I've got a 91 civic hatch in the shop. The MIL is on and it shows four codes, Injectors, EAC, TPS, and IAT. Once the light comes on the car goes into some kind of limp mode where it won't allow you to exceed 3500 RPM's.

All of these sensors are on the same harness, goes to a round connector at rear LH side of engine compartment. I inspected the major round connector, no corrosion or loose pins. Unfortunatly I don't have a pinouts on that round connector so I can't check that segment of the harness.

The plugs on 3 of those individual sensors are identical but the correct plug is on each one, checked that against a wiring diagram.

This one is got me stumped, any help on this would be appriciated.

Thanks,
Russell

 

I've unhooked the TPS, IAT, and EACV before and it won't cause that problem. Check the MAP sensor. If it becomes unhooked or recieves a positive pressure then it will put the car into limp mode. Check that, if that doesn't do anything for you it could possibly be the amp box for the injectors. If it starts to fail it would cause you to limp, however I've never heard of one going bad.

 

AMP box? My diagram for a 91 civic DX shows one side of the injectors coming from the main relay and the signal straight from the PCM.

Is the amp box a synonym for injector driver? If so I'm aware the injector drivers are in the PCM on this vehicle, if not I do not know what an amp box is.

 

Yeah its the injector driver. Sorry

 

This car had two problems. Furthur discussions with the customer revealed that he had just replaced a camshaft seal.

This led us to check the timing and it was off by one tooth. Timing belt adjusted, still hd two codes, one for EAC and one for IAT. I re-checked myself and indeed these two connectors were switched. I must have overlooked this the first time.

Here's to thoroughness!

-rp