Rebuilt Engine - Starts and runs for 20sec and then dies
 

(UPDATE - started but runs rough and exhaust GLOWS RED. Read below)

Hey all. I am the not yet happy owner of a 2004 rx8 that I bought with a bad engine.

I had the engine rebuilt by Kevin from RotaryResurrection.com and I have it in the car now.

Kevin did a good job and the rebuild and shipping were quick. He is busy though, so until he gets back to me I figured I'd also post here.

First the engine wouldn't start at all. I floodded and deflooded it a bunch of times. Then I found out it had 2 bad coils.

I replaced those
Squirted about 10ml of oil in the chambers for each rotor
Installed the plugs

car started and ran rough with a lof of smoke (as expected).

Kevin had instructed me to be ready to give the car some gas and keep the rpms between 2500-4000.

Unfortunately the car was not responsive to the loud pedal. Playing with the gas did almost nothing and after about 20 seconds the car died.

The MAF sensor and the TPS are plugged in. I feel like the car should have at least some response to the gas pedal.

Any ideas on what I should check? HALP!

Check your electrical connections to your fuel injectors and plugs too, make sure those wires aren't connecting coils to plugs in the wrong order.

Check for vacuum leaks, as they would reduce the impact of throttle application, as well as throw off MAF information.

Reset the e-shaft sensor profile if you haven't yet. It can remain stored even with a battery disconnect.

Do you have an OBD2 reader that you can watch live data with? Check your short term fuel trims and MAF values, one or both is probably way off from where it should be.

^ All that. Take a step back and make sure you did not miss anything.

Did you check the MOP connections? Sounds like you have a limp mode situation and the throttle isn't working properly

Could be a throttle wiring problem as well...

You need to go over all the electrical connections and make sure all is good

Yup +1 on the injector wiring, very easy to get wrong. And it took me a whole week of chasing my tail till I finally received advice to check the injector connectors.

I had this issue when I replaced a friends engine. I had removed the vac pump and didn't get all the connectors plugged back in. It would start, but the gas pedal had no effect and then died shortly after. Check that out. If you have the injectors mixed up, it should still run fine, the gas pedal would still give it gas, just not properly. I had this issue on my 8 for a year, didn't idle perfect until fully warm and ran for 20-30 minutes.

Thanks guys! good info!

I will leave the injector check for last since they are a pain to get to. Also If I remember right the wiring length is such that it is hard to get them wrong but i will check.

I will check again for vacuum leaks

I will see how to reset the shaft sensor profile, whatever that is.

a couple of questions, which I will search but in the meantime

- MOP? what is that.
- Vacuum pump. Will try to find out which that is. I think I have an idea.

There is no Vac pump? Not sure what he was thinking of...maybe the MOP...metering oil pump that injects oil into the rotor chambers...When it isn't reacting properly the ECU puts the system into limp mode and the throttle will only open marginally...and will not rev past about 3K rpm's slowly. This is the most common reason for the throttle not to work properly

The injector wiring for the rear sec and the rear primary injectors are often mixed up...there have been more than one instance on here that they have caused strange running...but the motor will usually run.....

I would check the plugs on the MOP...front passenger side of the motor.....and check to make sure the position switch wasn't damaged by the motor RE/RE..it is easy to do

I have seen many experienced techs and talented people popular on this forum get them wrong. It is THE PRIMARY mistake made by someone who may be good enough to install an engine.

Best of luck.

Paul.

Thanks Mazmart. I will check, the thing is how do i MAKE SURE I got them right.
I mean when I look at them again I will probably do them the same way, as what I did was follow the curves and lengths of the injector wires.

I will pull out the wiring diagram but I suspect they will have the same pair colored wired. Would be nice if I'm wrong

I was referring to the pump that turns on when you start up the car to get the cat up to temp on the passenger side. It is definitely there and there are definitely connectors there, and it will definitely cause this issue. And it is super easy to get the injectors wrong. The two that split apart from each other do not go to the two red injectors, instead one goes to a yellow and one goes to a red, but again, it shouldn't cause the car to not respond to the gas pedal. The only plug I have ever seen cause this issue is that one under the pump.

hesselrode are you talking about then fuel pump resistor?

If that was unplugged it would not start at all.

I have no clue what it goes to, it looks like a heat sink so maybe a resistor. All I know is when I replaced my friends engine, I accidentally left this unplugged. It started and died after about 20 seconds. Pressing the gas pedal did not rev the engine or affect the engine in any way. It would do nothing but die. I removed the pump to make for more room for pulling the engine. He may not have done this so it may not be the case. Attached is the picture I just took of the plug. It plugs into a silver heatsink under the pump.

The heat sink is the fuel pump resistor, leaving it unplugged would kill the fuel pump. You may have been running on residual fuel, or possibly even oil.

The pump there is the air injection pump, to heat up the cat faster when cold. I left mine unplugged for years while catless. It wont affect his problem, since in theory it could only make the ecu see lean, but the it's period of running is entirely contained within the ecu's open loop start up period, so the o2 is being ignored anyway.

