Interesting development with car problem

[jmead]

OK, I posted before about a problem I was having. Sometimes car would backfire off idle during acceleration. Would run ok after that, maybe a little lacking in power, but driveable. Got a suggestion about a bad AFM. Got a new (used) one....same thing. Another...same thing.

 

I took it off the road to fix the leaky gas tank. Fixed the tank, but now the car won't start. I can crank and crank, sometimes it will start for a second, run real rough and then quit, most of the time it doesn't even get that far.

 

But I tried something out of desperation. With the AFM connected to the ECU, but not to the intake...same thing....but when I disconnected the AFM all together (both from the intake and the computer), it started and ran! Now, I didn't run it very long (no filter), and I didn't try to drive it, but at least it started.

 

Now, what does this mean? Bad wiring? Something with the ECU? Did FI this old even have a "limp mode"?

 

So...any suggestions? I love this car, but I can't figure it out...I really cant stand to have it just sit in the garage.

 

Thanks for any input

[jmead]

...anyone?

[Drax240z]

I'm not really sure... but maybe you can list your car, engine and any mods and that will spark an idea. What did you do exactly with the fuel tank?

[jmead]

Ok, I've got a 76 280z

Basically stock, had a 60mm TB with same problems (replaced it with stocker), and a K&N cone filter. That is pretty much it (for now)

 

Also, for the gas tank. I drained it, washed it, cleaned it with a rust eating acid (metal ready), washed it again, dried it with hair dryer for 2 days, coated the inside with US standard fuel tank slealer, and as I let that dry I gave the outside 2 coats of POR-15.