PUMA GOING INTO CRAWL MODE

[tieds]

So the latest problem, right after putting a new starter motor in my 2010 Puma 110 is the wonderful predicament in which the truck almost always goes into crawl mode after sitting at traffic lights and idling for any amount of time. Take off, at 20 km/h, max, pull over, stop engine, restart and good to go.
No engine warning light, just has no guts and a line of angry drivers cursing behind me. Happened 15 times today!. It was happening a few weeks back and I servisoled all electrical plugs including ECU and it seemed to go away. But it’s Come right back, just when I was all chuffed with myself for replacing the starter motor!
Any thoughts from the rather more knowledgeable community out there?
regards to all

[one_iota]

On the odd occasion mine has had "dull moments" when the engine has lost power and gone into limp mode, In my case I understand that the ECU detects possible overheating and will reduce the throttle. This happens momentarily on hot days after working the engine up hill. This doesn't show up as a fault with the Nanocom reader. There is no indication on the temperature gauge either.

Never though has it happened to me at starting from prolonged idle. But maybe in your case something in the cooling system is triggering this response. I doubt the starter motor replacement is at fault. I'd be getting my cooling system checked.

[MLD]

the list of problems that may cause it is long as your arm. I had engine retardation as you describe when my EGR valve was on its way out. Was bad enough for the ECU to respond but was not throwing a fault code. EGR died not long after so the problem presented itself. Was interesting turning right across on coming traffic to lose all power.

Some may suggest the Vacuum control valve (VCV) on the fuel pump can cause a fuel retardation. In my experience a failing VCV heavily smokes on cold start up well before the ECU finds fault.

Others may have other experiences to point to a fault.

[shack]

Some may suggest the Vacuum control valve (VCV) on the fuel pump can cause a fuel retardation. In my experience a failing VCV heavily smokes on cold start up well before the ECU finds fault.

Others may have other experiences to point to a fault.

I think the VCV is a "volume control valve"

Auto correct might have done that!

[tieds]

the list of problems that may cause it is long as your arm. I had engine retardation as you describe when my EGR valve was on its way out. Was bad enough for the ECU to respond but was not throwing a fault code. EGR died not long after so the problem presented itself. Was interesting turning right across on coming traffic to lose all power.

Some may suggest the Vacuum control valve (VCV) on the fuel pump can cause a fuel retardation. In my experience a failing VCV heavily smokes on cold start up well before the ECU finds fault.

Others may have other experiences to point to a fault.

Yes, I wouldn’t be surprised if the EGR was the culprit, after all there’s still some skin left on my forearm after doing the starter motor!
I’m going to backprobe the 4 wire plug from the MAP to the ECU as this problem threw up a DTC that was Air Temp2 circuit high a month or so back but that was only once, all of the other crawl mode episodes haven’t resulted in an engine light/trouble code.
thanks for all the advice!
regards to all

[skidrov]

Have you checked for fault codes? EDIT: sorry yes you have. Didn't see your last reply.

Very broad rule of thumb: no fault code often means VCV. And then of course if a fault code, treat accordingly. You can have fault codes without a warning light.

VCV a common culprit and fairly easy to change.

[DazzaTD5]

As you mention the fact you turn off/ turn on its fine again...

*As it's a 2.4 i'd say change the suction control valve (SCV, FCV, VCV etc etc) as a good start if it has done 100K or more.
*I'd make sure its a DENSO one as I've replaced cheap cheap ones that have come from other workshops.
*You can actually buy a DENSO packaged one (as apposed to a denso in a LR box, nissan box etc) either way.

*The other obvious one on a 2.4 is the crankshaft position sensor, a FoMoCo one in a Ford box is a third of the LR boxed one, again dont buy a chinese one as they break while you fit them.

*The Defender TDCi (puma, 2007 - 2016) doesnt actually have a lot of fault codes in it, so the above 2 may or may not show, certainly the crankshaft position sensor, I've not had one with a related fault code, yet enough failures that I keep the above in stock.

*Outside of electrical the 2.4 can be prone to fuel pipe restrictions as there is no in tank pump to assist in delivery.

[Andrew_Barossa]

You can clear retarded mode by turning engine off and on while car is moving. Just don't switch all the way off and lock your steering lol. One click around towards off and one click back again. Only a temporary solution though before it eventually dies completely though.

MAP wiring issues fire a number of fault codes associated with MAPS/turbo. I've removed a few wiring issues in my 2.2 and now have reduced the number of turbo codes I get but still have 2 and goes into limp mode on smallest of hills. Probably not related to your issue but wiring to sensors controlling turbo are a common issue. As are air leaks in turbo loop.

[DiscoMick]

We've had it happen a couple of times when dragging our caravan up a very steep hill, but it clears as soon as the gas pedal is released, so yours sounds more serious happening at traffic lights. Never had that.

[big harold]

We've had it happen a couple of times when dragging our caravan up a very steep hill, but it clears as soon as the gas pedal is released, so yours sounds more serious happening at traffic lights. Never had that.
Do yourself a favour and buy one of these
Home Page - Adventure Kings (https://www.4wdsupacentre.com.au/4wd/electrical/engine-data-scan-computer.html)
Will allow you to monitor coolant temp real time and possibly save you an engine.
Mark