not a big inline, but an inline none the less.

A

Anonymous

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ALONG WITH MY 66 f100, i own a 1997 geo metro. the problem i have is it at one time got 50 mpg. it sputtered and then has been low powered and gotten 30 mpg. i have done every test i can think of and nothing,,, changed every part i can think of too, aside of expensive ones. o2 sensor is new, egr system is clean as can be... at idle it has a had time running smooth,,, engine shakes back and forth...... i have posted at a big metro site, and have gotten alot of good idea's, but didn't lead me anywhere... any help, i thank you for!! :idea: ;)
 
nope, the cam timing is good...when i use a scan tool or voltmeter to run tests on diff sensors they all show ok,,,, wondered if maybe my computer went bad... my buddy had one did the same thing,, he is a car tech, and he even had no luck... i had thought of pulling off the efi and retro'n a carb with a custom machined dist on it.... but i would like to get the efi fixed first....
 
brupp":2o30zl1l said:
nope, the cam timing is good...when i use a scan tool or voltmeter to run tests on diff sensors they all show ok....
Click to expand...

I am not very familiar with these engines; how does a scan tool verify cam timing? Please enlighten me.

My Bro-in-law has several of these cars and he really likes them. I doubt that a carb would give satisfation concerning MPG.
Joe
 
With out the check engine light on the computer will most likely tell you nothing. I think it is time to go back to the basics. If it is idling rough, most likely a cyl or two is not pulling its weight.

1 First and foremost is a compression test.
Look for even numbers

2 Read the spark plugs
look for normal color and even color if any.
 
Bro-in-law has bought, re-built, and sold several Metros, still drives two. He says valves, valves, valves :devilish:

According to him the lower end is almost indestructable but the top end tends to burn valves. He's a strict believer in Mobil 1 synthetic for these and has good success. Apparently the top end runs pretty hot, if there ever was a candidate for top quality synthetic oil it is the little overworked Metro.
Joe
 
well i checked the cam timing the correct way,,, i ment to say i have checked sensors with a scan tool and a voltmeter.... i guess that didn't come out right :LOL: i did a compression test and readings come out 150 psi across all three,,, not where i would like emm,, but they are even anyways... what is weird is it will get good mpg some days,45 mpg,,, then back down... doesn't matter if i run cheap gas or not so i have rulled out that.
my buddies metro he had just had a valve job done.... but you never know weirder things have happened.....i will probly order a top end gask kit ,,, atleast i will know.
 
Well, it isn't the cam timing and it isn't the valves; if either were bad you wouldn't have good compression. 150 psi is fine, I wouldn't even contemplate tearing it down.

Since you have already changed some parts with no benefit, I think the next thing I would do is double-check the grounding. Not being very familiar with this vehicle I can't say just exactly how to accomplish this, but I would locate the computer and see how it is grounded, then maybe run a separate ground wire to it from the battery; also to the engine block and car body.

Then sort out the ignition, after that on to the fuel delivery. Try watching it run in the dark to check for stray ignition voltage.
Have fun,
Joe
 
heh heh heh heh yea,,, will have to check all of the grounds.... one thing i forgot is it idles rough, then you crack the throttle very little,, bring up the rrrr's a bit ,, idle is as smooth as can be.... vacuum holds very steady also... fuel pressure is right where it needs to be ,, psi regulator is working good too.... last thing i wanted to check was the injector... the spay looks even,,, but maybe it is hanging up inside... but at 250-300 i don't want to swap emm on a hunch... :unsure: it also stumbles slightly at 1/4 throttle when under load... maybe a bad tps sensor... dunno...... why do i always take the problem vehicles!! :p :LOL:
 
strangely enough, the gauge hold solid,,, i will check again tonight to see if that still hold true... the last time i checked the vacuum was about a year ago. :unsure:
 
I ask because of the long-shot possibility that a valve could be sticking slightly open sometimes. The vacuum would go wacko of course.
Joe
 
yea my thoughts exactly,,,, i had thought to maybe a stuck valve ,bad cam or lifter or somthing,,, i have been told no by other wrench heads,, but hey, i have seen weird things,,, like a front disc brake with no pad on the piston side and only one disc on the rotor left!!! wore thru the one disc, then the fins and into the final disc!!! :shock:
p.s. what you do for work lazy jw???
 
Remember MPG will vary with the weather and driving habits.
I notice you are "up north" in MN. Cold weather drops MPG because the computer will kick in more fuel to richen the mix for good starting and while the engine is not up to full temp. The number of cold starts will make a difference on a tank full of fuel.
My Jeep see a large difference in MPG between winter and summer. A week of colder temps and I can see drop to 17 from 19.5 MPG on a tank.

A TPS is high wear item. More so on a stick shift car. Imagine have your throttle hooked to the volume knob on your radio in your car. How long do you think think the volume control would last?
 
well i double checked my vac , and it holds steady at just under 18,,,,, not to bad i guess.... one thing i forgot about the idle,,, it idles bad when cold only,, when it warms up it runs fine..... weather i lose some mpg,,, but i drop from 33 in the summer to 29 in the winter.... this thing needs new gaskets and seals in it ,, i would like to do a full change to syn oil when i get the bleeding fixed... but my 66 is first...
 
One thing that the Chebbie EFI is famous for is the coolant temp sensor that tells the computer how warm the engine is running will go bad and the computer thinks it is still not warmed up so it sends more fuel. Everything else is fine but will idle rough and burn more fuel. My daughter's pickup did this, swapping the sending unit cured it.
Joe
 
my plug color is a darker tan,,, is running rich... it doesn't seen to matter what brand of plug either...
 
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