Power cut off (not over boost)

Freelander1banger · May 2, 2022

Hi went and did some off-roading today; now I have a weird issue, when I get to 3/3.2k rpm the power gets cut, confirmed with live data boost drops right down to 4/5psi.

The moment it cuts boost/power it’s only at 13/14psi.

only fault code I’ve got is maf but that’s coded out, unplugged it anyway made no difference

ecu is bone dry still

any ideas?

bankz5152 · May 2, 2022

Could be map sensor.

Freelander1banger · May 2, 2022

bankz5152 said:
Could be map sensor.

Would I not expect to see some weird readings if that was the case?

bankz5152 · May 2, 2022

You may such as driver demand error or IAT errors. Also may show nothing.

Pull it out and give it a clean

Freelander1banger · May 2, 2022

bankz5152 said:
You may such as driver demand error or IAT errors. Also may show nothing.

Pull it out and give it a clean

Cheers I’ll give it a go, I think it’s water ingress as it was 3k at first then when I got home it’s 3.2 so almost like somethings drying out

sierrafery · May 3, 2022

You need a complete live data log to see all the inputs when it happens otherwise it's a guessing game, untill then check the turbo/intercooler hoses and clamps cos it can be a boost leak or hoses delaminated, if they are soft you need new ones

Freelander1banger · May 3, 2022

Ok i log everything later, only thing I saw that was strange was the injector balance was 20/30 on 1 and -20/30 on 3, do they fire together?

I was wondering if it’s just coincided I’ve sh*t an injector, it was also running on 4 cylinders this morning until warm

sierrafery · May 3, 2022

If one injector is gone the others are compensating and the whole balance goes mad, if the injector loom is not genuine it can be sh*t even if it's new and not leaking cos the contacts to the pins are weak on aftermarkets... dot that too https://www.landyzone.co.uk/land-rover/check-td5-fuel-pump-hp.358086/ cos it can run on LP up to 3000rpm

Freelander1banger · May 3, 2022

Yeah the loom did cross my mind it isn’t a genuine one. I’ll whip the rocker cover off and check contacts/reinstall before logging see if that makes any difference

sierrafery · May 3, 2022

Better fit a genuine one cos if it doesnt make any difference how do you know it's good cos you can't check the contacts in the head plug

Freelander1banger · May 3, 2022

£83 for a bloody harness on the landrover site, I might check connections with a multimeter first since it’s not an intermittent problem

sierrafery · May 3, 2022

Freelander1banger said:
£83 for a bloody harness on the landrover site, I might check connections with a multimeter first since it’s not an intermittent problem

Dont bother with a multimeter cos that can't confirm how the PWM signal passes at 80V between the ECU and injectors cos it's not about open circuit... go cheap and you might never find the culprit. Good luck

Freelander1banger · May 3, 2022

yeah i didn't realise it was such high voltage, i think ill leave it a few days and see if it dries out.. then try a genuine loom. Here is a log from roughly 2k rpm at WOT to 4kish you can see all boost is cut harshly, i was also going up a hill

Freelander1banger · May 3, 2022

I thought i started it a few seconds before I pressed record but it was recording before that, so i put my foot down around the 60/65 mark on the graphs

sierrafery · May 3, 2022

Unfortunately that kind of log is completely useless for me as i can figure out things only if all the values are in the same row in clear figures like nanocom files... do that pump pressure test i told you in post 8 cos that's doable with multimeter

Freelander1banger · May 3, 2022

That’s all I have unfortunately, the fuel pump was a brand new VDO unit a month or so ago, it also kicks out black smoke when it cuts boost, do you know what the underboost limit is?

sierrafery · May 3, 2022

If it kicks out black smoke it's most probably a boost leak so it's overfuelling then, check the turbo/intercooler hoses and for traces of black gunk around the clamps or where the leak is, maybe a crack , they can be delaminated as well

Freelander1banger · May 3, 2022

That was my first thought but it makes good boost and suddenly drops in previous experience it’s a slow taper, and coupled with dropping a cylinder on start up I’m betting they are connected.

I’m going to try a used injector on no1, I just unplugged the harness and it went from missing/smoking to just missing

plugged back in and disconnected no2 starts and dies

plug all back in runs just the same as when no.1 is disconnected just kicking out smoke

used injectors are £20 on eBay so I’ll bang one of them in, if it fixes it I’ll think about getting them all reconditioned

If it doesn’t I’ll cry and get a compression test on that cylinder

sierrafery · May 4, 2022

Freelander1banger said:
That was my first thought but it makes good boost and suddenly drops in previous experience it’s a slow taper,

There are cases when it's a tiny crack or leak which reacts only to higher pressure not from the beginning...i'd not rule this out just like that, a bad injector would create rough running of the engine all the way not cut the boost at a point and rarely black smoke cos a bad injector would not deliver more fuel... eventually less

Freelander1banger · May 4, 2022

sierrafery said:
There are cases when it's a tiny crack or leak which reacts only to higher pressure not from the beginning...i'd not rule this out just like that, a bad injector would create rough running of the engine all the way not cut the boost at a point and rarely black smoke cos a bad injector would not deliver more fuel... eventually less

I believe you to be correct, on the way home today I have the screal of death…

Already had the exhaust manifold skimmed before, so tried taking the belt off, nope still there, let it cool down get some soapy water on and start it, warped! So that will be coming off, I think I’ll try de webbing it and skimming again. Must of been going through the water that’s done it I recon.

I still think I have a duff injector as that’s been a long term issue getting worse, and too top it off I got a massive puncture.. thankfully my other car fits it mot today so I’m leaving the disco until I have some more patience

Power cut off (not over boost)

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