hadlowj

Ok rebuild and installed the engine on the black car. The starter is to slow to get it going so have to tow start, no problem there except it won't idle so keep my foot on the accelerator to try and run the engine in a bit, the problem is after a few minuets the throttle just ignores me, no matter what I do, I can stamp on the throttle and nothing happens and the car dies, I have tried driving it round the garden and then same thing happens, it decides it going to ignore me.

I have had a chat with ben and changed the throttle body but still same thing happens, I have checked the connections and again nothing wrong there. There are no warning lights on the dash, even after restarting it no check engine light or fault code. I have tried ECU resets, both the stamp on the brake 20 times until the gauges sweep and leaving the battery off. The battery is new so don't think it is that. I am so confused, when the car runs is sounds great just a minor squeak that sound like its coming from the clutch. I really do not know where to go from here, please help

Thanks
James

RIWWP

iTrader: (2)

Your post is hard to follow, and I'm going to guess that there is a language barrier.

Is this interpretation correct?
A) You had the engine rebuilt and re-installed in your 8 (which happens to be black)
B) Your engine will not start using the starter, and have to get it tow started
C) As the engine warms up it becomes more and more unresponsive to the throttle
D) You have replaced the throttle body
E) You have no CEL, and have accomplished several ECU resets


Assuming all of this to be accurate, these are the quick possibilities:
- Engine wasn't rebuilt correctly and it can't hold compression (due to the trouble as it warms up, our engines have more compression when cold)
- Ignition isn't firing properly (either old, damaged, or unseated connections)
- Fuel isn't being delivered properly (fuel injectors not properly connected or fuel injectors clogged)
- The ECU can't read the correct MAF data (disconnected or damaged, isn't delivering more fuel when you open the throttle plate)
- E-shaft sensor isn't properly reporting the position of the e-shaft (dirty or damaged)

StealthTL

iTrader: (1)

What RIWWP said, I'd suspect the MAF connection and the primary O2 sensor - these can really screw with the computer.

Also check that both circuits at the throttle pedal sensor are active, if the computer loses one of the inputs it will ignore the other.

hadlowj

Hi, sorry I posted it on many forums and forget people don't know my background. Almost
A) yes I rebuilt the engine (my second build)
B) No the starter only turns at about 170 rpm
C) No it is totally responsive then instantly completely ignores me and dies, it does not get worse and then die it is instant.
D) Yes I have tried replacing it but it makes no difference
E) Yes no warning lights or codes showing, and yes have tried many ECU resets.

Thanks James

RIWWP

iTrader: (2)

Gotcha.

They we can rule out compression, that would be a slowly dying failure. Does the throttle pedal cease to have any impact before the RPMs fall? Or at the same moment? What I mean is, does there seem to be a bit of a delay where the pedal stops responding and the engine holds it's own for a brief bit before the RPMs fall? Or is the pedal working up until the moment the RPM's fall?

hadlowj

Yes I think so, I will be there holding the throttle at say 3K and then the revs just plummet and then engine dies, I try pushing the throttle to save it but it just ignores me and the rev just drop all the way down to 0.

Thanks again
James

RIWWP

iTrader: (2)

I would say that this is a sudden loss of ignition or fuel.

The fact that you can hold the RPM at a certain point prior to it dying tells me that the throttle sensors and throttle body are working just fine.

Is there any commonalities between each occurance of this? Like is is always X number of minutes into the engine running, does it seem to have a temperature trigger? (assuming you can watch the coolant temp) Anything else that "always" seems to happen that you haven't considered as related? Like a quick vibration or a vibration frequency? How soon after it dies can you get it refired? Having to tow start it pretty much rules out an immediate re-fire I'm guessing.


Some of the things I'm tossing around my head are:
- Ignition is being "shaken loose" at some point in the chain
- Injector wiring is being "shaken loose" suddenly
- Fuel pump is overheating and just shutting down suddenly as it hits it's fail point. The time to restart lets it cool off
- ECU is seeing a pre-set water temp point and shifting to closed loop, which it can't self-support due to a sensor data input missing.

hadlowj

Humm, It dies after a few minuets, usually 3-5 mins don't think I have had it going longer than that, I can get it going again pretty much straight away, just reattach the tow rope and go again, it fires up, another few mins and does again, I only have to stock gauges to go bye and there is spike in the coolant temperature, I have checked all of the connections and made sure they are all properly in place. I am really stumped :/

RIWWP

iTrader: (2)

What do you mean by a "spike" in the coolant temp?

Kinda surprised you don't have an ODB2 reader if you are proficient enough to rebuild your own engine

hadlowj

Coolant dial get to its normal straight up position and goes no higher. I do have a ODB2 reader but its basic, it can read and clear engine check light codes.

RIWWP

iTrader: (2)

Ok, so no spike, staying normal.


If all of the connections are solid, coolant is staying fine and doesn't appear to be impacting this in any way (from an ECU shift in how it handles the input data), then my only remaining conclusion is that it's the fuel pump. I could still be wrong, could be forgetting something else.


Curious, what happened to require an engine rebuild? Failing fuel pump can lead to a lean spike that can damage/destroy engine seals.

hadlowj

Low compression was the cause of the rebuild. I have a spare fuel pump so will try swapping it out ans see what happens

hadlowj

Just an update, car just needed some running in, after 60 miles, it starts and idles cold, warm and hot :D

godesshunter

Was the fuel pump the problem?

hadlowj

No, I am not sure why it was ignoring me but once it started idling all the problems went away. I never got an error code or misfires so have no idea what was causing it before.

zoom44

wow missed this thread. the reason the car wont respond to throttle inputs after you sit still with your foot in it for awhile is because the PCM programming is designed that way. this bit of protective programming was added with a reflash associated with the recall that also included putting thermal protection blankets over the fuel tank and other things associated with the possibility of an overly hot exhaust warping the fuel tank enough to cause a rupture that allows fuel to leak onto the exhaust causing the car to catch fire.

zoom44

pdf explains what was changed bythe recall

https://www.rx8club.com/attachment.p...7&d=1254601401

AndrewE

mine was cutting out bad, no throttle imput(ignoring lol) for about 5 second or more and one time I was forced to pull over and it died completely. I'm pretty sure my pump is done, it was noisy when I got home yesterday, and was the first warm day we've had(16c/60f). Anyone pulled their pump with half a tank left? I'm thinking thats too much left in the tank.