Need Opinions on What's Next

[Sean S.]

Fuel lines reversed?
Engine ground connected?
Mechanical problem? (out of time, bad head)

No

Yes

Timing has been checked multiple times by complete tear down of the front covers. Also, if I bad head, I wouldn't expect to have even compression readings across all 6 cyls.


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[Sean S.]

Lift the fuel rail so you can see the injector tips, crank the car and watch. Sounds like you have a stuck injector, or it's being physically grounded causing a full open condition.

Also, if the car has a c109 connector, it can cause issues.

I'll have to pull the rail and check later today. It just seems weird to me that an overheat would damage a fuel injector, but weird things happen.

If you mean the c191 connector, it has already been reworked.


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[ForcedFirebird]

I'll have to pull the rail and check later today. It just seems weird to me that an overheat would damage a fuel injector, but weird things happen.

If you mean the c191 connector, it has already been reworked.


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The head came off, so everything was touched. Very easy for 30yr old parts to get damaged just from R&R.

[cscracker]

When I last rebuilt mine I put a newly rebuilt and matched set of injectors in, and one happened to be stuck open, causing a misfire. I had to put one of the old ones back in to fix it. If you have more than one stuck open, or perhaps an electrical problem keeping them open (melted wires? damaged during the work?), it could explain the symptoms.

[Sean S.]

Ok, so I think I'm getting closer. I replaced the ngk plugs with Bosch, it starts, but will not idle and is pouring gray/black smoke. The only way to keep the engine "running" is to start it with the pedal at wot and then it sputters and diesels and just pours smoke from the tailpipe. I know it's still running way rich, I'll be pulling the injectors next, (as recommended above), I just haven't had the time to do it. Maybe early tomorrow morning.

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[Sean S.]

Well, not the injectors ... All 6 fire a perfect mist when engine is cranked, no streams, no sputters, no misses, no constant on.

This is driving me insane.

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[Sean S.]

Update: after putting the injectors back in, the car will now poorly idle when started but die the instant the throttle is touched. I can still start the car with the throttle at wot which again causes a running condition sounding like hitting a rev limiter and tons of gray/black smoke from the tail. Mid range throttle seems to be getting more responsive( read: engine doesnt die when releasing from wot).

I'm back to thinking about a plugged cat.

Anyone have another idea?






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[ForcedFirebird]

Does it change when you unplug the AFM? A bad AFM could cause all of these issues.

[Sean S.]

Does it change when you unplug the AFM? A bad AFM could cause all of these issues.

AFM was swapped out with known good part. It's not the AFM.

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[Sean S.]

So it's down to the exhaust system. I think the cat is plugged internally. The car will not idle, but I am getting good response from mid range rpm (when I say good, I mean the car does not just die when the throttle is held), the smoke from the tail pipe has cleared up which suggests that the cat was so full of coolant, etc that it couldn't breathe. While trying to clear this out, the cat is now becoming super heated which also suggests that its done.

If anyone has a good working system they'd like to sell somewhere in the Bay Area, I'd be interested. I don't really want to drag that monster out and swap it with my system. I'd rather just put in a good used system.

[ForcedFirebird]

Take it for a hard drive and check the temp of the cat. It will be extremely hot if clogged.

[Sean S.]

It's extremely hot just blipping the throttle in the driveway. It's not driveable, it won't be able to get out of it's own way.

I'm thinking of separating the system and taking a look at the cat grid, but I'd rather just slam an entire working system back in the car. I have an aversion to exhaust work for some reason.

[ForcedFirebird]

Since you are in CA, you probably require a working cat.

Long trip from FL, but I just did an exhaust take-off with a good cat section. The m42 cat went NLA about a year ago, looks like the m20 did too (well aftermarket, anyways). :(

[Sean S.]

Not just a working cat, but a CARB legal or OEM cat. And they WILL check at smog time.