Very poor gas milage '93 cutlass supreme DOHC

[BlkndGoldCutlass]

Not right now but tomorrow ill hook it up to my snap-on solus to see if that's the case

[RobertISaar]

  rich_e777 said:

Higher octane fuel burns slower thus leaving more deposits and heat. 87 is perfectly fine.

 

http://www.pontiacstreetperformance.com/psp/mythsgas1.html

 

  Quote

1. Myth: The higher the octane, the slower the burn.

Fact: In many

cases, high octane gasoline has faster burning characteristics than low octane

gasoline. It is rarely slower.

[BlkndGoldCutlass]

Here is a diagram for the pcv on the 3.4

[95LQ1VERT]

The realization of spending about $4 more per tank on for premium 91 octane gas makes me want to use it more often, I put a little in my car today and it seemed to idle a wee bit better!

[BlkndGoldCutlass]

Had a chance to hook it up to the scanner and the tps showed. 54 at no throttle. So i replaced it and i helped a lil bit but it didnt fix my problems

[95 vert]

FPR leaking? Sure would cause idle surge, poor mileage. You'd think it would set a code though.

BTW, .54 would be normal for TPS at closed throttle.

[BlkndGoldCutlass]

Fpr? Yeah i replaced the tps anyway

[BlkndGoldCutlass]

Oh "Fuel Pressure Regulator" duh lol yeah thats a good idea ill check that out

too

[BlkndGoldCutlass]

Yeah fuel pressure is at 47 psi and looks good, Replaced the hose that the pcv valve is hooked up to cuz id looked worn. that seemed to fix a majority of it but im still concerned about the oil in the pcv valve.

[Night Fury]

Oil in the pcv valve is normal, that's what that system is

[rich_e777]

if you had a 3100 i`d tell you to put splash shields in your valve covers but with a LQ1(your case) im not sure how the pvc system is hooked up. One end of it is going to be dumping air back into your system for consumption, the other end is going to be sucking air from your engine. Find the end thats doing the sucking and identify why/where excess oil is coming from. If its so much oil that its going to effect engine operation your spark plugs will show. Run the engine for awhile drive it down the streeet and back then let it cool enough so you can pull a plug safely without damaging the cyl. head and wipe it off on a paper towel. Identify what wiped off the spark plug.

 

Bad idle and bad gas mileage with no codes is starting to sound like youve got internal damage to your engine. Bent valve or pushrod maybe, fingers crossed its not and im just wrong on that.

[95 vert]

No fuel leaking at the vacuum port on the FPR? That's what I was wanting you to check for

[BlkndGoldCutlass]

Couldnt get to the fpr today but from what i could see there was no leak

[19Cutlass94]

You wont see a leak. They have a diaphram inside and when that ruptures, is when they go bad. Youll need to pull the vacuum hose off to check.

[Crazy K]

I've checked several LQ1s for a spare FPR. I grab the vacuum hose connecting the FPR to the intake from where it hooks up to the plastic connector on the passenger side of the intake. unhook the line there and smell it for gas. If it smells of gas, it is bad. If it pees on you, it is REALLY bad. (been there, done that)

[BlkndGoldCutlass]

Ahh i see, how deep is the fpr on the LQ1?

[Galaxie500XL]

It's on the fuel rail, on the driver's side. You'll have to pull the plenum.

 

  BlkndGoldCutlass said:

Ahh i see, how deep is the fpr on the LQ1?

[BlkndGoldCutlass]

well i seemed to have fixed the idle surge and my mpg went up my 2. i havent checked the FPR yet though, But right now she is idling really low like 400-500 rpms and wants to stall when i have to many accessories going like radio ,heat, etc. i have no idea this time-- I am planning on putting the car away for the winter and drive my 94 cutlass over the winter. So should i just check/replace the fpr and all the intake gaskets over the winter?