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(Australia) 1997 Excel x3 fuel consumption

4K views 11 replies 3 participants last post by  sprint97 
#1 ·
Hey guys and girls,

Been reading around the forums for a while trying to fix my problem but after chasing a lot of leads ive come to a dead end.

Since the last basic service i did (oil, oil filter, air filter) I noticed my girlfriends car using excessive amounts of fuel. Not sure if it was performing this badly before but watched it closely after a service as I dont really drive it. Being a '97 model im not expecting the moon but currently only getting around 350-400km on mostly highway driving. Around town it can drop down to around 300 or less.

The first thing I did was check for codes bridging connections 4 and 15. Nothing. Received 4444.

Not knowing the history of the car I decided to go over most things to cover my bases.

replaced
- Fuel Filter
- ECT sensor
- o2 Sensor

and cleaned
- AIT sensor
- MAF sensor
- TPS sensor
- Throttle body

the last things i have done from the list are replace the o2 and ect sensor, reset the ecu and checked for codes again and now receive 4151, air/fuel ratio. Would this possibly be because the old sensors were not reading correctly and missing another more identifiable problem?

Any more light to be shed with this code or will i need to have a proper scanner plugged in for more information?

Or have I missed something completely and am stupid. Either way Id love some input just to have something to look at.
 
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#3 ·
thanks for the reply

It does have a top end tap at idle but impossible to hear at higher revs because of engine noise. Ive assumed this would be a stuck hydraulic lifter that would need cleaning. If this valve is not operating correctly could it cause a loss of compression? possibly a valve not closing all the way.

Ill do a dry and wet test to check for ring or valve culprit but would be nice to have an idea going in. I should have had the km's in the original post, 240,000km. So a fair few. No way is this car getting a strip down for low compression. Might have to bump up oil thickness if it needs it and move on to a new whip.

Cheers.
 
#4 ·
Today I've filled the tank and drove to the auto store with the intention of buying a compression tester and possibly a valve cleaner spray as a hail Mary. Before I walked into the store I thought to check for codes one more time, no codes anymore. I'll give the car one last chance on this tank before I start feeling really lost.
 
#5 ·
So currently driving down the coast and it's been a roller coaster of emotions with this bloody fuel issue. First tank on the highway we did over 500kms then the next 3 to follow got worse and worse. Currently gone through 3/4 of a tank and have done 250kms. All highway driving. I really wish I could have done a compression test
 
#6 ·
Well arrived in Brisbane this arvo and the last part of the trip the car has developed a fairly bad misfire. The girlfriends dad has a compression tester and the cylinders are all making 180 psi. **** good. All plugs have a build up of soot so my only thoughts now are spark. Is the build-up causing a misfire? If so how did the build-up occur. Or is the coil done? I've also thought about the plug gap as I've gauged them at 1.1mm (I'm sure I saw this as the specified gap) but maybe I'll reduce this? 0.9mm see how it goes. Hopefully someone reads this and has an opinion.
 
#7 ·
Maybe just grasping at straws on this one too. A while before the car had the service it would have a very intermittent starting issue where it would crank as long as you wanted but never fire. This was resolved by a simple clean of the crank angle sensor. Could this sensor be the source of bad economy and misfire? One day someone will pay attention to me.
 
#8 ·
Just to keep it all in one thread something else that bothers me is where the temp gauge sits. It never rises above a quarter. All cars I've ever seen stay at the half way mark at normal operating temperature. Is this just the way the gauge Is designed? The fans come on at idle so I guess the thermostat and sensors are working?
 
#10 ·
Swapped back to original coil for a laugh. No more misfire. Received a dodgy part!

Pulled the injectors for a basic inspection. Tips looked good gave them a clean with some solvent anyway for some grit around the general area.

Cleaned idle air control valve. Good amount of carbon came out of that.

Back to receiving cel code 4151. Air fuel correction.

So I'm left with the fuel side of things. Fuel pump, fuel pressure regulator, or injectors themselves. What's the path of diagnosis for this?

Not that anyone replies to this anyway. To google!
 
#11 · (Edited)
Swapped back to original coil for a laugh. No more misfire. Received a dodgy part!

...>>>>So I'm left with the fuel side of things. Fuel pump, fuel pressure regulator, or injectors themselves. What's the path of diagnosis for this?

Not that anyone replies to this anyway. To google!
Well my friend, you have certainly worked your way through
things ;o))
With the ICV....have you made sure it IS clean?
Use carb cleaner, spray down into it quite a bit while blocking off both ends and give it a good shake like a cocktail shaker...you should be able to hear the shuttle valve rattling, then drain it.

Next, you haven't mentioned the MAF (Mass Airflow ) sensor...these quite often go duff at this distance and have a strong bearing on fuel trims.
You can clean them insitu with MAF cleaner....made by CRC...don't use brake cleaner or carb cleaner...they're too viscous.
To remove it you will need Torx security bits as ordinary ones won't work.

Next you haven't mentioned the coolant temp. sensor....this is different to the gauge sensor and sends a signal to the ECM.
If this is duff the ECM will assume engine to be cold and enrichens the mixture.
both these are found on the side of the thermostat housing and the coolant sensor is the top bigger one....usually simpler to just replace them....they don't cost much.

Next, make sure the PCV valve is clean which is situated in the hose that runs from cam cover to throttle body....these usually gum up and need a good soak in carb cleaner....make sure the valve is rattling back and forth when you shake it.

I'm assuming you have tested the fuel system pressure and it's at spec?

I think you said you have checked or changed the O2 sensor?
Are you using the correct grade of plugs?
Clean air filter element?
Have you replaced the throttle position sensor?....They're cheap enough.
Same goes for Crank Position Sensor.

To clear your ECM disconnect the negative lead from the battery and touch the positive lead with it for about 10 seconds...., this will spool down all voltage activity which remains in the system and should reset to factory specs.

After all this see how it goes.
 
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