96' Mitsi Galant running rich, any ideas?

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holdenboy11, Mar 20, 7:17am
Owned this car for just over a year, and to say the least, its an uneconomical car.I've been given a few suggestions on how to make it run more efficiently (and more smoothly, as it idles quite rough), but I wanted to see what other advice was out there.

It has the 1.8L GDI engine, which I know has a great reputation, but while I own it or before selling I want to improve how it runs.Been told that it could be a faulty oxygen sensor, needs new injectors and a few other things.The new spark plugs showed dry carbon almost immediately after putting them in, just like the ones before them.

Any of you petrol heads know a likely problem/solution!

mrfxit, Mar 20, 7:42am
Mostly I would suspect it just needs a dang good clean

Air flow meter
Inlet manifolds
Air filter & hoses etc

holdenboy11, Mar 20, 8:05am
Would I need to replace the air flow meter or is there something you can actually to do it!I haven't actually replaced the air filter, it looks okay, but I guess that doesn't mean its working 100%.

I might see if I could get someone to give me a hand in cleaning the manifolds.I got rid of some gunk in the throttle body the other week but didnt use the proper cleaner stuff.Also started running the car on bp ultimate 98 instead of 95, it runs a tiny bit better because of either of these.

franc123, Mar 20, 8:06am
Place vehicle in crusher, press button, walk away. Don't even bother trying to make it run better, its still going to be a GDI Galant when you have finished. Could be all of the stuff you've been told already and then some, people have spent several thousand over time trying to get these dogs to run right and got no long lasting result. Also how uneconomical is uneconomical!

purple666, Mar 20, 8:11am
Rich!
Give it to my Mrs.
It won't be rich for long.

holdenboy11, Mar 20, 8:22am
Lol I'm sure there are better options than that, hoping for a better return than I would get for a piece of squished metal.It's hard to say, but it costs $40-50 to fuel up each week, although I probably do over 100km a week in and out of middle of Hamilton from Hillcrest and to Te Rapa a lot.

wilgil, Mar 20, 7:20pm
Where did you get the idea that ANY GDI engine had a great reputation! (did I read that right!) The intake manifolds need to be cleaned out, as do your inlet valves - the GDI is pretty famous for poor economy as they get older and start to gum up. If you google enough, you will find a couple of websites that show you how to strip it down and clean it up.

mrfxit, Mar 20, 8:19pm
A good running early GDI . IS nice, but as others have said, they get clogged up with crud over time.
The early 1800gdi was the worst of the lot but thats partly because ppl were running them on 91 fuel.
They were designed to run on Japans 105 octane & a lower grade causes all sorts of problems in most of those early gdi vehicles.

There are a few various tuning tricks around but mostly only work on "clean" engines to start with.
I hope you have been running it on 96 or 98 grade fuel, the higher, the better.

By the sounds of it, it's going to be a manifolds off & possibly heads off job to TOTALLY clean the top half of the engine.
Hard to say about the heads until the manifold etc is off for cleaning.
****
It's a little tricky diagnosing those for the precise problem but 95% of thetime it's gunk buildup in the manifold system (air cleaner to engine)

holdenboy11, Mar 20, 9:10pm
Sorry that was some sneaky sarcasm haha.

Alright so it looks like I'm going to be cleaning it over the next few weekends.I'll do that before I try replacing anything, seems like a wise order.

jason18, Mar 20, 9:14pm
Would that upper engine cleaner do the job for this fulla ya reckon guys!

mrfxit, Mar 20, 9:21pm
Might & might not . kill or cure either way.
It's a little bit like engine oil flush's in high km engines = kill or cure.

holdenboy11, Mar 20, 10:45pm
I like the sounds of cure but not kill.Would that really compare to actually taking it out and giving it a good clean!

bigfatmat1, Mar 21, 2:18am
I found that throttle body cleaner from crc quite good. spray it in start it up suck the shit through the engine lol

wilgil, Mar 21, 4:41am
There is a Wurth product that people use.
Yeah, sorry, didn't recognise the sarcasm.

n3d4sp3d, Mar 21, 4:41am
go to local mitsi dealer and ask for a can of shuma spray manifold and head with it let it sit 4 24 hrs. Waterblast manifold then refit it push car out side and start with wide open throttle when it fires it will smoke like anything. make sure the plugs are out while it soaking or it will never fire.

intrade, Mar 21, 5:16am
most common fault for running rich is faulty lambda O2 sensor ignoring the fact that its A gdi heap that only causes problems ever.

holdenboy11, Mar 21, 5:20am
It's called shuma spray!Is there anything else that could be used!Alright if we end up doing that I'll keep it in mind, thanks.

holdenboy11, Mar 21, 5:34am
Sorry must have overlooked your post, I included this info but got rid of it because there was too much in the end lol.Previous owner had it on 91, been running it on 95 the last year since I bought it, just recently started using 98 too.

Myself and friend just bought a cheap diagnostics tool with software, but I'll definitely try a range of things that will all help a little.

mrfxit, Mar 21, 7:48am
DING . ;-(
" Previous owner had it on 91, been running it on 95 the last year since I bought it, just recently started using 98 too"

" things that make you go . mmmmm"

holdenboy11, Mar 21, 10:22pm
Yep I've almost bought one of these a couple of times, but I've put it aside to do some cheaper DIY things first lol.

mechnificent, Mar 22, 1:27am
Test the O2 sensor. that's the recommended procedure before replacing them.

holdenboy11, Mar 22, 8:28pm
As in like a voltage test or whatever!

mechnificent, Mar 24, 12:31am
Yeah, a voltage test. If you do it at the computer's plug then you will have confirmed all the wiring and connectors to and from the O2 sensor as well. then you can eliminate that from your list.

clark20, Mar 24, 1:10am
Can the injectors be cleaned with these GDI models! Injectors gum and don't close properly, using more fuel

holdenboy11, Mar 24, 4:36am
Ahh right, well a mate of mine bought a cheap OBDII scanner (ELM327) but we haven't found software that works yet.But this test can be done straight on the plug though right!