after reading the countless posts about this problem, I'm still not certain about something. The cold start 9th injector. where is this located?how can I test it? the cold start problem that I'm having is like this: I start to crank (4 second intervals)after three attempts I here the electric fuel pump repressurize and then I crank on the 4th attempt and engine sputters.three more attempts with sputtering the engine fires and runs perfectly.I also have the infamous vacuum leak at the heater control that is causing no heat situation.can both problems be related? I replaced the thermostat and heater control valve yesterday......please camaro Gods help me. 1987 5.7 TPI IROC all stock, smog pump removed,lines blocked off

 

I think the 9th injector is under the upper plenum in the back by the distributor. Not sure how to troubleshoot it. I kept having the same problem with the heater control valve. I just removed it all together and that took care of that problem. Not sure if I'v helped much.

 

The cold start inj is mounted in the drivers side runner where it attaches to the intake. The PCV hose goes right over the top of it. It has a small metal fuel line that runs towards rear of eng, wraps around the rear-most runner and connects to the rear of the drivers side fuel rail. As far as testing it goes, you need to verify you're getting fuel press first. See below.

A vacuum leak will make eng more difficult to start. Need to fix that.

Does the fuel pump come on when you first move the key to the "run" (not start) position? It should run for a couple of seconds then shut off. If it doesn't, you need to check the fuel pump relay/wiring.

There's an oil press switch that can also power to fuel pump. If you crank long enough to build up oil press, that switch will eventually close and power the fuel pump.

 

first of all, thank you for the detailed location, it really helps when somebody knows what they are talking about....so kudos to you!...The fuel pump does not turn on until about the third try.the oil pressure guage instantly shows a strong reading.so the next question is where is the relay?
thanks again, Bob

 

The fuel pump relay in on the drivers side firewall. Just outboard of the brake master cyl. There should be 3 relays in that location. MAF power, MAF burn-off and the fuel pump relay. I believe all 3 relays are interchangeable, so you can swap them around to see if you can get the fuel pump to come on just by turning the ign switch to the "run" position.

Attached is a wiring schematic that shows wire colors for the fuel pump relay. It should help identify and troubleshoot the relay.

I've seen pics on this board of the fuel pump relay, but can't seem to find one at the moment.