Misfire Problem

[EWAustin]

OK,
So,

After all my efforts/problems (changing engines, oil pump valve falling out=no oil pressure, etc etc etc) I've still got a miss.
I put my stethoscope on all four injectors and they were making a nice clicking noise like they should.
My distributor cap and rotor were looking pretty crummy and old so I replaced those today and it still missed.
I measured the resistance of all four spark plug wires and those were good too.
I hooked up the timing light to all four spark plug wires and all 4 showed spark.
So I pulled the plugs.... Number three looks BRAND NEW. Like it has never fired on that cylinder.
Tomorrow I'm gonna hook up a test lamp to the injector plug to see that it's getting a signal and measure the resistance of the injector itself.

Anybody got any more Ideas?

-Eric

[DCM]

OK,
So,

After all my efforts/problems (changing engines, oil pump valve falling out=no oil pressure, etc etc etc) I've still got a miss.
I put my stethoscope on all four injectors and they were making a nice clicking noise like they should.
My distributor cap and rotor were looking pretty crummy and old so I replaced those today and it still missed.
I measured the resistance of all four spark plug wires and those were good too.
I hooked up the timing light to all four spark plug wires and all 4 showed spark.
So I pulled the plugs.... Number three looks BRAND NEW. Like it has never fired on that cylinder.
Tomorrow I'm gonna hook up a test lamp to the injector plug to see that it's getting a signal and measure the resistance of the injector itself.

Anybody got any more Ideas?

-Eric

An injector that is still operating, but plugged.

[EWAustin]

Is there any way to check that without pulling it? That's a PITA on this engine.
So let's say I do pull the injector, how would I clean it, just hook up an air compressor backwards and give the injector some power to open it?

[the tick]

Tomorrow I'm gonna hook up a test lamp to the injector plug to see that it's getting a signal.

-Eric

I never heard of this one. Does this work? What kind of "test light" do you need (I have a standard 12v clip/probe type)? What voltage can you expect to see there?

[PeteySi]

Maybe run a can of seafoam or other injector cleaner/solvent through it? Can't hurt, and it may be easier than the PITA injector removal.

On the other hand, I don't know that you want to run for 200 miles with a misfiire. Once had an old Subaru GL that was misfiring. Gasoline got dumped down the exhaust manifold, and the ceramics in the cat melted into a ball that jammed up the exhaust system. During diagnosis, the intake spit back in my face from the backpressure. NO GOOD!

[wannabfast]

well i bet its the injector where the plug still looks new thats dry... thats gonna be the only injector you are gonna need to check i think

[EWAustin]

The test light I have for testing injectors is one that my little brother made, it's just a 3v LED that works both directions, but lights up different colors depending on polarity you also have to put a resistor in there too. 300-500ohm is good. So then you just plug that into the harness and start the car to see if it blinks. If it doesn't blink then there is no signal, if it does blink then the injector is the problem.

[EWAustin]

Well, the test light showed that the injector was getting a signal, and the spark plug visibly sparked when I started the engine with the spark plug removed, so I guess my injectors are plugged.
So far I found a place (www.witchhunter.com) that will clean, test, and return injectors for $15 each.
Anybody know of a place locally that can do this? I would like to avoid down time.

Thanks,
-Eric

[wannabfast]

15 each?! thats pretty damn cheap.. so long as you dont have to replace any

[EWAustin]

See, that's what I was thinking, but Dad is trying to convince me that I'm just throwing money at the car. I have a couple extra injectors, but they're cruddy and covered in grease/sand. So I don't wanna put any of those on my car. So what I was thinking of doing is taking all my injectors, send them out and whichever four come out the closest matched put those in.
Thoughts?

[weidnerpaul]

See, that's what I was thinking, but Dad is trying to convince me that I'm just throwing money at the car. I have a couple extra injectors, but they're cruddy and covered in grease/sand. So I don't wanna put any of those on my car. So what I was thinking of doing is taking all my injectors, send them out and whichever four come out the closest matched put those in.
Thoughts?

Just convert the damn car to Webers!!!

:evil:

[PeteySi]

See, that's what I was thinking, but Dad is trying to convince me that I'm just throwing money at the car.

Take the ol' Mare out back and shoot 'er? After all she's done for you? Seriously, it seems like you've invested a good chunk of change and a whole ton of time. Is this the straw that broke the camel's back? What about used injectors?

[EWAustin]

Shoot her ???? no way, for one I don't have half of what I should invested in this car, I payed $600 for the car, $100 for the extra engine, $80 for the headgasket set, $60 for a new oil pressure sender, about another $80 for misc stuff (dist cap, rotor, permatex, carb cleaner, etc etc etc) So I have less than $1000 in it, last one I saw for sale was $1800 and not in this good of condition. Oh yeah, I threw a set of used snow tires on it too, but I don't think those count towards the price of the car.

Now, about those Webers... There's a set of 40DCOEs off of an Alfa Romeo on E-Bay for $400 (45DCOEs for $200, but 6 days left) and with a little bit of work I could make an adaptor for $60-80. But somehow I think reconditioning the injectors would be cheaper and more reliable. (anybody know if Webers like snow?)


-Eric

[EWAustin]

You know, I do have my Dad's old intake manifold and Solex from his '71 2002... I wonder if I could make that fit... But then, there is a reason he switched to a Weber, and it wasn't only for the extra power.

[weidnerpaul]

You know, I do have my Dad's old intake manifold and Solex from his '71 2002... I wonder if I could make that fit... But then, there is a reason he switched to a Weber, and it wasn't only for the extra power.

Webers = Tuneable

BTW, The way you're going (keep track of $$$) I think you have a Grassroots Motorsports 2006 challenge car going...

[phile]

You know, I do have my Dad's old intake manifold and Solex from his '71 2002... I wonder if I could make that fit... But then, there is a reason he switched to a Weber, and it wasn't only for the extra power.
Solex? Throw it away now. Why do you think he put on a Weber? Because the only good Solex is a dead Solex. I rebuilt one once. Can't think why I bothered. I'm no carbbie expert, but I didn't have to be an expert to see it was absolute junk.

Unless you need to keep a Solex to run in a stock class with a car cursed with a Solex from the factory, the easiest thing to do is replace it with a down-draft Weber on the factory manifold. Your dad probably put on a side-draft manifold with a side-draft Weber. This is better for track use but more problematic for a streeter.

I suggest you get the FI working. Webers are nice, but the future does not belong to carburetors.

[wannabfast]

but the point of carbs is less computer control...

[EWAustin]

Yeah, the Solex comment was more of a joke than anything, I wouldn't even consider doing that to my "baby"

GRM: Mike (SmokingTiresV6) and I are talking, we might have a plan.