New engine in - blowing 30amp fuse when trying to start!

[Cr33do]

Evening,

We have fitted our new engine but when trying to start it it's blowing the 30amp fuse in the top right hand corner of the engine fuse box!

I can connect the battery, lock and unlock the car fine turn ignition to position 2 and get check lights etc. it's only when I attempt to start it the fuse blows. I initially thought it was the starter motor but not sure now.

All 3 earth points are secure. Where should I start looking? Is it the starter trigger wire that uses this particular fuse?

Help!

Nick

 

[Cr33do]

Admin. please move to electrical section. Thought I was posting in the correct section.

 

[Cr33do]

This is really starting to bug me now

3 fuses later and still in the same situation - I hate electrics!

Double checked starter motor connections and found an old post mentioning Pre cat sensor wire can cause similar issues but all check out ok.

Ignition II doesn't cause any problems. Only when trying to start it.

Rarrrrr

 

[Cr33do]

Update.

When I remove the starter relay the fuse doesn't pop. What this telling me / does it narrow down the cause?

I presume all this relay does is send 12v down the starter trigger wire when the ignition switch closes the other side of the relay?

One other question. Top right hand fuse in the engine bay, the one that keeps blowing. Is that definately meant to be 30amp rating?

 

[mantis946]

EDIT: Pichers are always easier

 

[182_Adam]

its a short circuit (earthing out to early) on the starter circuit. without the vehicle its very difficult to diagnose but possibly something either in relay or between sm and relay.

 

[Cr33do]

Thanks for the pictures and advice.

Intresting as our 30 amp fuse is where the 60 amp fuse is in your picture. I.e- they are swapped around. Before the engine came out and went back in it used to start with the 30amp in place though?

I thought that the starter trigger circuit is at fault hence it not blowing when the relay is out. We have tested the relay in another Clio and that car starts fine. The trigger wire (white) runs from relay to starter motor. Does the other side of the relay (same white wire) run to the ecu? As it looks like both run down into the engine loom beneath the airbox etc


Thanks

 

[Cr33do]

For reference

 

[Cr33do]

I suppose as our car is a 172 cup the 30amp fuse might be correct? Maybe it doesn't protect as many power sources as a 182 ff for example. Just guessing really.

 

[sprintcup]

You've proved the relay on another car, the next job would be to disconnect the wires to the SM, make sure they are safe replace the fuse and try again prove the wireing and reconnect one at a time, you could also do with putting an amp meter in line on the other SM on the other car and see what current it pulls, is the engine high compression by any chane?

Regards Russ......

 

[Meek_racing]

Yup its very high comp. Is this a common issue?

 

[Cr33do]

Russ. Thanks for the response.

It must be the trigger wire side of the starter motor as the permenant live (big inline fuse) has a constant connection to the sm solenoid and the sm is earthed via its body. I will disconnect the spade connection and retry.

Interesting you ask about high comp. I was discussing this with Mike (Meek_racing) earlier. I did wonder if it could be a side affect. Not sure of exact CR. but it has Wosner 12.8:1 and it's head has been skimmed. I thought we might get 1/4 turn from the starter before it protested. It's doing nothing though. This is a fresh built engine too, non run-in engine.

Thanks, Nick.

 

[Andyrg@ ClioTurbo]

simply replace the "Remote" wire from the starter to the relay, i guess you have a break in it causing ti to earth out on turn of the key when that remote wire becomes active ( only on 3rd turn )

 

[Cr33do]

simply replace the "Remote" wire from the starter to the relay, i guess you have a break in it causing ti to earth out on turn of the key when that remote wire becomes active ( only on 3rd turn )

Good call. Easier than stripping back the loom and inspecting for damage

Still interested to hear if high-comp build could cause a similar fault.

 

[Andyrg@ ClioTurbo]

i wouldn't think so mate. even if the starter was stuck it wouldn't blow the fuse straight away so cranking a Hight Compression Motor isnt going to cause that . or my ITB HC unit was fine, infact it fired up better

Try what i suggest first

 

[Rob669]

I take out the 30 amp fuse if I'm going to depressurise the fuel system so I thought it controls the fuel pump.

 

[sprintcup]

simply replace the "Remote" wire from the starter to the relay, i guess you have a break in it causing ti to earth out on turn of the key when that remote wire becomes active ( only on 3rd turn )

This sounds more like it tbh, I thought with your HC build it would exagerate the problem, but it doe's seem like a dead short, with HC engines if you have problems they can use 24v start but obviously this isn't a problem with the F4R engines and starter system, hope you sort it.

Regards Russ........