These two components are not connected.


Opening the throttle would only help if it is starving for air. If it is starving for gas (for any reason) adding more air isnt going to produce any result, except maybe stalling it faster. I can see how leaving that resistor unplugged would have similar symptoms for a start or two.

Exactly.

Take off accordian hose on intake......and see if the throttle butterfly responds when you push on the gas pedal....

Thanks guys. here's an update.

I bought an uprated starter and the thing fired right up. Smoked heavily in the beginning and ran rough as expected from a new engine, HOWEVER after about 5 minutes we noticed the exhaust getting really hot and actually GLOWING RED.

Turned off the car. Suspected due to the many attempts to start it there was a lot of fuel and oil in the exhaust which was burning off.

In about an hour started it again. This time didn't let it get that hot. Shut off at first signs of getting too hot. Strangely it starts getting hot AFTER the cat first. While running the car backfired loudly a bunch of times and sounded like there is metallic rattling in the exhaust.

I would assume if the cat is blocked/melted the heat would build up before the cat first. This still leads me to believe that the excessive heat might be because of buildup of junk in the exhaust.

By the way let me say I bought this car from an auction and it never ran. Engine was bad (low compression). So it may have had missfiring issues that could have killed the cat even before I got it ... but i still hope I don't have to get another one.

I checked the check engine errors and got this (each error was listed twice .. don't know why):

P0037 (x2) – Rear HO2S heater control circuit low ON 2 HO2S heater
P0302 (x2) – Rear Rotor misfire

I spent most of the day researching and reading up on what I should do and here's my list:

1. Add Seafoam to fuel
2. Replace trailing plugs’ coil packs
3. Check spark plugs on rear rotor
4. Check rear O2 sensor – wiring or sensor melted?
5. Clean MAF (Mass Air-Flow Sensor) and IAT (Intake Air temperature Sensor)
6. Clean ESS (Eccentric Shaft Sensor)
7. Check if throttle plate responds to throttle pedal
8. Reset VRAM & Reset KAM
9. Disconnect Battery for 20 min
10. Check Injector Wiring Position
11. Start and watch live data on OBD reader
12. If no luck check catalytic converter to make sure it’s not clogged



To Reset VRAM & KAM

1. place the keys in the ignition and turn to the ON position but do not start
2. Pump the brake pedal about 20+ times in 10 seconds until the oil level needle goes to the right then back to the left.
3. turn key to off position.
4. Hold down the Trip Reset button and turn the key to the ON position
5. Wait for the odometer to read TEST, then turn the key to the off position
6. Repeat steps 4 & 5

This will reset the Vram and Kam, and will allow your engine to learn any new parts you have added.


Any other ideas?

Glowing after the cat + rattling in the exhaust means that your cat elements are likely stuffed down the pipe farther, creating a clog there. Not uncommon. A destroyed cat from the prior owner is also reasonable to assume.

Started right up every time 10-20 times. Wasn't just a couple times. But he fixes it anyway. Good job.

Ok, another update. I had gotten the injector plugs wrong. Rearranged and put everything together, cleaned MAF, IAT and ESS sensors and replaced there 2 remaining old coils.

Also removed the midpipe to check on the cat ... omg, it is properly f****d! Will take a pic at noon when I go home to clean out the pipe and put it back on so I can try starting again.

I doubt my 3 starts for a few minutes would do that much damage but who knows. Either way, I'm in the market for a new cat. Will look on here for used OEM or cheap alternatives.

Hmm. I wonder if it allows the fuel pump to build pressure very briefly on each start before shutting the fuel pump down. It should disable the pump completely, but perhaps not?

Interesting.


:) :icon_tup:

It's likely the cat was dead from the prior owner. Running on even a single fading coil can kill a cat in a matter of a few hundred miles. A completely dead coil or more than one fading coil can kill it even faster than that.

I will read up but I found walker and magnaflow midpipes with cat on ebay for less than $300. Any feedback on those? Probably louder than stock. I want that car to be as quiet as possible ...

Get in contact with HiFlight. He has had success with a $100 cat. Most other cats don't survive under our exhaust heat. You will have to have it welded into a midpipe of some sort. A cat will quiet any midpipe down, but you should aim to have one that will survive. Most cats last less than 100 miles.

Ok, just got back from my "lunch break". IT STARTED AND RUNS!!!
Turns out it was injectors connected wrong and a completely f****d cat. I will post a pic in a second. But yes it runs sooooo smooth and actually idles on its own.

There was a lot of wordy posts I had to sift through but found all the answers I needed. Thank god for this forum!

Now, as far as the cat situation, the Magnaflow has a 5 year warranty. I figure I may give it a go.

I will also contact HiFlight. Someone had posted a link to a Magnaflow metal cat on summitracing for about $100. It may have actually been him. I have a welder, so I may go that route first.

Thanks RIWWP. Much appreciated. Where exactly do you live? I'm in Milltown, NJ. Not far from the poconos and nyc. I iwll keep an eye on the forum for upcoming tri-state area meets.