My Fuel Problem

mrvette

Phantom of the Opera
Joined
Mar 24, 2008
Messages
15,207
Location
NE Florida
I am not happy with the continued required use of Techron to keep the engine running smooth....gets expensive....

I blame the ethanol, which here in Florida, I think is 1/2 water.....

There basically are NO Chevron stations nearby...not even a Texaco....

one thing I notice is....somehow the engine was very unhappy with 89 octane, but have been forced into it was lack of high test....but techron in a tank of 89, and the engine does NOT PING.....without it, surely it will....strange....

I still come back that changing the computer which was a desperation play some 2? years ago, to find out WTF is the cause of this highly intermittant raggedy idle crap....that the problem is NOT the computer, but the friggin' fuel....so is there anything about 'modern' fuels that maybe a new super computer can figger out to actually make better economy, and smoother idle, amd maybe more power?? this using my existing mechanical setup???

:bump::trumpet:
 
mrvette...you're not running an ESC/knock sensor?

Big G, shame we couldn't have met when I was in Austin some months ago....but it was a fast trip anyway....

anyways, yes it's a GM 1227730 late TPI speed density computer with Cal Pak done aftermarket, and wired like a '91 F body....

Car has not moved in some 2 days, and so just now, the damn thing smooth as baby's butt....go figger....72F out side...zero humidity.... I have all the spark shit and knock sensor, and no there are no false signals....took a 'scope' and hung it on the line, if I hammer on the block, I can see signals, but nothing when engine is running....at idle....my scope is a/c powered and I dont have THAT much power cord...:harhar::harhar:

I just refuse to believe that somehow those injectors are to the point of being whatever in performance.....

I thinking of taking a L98 rail setup, with the crescent retaining clips, and going form injector to injector with a 20 hz firing pulse on it, on a bench, and recycle fuel through them one at a time, and find out just what is the truth about dispersion and pressures, and whatever.....

maybe next step, at this time, I have another set of injectors and can install them again, maybe.....just for giggles....

then take what in there NOW, and do the above tests....

I WILL get to the bottom of this POS if I need a hammer from HELL....

:harhar::harhar::harhar:
 
Since you're running batch-fire, a slightly plugged injector shouldn't cause a rough idle. Plus, I don't think injectors are fuel/octane sensitive. But a good flush would be a good thing. Possibly a vacuum leak somewhere, but I assume you have covered those bases. I have a Snap-on scanner and have an LED on the scanner flash on every knock pick-up. It lights when you tap the block by the sensor. Would be good to hook up a scanner and look at you sensor values when the idle is erratic. Bet you would find the culprit.
 
WHY NOT?? any injector not firing denies fuel...misfire...fucked up pattern?? same thihg, fuel hanging in the passage like a messed up carb calibration???

vacuum is tied up tightly....I can't see it, gauge and all steady....

I should get you a reading at idle rpm and give you the cam specs to get a opinion....tmrw project if I see the note....

I do not have a sophisticated scanner, just enought to read codes....
and give values...

# of knocks, crossoevers on O2 etc....

:crap:
 
WHY NOT?? any injector not firing denies fuel...misfire...fucked up pattern?? same thihg, fuel hanging in the passage like a messed up carb calibration???

vacuum is tied up tightly....I can't see it, gauge and all steady....

I should get you a reading at idle rpm and give you the cam specs to get a opinion....tmrw project if I see the note....

I do not have a sophisticated scanner, just enought to read codes....
and give values...

# of knocks, crossoevers on O2 etc....

:crap:

Gene have you ruled out an ign problem??? or a wiring problem to the injectors?????
 
WHY NOT?? any injector not firing denies fuel...misfire...fucked up pattern?? same thihg, fuel hanging in the passage like a messed up carb calibration???

vacuum is tied up tightly....I can't see it, gauge and all steady....

I should get you a reading at idle rpm and give you the cam specs to get a opinion....tmrw project if I see the note....

I do not have a sophisticated scanner, just enought to read codes....
and give values...

# of knocks, crossoevers on O2 etc....

:crap:

Gene have you ruled out an ign problem??? or a wiring problem to the injectors?????

I have gone ape shit all over that crap ad nauseum....Jacobs wire plug ends...new wires, cap, different dizzy, whole damn thing...nothing....

it WAS somewhat intermittant with plug boots, but the Jacob ceramics have cured that....still when it's right, it's very very right....
still come back to fuel....

wife's car, a 99 Escort...I have had to change wires and plugs both to keep it smooth over the years....now today it's running same...sometimes smooth as silk, other times ragged as a doll....

fuel, is the only common thing...but that worn out old Dodge van 318 with a 2 bbl on top runs forever, and never missed a note....so go figger...

HOW long can injectors last??? 60k miles....MORE???

are they a one way replace or DIE type built in device???
 
mrvette;25646[B said:
]WHY NOT??[/B] any injector not firing denies fuel...misfire...fucked up pattern?? same thihg, fuel hanging in the passage like a messed up carb calibration???

vacuum is tied up tightly....I can't see it, gauge and all steady....

I should get you a reading at idle rpm and give you the cam specs to get a opinion....tmrw project if I see the note....

I do not have a sophisticated scanner, just enought to read codes....
and give values...

# of knocks, crossoevers on O2 etc....

:crap:
Batch fire engines can share fuel from an adjacent cylinder. I think some residual vapors back up into the plenum.Try pulling an injector connector at idle. It won't have a hard miss like a bad plug or wire. There will be a small rpm drop, as that cylinder is running very lean.

My scanner reads all available engine parameters in real time. Is very helpful at times...but useless at other times..:eek: I'm surprised you don't have some sort of diagnostic software and aldl-serial cable for a lap-top. Should be free-ware by now.
 
mrvette;25646[B said:
]WHY NOT??[/B] any injector not firing denies fuel...misfire...fucked up pattern?? same thihg, fuel hanging in the passage like a messed up carb calibration???

vacuum is tied up tightly....I can't see it, gauge and all steady....

I should get you a reading at idle rpm and give you the cam specs to get a opinion....tmrw project if I see the note....

I do not have a sophisticated scanner, just enought to read codes....
and give values...

# of knocks, crossoevers on O2 etc....

:crap:
Batch fire engines can share fuel from an adjacent cylinder. I think some residual vapors back up into the plenum.Try pulling an injector connector at idle. It won't have a hard miss like a bad plug or wire. There will be a small rpm drop, as that cylinder is running very lean.

My scanner reads all available engine parameters in real time. Is very helpful at times...but useless at other times..:eek: I'm surprised you don't have some sort of diagnostic software and aldl-serial cable for a lap-top. Should be free-ware by now.

When I tried the Bowling/Grippo -Megasquirt computer some years ago, the install did not go well at all, and so I doubt any laptop I can get is likely to do anything with a stock computer either, the scanner I have is reading all the information ona 2x6" screen and I scroll through...but there is no way in hell it has any information related cyl by cyl....not wired except to the ALDL and so no ref to #1 cyl.....I would have to have something totally way in hell over what I have now to do that .....MONEY....much less the 200 bux to a garage with dubious results to boot....

then I have to catch it in the act....I think I"m going to the Ford 24# injectors and try them for a while, see what happens...

:cussing:
 
Gene, buy an ALDL interface cable and look into ScannerPro. You would have to track down the definition files for your 7730 computer. I have done this for the old MEFI GM ECU that was on RamJet before I realized that trying to tune the damn thing with Tunerpro was way two tedious and limited. I broke down and bought the Accel Gen VII system and have never looked back. Except when you guys drag me back here on the forum. :D:lol:

Bullshark
 
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