P38 cold start issues

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Sorry I suppose you are right if you don’t know what to look for.
We can show you how to spanner your way through it step by step here but once you get your Nanocom itl be clear and you’ll get right to the problem.
It should spin up straight away when cold.
 
bionicbob said:
Single exhaust alloy manifo
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Ok first of all a few questions. How long does the glow light come on for before it extinguishes and you engage starter? How do you know all the glow plugs are working? What colour is the engine temp sensor in head behind injection pump have you checked connection to it? What colour is the ECU temp sensor between inlet three and four have you checked connections to it? Your symptoms are classic of duff glow plugs. Answer all and we can make progress.
 
single exhaust alloy
wammers said:
Ok first of all a few questions. How long does the glow light come on for before it extinguishes and you engage starter? How do you know all the glow plugs are working? What colour is the engine temp sensor in head behind injection pump have you checked connection to it? What colour is the ECU temp sensor between inlet three and four have you checked connections to it? Your symptoms are classic of duff glow plugs. Answer all and we can make progress.
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right just to clarify i have been a mechanic for over 30 years so for give me if i sound a bit stupid lol i just cant stand mondern electrics
right the temp sensor behind the pump is blue the one in the middle is green im showing a voltage at each plug and also an earth the heater plugs have been out and checked all working fine the light stays on for about 5 seconds every time hot or cold even tho the temp gauge dosnt work
 
bionicbob said:
single exhaust alloy

right just to clarify i have been a mechanic for over 30 years so for give me if i sound a bit stupid lol i just cant stand mondern electrics
right the temp sensor behind the pump is blue the one in the middle is green im showing a voltage at each plug and also an earth the heater plugs have been out and checked all working fine the light stays on for about 5 seconds every time hot or cold even tho the temp gauge dosnt work
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So, the glow light should not come on when hot and stay on longer than that when cold, has a hot start mod been fitted? If diagnostics say there is no ECU temperature reading, that really needs to be rectified as a first step as it should e controlling the time the glow plugs stay on.
If you do not like electronics, the P38 may not be the car for you, but if you stick at it with advice and diagnostics it will get sorted.
 
Datatek said:
So, the glow light should not come on when hot and stay on longer than that when cold, has a hot start mod been fitted? If diagnostics say there is no ECU temperature reading, that really needs to be rectified as a first step as it should e controlling the time the glow plugs stay on.
If you do not like electronics, the P38 may not be the car for you, but if you stick at it with advice and diagnostics it will get sorted.
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i dont think any mechanic likes electrics lolbut like i said my solus says that the engine and fuel temp show -35
but will recheck when nanocom comes
 
also tried some thing differnt this morning used the heater 4 times before starting fired straight up but at high revs kicked a bit of smoke out unburnt diesel then stoped restarted straight away as normal take 3 tries to start
 
bionicbob said:
single exhaust alloy

right just to clarify i have been a mechanic for over 30 years so for give me if i sound a bit stupid lol i just cant stand mondern electrics
right the temp sensor behind the pump is blue the one in the middle is green im showing a voltage at each plug and also an earth the heater plugs have been out and checked all working fine the light stays on for about 5 seconds every time hot or cold even tho the temp gauge dosnt work
Click to expand...

Right glows out and checked. All working and glowing hot. The green temp sensor is the ECU sensor glows should not come on with a warm engine. How much voltage is at each glow plug? The connectors on the glow relay can develop bad contact over time check them clean and tighten up. You either have a hot start fitted or the green ECU temp sensor is duff. The ECU switches glows plugs for various times subject to engine temp derived from green sensor. The blue sensor is for dash gauge only, they do fail it has nothing to do with ECU.. I take it if a blue sensor is fitted you have aircon. You must not use the starter with glow plug lamp lit. You have a few things to check.
 
bionicbob said:
also tried some thing differnt this morning used the heater 4 times before starting fired straight up but at high revs kicked a bit of smoke out unburnt diesel then stoped restarted straight away as normal take 3 tries to start
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As already said your symptoms are classic duff glows or lack of voltage there to. It is normal from a cold start for the engine to rev 1100/1200 RPM then drop to idle as temp sensor detects warming. You need to check if you have a hot start fitted and disconnect it to do some checks. As said look at glow relay (in ECU box) check contacts, each plug is supplied by a seperate wire, check the contacts. Clean and tighten them.
 
wammers said:
As already said your symptoms are classic duff glows or lack of voltage there to. It is normal from a cold start for the engine to rev 1100/1200 RPM then drop to idle as temp sensor detects warming. You need to check if you have a hot start fitted and disconnect it to do some checks. As said look at glow relay (in ECU box) check contacts, each plug is supplied by a seperate wire, check the contacts. Clean and tighten them.
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right just checked it as the hot start fitted so would this cause the cold start problems?
 
bionicbob said:
right just checked it as the hot start fitted so would this cause the cold start problems?
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Could be depending on what type it is, it could be restricting glows to five seconds when the engine temp demands ten or eleven. As said disconnect it check glow relay as said and see what you get. It may have been fitted to mask a problem. You can always reconnect if no joy.
 
On hot start there will be a black/yellow wire that has been cut to join into the hot start. Just disconnect and join the wire back up for standard operation.
 
wammers said:
Could be depending on what type it is, it could be restricting glows to five seconds when the engine temp demands ten or eleven. As said disconnect it check glow relay as said and see what you get. It may have been fitted to mask a problem. You can always reconnect if no joy.
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think i might have just found a fuel leak on the feed pipe so moved the one way valve to before the filter rather than after dont know why it was fitted like that as i always fit them before
 
bionicbob said:
think i might have just found a fuel leak on the feed pipe so moved the one way valve to before the filter rather than after dont know why it was fitted like that as i always fit them before
Click to expand...

The one way valve or primer bulb (if fitted) as you say should always be before the filter.
 
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