Triple Black 88

I have an 88 Corvette and last week while driving home, it stalled while driving and wouldn't start back up. Had it towed to my local shop who said they believe the injectors "shorted out" and they would need to replace them. I'm not a mechanic but can this happen? Can all 8 just short out? Like I said, I'm not a mechanic, so I'm not sure what to do or what questions to ask. I've been going to this shop for over 10 yrs without any issues. I'm sure they checked fuel pressure, spark, etc...

Any ideas or advice?
Thanks

VikingTrad3r

VikingTrad3r

NavAir

Yes. The 4 on each side are wired in parallel, so if one shorts, the 4 on that side won't work. As I recall, they should read about 16 Ohms each. Sometimes when they short, it is temperature-dependent, so you have to measure them when they are hot (failed).

Steve

Triple Black 88

Thanks guys, I will follow up with him today.

GREGGPENN

Interesting. I would expect a series setup to cause an entire bank's failure. Multi-light fixtures (in your home) are wired in parallel so each light can work independently. You may be right about one injector "taking out" an entire bank but I'd question the method of wiring. And, if truely shorted, you wouldn't have to measure hot/cold. Dead is dead. Plus, if it won't restart after sitting, you should be able to measure abnormally low (or no) resistance when cold. I will add that L98's only have one O2 sensor on the DS bank. In closed loop, I could see that preventing any operation (fault). Unless a "broken injector circuit" causes ECM shut-down, why wouldn't SOME cylinders still fire?

There is an injector "driver" that controls when injectors squirt. It's one thing I've yet to read up on so I don't know if there's one driver, one driver for each bank, or ???? A failed driver or even burnt wire to the injector bank seems way more likely to have caused a shut-down....if, indeed, it's a fueling problem. I also question the mechanic/diagnosis.

That said, if one/more injectors failed, are original, AND need replacing, having 30-yr-old injectors would absolutely warrant ALL being replaced.

gerardvg

The injector fuse would blow if an injector is shorted, just measure which injector is shorted unclip it and the car will then run on 7 cylinders.
Most likely the fuel pump has failed, I cant see multiple injector failures at the same time .....
Contact FIC and get some cheap bosch 3 injectors, nothing lasts forever but seriously get a second opinion.

belairbrian

If we look at this from a circuit perspective it's Like this. Injectors are essentially solenoids with fuel passing through. They are a coil with a rod inside. When current flows through the rod pulls back. When a coil shorts, it either shorts at the input output wire or some where in the coil. The short results in a low or no resistance path, In a parallel circuit this becomes the path of least resistance so current doesn't flow through the other branches (injectors). In a series circuit a shorted injector would not fire but the others would still be in the current path and would still fire. Conversely in a parallel circuit an open injector would not fire but the others would. This is how the home lighting circuit works. Light bulbs almost always fail in an open state. In the event a light fixture shorted a fuse/breaker would open. In a series circuit one open injector would stop all from working, because the circuit would not be complete.

Sorry the electronics geek came out.

JimLentz

In the parallel scenario above if one or more injectors is low resistance the others will still fire. The only way they won't fire is if one or more of the injectors is low enough resistance to blow the fuse for that bank then none of them can fire.

belairbrian

Maybe, maybe not. It would depend on the effective resistance of the circuit as a whole. Assuming a low resistance in one or two injectors allowed sufficient current to flow and create a sufficient magnetic field to form in other injectors then they would fire. But you could also run into a situation where the other injectors prevent a fuse from blowing but cannot create a sufficient magnetic field to actuate or fully actuate themselves. I don't think anyone could come up with a exact answer.

Just too many variables even the mechanical friction of a worn injector would need to be considered.
Would a fully shorted injector always blow the fuse. It may be the driver circuit would cause enough resistance to prevent dead short of the fuse.
Inductive circuits can certainly be interesting to troubleshoot.

JimLentz

Theoretically the fuse would never blow given that specific scenario, but why design a circuit where the fuse would not blow given a short on an injector?

mickey5

my multecs failed after 23 years and 50K miles. Drove it 100 miles from home and it ran perfect. Shut it off and 15 minutes later tried to start it. Turned over fine but wouldn't fire. after an hour or so it started right up and ran fine...for about 30 minutes. Started a steady miss so I limped it home. Shut it off and wouldn't start. left it for an hour and it started right up but then started missing after 15 minutes.

This went on for several weeks until I found a Vette tech that found the bad 2 injectors. Ethanol fuel killed them. Heat soak brought it on

kael

In parallel, power controls on or off of all the lights. When the power is on, each light has a switch to control itself. If power is off, the light can't switch on.

Injectors don't have a switch, they get "on/off" from the ECM/relay.

As far as shorts lowering resistance, no, not in parallel circuits. The only way that might seem to happen is if the current through the short actually impacts the power source, as in its voltage drops so low that other items in parallel don't "work". In case of all resistors, the non-shorted resistors would show lower current, as expected from I=V/R.