I have a friend with a 88 928 with a devek 6 liter stroker on it. He called me trying to find out why he couldnt get it started, plus when it was running, it was not idling right. It was stalling at idle, with the idle hunting badly, like the idle stablizer valve was bad or the idle switch was disconnected.anyway, we got it started by going through the normal tests. spark, yes........... jump fuel pump relay, yes, it humms................ turn the key, no hum from relay. jump the EZK relay, no change............... jump the LH relay and............YEP, it starts.
928 international recommended a relay that can be bought for cheap. $12 and he put the relay in, not only does it start rigth up as expected, but it runs like a champ and the idle issue is completely gone. Has anyone heard of this? Idle is higher, near 1000rpm vs the 600 and hunting it was doing earlier. i wonder if it was a voltage or relay issue feeding the LH box??

Anyway, he is a happy camper.

mk

 

relay relay relay

 

More liekey a voltage issue feeding the injectors.... which come from the LH relay.

 

EZK relay is low current. Fuel Pump and LH relays are high current.

Cheap relays are just that, cheap. Are you sure the $12 relay meets the same amp rating as the original equipment?

 

makes sense. so, at idle, the relay has too much of a voltage drop across it because it is going out (failing) the new relay is NEW and the LH gets the juice it needs. before, when running at high rpm, the alternator is putting out a higher voltage and maybe masks the problem for a little while.

So, have a hunting idle issue, check that relay as well!

I think the relay was a VW version of the same relay. I think it was 30-40amp. (40amp is our relay if I remember correctly) anyway, heck, if it starts to go out, he knows what to look for

Thanks,

Mk

 

~$5 and rated at 40 amps... that should be more than enough.

http://www.pelicanparts.com/cgi-bin/...ction%20System

Dan
'91 928GT S/C 475hp/460lb.ft

 

Ah I see my work is done here....Relay Relay Relay

 

Mark, were his running issues affiliated with a specific temperature range, such as cold or warm?

Just wondering as I'm looking to replace the LH, EZK and fuel pump relays for the hell of it because I know they are OLD.

 

He is in Arizona. Its been a problem warm or cold. he has been bugging the heck out of me with the issue for 5 months now! I think its great that its fixed!! pretty funny fix though. Who would have guessed.
mk

 

On warm temps, my issue arises. So far I seem to associate with disconnecting/reconnecting the battery, causing the LH to learn again. It couldn't hurt to spend ~$20 on 3 relays powering the brains and the pump. I may go the same route as your buddy.

Good to hear his issue was solved by doing this!

 

you could always jumper the relay, though make sure this is ok by the experts. I think he jumpered it and the car started. he might have done this with a similar relay. for sure, he jumpered the EZK first, but that didnt start the car.

mk

 

I have been struggling with idle stall and bad idle hunting issues on my S4/MY88 since months, now. my mechanic is unable to fix... Maybe this LH relay could be the root cause? Where is this relay located?

Thanks

 

go to 928gt.com on page 2 under tips and links print out a fuse relay chart

 

That's the 53B relay and at $5 each most customers change them all. Cheap insurance.

 

Be aware that there are different sources for these relays with differing quality standards. It's OK to buy cheeeeeap ones, but if you go that route, stock up on spares at the same time.