I'm trying to help my QC manager out. His car is at the local gargae and the mechanic is stumped. Here's the background:

1991 chevy cavalier, 2.2 engine “G” , 4-cylinder. Cold start problem – engine cranks but will not start (eventually it will start) – no pulse at injector – if ignition is on position for a minute or two it will start (pulse at injector). When shut off then tried to start 20 minutes later - no pulse – no start. Key left on position 2 minutes the car starts. Tried anther ecm, replaced crank sensor and ignition module, at this point we are at a dead end. Can there be something in the fuel regulator???

I'm an electronic moron, but I'll be happy to play middle man with any questions/suggestions.
Thanks,
Tom

Possibly problem with the oil sending circuit? I know that they won't start until there is recognized oil pressure, which actuates fuel pump. Just a guess.

A guess is as good as anything at this point...thanks!

Fuel pump relay can cause that.

Thanks, Dean. I'll pass that along.

The mechanic just called him back and said, "There is no injector pulse at injector, put a jumper from ecm to injector (blue wire) still no pulse. After a timespan there is a pulse and car runs fine"

I would scan it before doing anything else, if you have not. It should show some sensor or gadget out of range.

Have you checked that there is the proper fuel pressure in the rail at initial start? A gage is best. A failed check valve will drop fuel pressure and the pump takes a long time to build it enough to start.

If all of that is good, and you have determined a loss of the signal that activates the injectors, check the items that must be working to fire the injectors, oil pressure(new to me), the crank and or cam sensor, brake or trans interlock, air pressure, air and coolant temp sensors, etc. There is probably a timing function that shuts the injectors off after a certain number of revolutions w/o firing also.

It really sounds like a computer circuit ground or open issue, of fthe top of my head.

Next up would be intermittent failure of a sensor or coil, apparently in the cold state vice the hot state.

Had an 87 Cavalier one time, with the converter lockup solenoid prob...

Might be something on here. http://www.topix.com/forum/autos/chevrolet-cavalier

Rob

Fuel pump relay can cause that.

Exactly what I was thinking

Take a look under the battery tray, there will be a large engine connector. See if any battery acid has dripped on it. Ask me how I know.

Need to know what he is loosing. With the key on the red wire at the injector should have power as the blue wire is grounded by the PCM to make the injector pulse. If when the key is on there is no power on the red wire then he needs to make sure the ECM 10 amp fuse has power to it. Could have problem with ignition switch. If there is power at the fuse but not at the injector then problem may be a broken wire or fuse terminal could be spread and not getting contact. I am assuming he is using a noid light to confirm no injector pulse. Fuel pump relay will not cause no injector pulse in this vehicle. I worked for GM dealers for 19 years if you want I would be happy to talk with your mechanic. PM me and I'll give you my phone #.

is this one of those smart IP clusters going into theft mode??:D