leaking injector - the silent killer?

[ajm55]

Been seeing too many posts indicating that a leaking injector can result in catastrophe. Yet it is often undetectable - much like high blood pressure or high cholesterol, both of which can cut you down without warning.

Are there no tell-tale signs with a leaking injector? If, for instance, cylinder 1 injector goes bad without throwing a code, will this not at least affect AFRs or fuel trims on bank 1?

If there is not always fore-warning in some form or another, then we are effectively sitting on ticking timebombs. Surely, with modern technology, there must be a way of averting catastrophe?

[M5Rick]

Originally Posted by ajm55

Been seeing too many posts indicating that a leaking injector can result in catastrophe. Yet it is often undetectable - much like high blood pressure or high cholesterol, both of which can cut you down without warning.

Are there no tell-tale signs with a leaking injector? If, for instance, cylinder 1 injector goes bad without throwing a code, will this not at least affect AFRs or fuel trims on bank 1?

If there is not always fore-warning in some form or another, then we are effectively sitting on ticking timebombs. Surely, with modern technology, there must be a way of averting catastrophe?

As soon as a smell of petrol is suspected which is a tell tale sign then engine should be stopped. A good quality fuel should be used and I add red Redex fuel additive to lessen the risk of a blocked injector.

[M5_Raz]

Originally Posted by M5Rick

As soon as a smell of petrol is suspected which is a tell tale sign then engine should be stopped. A good quality fuel should be used and I add red Redex fuel additive to lessen the risk of a blocked injector.

This doesn't apply if you're catless

You can also remove the oil cap periodically and smell the oil for excessive gas odor.

[M5Rick]

Originally Posted by M5_Raz

This doesn't apply if you're catless

You can also remove the oil cap periodically and smell the oil for excessive gas odor.

Another sign is white smoke from behind with rough running?

[M5_Raz]

Originally Posted by M5Rick

Another sign is white smoke from behind with rough running?

I had a leaky injector on past car and it was a lot of constant blueish/black smoke. Black from the unburnt gas and blueish from the diluted oil.

And yeah, the car runs very rough. I've heard stories where it didn't on these cars, which is kind of worrisome.

[M5Rick]

Originally Posted by M5_Raz

I had a leaky injector on past car and it was a lot of constant blueish/black smoke. Black from the unburnt gas and blueish from the diluted oil.

And yeah, the car runs very rough. I've heard stories where it didn't on these cars, which is kind of worrisome.

I take mine into BMW for it's yearly safety and co2 gas test and they give it a free side check also.

[ajm55]

Originally Posted by M5Rick

I take mine into BMW for it's yearly safety and co2 gas test and they give it a free side check also.

Thanks for the feedback gents. Is BMW able to test whether an injector is leaking

[M5Rick]

Originally Posted by ajm55

Thanks for the feedback gents. Is BMW able to test whether an injector is leaking

You best check that from your own end, when a co2 test is done here any abnormality will come up. Just take it in to you nearest BMW agent.

[ajm55]

Originally Posted by M5Rick

You best check that from your own end, when a co2 test is done here any abnormality will come up. Just take it in to you nearest BMW agent.

Thanks Rick, I'll investigate

[Kamate]

You can also send a sample of your used oil into the lab to get it analyze. A leaky injector will likely show up in the test.

[ajm55]

Originally Posted by Kamate

You can also send a sample of your used oil into the lab to get it analyze. A leaky injector will likely show up in the test.

Thanks. I did that a few years back and there was some fuel detected in the oil. I was told however that this is not uncommon with direct injection motors especially if you run ethanol (which I do)

[technician117]

Leaky injectors can usually be discovered if you're paying attention. It's when it leaks really badly or sticks open that causes the engine failure. Usually induced by heavy loads/strain on the engine. Remember that heavy load doesn't mean WOT pulls to redline. You could be "lugging" the engine up a hill for instance.

Keeping aware of how the engine is running, noting any smells as mentioned, and not putting off preventative maintenance, which unfortunately includes fuel injectors.

