Hey everybody!

In the process of rebuilding the engine i saw what i smelled before - the results of running way too rich for a long time... a thick layer of carbon everywhere...

well here's other simptoms: gasoline smell from the exhaust, high gasoline mileage (13-14 MPG or 18 liters per 100 km of any style city driving), relatively low power and rough idle...

Here's what i already tried to fix the problem:
*) replaced the water thermo sensor (the one on the water pump)
*) tested AFM with a DMM (it is withing specs) and even try to replace it with a different one - still the same...
*) replaced o2 sensor with a Bosch one
*) cleaned fuel injectors
*) replaced the vacuum hoses with a silicone ones
*) tuned TPS by the FSM
*) checked for error codes from ECU - found none
*) ACV is blocked off
*) Ignition re-setted

actually i'm running out of new ideas what to look for... don't wanna lay a new layer of carbon on a newly rebuilt engine, so please help me out with this...

Thanks in advance!

 

forgot to mention new spark plugs and wires...

 

bump...

Where're all RX-7 gurus?

 

So after doing all of those repairs/tests you are still getting 13/14mpg?

 

Yes!!! And that is not even a complete list... As i did many small things like replaced a fuel pump and FPR... i was thinking that it is possible that the fuel pressure is not within spec... still the same after that...

Is that could have something to do with a tired motor? I started my rebuild because it has more than 160 k miles and the compression was poor... But in my opinion barely this is not related things...

 

dont worry i just adjusted my idle do to the ampage when light and fan are going at the same time. All of a sudden I smell gas to, but I lean her out abit witht the adjustor thingy for lean/rich. I'll see if that works. Oh by the way I only get like 180 miles per tank.

 

Before that rebuild did that engine oil heavily smell like gas?

 

hmm... after it was heavy flooded - yes... but normally i don't think so... Why?

 

i didnt see any mention of a fuel filter, these when severly clogged can cause very large drops in MPG

 

I replaced it twice... As i said i forgot to mention some minor things... Actually i've replaced both: hi-pres side and in-tank lo-pressure one...

 

Bump... No ideas?

Icemark, ReTED, Aaron and other gurus where r u?

 

Bump again...

 

what was/is compression ?
good spark on all 4 plugs verified???
no vacuum leaks?

 

Hey Higgi!

I haven't measured compression before the rebuild, but from what i've seen inside of the engine, i think it was low.

Spark was good and haven't found any vacuum leaks.

You think low compression could be related to high mileage?

 

low compression could affect mileage

 

You could have some weak grounds that aren't allowing enough current to flow to the ignition.....?

 

Than it would result in a weak spark, right? And the spark was ok.

Higgi, how bad it can affect mileage?

 

Spark was OK and all 4 sparkplugs had correct color when u pulled them out?

i guess wideband could tell you if you are running generally rich all over powerband, or just sometimes/some ranges

 

No they've had a carbon layer - a sign of running rich...

I believe Wideband would cost $200+... Am i right?

 

Im glad i see somebody else is having the same probs as me...Well im not happy you are having them but rather that i might be able to find out whats wrong with mine . Same probs with mine to what you are saying. Everything in my motor smells like gas including the Air Filter when i went to replace it. Could it have anything to do with the ignition timing? Maybe the spark is good but what if its not sparking at the right moment?

 

+1 for having the same problem. Im going to buy a crane cams hi-6 ignition box and see if that helps.

 

Hi6 does not replace anything, so if you have something broken, this amplifier is not going to 'fix it'. Sometimes it takes a lot of time and work to find source of problem, but band aids are not fixing it.

 

I am running waaaaaaay too rich as well... will try all the suggestions in this thread.
/subscribe

Have you guys considered a leaky pulsation damper? It causes a heavy smell of raw fuel, and might even be leaking so much that it reduces mileage considerably. Since it's a massive fire hazard, I'm getting it replaced before I try to tune my motor for fuel efficiency.

 

i got an s5 so that shouldn't be a problem.

 

Negative! It fails on S5's as well. It fails on S6's as well. It's just less likely.