New CFI injectors source?

69427

69427

The Artist formerly known as Turbo84
Joined
Mar 30, 2008
Messages
2,972
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Clinging to my guns and religion in KCMO.
Well, the '84 has been sitting around for the better part of 6 years due to a bunch of silliness getting in the way. Tried to start it up over the winter and had nothing but problems. Looks like one of the injectors is eff'd up, as I'm seeing a lousy spray pattern. I've got some spare injectors, but they appear to be more victims of the move, as I can't find them anywhere. So, I'm looking for recommended vendors of these injectors. I'm using a 2bbl TBI off of 454, but I assume these injectors are physically interchangeable. Any place someone can recommend?

Thanks!
 
Injectors Plus....wasn't he a member here? They have them and larger sizes too.

L & R are not the same! The dr. side one is a tad smaller than the pass side one.
 
Finally found the spare TBI (with injectors) the other day after losing it in the move. I swapped out the leftside injector and started up the engine today. It starts, but won't run steady state, requiring continual applications of throttle to keep running. The injector pattern looks normal now with the "new" injector, so I'm not suspecting that as the problem at the moment. It seems like the engine just leans out big time when I let off the throttle. I checked for vacuum leaks, but didn't find anything abnormal yet. I have an auxillary O2 sensor in the turbo downpipe, which kept reading lean, but in all honesty I'm not convinced that it ever got hot enough to give an accurate reading (due to the repeated stalls and having to keep restarting the engine). The fuel is almost a year old, but I've had older fuel than that in the '69 and it would run, so I don't think that's the problem. I don't have a fuel pressure gauge on it (and no easy way to install one), so I don't know if the pressure is lower than it should be. I suppose if the MAP sensor took a crap and indicated low MAP (high vacuum) all the time it would lean out the fuel. Maybe I'll hook up my 'scope to the MAP output and see what it looks like.
I hate to grasp for straws, but I suppose I could have lost a calibration bit in the EPROM, and that's screwing up the fuel table, but that seems like a stretch. I haven't checked for any codes yet, as the air was getting pretty bad in the barn from running the engine, and I was kind of tired of messing with it anyway.

Not necessarily looking for answers (although I'd take it), but I guess I just needed to vent my frustrations about the car. It ran great when it went into storage a few years ago (at the start of our move back to the midwest), and now it runs like shit.

Oh well, tomorrow is another day.
 
WARM air makes everything run better, including US....

cracked vacuum hose??? block everything except MAP sensor and see what happens...I use a clamp or vice grips once I know the engine end of the hose is secure....

course when running, if you pinch with long nose pliars you will see the effect quickly....:clobbered:
 
Just a long shot, but since your in the midwest now, I'd check for critters in the muffler/tailpipe. Makes for all kinds of issues, like the old potato trick.:cussing:
 
BBShark said:
Twin_Turbo said:
L & R are not the same! The dr. side one is a tad smaller than the pass side one.
Click to expand...

The tiltle of this tread is CFI but mention made of TBI. I'm confused, which one has different L&R injectors?
Click to expand...

I apologize for the confusion. That was my fault. I'm running a 454 2bbl TBI on the engine, and was looking for sources of replacement injectors. I figured that a place that sold CFI injectors would possibly also have a selection of different sizes that would meet my need.

Again, sorry for the confusion.

(As TT mentioned, the CFI units use two different rate injectors.)
 
If you are using a 2bbl TBI, those were around till the mid 90's so GM would probably still have sets of injectors.

Just ebay GM tbi injectors and a bunch will come up.
 
