of the high overheat, but sometimes the continuous stops and starts is enough to warp the head. Let us know if you find anything.
It depends on how much coolant is getting out. If it was a somewhat slow leak into the cylinders, the cat is hot enough to evaporate the coolant and there wouldn't be any smoke at all.
Does the vehicle struggle to start first thing in the morning (after sitting 6, 8 hours+)? Otherwise, it's extremely hard to tell what may be going on. As Tom mentioned above, if spark is there, it's either related to fuel (doubtful), air (restrictions of some sort), or compression. You said compression is decent (spec says 135 minimum so you're ok), but that really only is half the story of the mechanical bits. Technically when I have to diag something like this, I'll start with a compression test, but immediately follow it with a leakdown test. This will 100% pinpoint if there is a leak from either intake valves, exhaust valves, through the piston rings, or a headgasket/between the cylinders issue. Sometimes compression can be good but a leakdown will show something else.
Otherwise the only thing that concerns me is that you said you kept it out of the high overheat, but sometimes the continuous stops and starts is enough to warp the head. Let us know if you find anything.
-Shane
Thanks for getting back to me guys. I think I may have been my cooling fan. The wires look like they may have been shorting out a little bit at some point hopefully that's just it maybe water got in after the Portland trip or something like that. It does have a hard start in the morning at times, almost shudders for a sec then revs up.
Thanks for getting back to me guys. I think I may have been my cooling fan. The wires look like they may have been shorting out a little bit at some point hopefully that's just it maybe water got in after the Portland trip or something like that. It does have a hard start in the morning at times, almost shudders for a sec then revs up.
I mean, it could have something to do with it, but that still doesn't identify the potential coolant leak you mentioned.
If you have access to a leak down, do that. Another option if you have a boroscope is to pressure test the cooling system again and then after it's "leaked", take a look into the cylinders and see if there's any in there. If the coolant isn't leaking from somewhere visible, it's going into the engine somewhere.
I mean, it could have something to do with it, but that still doesn't identify the potential coolant leak you mentioned.
If you have access to a leak down, do that. Another option if you have a boroscope is to pressure test the cooling system again and then after it's "leaked", take a look into the cylinders and see if there's any in there. If the coolant isn't leaking from somewhere visible, it's going into the engine somewhere.
-Shane
Forgot to mention... it has a small leak between the exhaust header and engine (its a liquid cooled header) seeps down a bolt and drips on the exhaust. I'm trying to make time to replace it this week. Subframe, turbo and exhaust have to go.. seems like a common problem with these Acuras.
You should replace that exhaust gasket. Be ready to spray those bolts. Spray them really well and let them soak for awhile then be gentle breaking them open. Keep extra bolts on hand just in case. As well as the drill and bits to drill out the old rusted bolts if needed.
When you have the hard start in the morning, does any smoke come out the back once it finally fires? If so, what color? The symptom you just described (shudders a bit, then fires) is exactly what a previous car of mine did when it had a leaky fuel pressure regulator. Sitting for a short while, it would fire up fine. Overnights it would chug bad in the morning and belt out black smoke as it worked out all the fuel that leaked into it. If the car isn't delivering the fuel it thinks it should be getting, that could also result in your misfires. Just another thing to consider if your other checks don't turn up an obvious solution.
When you have the hard start in the morning, does any smoke come out the back once it finally fires? If so, what color? The symptom you just described (shudders a bit, then fires) is exactly what a previous car of mine did when it had a leaky fuel pressure regulator. Sitting for a short while, it would fire up fine. Overnights it would chug bad in the morning and belt out black smoke as it worked out all the fuel that leaked into it. If the car isn't delivering the fuel it thinks it should be getting, that could also result in your misfires. Just another thing to consider if your other checks don't turn up an obvious solution.
No I don't see any smoke just vapor. I was thinking fuel problem for that exact reason it's not just a constant cylinder misfire it's throughout all for eventually
I like ngk because our oem spark plugs are the ngk laser iridium. So it seems like ngk would be a good choice for the coil packs too. I like those on muscle cars, I feel like ngk are more import tuner.
10-08-2018, 12:19 PM
