Hi, i fitted my rx-8 with an used engine, now the car starts normally, and idles, but doesn´t rev, it revs but it sounds like missfires.

The obd scanner tells me that there is something wrong with cylinder 1.

I have new sparkplugs, wires and coils. I also installed a new clutch.

Can the problem be the maf, o2 or the eccentric shaft censor?

CEL ERROR CODES:

P0301
P0410
P0172
P0000
P0300
U0073

---------------------------------------------

SOLVED, SOLUTION: INJECTOR CABLES WHERE CONNECTED WRONG



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double check your plug wires. check to make sure you didnt crack a plug. reset the ess

 

I´ve tested with 2 different sparkplugs/wires and coils. by reseting the ess do you mean:

1. switch ignition to ON
2. press 20times on the break pedal within 8 seconds, turn off --->start

 

yes

 

i mean make sure the wires are on the correct coils/plugs. did you label the injector connections when you removed the engine? i got a misfire once after changing my plugs. it ended up being cracked porclin on the new plug.

 

Yes i think the cols/plugs are in the right order

 

ok how about the injectors? many people have hooked them up wrong. idk if it would give you a misfire tho. is the ess clean, in the right position and reset?

 

is there a scheme somewhere how the injectors need to be connected? How about the cat? I haven´t cleaned the ess, and by the reset you mean the 1-2step i told earlier? If so the ess is reset.

 

yes thats the reset i mean. cleaning it is easy, just wipe it off. i remember someone had problems because their ess was bent or something like that. the injector diagram i dont have but i know its on this site. iirc 9k recently asked for it or he posted it.

 

https://www.rx8club.com/tech-garage-...r-info-150432/

This thread?

 

this is an 4-port -5speed manual engine

 

no i was refering to the connectors on the injectors. im not an expert on this so hopefully someone that knows more than me will chime in

 

got a buddy with an RX8? Swap your MAF sensor just to rule that out.

 

Can you define "won't rev"?

A) Stumbles and breaks up, preventing the revs from increasing past a general area
B) Hits a hard limit like the 9k fuel cut, only much lower
C) Throttle pedal has no effect and revs remain at idle
D) Will rev through the whole range in neutral, but has trouble doing it
E) Something else?

Is there a difference between when it is in neutral vs driving under load?

 

There are only around 50 rx-8 in Finland, so i don´t really know anyone

 

I have to get back to you tomorrow, but I think it´s A, i´m not sure so i´ll check tomorrow witch my mechanic

 

If you confirm that it's A, make sure you know what RPM area it's breaking up at and won't go past. If it's in the ~3,000rpm range, ask if he keeps it there for ~10-15 seconds, will gas start dripping from the tail pipes? This is one possibility when the MAF isn't reporting information to the ECU, either due to being unplugged, damaged, or wiring damaged. The engine starts flooding out from adding crazy amounts of fuel.

 

Thanks, i will ask tomorrow. How do i know there is no broken seal? We haven´t done an compression test yet. my broken engine sounded like a tractor when cyl2 was completly destroyed

 

Compression test is really the only way. However, compression affects low rpm before high rpm, or the problems are more pronounced at low rpm than high rpm, so compression doesn't sound like it's your problem here. Not to say you don't also have a compression problem, but I seriously doubt it's causing your specific rev problem.

 

If i remember right, when they started the car the first time, it had a hard time to idle, the engine turned off

 

That could be anything just about, including just fuel trims being completely reset.

From my own experience with engine replacements, the most likely culprits are just something not hooked up right, usually a grounding point or a sensor, or similar connection points hooked up backwards.

It might be something else of course, but it's usually something quite 'obvious' once it's found (but drives you nuts until you find it)

 

I called him 5 min ago, he told me that the engine has a hard time reving, you have to play with it a while to get it up to full rpm:s , and while doing this it´s stumbles. And when you let go off the throttle the engine stops. the car idles, but sometimes it turns off.

 

That sounds like a fuel and/or spark delivery problem (hardly news though).

Some thoughts:
- validate that the coil harness is plugged into the coils in the right order. Reversing the harness would change what the ECU thinks it's firing and when
- check for a fraying water pump/alternator belt, as frays could be hitting the ESS randomly and randomly screwing up the ESS signal (had this happen before on a different car)
- verify that the engine block ground is clean and secure
- verify that all 4 plugs are still in good condition. They have been known to crack on installation sometimes, though less of a concern if the plugs were installed before the engine was put in
- verify that the injector harness plugs are plug into the correct fuel injectors and something isn't swapped accidentally

 

Was the original engine a Lo-power 4 port or a Hi-power 6 port?

 

both engines are 4-port 5speel manual, otherwise they would not fit