[Marquis de Saab]

This is an everlasting subject with thousands of answers to it, so I don't feel that bad for starting another MPG thread.
Thing is my car became very lazy lately. Someone might suggest it's because of global spring warming and t5 reacting bad on it. Is it? My gas mileage is also getting bad. Last week I've been doing some longer routs, with a lot of highway. My average highway speed was between 85-95mph (maybe there's the catch), after which my final calculation came under 20 MPG. Is this OK? Problem is I don't get much better even when doing constant 70mph... which is boring by the way.
But to go back on the begining - laziness. I became very frustrated after I had a Citroen C3 (for US guys it's a small French car with 1.4 n/a engine) in my tail on 90mph and I couldn't get rid of it with a full throttle ;oops:!!!! It took ages to go up on 110. I was too fast to downshift in 4th and in 5th accelerating was sloooooow! It wasn't like that before. Is it because I now have 215 wide tires on my LPT (154 hp) or 32C degree outside temp has something to do with it... or there is something to check on my engine? Should I try installing MBC+A on my LPT, will that improve things, both in MPG and throttle response?

 

[mg_td]

check your spark plugs, sounds like the culprit.

 

[Peyton]

BG induction Cleaning

I work at a shop at this happens a lot

At most of the shop in my area and in your's (probly) use BG products, just ask them if they do. After you fing one, you are going to want them to do a Induction kit, might call it cleaning the fuel injestors. The kit around her is about $130. like $30 for the chemicals, and $75 for the labor!

It is a three step process

A can of 44k which is like Stp (that you put in your gas tank) BUT IS 1000 times better

Then they ues a throttle body cleaner, but the it not only cleans the carbon and stuff all out, but it really lubracates it too.

Then THE MOST IMPORTANT is the fuel injector cleaner, which is put in throught the vacum lines that burns and cleans all the the Carbon depoitsof the valves, and intake manifold!

THIS WILL DO SO MUCH, FOR BEING SO SIMPLE, AND SHOULD SLOVE THE PROBLEM!!!

You can't buy these kits, they are only sold to shops, and they also do them at the dealers

 

[mg_td]

i still say check your plugs, fouled plugs go a long way to reducing gas mileage and response, though some fuel system cleaner would serve you well too.

 

[Marquis de Saab]

i still say check your plugs, fouled plugs go a long way to reducing gas mileage and response, though some fuel system cleaner would serve you well too.

A week ago I made a post in a thread dedicated to spark plugs, where I commented that I had my sparks cleaned and regapped a day ago and it made no improvement, so spark plugs are off the subject, unless I need new one, which I doubt because current did 6k mls. I always used "by the book" NGK's.
About injectors cleaning, I was planning to do that these days, it costs even less here - about 10$/each, probably 10$ extra to do the rest of the intake.
Anything else on mind?

 

[G96nt]

sluggish reaction and poor MPG = retarded Timing.
that's easy.

Finding out WHY it's retarding is the difficult part.
Spark plugs and a gapper are $8...
check 'em.. or replace them it's been more than 6 months.

Like Some of these guys suggest, try running some sort of Carbon-deposit cleaner. I dont' know if they make it anymore, but mopar used to make an aerosol cleaner: mopar combustion chamber cleaner (MCCC) and you would just apray it in pre-TB and it would blow all the crap out of the motor.

if you want, run the car pretty hot and try and break the front 02 sensor free to get a look @ its condition. it's possible that Winter-mix gas fouled it up good.

 

[PMI]

Injectors are the most likely suspect because it could cause both excessive fuel consumption and poor acceleration. After that, in order of likelihood,

Leak in the line from the throttle body to the fuel pressure regulator or something else making the engine run rich (fuel consumption).

Blown PCV valve, allowing boost to pressurize the valve cover and crank case (valve cover would probably have leaks)

Air leak at one of the intercooler hoses or clamps.

Less likely, a leak in one of the BPC valve lines could make it so the waste gate does not respond fast enough when you want maximum boost.

 

[poyntz]

Something else

Also look at the MAF sensor.
Had mine replaced the other day and it has made a difference to my car.

I'd whack in some STP or other injector cleaner for two tanks, you can still get carbon cleaners - just spray into the air intake
Sparks are cheap enough, but it could also be the HT leads themselves.

 

[Marquis de Saab]

Just like I suspected, there are dozens of answers and solutions to this problem, but non of them is expensive to go through, so I'll start with it and do it one by one. Anyways it's a part of regular maintainance.
I have few questions for you all before I take my first step, basicly they come from my poor understanding of shortcuts in written English:
- what is "pre-TB" (place where I should spray some carbon-deposit cleaner)? Is it (maybe) OK if I take out air filter and do it there or what?
- where/what is MAF sensor?
- what are "HT leads"?
Although these may sound stupid or basic to you, English is not my basic, so if I could only figure TB, MAF, HT... it would solve the mistery, and your answers on which I'm truly grateful can get "third" dimension.
Thank you all,
MdS

 

[G96nt]

Pre-TB is before the throttle-body....

Most would just pop off the TB elbow (assuming you have a turbo) And Spray the cleaner right into the TB and intake manifold.

 

[Marquis de Saab]

Pre-TB is before the throttle-body....

Most would just pop off the TB elbow (assuming you have a turbo) And Spray the cleaner right into the TB and intake manifold.

Got that! Thanks! When I think of my idea again... man, some cleaning it would be, to spray highly agressive chemical over the plastic parts of air filter ;oops:... clean it out of the engine bay!

 

[PMI]

I assume your engine is in better shape than mine, but in my case just spraying cleaner into the top of the throttle body did not do much. The already clean surfaces of the bore got more shiny (see pic), but the ring of crud around the throttle plate did not just disappear.

I had to open the throttle plate by pulling forward on the arm, then clean the layer of old oil around the area where the throttle plate seals using a rag soaked in isopropyl alcohol, then clean and oil the plate pivot points. Same with the IAC valve on the left of the throttle body, cleaner alone did not help.

With all that, my idle is still not very smooth. The throttle plate moves easily now, but there is still something sticking in the throttle linkage, return springs, or the return spring sleeve bearing... I have not seen a single solution to the sticking throttle in the ng900 or early 9-3 models... good luck.

 

[Marquis de Saab]

I'll give it a try, that and new sparks and injectors ultra-sound cleaning... we'll see the results.
Thanks

 

[earthworm]

Marquis,

Automatic or 5 speed manual ??
The automatic has winter and "sport" settings, watch that one of these was nor inadvertently selected.

Ensure that the clutch is not slipping..

HT = high tension (the sparking plug cables) - for the non- turbo Saab.
LPT = Liquidified Petroleum Tank - a wild guess !!
MAF or MAS = Mass air flow or mass air sensor, A device controlling the engine(fuel maagement)..located between the AF and the TB..

Getting so a man needs a glossary to read these forums and use the computer..

 

[Marquis de Saab]

Automatic or 5 speed manual ??

Ensure that the clutch is not slipping..

LPT = Liquidified Petroleum Tank - a wild guess !!

Car is manual, I would have noticed slipping clutch by rpm raising without acceleration... not the case.
LPT is the one I used - Lite Pressure Turbo... I guess that one is rare in the States, but with high-priced gasoline quite frequent in Europe, 154 hp, same engine/turbo as FBT (Full Blow Turbo) but with different ECU setting, no boost gauge on the dash (they thought I may never need it :evil: ).
Cheers!