P38A 2.5dt FIP static timing & ominous HotStart found

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RangeRoller dt said:
Uh oh, look what I found...:eek:


View attachment 184528
It’s an original TigaPiglet design :)

I’m guessing it doesn’t actually work.
One connector has nothing on it so why put one on there??

Whomever did the job labelled it, so not anyone I know :p:D
Click to expand...
Looks like a home made hot start mod, I'd disconnect it because if it remains active, the engine will be running on cold settings all the time.
 
Working hotstart should help in theory, if I can get it working.
Or it is working but my FIP is totally screwed :eek::D
no g.plug in cyl1 doesn’t help, tried to crimp the wire and now it’s too short to reach :rolleyes: I don’t do electrics for good reason lol

The one I have is the original design, the one you buy on eBay is same thing more or less. some have a timer to go off after starting.
 
Grrrrrr said:
Cannot remember what is in the hot-start. Doesn't it have a timer? Either way, if his FIP is tired I'll bet he needs it.
Click to expand...
Basically the hot start mod bypasses the EDC temperature sensor to fool it into thinking the engine is cold. A timer is essential or the engine will always run on cold settings.
 
RangeRoller dt said:
Remember my head sensor thread? ^^ this is probably why it went weird on me after new sensors :rolleyes:

You are right best option is itl have to come out.
Where do the two cables that go through the ecu case lead to or is there an easier way to stop it?
Thankyou for your patience :)
Click to expand...

I think @Dopey helped come up with that fix so he'd know.
 
Think your right, was an old thread I read long time ago when I only used to borrow (now my) P38 when Defender was in for work.

Awesome age for LZ back then, everyone chipping in together pioneering new ideas, that still have not been superceeded :)

Wonder what happened to TigaPiglet? :confused:He stated it wasn’t him that brought out the kit you now buy just the original idea of a transistor in a relay, like an happy accident :cool: Was @wantaquad that added the timer??
 
Last edited:
RangeRoller dt said:
Remember my head sensor thread? ^^ this is probably why it went weird on me after new sensors :rolleyes:

You are right best option is itl have to come out.
Where do the two cables that go through the ecu case lead to or is there an easier way to stop it?
Thankyou for your patience :)
Click to expand...
As it's a mod, I cannot tell you where the wires go. Unless you want to physically trace them, just remove the relay and tape the connectors up individually.
 
There is a black one coming from the relay to an earth under the fuse box, also a red one goes round to bulkhead?

I decided to cut the wires connected to the original loom, then joined them. They are soldered in well from the mod and I can put them back if it causes catastrophic hissy fits or leave as is if it improves
481CACA4-C754-4A58-A48F-5F9FE668B411.jpeg
 
RangeRoller dt said:
There is a black one coming from the relay to an earth under the fuse box, also a red one goes round to bulkhead?

I decided to cut the wires connected to the original loom, then joined them. They are soldered in well from the mod and I can put them back if it causes catastrophic hissy fits or leave as is if it improves
View attachment 184751
Click to expand...

You need to look what the two blue wires are connected to. On a normal hot start mod there are four wires. They are all connected to wires within the ECU box. You have an ignition powered feed and a ground, you cut the Grey/Blue sensor feed to the ECU and connect the other two wires to each end of those. The hot start has a timer, usually 30 seconds. When powered it presents a resistance to the ECU through the connections to the sensor wire that represents a cold engine. So cold start fuel is set and glow plugs are active. After 30 seconds it cuts out and normal sensor readings go to the ECU. IF the two blue are connected to a cut sensor feed wire they will need to be connected together. But before doing that ensure that is where they are connected. Don't connect the without checking.
 
wammers said:
You need to look what the two blue wires are connected to. On a normal hot start mod there are four wires. They are all connected to wires within the ECU box. You have an ignition powered feed and a ground, you cut the Grey/Blue sensor feed to the ECU and connect the other two wires to each end of those. The hot start has a timer, usually 30 seconds. When powered it presents a resistance to the ECU through the connections to the sensor wire that represents a cold engine. So cold start fuel is set and glow plugs are active. After 30 seconds it cuts out and normal sensor readings go to the ECU. IF the two blue are connected to a cut sensor feed wire they will need to be connected together. But before doing that ensure that is where they are connected. Don't connect the without checking.
Click to expand...

Cold is 0V? So relay breaks circuit with ignition turning on and then as timer expires the relay connects the wires and the circuit is complete?
 
Grrrrrr said:
Cold is 0V? So relay breaks circuit with ignition turning on and then as timer expires the relay connects the wires and the circuit is complete?
Click to expand...

Some cheapy cheap hot fixes are just a relay and a manual switch on the dash. I would be interested to know where the Red and Black wires through the back of the ECU box terminate. And what the two Blue wires in the ECU box connect to.
 
Grrrrrr said:
Cold is 0V? So relay breaks circuit with ignition turning on and then as timer expires the relay connects the wires and the circuit is complete?
Click to expand...
Cold is high resistance, hot is low resistance. Relay breaks the sensor wire and inserts a resistance in series with the sensor when the ignition is switched on, the timer de-energises the relay after 30 seconds or so remaking the direct connexion to the sensor.
 
wammers said:
a manual switch on the dash.
I would be interested to know where the Red and Black wires through the back of the ECU box terminate. And what the two Blue wires in the ECU box connect to.
Click to expand...

I do have a manual switch cut into my dash. The two cables from it run toward the hot start area but aren’t connected to any thing. Always wondered what they used it for - another mystery solved :)

Off the top of my head the two blue wires go to a black/grey wire on ecu loom - they have a resistor across them on the relay.
Black from relay goes to bolt on the frame aside the fusebox.
Red goes up the wing - into bulkhead I believe.
One relay pin is blanked with a spade connector sealed with silicone.

Il get some better pictures of it for you and try and trace the red one
 
RangeRoller dt said:
I do have a manual switch cut into my dash. The two cables from it run toward the hot start area but aren’t connected to any thing. Always wondered what they used it for - another mystery solved :)

Off the top of my head the two blue wires go to a black/grey wire on ecu loom - they have a resistor across them on the relay.
Black from relay goes to bolt on the frame aside the fusebox.
Red goes up the wing - into bulkhead I believe.
One relay pin is blanked with a spade connector sealed with silicone.

Il get some better pictures of it for you and try and trace the red one
Click to expand...

Only Black/Grey wire i can find goes from pin 24 ECM to pin 13 Hevac control unit. If it is indeed a manually switchable hot start they should be connected to each end of a cut Grey/Blue sensor wire.
 
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