holbrook

1st start after rebuild I have an 06 Mazda RX8 that i did a rebuild on. Engine is back in the car and I reset the ECU. The car will not idle or start unless I give it gas. I called Atkins Rotary and they told me to reset the ECU and to not give the car gas when I start it because, the ECU needs to figure out the fuel air mixture for it to start and stay running on its own. The car cranks but won't catch, any ideas? I used the clubs page to make sure i have the spark plugs,spark plug wires, coil wires and fuel injectors wires in the correct locations. Any help would be great at this point.

9krpmrx8

iTrader: (46)

Low compression is likely. There is a chance if you just drive it will improve. But that is just a guess.

did Atkins rebuild it?

holbrook

No, the compression is good. I checked it after i rebuilt it. I used the Renesis series 1 injector wiring diagram.( Rear secondary= black & blue wires,Rear primary #2 = white & green wires, Rear primary #1 =light green & black wires with tan tape, Front primary #1 = light green & red wires with white tape, Front primary #2 =black & blue wires, Front secondary green & red wires.) Then I checked the spark plugs & wires. Front to rear of the engine (LF, TF, LR, TR) Then I checked the wires to the coil packs. ( Lead front is a green wire, Trailing front is a white wire, Leading rear is a yellow & green wire, Trailing rear is a blue & orange wire) Any help would be great.

9krpmrx8

iTrader: (46)

How did you check it?

holbrook

Checked in accordance with the Mazda mechanics manual is the short answer. Thats not the issue and I don't have time to keep going over the same thing. Thank you for your input. Any other suggestions? The problem is that It won't idle on its own or start without giving it gas. It runs fine other than that.

Loki

iTrader: (1)

How fast is your starter turning? When it's running, what is the rpm, airflow g/sec, LTFT and STFT? If you have to give it gas, perhaps there's a vacuum leak or the amount of air and fuel is not adding up.

BTW it's normal for compression to be a bit low on a fresh rebuild, it improves as things wear in. You're getting the questions you're getting only because people before you have mucked up those exact things

9krpmrx8

iTrader: (46)

I love how all these new guys (and not so new guys) rebuild their engines and then when it doesn't run they refuse to admit it could be a shitty rebuild.

The "Mazda mechanics manual" may be your short answer, but it's the wrong one as it would have told you that a compression test with a rotary specific compression test is the only way you can know if the compression is solid or not. I mean you could also check vacuum at idle, but it doesn't idle so.............

A properly rebuilt engine should have compression from the get go and start right up. The problem is what most people think is proper, is not.

holbrook

Starter cranking normal speed. The rpm gauge reads 0 until it catches when I give it gas, Rpms are 500 to 4000 depending how much gas I give it.

holbrook

I love it when people are negative and judgmental instead of helpful. I also find it great when they assume things instead of knowing.

Loki

iTrader: (1)

Normal is not a number, if it's below 250 rpm, it's not helping you. Get an OBD gauge and get numbers. Without that, it's hard to offer any specific help. Also when you rebuilt it, did you check that the big parts haven't warped or were actually reusable?

holbrook

Loki, Thanks for the help. Yes Atkins Rotary Had me mic all Irons, crank, rotor housing, and rotors. Any suggestion i haven't done are helpful. Can anyone confirm the wiring I mentioned earlier in this form?

9krpmrx8

iTrader: (46)

So don't let us assume, post up your numbers or admit you have no idea what the compression is.

9krpmrx8

iTrader: (46)

9krpmrx8

iTrader: (46)

FYI, the wire colors don't always match these. But it doesn't matter since it's likely not your problem anyway.

holbrook

Thanks 9Krmprx8. This is what I used.Is this and 2nd diagram you posted the same thing as this one? I will post the compression numbers when I get back , if I don't figure it out first. If I do I will post what the problem is / was.

holbrook

Anything confirmation on the coil pack wiring?

holbrook

One other quick question. Both vacuum nipples on the aluminum part of the intake manifold are supposed to be capped off right? If not where do they go?

200.mph

iTrader: (9)

yes, capped off

Dave04

Make sure you have the fuel pump resistor plugged in. It's located under your air pump on the passenger side, easy to forget. If everything is plugged in correctly and assembled right it should fire right up. Yes the ECU will need to relearn the fuel trims but that shouldn't cause major running issues.

When I started my rebuild for the first time it would start, pop through intake and then die within about 5 seconds. I forgot to plug the resistor in.... Luckily I found the issue right away.

9krpmrx8

iTrader: (46)

It wouldn't "run fine" once he got it started if the resistor was unplugged.

Dave04

I know that, found that out from experience. lol


Unless I miss read, he never said anywhere that the car "runs fine" once started. Just trying to help, it only takes a second to check..

holbrook

I just listen to Atkins Rotary and just kept cranking it until the ECU learned on its own. Now it runs and idles like it's suppose to. Thanks for the help everyone! I never thought it was going to start on its own but, it did.

9krpmrx8

iTrader: (46)

Riiiiigggghhhhhhhhttttt.

Loki

iTrader: (1)

I would definitely get some OBD data now that it's running. At least to confirm everything is OK. It's a bit weird though, there is nothing for the ECU to learn when you're cranking, the O2 sensor is cold and not providing useful feedback. In fact if it's cranking without firing, even if the O2 sensor worked, there is no combustion for it to measure. Maybe it's adapting to sensor calibrations, but that's about it. Speaking of which, did you reset the ESS profile prior to all this?

holbrook

Once again thank you everyone for the advice! This was my first Rotary rebuild and there was a lot of info that wasn't in the DVD I bought from Atkins Rotary for 35.00 dollars that cover the RX8 engine. The video the sell you is for an RX7 engine so the concept is the same but there are differences. The 1300.00 dollar rebuild kit That I bought from Atkins Rotary is mostly seals with the exception of the rotor and main bearings I pressed in. I found out there is not an al inclusive kit. You have to know what you want to replace before you buy a kit. Example is if you want all new internal parts, they have a kit that covers all seals but, you need to tell them what other parts you need, like end play bearings for the crank shaft, oil pump, rotors, gears, etc.
Prior to cranking the engine again after I got information from y'all, I was able to take a peak at another RX8 to make sure I had all the vacuum hoses and electrical plug in where they went. I was unsure of this because, this is my sons car and him and his friends where the ones that pulled the engine out of the car when I was not home. Then I rest the ECU as instructed by Atkins Rotary and cranked it until it finally caught on its own. Now it starts and idles like a new car with no check engine lights on. Thank y'all! I could not have done it without your input.