Ignition Relay

[Guest FIRSTBUILD]

just wondering if any one has noticed how hot the ign relay runs on an efi? I have been investigating a strange fault car, it on my car and have noticed the relay is really warm.

 

my car starts really well from cold then drive 20 miles - leave it for 4 hrs and it wont start ! leave it 24hrs and it will start first time ?

 

Usually when it wont start I keep flicking the ign. on and off (10 or 15 times) and then it fires up so I keep thinking about the relay ?

 

 

any ideas ?

 

thanks Steve

[agent_zed]

trying to think logically it could be something like the starter motor solenoid as if you run it it will heat up being next to the engine and will retain a lot of heat as it is quite large. Could cause it to stick. That would explain why it would take a while before it works again, although it really is a guess on my part as iam not that good with electrics. If you have a spare starter might be worth changing it to rule it out. Or the tried and tested 'hit it with a hammer' technique works on my sisters car... HTH

Edited April 7, 2008 by agent_zed

[Longboarder]

Not enough information in the not starting bit. When you turn the key 4 hours after a run is there silence, or does the starter solenoid clunk, or does the starter turn the engine at a good speed but it doesn't fire, or does it turn over very slowly? Does it cough and backfire but won't run when you try?

If it turns over OK but doesn't fire does the exhaust reek of petrol? Have you checked for a spark? If you drive for more than 20 miles does the engine die or is it only if you switch off that you can't restart? Will it restart if you try immediately after switching off or is it only if you wait some time and then try?

 

Nigel

[Guest FIRSTBUILD]

Not enough information in the not starting bit. When you turn the key 4 hours after a run is there silence, or does the starter solenoid clunk, or does the starter turn the engine at a good speed but it doesn't fire, or does it turn over very slowly? Does it cough and backfire but won't run when you try?

If it turns over OK but doesn't fire does the exhaust reek of petrol? Have you checked for a spark? If you drive for more than 20 miles does the engine die or is it only if you switch off that you can't restart? Will it restart if you try immediately after switching off or is it only if you wait some time and then try?

 

Nigel

 

thanks for your reply I am glad the fault caught your attention

-- the car always starts from cold (15hrs to three weeks)

it will do any distance without failing

when I try to start it after the four hr rest following the twenty mile drive it turns over really well -the fuel pump operates correctly - it has good spark - I think I can hear the injectors (do they "click"?)

 

I have a battery kill switch and what seems to make it start is flicking that on and off - perhaps waking up the ecu or a lazy relay ?? just a guess/

 

Once when it didnt start I squirted some wd40 in the throttle body and it fired - I think its injtors or what controls them - the ignition relay gets quite warm after about five minutes of runningbut remains at the same temparature.

 

any help would be great

 

thank

[Longboarder]

Sounds electrically OK from the ignition side. If it starts on a squirt of WD40 or any easy start, etc then I would be guessing on fuel starvation. Then thinking vapour lock from heat into fuel system when stopped. You say using the kill switch off/on several times may clear it also.

Have you got a good fuel return to the tank or swirl pot. Also check fuel pump and fuel pump relay. Any relay that seems to get hot should be checked. Is it rated for the current it is carrying. Are internal contacts and the terminals clean. I would be thinking that if you get a vapour lock is the enough fuel flow to feed the injectors when the ECU switches the fuel relay for the couple of seconds only that it gives when you first switch on.

 

Nigel