Thread: Hard to start start Td5 after remap.

Originally Posted by DANNY2503

Hi guys, I have an issue that myself and a couple other techs have struggled to diagnose.
Its a 2004 Td5 Auto, larger Intercooler, EGR Delete, DEcat Exhaust.

When we initially got this car in it would take for ever to start when cold with foot to the floor. After some diagnosis and changing some parts over we replaced the ECU with a std non mapped one and rectified the problem by about 90%. We still had an issue that when first cranked it would start and die immeadiately but on second start it would run rough for a second or two and then be fine.
With both ECU’s it would start problem free on first click of the key when it was hot.
I had another map done for the vehicle and have now gone back to the initial problem where it is an absolute PITA to start when cold or just warm.
I have replaced
Injector Loom
injector Seals and washers
fuel pump
maf sensor (even though tested good)
map sensor (inlet manifold)
ECU (as stated above)
what is confusing us all now is that the 2 different mapped ECU’s have created the same issue and with a std ECU it wasn’t perfect but 1000 times better.
Im thinking that a Full Fuel Pressure Reg change is next on the list, but thought I would post here if anyone else has come across this issue.
Cheers In Advance.

Have you checked glow plugs? Being hard to start when cold yet easy to start when it’s been running suggests this could be something to look at.

Have you checked the fuel filter ?
When the filter gets changed the original o ring can stay in place and you end up with 2 seals
Also behind the fuel reg is a small fine filter that goes into the head that can become clogged so if changing the reg check that out

Originally Posted by fatsam

Have you checked glow plugs? Being hard to start when cold yet easy to start when it’s been running suggests this could be something to look at.

It was certainly something I was going to consider utill the change of the ECU to standard, which made the starting nearly normal. I though maybe a problem with the software, so had a a new map done with a new ECU and now back to square one.

Have you checked the air bleed valve in the fuel filter head. When these fail they bleed air back and hard to start when cold

Originally Posted by rangieman

Have you checked the fuel filter ?
When the filter gets changed the original o ring can stay in place and you end up with 2 seals
Also behind the fuel reg is a small fine filter that goes into the head that can become clogged so if changing the reg check that out

This was one of the first things that were done.
Cheers
Danny

Originally Posted by DANNY2503

It was certainly something I was going to consider utill the change of the ECU to standard, which made the starting nearly normal. I though maybe a problem with the software, so had a a new map done with a new ECU and now back to square one.

Hmm, can someone check the remap to see if it includes the glow plug cycle?

Does the glow plug light come up when you turn the ignition on before starting?

The scenario you are describing certainly suggests it’s worth spending time working out if the glow plugs are activating.

Originally Posted by fatsam

Hmm, can someone check the remap to see if it includes the glow plug cycle?

Does the glow plug light come up when you turn the ignition on before starting?

The scenario you are describing certainly suggests it’s worth spending time working out if the glow plugs are activating.

Plight dies come on as per normal mate and yes I think I will check the wiring first and then replace the glow plugs next.

Its a different remap to the first one on a different ECU so I don’t believe that it could be wrong twice.

No fuel pump cavitation noises with ign on eng off?
Cam timing / inj bump clearance OK ?
Compression good , no blow by when its running?
Fuel pressure ok ?If yes and it has good performance when running you can probably discount fpr, unless its leaking.
Also worth a check of the wiring to the ecu , could be getting disturbed when changing