Location of fuel pump relay in 90 corvette conv.

I intermittantly lose fuel preasure, so I bought a new relay, but I cannot find it's hidding place. Can someone help?  Sure appreciate the assist.  Marty  

here is the component locator for your year  copy  the link and paste it in a new window...  i have not worked on the 90 to 96 models... so i cannot tell you if the relay is under the hood or under the dash...


http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/08/fc/a5/large/0900c1528008fca5.gif

here is the one for the LT5 motor

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/08/fc/a6/large/0900c1528008fca6.gif


on 89 models.. they are on the engine side of the power brake booster...

here is the engine diagram

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/08/fd/9a/large/0900c1528008fd9a.gif

here is the fuel pump wiring diagram for 90 to 96 corvettes

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/08/fd/ac/large/0900c1528008fdac.gif  

Hey man! sure thank you for the info. I guess I need to find if the problem is
primary or secondary. I had the dash apart and could not find that illusive critter, but I'll look again.  So many thanks waynep....   marty  

I found the relays.Now too find out which is what.  Why didn't the factory mark any of this stuff?  So can  ya tell me what the different relays control?   Thanks  again--   Marty  

there are better component locator images available in factory service manuals... and online through eautorepair.net or alldatadiy.com

i usually use the color of the wires....      

there are also neat devices used by telephone guys...   that put tones into wires... and another unit with a pointer and a speaker to search for the tone on wires...    they really do work... but are usually not cheep...

curious....

any chance that the anti theft system built into the ignition lock cylinder is acting up?????when this happens... usually the anti theft light on the dashboard will flash....


i was in a hurry the other day when i posted the wiring diagrams...   when you look at the lower half of this diagram... you will see a lead that says .. to oil pressure switch...

so i would think that this system unlike some of the earlier C4's used the relay to prime the system when the key is turned on and while cranking the engine...  but when the oil pressure comes up...  the 2 wire or usually 3 wire oil pressure switch runs the fuel pump as long as there is oil pressure...

i have seen the oil pressure switches fail...    i have seen the connector pig tails go bad...   i have also found debris in the oil passage that blocked the opening in the oil pressure switch port...

this oil pressure switch should be located under the distributer behind the intake screwed into the top of the block...

this is what the oil pressure switch looks like

http://contentinfo.autozone.com/znetcs/product-info/en/US/wl2/PS168/image/8/

how it works...

one terminal is the oil pressure switch... it has a variable resistance that changes with oil pressure.. this controls the gauge unit...     the other 2 terminals will not have any contact between each other or to the base when tested with an ohm meter...

when the oil pressure comes up.. these pair of contacts are connected and the fuel pump gets power ..

when fuel pump relays go bad.. you will end up with long crank times as the fuel pump does not come on with the key .. only when the oil pump builds enough pressure to trip the switch...


a few more things... are you sure that the fuel pump in the tank is not going bad...   they do act strange with the extra ethanol in todays fuels...   is it noisy????   is so change it... and the filter sock....    try to buy one from some place that has a life time warrantee on it... and can be exchanged easily...  i have had more than one ... fail ...

it only takes about half an hour to change  the electric fuel pump...   right through the gas cap cover door..  do plan ahead... pick up a new tank gasket from GM...   it does not come in the fuel pump kit...  the sending unit is bolted in with a bunch of bolts...