P38A Engine turns over but not starting

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Well popped round to peters plugged in the laptop reading no faults. He has check a fair few things its not the fuel pump it will start as said with a squirt of brake cleaner. Today it was smoking running very rich unplugged the maf no difference to its running its a non genuin so peters gonna replace it and report back
 
biketeacherdave said:
Well popped round to peters plugged in the laptop reading no faults. He has check a fair few things its not the fuel pump it will start as said with a squirt of brake cleaner. Today it was smoking running very rich unplugged the maf no difference to its running its a non genuin so peters gonna replace it and report back
Click to expand...
A big thank you to Dave for coming round with his laptop.
I've had a look for the old genuine MAF but it must of got throw out! So now looking for a genuine 4.0 GEMS MAF.
Once started on brake cleaner, it was running VERY rich & black, we did reconnect the maf back in to the hoses etc, but made no difference!
 
Try a known good maf. These are very sensitive and provide most of the primary fueling information on a petrol engine.
 
Jaguar aj16 maf is also identical (apart from angle of the plug) 20am Lucas sagem. Search jaguar x300 maf. 4 and 4.6 are identical. Fake ones are a total loss and can burn out the ecu by shorting inside.
 
There are 5 jag ones on eBay atm. My jag is running on a p38 one at. There's more room in a p38. There either right or wrong they can be checked for voltage a 3 different rpms.
 
Just on the off chance if a new maf doesn't do the trick check all the tracks in the ecu one ( the earth) may be burnt out and cause these issues. ( The maf may have shorted and caused this) a tell tale is to smell the inside of the ecu if it smells burnt you've found your issue. The fix is easy just solder a small bridge wire( with your new maf not the old one) slim chance but worth a look.
Jb
 
storm said:
I borrowed OBD reader, it only showed 2 faults relating to the MAF, these most likely occurred when I disconnected it. Cleared faults, but still did not start, faults did not re occur.
I should of said when I did get it running, the lightest pressure on the gas stopped the engine, but if you gave it a bit more it would hesitate & then build up the revs, once above approx. 1200rpm it would increase smoothly.
Click to expand...

note.. the MAF may not throw a fault code.. if it is bust it will but if it is old and worn it wont, it just wont be reading the mass of air correctly passing through it. for all the system knows its working.. which it is.. just mis reading.... you need to look at the live data to see what flow it is reading.

I had this on my boxster which uses a bosch MAF sensor a couple of years back.. no fault code, but the maf readings were way down..
 
I feel clouds of black smoke and difficulty starting isn't obvious maf issues. It's more like I had when the ecu track was burnt. Adams suggested the only other way this could happen was
New dodgy mafs( apart from wires touching.)
 
johnnyb70 said:
I feel clouds of black smoke and difficulty starting isn't obvious maf issues. It's more like I had when the ecu track was burnt. Adams suggested the only other way this could happen was
New dodgy mafs( apart from wires touching.)
Click to expand...
Thanks for all your info johnyb70, good to know jag ones are the same. It did have a new unbranded maf a short while ago. I will also have a sniff of the ecu to see if it smells burnt. Is this the one behind the battery??
 
Yes unscrew cover ,unplug, then remove 6 torq screws and sniff. Look for a burnt track on the PCB it goes to the middle plug. Don't worry you won't harm it. The actual chips are inside. Unfortunately the case is like a shell ie 12 torq screws but I think you need the one with the sticker.
 
Check rave but you need live data and the jag repair guide has the figures if you can find a snippet.
 
I'll try to find the figures. Gomog may have them to but I don't think so( this is an enthusiast guide for the plus 8 engine management)
 
For me it confirmed the secondary position that land Rover always gave the engine over their other tweaks (off road paraphenalia etc) and is probably why Land Rover stuck with the v8 despite it's many issues.
 
johnnyb70 said:
Just on the off chance if a new maf doesn't do the trick check all the tracks in the ecu one ( the earth) may be burnt out and cause these issues. ( The maf may have shorted and caused this) a tell tale is to smell the inside of the ecu if it smells burnt you've found your issue. The fix is easy just solder a small bridge wire( with your new maf not the old one) slim chance but worth a look.
Jb
Click to expand...

Hi Johnyb, I have nor opened up the ECU didnt smell burnt, but found a track that does not look good, I have attached images which I hope you can see. the track is the outer one in the bottom left corner when the connections are at the bottom.
You say solder a bridge wire, is this on the circuit board between the two points of the burnt track? or on the maf?

Thanks for pointing me in this direction!
ecu1.JPG
ecu2.JPG
ecu3.JPG
 
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