ericlift

Hey guys, I had a Reman installed about 400 miles ago when I was having issues getting my original engine at 107k and god awful compression (high 50s at ~280) to start. But it would never cut off on me, now with the reman thou thats not the case. It starts fine hot or cold as long as it was shut off, however it tends to stall out of nowhere, Once was at a traffic light at idle with 1/4 tank gas, once was in highway traffic at 20mph at 3/4 gas, once at 75 mph cruising on the highway at 7/8 gas. I had it towed to Mazda and they said the E-shaft sensor was installed incorrectly (I'm not quite sure how, they didn't feel like elaborating as to what that meant) so they "fixed" it, drove it another 200 miles to its final destination, seemed all fine and good after that. Then I drove somewhere, left it off for about an hour, started the car and then after about a minute warming up, not yet to op temp or at nom idle, it died, no noise, no surge, the rpm just slowly dropped to 0. Tried to start it, no fuel, I thought ok fuel pump is bad, I pushed it to the shade to cool down, started it again, without letting it down to nom idle, kept rpms up, and drove it home. Since then, I tried to start it again, same thing: starts, runs for about a minute, and then just quietly cuts off. Tried to start it again after that, started just fine, after a few seconds died.

As stated before, Reman engine with 400 miles. BHR ignition with maybe 1k miles. I have cleaned the maf, I have a new fuel pump to go in, but I don't think thats my only issue anymore.

All the while I have NOT gotten a single check engine light. The logs say everything is normal, but of course it doesn't freeze frame when it dies because no cel so I can't be positive of when it stops logging.

Onto questions/advice seeking:
Replace MAF? would that cause these sort of issues with no CEL?
Replace E-shaft Sensor? If it were the problem I should totally be getting a CEL.
Fuel Pump? Doesn't seem like the only issue but I'm replacing it this weekend.
Electrical? I don't lose electrical when it dies so I'm not to certain but at this point I'm willing to try everything.
Cat? I still have stock cat which I'm sure is toast at this point, but again no CEL and this is some pretty serious issues so if the Cat were this bad I'd expect a CEL
Maybe losing electrical to E-shaft Sensor? This is really the only thing I can think of....

Some input would be appreciated, I would hope its not compression being a factory reman with <1k but I guess the past has shown us all that its still a possibility.

I'm mad about the CEL mostly. Everyone complains that they can't get theirs to turn off but I just wish mine would turn on so I can see whats wrong!!

TeamRX8

iTrader: (25)

I'd suspect fuel pump. They can be fine cold, then heat up and seize/slow down. And no cel from it either. You'd need a pressure gauge that can read it while running to be sure so you can see what it's doing.

ericlift

Replaced the fuel pump, tested it out to make sure everything was connected properly and it all seemed right. I tried to start it but it just wasn't feeling up to it. Had the battery checked and it was pretty low, left it to charge for a few hours back to full and tried again. Still no luck. Starter was going a little slower than normal but it still didn't sound right, figured it was flooded so I did the deflood procedure, still nothing. Pulled the spark plugs, cleaned them off, dried them, stuck em back in, and continued deflood. still nothing.

Do I continue trying the deflood until it works? I know it can be stubborn but I ran out of time today so I'd need to do it again later.

Other than that I'm really at a loss as to what to do at this point, I really don't want to take it to Mazda to get it figured out because thatll cost an arm and a leg and itd probably be cheaper to buy another roller and swap everything over and try again from scratch.

TeamRX8

iTrader: (25)

By "suspect" I meant test it, not replace it.

ericlift

I know, and I know my old fuel pump was going bad, its pressure was only slightly higher than whats required to run the engine, tested around 30 psi, which is why it was being replaced. But as I stated, I don't think it was my only issue anymore because when the engine would stall, I would be able to start it again right away, so if it had stalled due to fuel pump failure, I would think that it would require at least a few minutes for the fuel pump to cool down back to a temperature where it could pump properly.

I was trying to ascertain whether the issues I'm having could have come purely from fuel pump failure or whether it had become a combination of issues that included the fuel pump. Sorry for the confusion

Loki

iTrader: (1)

Can you get fuel trim data from OBD when this happens? Or MAF airflow g/sec?
It could be stalling out because there's a big vacuum leak somewhere and the computer can't trim fuel far enough to compensate. There wouldn't be a CEL for that.

How old are ignition coils and spark plugs?

And if you believe you cat might be dead, better get that confirmed/denied before it kills your new engine.

Lookalike

When you installed the fuel pump, did you clean out the filter sock before reinstalling it? I had a very similar issue with mine and turned out to be the sock being so dirty that the fuel pump had trouble getting fuel in, especially at lower fuel levels. Cleaned it then it ran like a champ for another 40K until I upgraded it for an S2 assembly.

TeamRX8

iTrader: (25)

You might check the fuel pump low speed resistor or jumper around it at the relay to make sure it stays in full pump speed mode and see if stays running. Ideally having a fuel pressure guage you can see when it's running would be best.

ericlift

Sadly I can't get the data now because I can't get it started. But I've been busy with work so I haven't had time to play around with it. Probably flooded or bad battery because I killed it emptying the tank... Coils are BHR maybe 1k old so I doubt they are the cause. Plugs are a bit older, about 5k. But I didn't think to replace them with ignition because they weren't that old. Probably should have now that I think about it.

It was a new pump assembly rather than just changing the pump so I would hope that the sock isn't clogged already. Unless the manufacture put a plug in that's supposed to be removed before installation but I didn't see one and one wasn't mentioned in instructions so I doubt it.

I'll look into that, hopefully I can get it running some point this weekend when I'm off work and get a look at that data. I got a couple car buddies coming up so hopefully they can help out.

Thanks for your help everyone! For not being able to use my car the past couple months and missing almost 3/4 of the autocross season its a little disappointing but hopefully that means I'll be back in full swing next season

lucky7willow

iTrader: (1)

Sounds like the fuel injector connectors are connected in the wrong sequence. If the four primary fuel injector connectors are mixed up; you wont get a check engine light, the car will run and drive, then stall randomly. I lost count on how many RX8s I found this simple mistake on. Hope this helps.

ericlift

Of all the things.... I guess that's why they say check the easiest things first, the reason it wouldnt start after I changed the fuel pump was because the ignition ground disconnected. And now it runs like a dream so the fuel pump and ground were the issue. Thanks everyone for your help!

TeamRX8

iTrader: (25)

That will do it for sure. Glad you were able to resolve the problem.