relay problem.....

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relay problem.....; high revs, OVP or fuel relay?
Topic Started: Fri Nov 6, 2009 9:59 pm (84 Views)
jimbojones	Fri Nov 6, 2009 9:59 pm Post #1
Newbie Posts: 16 Group: Members Member #2,587 Joined: April 27, 2008	hey guys, have a 1993 1.8 manual and for the last two years my revs have been varying quite alot, the engine used to "snore" in idle and often cut out when coming from high revs, especially when changing into reverse after a short journey. Recently however my FP relay seems to have given up, the engine is idling quite high and i did as recommended in other posts and checked the fuse in the OVP and it was fine, also blocked the air flow to see if the FP relay would kick but it didn't. took both ovp and fp relays out and cleaned contacts but it made no difference, both units are sealed so im wary of opening them, however if i take out the ovp relay altogether the revs drop somewhat but still no response from the FP relay if i squeeze the air inflow, just wondering if you guys knew which relay is the problem or if its worth opening them up to see? if i open them up would any problem be easily apparent to a noob? thanks for any help regards, JJ



Ukmerctechie	Fri Nov 6, 2009 10:04 pm Post #2
Member Posts: 2,153 Group: Members Member #454 Joined: August 12, 2006	What response are you looking from off of the Fuel pump relay? A song/dance/cabaret act? The engine runs so the FP relay is working. I would be checking the Idle valve and also the connections in the OVP circuit board. Edited by Ukmerctechie, Fri Nov 6, 2009 10:07 pm.



kentronix	Fri Nov 6, 2009 10:13 pm Post #3
Admin, if only I could shut up for a week or halfords had an autoglym sale neil would overtake Posts: 16,305 Group: Admin Member #147 Joined: January 20, 2006	Doesnt sound like the fuel pump relay. Could well be worth opening up the ovp.



stwat	Fri Nov 6, 2009 10:24 pm Post #4
Moderator Posts: 12,305 Group: Moderator Member #28 Joined: November 11, 2005	The idle control valve may need a clean out. Also the afm plate might need setting correctly and cleaning out under it. It could be lots of things to be honest. It might be worth getting the car tuned up to see if that helps.



jimbojones	Sat Nov 7, 2009 12:07 am Post #5
Newbie Posts: 16 Group: Members Member #2,587 Joined: April 27, 2008	Read this on the high revs post for a 2.3 (http://s14.zetaboards.com/mercedes_190_club/topic/222083/1/)- OK try squeezing the pipe the goes into the idle control valve. Squeeze it tight and it should limit the air going in. The revs should drop but then the computer should try and adjust its revs up to counter for it. If it does, then your OVP, idle control valve and everything is OK. In that case it's probably an air leak or something.... - so was looking for the drop and rise in revs mentioned above but didnt get anything when i tried it, possibly it could be differnt for the 16v than the 1.8? Think ill start with the OPV and have look inside that, cheers for the advice



jimbojones	Sat Nov 7, 2009 10:31 pm Post #6
Newbie Posts: 16 Group: Members Member #2,587 Joined: April 27, 2008	just opened up the OVP and checked the joints and resoldered any that looked suspicious, checked the springs and still reving far too high, anybody got any pics or tips on getting at the idle control valve? thanks



190E.sg	Sun Nov 8, 2009 3:22 am Post #7
Member Posts: 130 Group: Members Member #22 Joined: November 9, 2005	If the fuse on the OVP relay is not blown, changing it won't help. Suggest you get one from the breaker and test it. If it works, buy it. If not then it is not the fault of the OVP relay.



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