[M5Rick]

I say again use red Redex available from Costco and add too your fuel at fill up to cut the risk.

[Kamate]

Originally Posted by ajm55

Thanks. I did that a few years back and there was some fuel detected in the oil. I was told however that this is not uncommon with direct injection motors especially if you run ethanol (which I do)

Yea, as long as it measures under 2% dilution then you know you don’t have a leaky injectors. Even if you run ethanol, you still don’t want the reading to be way too high anyway. If it’s too high, you may want to change your oil a little earlier. It just another way to check and have a peace of mind.

[ajm55]

Originally Posted by Kamate

Yea, as long as it measures under 2% dilution then you know you don’t have a leaky injectors. Even if you run ethanol, you still don’t want the reading to be way too high anyway. If it’s too high, you may want to change your oil a little earlier. It just another way to check and have a peace of mind.

Thanks. I bought the car with 48,000 kms. It's now done just over 70k. Since buying, I've had the oil changed every 5,000 kms

[ajm55]

Originally Posted by M5Rick

I say again use red Redex available from Costco and add too your fuel at fill up to cut the risk.

Haven't seen Redex locally (South Africa). I've been using Liqui Moly injector cleaner with every 3rd fill-up. I was told the other day to rather use NF 3 in 1 Fuel System cleaner which is formulated specifically for direct injection engines so I'm trying to get hold of a few bottles

[ajm55]

Originally Posted by technician117

Leaky injectors can usually be discovered if you're paying attention. It's when it leaks really badly or sticks open that causes the engine failure. Usually induced by heavy loads/strain on the engine. Remember that heavy load doesn't mean WOT pulls to redline. You could be "lugging" the engine up a hill for instance.

Keeping aware of how the engine is running, noting any smells as mentioned, and not putting off preventative maintenance, which unfortunately includes fuel injectors.

Thanks. No symptoms noticeable as yet. Car runs smooth and like a beast. You mention changing the injectors as part of preventative maintenance. At what mileage would you recommend doing that (assuming that there are no symptoms of injector issues)?

[technician117]

Originally Posted by ajm55

Thanks. No symptoms noticeable as yet. Car runs smooth and like a beast. You mention changing the injectors as part of preventative maintenance. At what mileage would you recommend doing that (assuming that there are no symptoms of injector issues)?

50-75k miles seems to be the range when we see more problems.

[M5Rick]

Originally Posted by ajm55

Haven't seen Redex locally (South Africa). I've been using Liqui Moly injector cleaner with every 3rd fill-up. I was told the other day to rather use NF 3 in 1 Fuel System cleaner which is formulated specifically for direct injection engines so I'm trying to get hold of a few bottles

Never heard of NF 3 in 1 cleaner, who makes it.

[ajm55]

Originally Posted by M5Rick

Never heard of NF 3 in 1 cleaner, who makes it.

"NF additives" is an Australian brand. Check out their website at nfadditives.com.

I've been using their (NF ultra) octane booster for years to compensate for our sub-standard fuel and my data logs show that it works better than the many others I've tried, which include Torco and Rislone. There are reports indicating that their octane booster will eventually foul your plugs, but how soon will depend on the strength of the mixture. Hasn't happened on any of my cars yet.

I've also managed to source Redex locally so will alternate between the Redex and NF injector cleaners

[ajm55]

Originally Posted by technician117

50-75k miles seems to be the range when we see more problems.

Ok thanks. I'm still some way off the lower number but will monitor with this in mind

[M5Rick]

Originally Posted by ajm55

"NF additives" is an Australian brand. Check out their website at nfadditives.com.

I've been using their (NF ultra) octane booster for years to compensate for our sub-standard fuel and my data logs show that it works better than the many others I've tried, which include Torco and Rislone. There are reports indicating that their octane booster will eventually foul your plugs, but how soon will depend on the strength of the mixture. Hasn't happened on any of my cars yet.

I've also managed to source Redex locally so will alternate between the Redex and NF injector cleaners

Thanks,I'll do that.