Serious running issues

Hi again all, sorry if this is long winded.

This problem has me confused, my car appears to have a completely dead no 1 cylinder as unplugging the corresponding HT lead causes no change to the running (I believe it’s cylinder 1, rightmost on the front bank).
The car starts and idles normally initially but after the idle settles down a second later it begins missing and shaking. Cylinder no 1 always has the misfire in spite of swapping spark plugs around.

I’m unsure if this is related but prior to this I had an unresolved issue where the car would cut out abruptly under high load and high rpm conditions (>5000rpm), as if I had stopped accelerating completely despite staying wide open throttle, before it would come back to life after about 6 seconds. This progressed over time whereby the car would cut out at progressively lower rpm and load levels to the point where it was barely driveable.

Before I was able to resolve the cutting out, this misfiring issue has started overnight which i’ve also failed to fix making me think both are related somehow.

Things i’ve done:

  • Replaced all spark plugs with NGKs
  • New HT leads
  • 3 new coil packs
  • New fuel filter
  • Replaced ECU capacitors (one had failed)
  • Tried unplugging the MAF (issues persist)

I also pulled cylinder 1 spark plug and checked for spark, and there does appear to be.

The only thing I can think of is possibly a bad injector(s), but i’m just guessing at this point :slightly_frowning_face:

It might be a bad injector, but if it starts and initially idles normally, maybe not. Might be worth removing them and doing a DIY clean (plenty of videos on YouTube involving a 9v battery, bit of wire, some fuel hose and a can of carb cleaner) to check the spray pattern.

Is it possible the leaky capacitor damaged the circuit board or another component? Do you have access to a known good ECU you could swap in and test?

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I don’t have another ECU unfortunately. Only one of the capacitors had failed and it barely etched the board so I find it unlikely that’s the issue, can’t be certain though.

All i can think to do us to remove the fuel rails and go from there.

before removing all the fuel rail id take a big screwdriver and put it against the injector and put your ear up to it to see if you hear a consistent clicking when its running. if its not consistent or no clicking at all, its the injector. Check your IAC and clean it off if its dirty and/or double check for vacuum leaks.

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Update, ended up pulling the rail entirely.
All 6 injector inlets are full of rusty debris to the point where they are almost completely clogged, the rail itself looks clean.
I’m surprised the car ran at all really.

Suppose i’ll look at getting the injectors cleaned or try and find some new ones.

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not looking too clever

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Cleaning those out will hopefully make a difference. What does the inside of the fuel tank look like? I assume that’s where the rusty stuff came from.

Can you just get them reconditioned? I’m sure that it will cost less than new ones

The tank is quite rusty, the fuel filter was original so I guess it let some rust through - changed that now so hopefully sorted.
The injectors apparently have a little micro filter at the top, i’ve ordered some new ones so we’ll see if that fixes it.
This car has had so many strange issues I swear, hopefully this will be the last thing so I can actually drive it :sweat_smile:

A set of new injectors would have set you back a fair bit

Would it not have been better to send them off to injector clean to be cleaned and flow tested ?

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This is what i’ll do if changing the micro filters doesn’t work.
I didn’t realise the injectors had these until I took them out.

Just a quick update for anyone interested, the main cause of my problem was an incredibly rusted fuel tank due to the car being stored long term without fuel. It was bad to the point of the pump pickup becoming blocked starving fuel flow.

I dissolved the rust within the tank with a citric acid solution, made up from 2 cups of powder to 1 litre of hot water.

I filled the tank about halfway with acid, and let it sit for 2 days, turning it every now and then to ensure coverage of the internal surfaces.

After 2 days I drained the tank, pressure washed it internally to the best of my ability and used a heat gun to dry it as quickly as possible to prevent new rust forming.

Next was hoovering the tank to remove the final traces of dry flaky rust within.

I then tipped in 1 litre of the cheapest engine oil from my local wilko to coat the tank until I was ready to reinstall it.

I didn’t take a picture before unfortunately but I did take some during and after the cleaning process.

The entire inside of the tank was coated with rust similar to that on the baffle plate above. You can see the part of the plate below the water line beginning to become clean and silver.

Last bits of rust

The final product.

After cleaning out the tank and injectors, along with replacing the fuel filter, the car finally has loads of power and doesn’t act up at all.

Also here is a picture of an injector after changing the internal filter.

I removed the old one by screwing a wood screw into it and pulling it out with a pliers.

The new one was installed simply by hammering it in unttil flush.