 

[Cr33do]

Thanks for the suggestions/help guys (including a bit of remote support from Fred @ BTM today)

Fred noticed that our 30amp fuse was sitting in the wrong position (compared to a cup he currently has in AND the image Mantis946 posted above). Ours currently sits in the "red" fuse holder and it appears normal to have a 60amp installed there. So i thought initially to swap them around.......then proceeded to take a step backwards

I swapped the fuses and when turning to ignition II some of the relays had a field day(clicking constantly) and the green "gearbox/lever" light flashed on the dash. No idea what it meant but it didnt sound good. After several seconds the relays calmed down and the "stop" light continued to flash on the dash. ****!

I inspected the 60 and 30 amp fuses i had swapped and they were both fine. So i swapped them back just to their "original" position and tried to start it again. Same thing! Relay noises and flashing light. WTF! So i then took out the two black, one purple, and one brown relay - cleaned the contacts (badly oxidised), put them back in and alls good again. By that i mean no clicking relays or flashing dash lights. And the throttle body and fuel pump is wurring away as it should. So now we are roughly back to square one

I then ran a new (27amp rated) wire down from the relay to the starter remote connection. I can now attempt to start the car without blowing the 30amp fuse However, it still doesnt start The starter doesnt make a sound; nothing! I have checked the main permanent +ve feed is showing 12volts and can also see 12volts show on the remote connection when i try starting it. This falls back to 0 volts when i release the key (as expected).

So now i wonder if we have dead/stuck starter.

Cheers,
Nick

 

[Cr33do]

Thinking about it logically the next thing to try is putting a known working battery in the car. Our battery, despite just being recently charged, hasnt been used for 10 months so im not sure of its cranking power anymore. If that doesnt work its either trying to move the starter by rocking the car in gear or bump starting the car (which i dont really want to do), or the final option; remove the starter motor

 

[sprintcup]

Thinking about it logically the next thing to try is putting a known working battery in the car. Our battery, despite just being recently charged, hasnt been used for 10 months so im not sure of its cranking power anymore. If that doesnt work its either trying to move the starter by rocking the car in gear or bump starting the car (which i dont really want to do), or the final option; remove the starter motor

I'd remove the starter and make sure it's running free, I assume this is not an easy job, if you've got the wire could you wire the 2 Battery's in parrallel when charged it'll give you more current for the starter.

Regards Russ.

 

[Cr33do]

Yes. I'm thinking towards a starter fault to be honest. I cannot see another reason for it. Fred is coming over to take a look at it some time soon. No doubt he will spot something! I even tried earthing the engine using a jump lead but no luck. It's still blowing the fuse again despite the new trigger wire

 

[Cr33do]

Mini update.

Mike found a spare starter motor and I have just tested it off the car by using our trigger wire and jump leads to create permanent live and earth. Worked fine and no blown fuse

Pretty sure the old solenoid is to blame but only one true way of finding out- swap the starter out tomorrow. Lovely job!

 

[sprintcup]

Result, so the starter is an awkward job then ?

Regards Russ......

 

[Cr33do]

Never swapped one before Russ. But it's at the back of the engine under the exhaust manifold! Only 2 wires and 3 bolts but I expect it to be a fiddley so and so. Will report back tomorrow.

 

[Dan519]

you sure its not shorting on the heatshield?

 

[Cr33do]

Hi Dan,

I don't think so. I cannot see a heatshield around that area. We have the main heatshield on the bulkhead (nimbus) but ours doesn't have another one. I know there should be one around the rack area but it's not fitted.

The way I see it now, possibly over simplified:

Earth must be ok because the motor bolts direct to box and I have created known good strap back to -ve battery term

Permanent live must be ok along the length of its cable as we would have other issues, like it blowing the inline fuse

Trigger wire from relay to sm is now new and engages the new starter solenoid fine off the car

So logically, to me anyway, the proble lies on the old sm/solenoid.

Find out in a bit. Cheers.

 

[Cr33do]

Bargain!!

Old sm out and the solenoid doesn't switch when hard wired

Fun and games of fitting the new one now. Report back later

 

[Norfolknchance]

Hiya we had this on our race car it turned out that the starter motor main feed was arcing across to the exhaust manifold because it had been taken off and put back in the wrong position and the heat Sheild was missing,when you have replaced the starter you have moved the wireing thus stopping the short,Will be worth getting the starter checked hope this helps

 

[Cr33do]

New starter in and great news! Works a treat

Not sure why the old solenoid packed up but that was definately at fault here.

Thanks to everyone who offered suggestions /advice in this thread

Nick

Now just need to work out why the Dbw throttle body isnt working compared to the throttle pedal input. Will progress that problem in our project thread which I will update later