1999 defender 90 td5 random misfire

1

168brad

New Member

Posts

10

Location

Bicester

• Aug 1, 2013

• #1

Hi there my td5 after driving for 10 mins or so develops a misfire ! but if i switch off then back on its fine for a while again ! its showing no engine faults on the diagnostic ! any ideas would be appreciated

 

SteveT247

Active Member

Posts

343

Location

Midlands

• Aug 1, 2013

• #2

Have you checked the red ECU plug for oil? This can often cause a misfire or poor running.

 

1

168brad

New Member

Posts

10

Location

Bicester

• Aug 1, 2013

• #3

just looked steve its minging with oil ! wat to do unplug & just clean it up ? thanks for help , brad

 

johnlad

Well-Known Member

Posts

5,627

Location

Blackpool

• Aug 1, 2013

• #4

168brad said:

just looked steve its minging with oil ! wat to do unplug & just clean it up ? thanks for help , brad

Click to expand...

clean with electrical contact cleaner for now but order a new injection loom and fit that at your earliest convenience

 

1

168brad

New Member

Posts

10

Location

Bicester

• Aug 1, 2013

• #5

thanks johnlad but wheres the oil come from ? & what happens if its left ?

 

johnlad

Well-Known Member

Posts

5,627

Location

Blackpool

• Aug 1, 2013

• #6

168brad said:

thanks johnlad but wheres the oil come from ? & what happens if its left ?

Click to expand...

the oil is from inside the rocker cover, it travels down the injector loom due to poor seals and reaches the ecu, where it corrupts the signals from the ecu, causing allsorts of running issues

 

Brown

Well-Known Member

Full Member

Posts

7,992

Location

East Midlands

• Aug 1, 2013

• #7

Also, there's a multiplug where the wiring loom goes inside the cylinder head, on the driver's side front. Unplug it and leave the bit attached to the engine loom pointing downwards to drain for a while and then give it a clean with something - I used carb cleaner. The oil causes shorting between the pins here which doesn't exactly help the performance.

 

1

168brad

New Member

Posts

10

Location

Bicester

• Aug 3, 2013

• #8

thanks guys i totally get it now ! i had this 90 for 4 years now other than general servicing never had any probs at all even though its done 170 + k . i ordered the new loom should be here today! the misfire is getting worse starting after about 2 mins driving & dont clear now when turned off then on. lets see what happens

 

SteveT247

Active Member

Posts

343

Location

Midlands

• Aug 3, 2013

• #9

With the new loom fitted, still keep checking the red plug for a couple of weeks as it can still get some oil from oil that has already worked its way up.