Car starts with injectors unplugged

[Lani Kai]

I have a 1978 280Z into which I recently swapped a rebuilt L28 engine. It took me over a month to get the car started, and to be honest I'm not sure how I fixed it. One day I walked into the garage, turned the key, and it fired right up.

The trouble is, the car won't start or run with the fuel injectors plugged in. I had replaced the injectors not long before replacing the engine, so I'm fairly certain they didn't all get stuck open at the same time.

Currently, the car starts with the injectors unplugged and the cold start valve plugged in. If I plug in the injectors or unplug the cold start, the car will not start. The idle is a bit high right now and the engine does not want to rev past 2,000rpm.

While idling, the car remains running with injectors AND cold start unplugged. Plugging the injectors in lowers the RPM. With three injectors plugged in, the car is barely running and spitting out black smoke from the exhaust.

Did all of my injectors simultaneously get stuck when I did an engine swap, or have I accidentally created a car that runs on no fuel? Or is there somewhere else I should be looking?

[zKars]

You have a leaking cold start valve that doesn't care if the connector is on it or if power is supplied. Maybe it leaks worse with power on. Remove the fuel supply hose to it and test again to confirm.

Nice job of trouble shooting so far. Keep up the details.

Jim

[conedodger]

Probably leaky injectors. Pull them and replace or have them cleaned and flow tested.

[Lani Kai]

You have a leaking cold start valve that doesn't care if the connector is on it or if power is supplied. Maybe it leaks worse with power on. Remove the fuel supply hose to it and test again to confirm.

Nice job of trouble shooting so far. Keep up the details.

Jim

I tried this and it fired right up. It must have quite a ridiculous leak.

Thanks!

[Hardwyre]

I'm running a cam in my '76. I need to get my air/fuel wideband in, but with the cold start connected, if I don't get it running on the first fire up, it floods. I've run it for months without the cold start and have never had that flood-like problem. Most likely its probably never been replaced even though your injectors were.

[Zs-ondabrain]

where in Washington are you?

[sblake01]

I'm running a cam in my '76. I need to get my air/fuel wideband in, but with the cold start connected, if I don't get it running on the first fire up, it floods. I've run it for months without the cold start and have never had that flood-like problem. Most likely its probably never been replaced even though your injectors were.

Not really sure how useful that info is in this case. It sounds to me like you either also had a bad cold start valve or you've done other things to affect the mixture/volume of fuel upon start up. When everything is right, the cold start valve only runs as long as the thermotime switch allows it to which is, as I recall, a total of 8 seconds. Cams, air/fuel wideband's etc. are aftermarket mods and lead to a different troubleshooting algorithm than that of a stock system. Edited June 22, 2010 by sblake01