Power loss then power back again

[Thrumbleux]

Have you checked earth leads? The coils need a good earth. I have an additional earth lead attached via the bolt that retains the top of the dipstick tube. Direct earth without having to pass through the cylinder head bolts.

HT ignition mis-fires are more likely under load (ie, throttle on pulling) as the additional cylinder pressure inhibits spark production at the plug tip.If it is missing when idling, check for stray sparks around the coils and leads in darkness. Sometimes audible, and sometimes leaves a mark.

Possibly this has already been covered, but rereading pages on this forum is a nightmare!

[Minigirl]

I thought it was just me lol i keep getting error messages on this forum...

Idling is fine and also town driving is fine its just 50+ that is the problem

I will try another going from the tube to the chassis

Thanks

[Minigirl]

I have a bluetooth obd scanner and Torque lite app on my phone and it shows No logged error codes but theres a option that says pending errors and it said Error P0141 which google says -

Error code P0141 is described as Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)

Surely if that was an active error it would light the engine management light after the 300+ miles I have had this problem?

Thanks

[BobbaFett]

I had something similar on mine but it tended to only happen if I was in 5th or 6th under acceleration, if I took my foot off the accelerator and put it back on again quickly the car would instantly go into safe mode - if I was driving normally the car was absolutely fine. I changed the cycle valve but whilst I was doing that I noticed that my crankcase breather pipe had a tiny split in it after the valve but before the throttle body and also the pipe from the cycle valve to the turbo also had a split in it right at the connection to the turbo. Replaced the breather pipe and chopped the split part off the turbo pipe and re-seated it and the issue has now gone.

[Minigirl]

Thanks i will check that as well.

Car drove best it has for months today, only did the issue once in 40 miles and that was going up a slight hill where it dropped from 60 - 50 when going up the hill but after that it was fine

I wonder if the ecu just has to relearn its fueling due to the new manifold, gasket and vacuum pipes sorting the leaks out??



Watch it run like **** tomorrow... Lol...

[Mr T]

Have you thought about the Crank Rotation Sensor? Might have an intermittent fault causing a miss fire.

http://www.evilution.co.uk/888

[Minigirl]

Just checked my pending error codes screenshot again and there was a Error Code P0335 logged which seems to be related to the crank sensor... Come to think of it there has been twice when the car just turned over and wouldn't start.

Is bosch the best to go with or is there any others that are good?

Thanks

[Minigirl]

Cleared the codes the other day done about 60 miles since and the problem happened a few times so checked for any errors and the only one now is P0141 Lambda heater fault

[Thrumbleux]

Crank position sensors usually cause the engine to quit when it's trying to idle when hot ('cut out at junction' is a common complaint) and allow engine to restart after 20 mins of cooling.
Can't see why Lambda heater fault should cause mis-fire. The heating AFAIK is for cold start to bring it up to temperature sooner. I'm mentioning these things as suggestions not absolutes - these cars can be downright fickle ('tell me something I don't know' she says).

[Minigirl]

Thats why im guessing it hasnt put a engine management light on as its just the heating element of the lambda sensor and not the main part thats failed.

I tried running another earth from the dipstick tube bolt to where the cat heater pump is mounted cleaned the area to bare metal but still the same.


I noticed the actuator for the wastegate has been bodged in the past, a nipple has been snapped off and replaced with copper brake pipe and bonded up....


Getting some leads from euro car parts, only cheap £20 ones so might not last that long but worth a try to see if the problem goes, if it does i will invest in better quality ones if they fail in the future

Thanks

[Thrumbleux]

Are all the connections on the wastegate actuator correctly placed? I think FQ101 has a diagram. If someone has been there before, and they are a PITA to connect as the tubes are so short they can only be connected with the actuator in place and you are blind doing it. If you are going to investigate that, in advance, buy some 3mm ID diesel spill hose and re-do the tubes with sufficient length so that you can make all the connections before mounting the actuator. Makes life a whole lot easier.
Got to admire your perseverance and get-it-done attitude. You will sort that car!

[BobbaFett]

Just to add a quick question, can you use fuel hose then to re-pipe the actuator and cycle valve then? Something I'm looking at doing since the issues I had where I replaced the cycle valve and had to trim the turbo side hose back - longer hoses would make it far easier to change the cycle valve etc in the future.

[Minigirl]

Hooked a draper vacuum gauge up as it says it can check boost pressure and anything above 5psi seems to make the needle bounce about. Eg at 6psi it will bounce between 7 and 6 psi. At 60mph 2500rpm in 6th the needle bounces around 7 and 8 psi is that correct boost pressure?

4th gear at 4000rpm saw i think 10psi

I teed into the vacuum line on the side of the turbo

Thanks

[Minigirl]

New bottom ht leads fitted and still the same issue will try fit the tops tonight but looks like the inlet manifold needs removed to get to the coils?

Thanks

[Minigirl]

Connected my obd reader while driving as that has a boost psi display and the moat boost I saw was 8psi and that was 4,500rpm in 3rd and 4th. Thats about 0.55bar isnt it?

What is the standard boost for a 700cc 450?