i have recently installed a rebuilt engine in my 90tt manual. she runs fine at standstill but as soon as i pull away the ign con fuse blows in the engine bay relay box. its the 10amp one. i have checked and checked for trapped wires, bad earths and even tried tilting engine and box and yanking on loom/connections and nothing. but soon as i pull away bang the fuse goes. was gonna disconnect the alternator and try and drive it then?????

any ideas???

That particular fuse runs a common power to several sensors including the auxilary air valve at the rear of the engine, most likely you have a faulty solenoid or connector, when you drive away the ecu controls the earth pulse to the solenoid, this is when the fuse will blow, do not be tempted to ignore this or replace the fuse with a higher value as that could potentially damage the ecu output track.

 

My advice would be to take remove all the connectors to the valve and check them and the solenoids for any damage.

 

Daveman

That particular fuse runs a common power to several sensors including the auxilary air valve at the rear of the engine, most likely you have a faulty solenoid or connector, when you drive away the ecu controls the earth pulse to the solenoid, this is when the fuse will blow, do not be tempted to ignore this or replace the fuse with a higher value as that could potentially damage the ecu output track.

 

My advice would be to take remove all the connectors to the valve and check them and the solenoids for any damage.

 

Daveman

hi mate thanks for getting back to me. could you be more specific on the location of this solenoid and what does it do?

thanks again

A little complicated to explain here but will try though, the valve is located at the rear of the engine close to the battery area, there are 3 connectors on the unit, some amount of cable moving will be required to gain access, the most likely faulty one of the three is the top one nearest to the battery, this is the one that switches rapidly when moving away and is the one that can damage the ecu.

 

If you cannot see any damage just disconnect the connectors and take a short test drive but for safety replace the fuse with a lower value, the idle may well be a problem but you can keep it going just for the test.

 

Be aware that the ign fuse also serves other circuits but the above is the most likely cause, any more info you gather after the tests will help so post back.

 

 

 

Daveman

i tried disconnecting the stock boost sensor and it worked! for about 3 minutes. it drove up and down the road fine. i was chuffed but as i pulled back in bang there goes the fuse again. wtf is going on. very confused

 

any thoughts?

Daveman