Well, still playing around trying to get the engine running. I disconnected all the extra vacuum lines but no change in operation (still stalls unless the throttle is feathered). I was curious if I lost a bit in the EPROM chip (I've been running a 2732 EPROM while I'm getting the fuel and spark curves dialed in). I can use upper or lower addresses in the EPROM by way of a toggle switch on the adapter board, and I keep the old calibration in one half while I test out the new calibration in the other half of the EPROM. I swapped addresses but no change. I hooked up a spare MAP sensor and started it, but still the same stalls. I hooked up one of those "Noid" lights to the injector wires, and the light intensity modulations showed me that the ECM is definitely widening the pulsewidths when I feather the throttle. I don't have a reading on the fuel pressure yet, as I don't have a convenient way to hook into the fuel line. The pump is a low mileage LT1 pump, but I suppose it's always possible that it could have a problem. If I don't find issues elsewhere I'll come back to that and make an inline line that I can plug in between the fuel line and the throttle body and hook it to a fuel pressure gauge.
I haven't checked the temp sensor voltage yet to see if it's reading (IIRC) low voltage, which would indicate a warm engine and causing a leaner fuel pulse. Seems improbable, but it won't cost me any money to check it.
I also need to check the IAC to see if it is stuck open, perhaps allowing just enough bypass air into the engine, leaning it out. I don't know if that's physically possible (allowing enough air), but I'm starting to run out of ideas.
I could hook up my 'scope to the sensors and see what's happening, but I'm hoping to figure it out before I have to get fancy.
That's it, just typing while I'm thinking. If I've missed something obvious let me know.
 
I wonder if maybe the LT1 pump is too much for it....

:flash: maybe dial back the pump power a tad? do like I did years ago with a Carter pump, stick a series resistor to the pump so it's running at lower voltage/power...sorry I have no clue these daze as to what values, only been 35 years.....
 
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I'll be home over the weekend- I've got a scan tool if you want to plug it in. It will give you a picture of what everything is doing.
 
I assume we're talking about a Gen II LT1? Port fuel injection uses much higher pressures than TBI. I have to agree with Gene that it would be one of the first things I'd look at.

Have you checked the idle control valve on the throttle body? My BMW had horrible idle problems recently - it turned out that the control valve was a bit out of whack, and every non-water rubber line on top of the engine had started to crumble. Air and vacuum leaks everywhere. Even if the hoses look OK, they might have nearly invisible cracks. Illustration: Years ago my dad and I had a 1941 Chevy military 4x4 with a GMC engine. On the drive home, it started blowing oil every which way. My dad had it towed to a good local mechanic's shop, he couldn't find the issue. I went to check it out after school one day and found a hairline split in a rubber hose that fed the oil pressure gauge. When it wasn't under pressure, that split was almost entirely invisible. A local hydraulic shop made a new line, the massive leak went away, and I impressed the hell out of the mechanic. Long story short...look over any vacuum or PCV lines very carefully.
 
Neighbor had the same issue. New fuel pump cured it. I always thought they just fail and stop, but apparently not.
Fuel filter, regulator, pump pressure, filter sock,lines. That's the stuff that gums up sitting.
 
mrvette said:
I wonder if maybe the LT1 pump is too much for it....

:flash: maybe dial back the pump power a tad? do like I did years ago with a Carter pump, stick a series resistor to the pump so it's running at lower voltage/power...sorry I have no clue these daze as to what values, only been 35 years.....
Click to expand...

The LT1 pump has been in the car for almost 20 years, and has hundreds of trouble-free track miles on it.

I haven't had the opportunity to check for fuel pressure/regulator issues yet. It's not belching out black smoke, so I don't think that it's an overpressure issue. It's fine under neutral accels, but just won't idle.
 
TimAT said:
I'll be home over the weekend- I've got a scan tool if you want to plug it in. It will give you a picture of what everything is doing.
Click to expand...

I appreciate it! I've got an older scan tool, but I haven't plugged into it yet. If mine doesn't give me enough info I'll check in with you to see if yours can extract a bit more out of the ECM. Given the vintage of the original ECM I don't expect much. I'll be going deeper into this issue on the '84 next week. I'm currently distracted finishing up the '69 for a track day on Friday.
 
big2bird said:
69427 said:
It's fine under neutral accels, but just won't idle.
Click to expand...

Idle control solenoid gummed up?
Click to expand...

I'm curious about that too. I'm going to rope a relative into toggling the ignition switch while I shine a flashlight into the pintle seat area to see if I can see the thing move (seat and retract to the start position).
 
check for a cracked plastic map sensor line, blistering cts sensor pigtail. TBI will regulate and port efi pump down to 13psi.

also check to see the injectors have solid connection and if they move see if fuel spraying quits.
 
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