1993 940 turbo fuel injector relay issues

It is likely a fuel pump relay. This is a white relay behind the ashtray in the center console. Remove it and if you are handy open pull it out of the case noting the way it came out. You should resolder the circuit board that holds two relays and you should also clean out the relay contacts. This can be done by folding as sliver of fine abrasive paper so that both sides can work the contacts. Hold the abrasive sliver with tweezers and work it in between the contacts. Either that or spend $50.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

Boris Mohar wrote:

Specifically, th VO;lvo relyas seem to have a penchant for cracked solder joints inside of them. Remove the relay, then open the case. Resolder each of the solder joints even if they look OK. If you don't know how to solder, find a fried who does. It isn't difficult. See:

the contact points in a relay are plated. Once they get tothe point of needing to be sanded, they need to be replaced. Whathappens is this- the contact points should be fairly flat with a largecontact area. Often they are nt. The electricity arcs between them,and usually that's OK, but eventually the arcing canwear through theplating, or foreign matter gets between them and becomes carbonized.This can weld to the surface, or cause arcing on a very small ppintthat wears through the surfact of the opposite contact. Whatever thecase, the surface becomes pitted and the plating is lost. Once thishappens, sanding and burnishing can give the relay a bit more life,but in all but the most benign cases, teh relay will eventuially failagain, and at greater frequency the more it is done. If the contact area looks ugly, try this- take a dollar bill and cut a strip about 3/8" wide off one edge. wet it with WD40 and then rub in some flour of pumice. it is a very fine abrasive. Then place this between teh contacts and pull it through. Repeat until the contacts are smooth and shiny. Clean the contacts up with alcohol to remove all traces of the WD40 and pumice. But ifyou do this it would be best to have a spare relay on order. You will probably need it- sooner or later.

Bottom line- relays are a way for a small switch that can handle only small electrical loads to turn on and off something that takes a high current load. A relay does this mechanically with an electromagnet. A better solution is a solid-state relay which can have a life span of ten-fold or more over a mechanical relay. Hmm... I have a 10 amphere one sitting right in front of me... Hmmm.... Off to look at the wiring diagram! ;-)

__ __ Randy & \ \/ /alerie's \__/olvos '90 245 Estate - '93 965 Estate "Shelby" & "Kate"