I'm hoping someone out there can help me -- two garages here so far have been unable and I am not interested in replacing my engine piece-by-piece until someone gets lucky and it works. Here's the problem:

Sometimes my SE just won't start, and if I come back 3 hours later, it starts right away. This is not a flooding problem. Seems like there is just no ignition. The battery and starter are fine (battery is new, alternator is clearly working), and I recently replaced all ignition cables and spark plugs. There is no temperature dependency.

When running, all is fine until something weird happens. It's like hitting a brick wall. All of a sudden I lose power and the RPMs start dropping. If I apply the throttle, the car starts shaking like crazy. It's almost as if an entire rotor is not firing. This can persist for 2-5 minutes and then it self-corrects. I originally thought it was the TPS, but am not sure at this point. I suspect the two problems are related.

Took it in to my garage, where they suspected the spark plugs. Told me that the plugs were badly corroded and could break off and be disaster. I thought this was ridiculous so I took it to Mazda Masters here in Sunnyvale. They have changed owners and the new guy told me he was certain problem was spark plugs. I said go ahead and he replaced the plugs (they were not seized but clearly shot), fuel filter and air filter. Car ran fine for 20 miles and then problem happened again. Clearly it's not the plugs, ignition cables, battery, fuel filter, etc. I suspect it's one or both of the coils driving the plugs.

Can anyone comment on this problem ? Thank you in advance.

 

clogged cat?

 

yea i would also say check the cat

 

I've been killing myself for about 2 months off and on with random problems, but do yourself a favor and check all of your gronds 1 could be loose or shaky and make a bad ground when you turn or hit a bump or something.='s possible no spark at times. also when that initially happens pull over and see or smell if there is any raw fuel on the plugs..meaning no spark at that time.

 

thanks for the replies. I called up the mechanic today and he said it *could* be the fuel pump. I have a couple of concerns -- not alot of time to invest and not alot of money either.

I told him that I was concerned about replacing the engine piece by piece and that the car was probably only worth $1K. Since it's intermittent, I can't believe it's the fuel pump but rather some sort of control system or electrical problem, but these are just hunches. Any other feedback you can give me would be greatly appreciated.

thanks.

 

Car was doing this again today on the way home from work. This time, I let it slow down on its own and pulled over. The revs were rough at idle, and I could definitely smell gasoline. I'm almost convinced that half the plugs aren't firing.

Any ideas? thanks.

 

Have you checked the TPS? Make sure the gas smell isn't a leaking pulsation damper.

 

If the gas smell is the Dampner this is a quick fix for it

http://www.rotaryresurrection.com/ro...pulsation.html

 

it's bad. will check this weekend. I replaced it 18 months ago with a used TPS from someone else and that cleared up a similar problem.

What's different this time is that the idle appears to be affected too. I can check the TPS easily but buying one is another story. Does anyone out there have a spare they'd be willing to sell ?

thanks

 

I got a nice used one from BanzaiRacing in Indiana... I think it's banzairacing.com... mine was $30.

Josh

 

but the website didn't work. any chance you could get the real address ? thanks.

 

Our correct web address:

www.banzairacing.net

 

For those of you following this weekend mechanic who has very very very little time, here's the update:

Checked the TPS with a multimeter. Initially looked completely shot, but then after turning the adjustment screw at least 10 times, I got it to the 0-1 position where only one side was on. Turns out my mechanic obviously didn't know what he was doing when he told me that they "adjusted" it. It was way way off. But, the "good" news is that the TPS is just fine.

I found a website that told how to buildup a diagnostic checker, http://www.teamfc3s.org/info/article...odes/main.html

I did this with interesting results. I used a blue and a red LED. After letting the engine warm up for a good 10-15 minutes, I shut it off and then installed the "checker". Turned the ignition to ON and both LEDs came on for 3 seconds, as they should, and then nothing, meaning all is well. The real surprise then came -- car wouldn't start. It was turning over (starter OK) but just no ignition. Code checker showed no problems! I let it sit for an hour and then it started fine, with a nice cloud of white smoke out the back, I suppose due to it having a bunch of gas to deal with. This has happened before, about every 2 days. As I stated earlier, I strongly suspect it's related to my rough shaking problem.

So, here's what I know is not the problem: plugs, ignition cables, fuel filter (all new), TPS (checked out fine). So, my strategy is to leave the code checker installed, drive around until the shaking/loss of power problem returns, and immediately pull over and check the LEDs. Hopefully they will tell me something; I hope to do this tomorrow. If that proves fruitless, I am getting an ignition cable inductive checker to see if there's any spark happening when the problem returns.

Comments ?

 

drove to work this morning, after a minute on the road engine started stuttering again. Pulled over and Blue LED (DCC1) was flashing. 3 short flashes, then long pause, 3 short flashes...

According to teamfc3s, this means Water Thermo Sensor. I don't think that's what's causing my problem but it probably is bad. I'm going to get the multimeter on that sometime this week. They also state that the DCC shows the lowest code, so there could be other problems (ie, higher codes) that are not being displayed until this one is fixed. We'll see.

Am also going to look into a way of checking for current in the ignition cables. I really do suspect one of the coils. Will post progress. As always, opinions, comments, suggestions, leads are appreciated. thanks.

 

a used leading or training coil can be had from a yard for around $25 each

 

I had a similar problem.....replaced the motor with a new one and haven't had the problem at all. I never found out why it did that until the motor finally blew and I got myself a Reman. with only 4k on it.

 

That sounds like the standard RX-7 repair manual solution: replace motor. See it everywhere in there (smile).

Sort of like a Far Side comic I saw once: Vet's Guide to Horse Care. There's a vet with the book open and after every symptom (whether it be broken leg, runny nose, etc), it says "shoot horse". Love that one !

 

i had a similar prob with my 87 n/a a few years ago an i found out it was on of the leading coils it wasn't working correctly so it would cause it to shutter and miss fire and also flood once in awhile

 

Willsmazdarx7: What were the symptoms ? did it still run even though the leading coil was not working well ?

One philosophical problem I'm having with this is "how could the coil work sometimes and not others"? thanks

 

My S5 has the EXACT same symptoms, so I hope to find the real problem...I have replaced my tps with a brand new one... $200 later, it still does it! I have no cats to be clogged, and the coil idea is where I was leaning to believe the issue lies. I have not checked them yet (nor do I know how), but I am still using the search feature on this site. Thanks in advance.