Diesel engine injector cleaning

[PEW]

My wife runs her own small floristry business. She bought a 4 year old, ex-UK Post Office, Ford 1800cc diesel engined (non-turbo) van. It has always been a bit reluctant to start when the engine is cold, but it fires up much better once the engine has run once for the day. I notice it's irrespective of the outside air temperature, therefore don't think it's a fuel pre-heater fault.

She has told me today that it has recently begun to "stumble" and misfire a little. I suspect both problems might be caused by dirty injectors. As a start I have bought a couple of bottles of injector cleaning liquid (fuel additive). If this doesn't fix it, what else should I consider?

Generally speaking, how effective are these additives?

Any advice gratefully accepted as I don't have a lot of experience on diesels.

I am reluctant to take the van to our Ford Dealer (never again!) as last time she went there for advice, they tried to persuade her to scrap the van and buy a new one (at 3 times the cost) just because it needed new anti-roll bar links and a split rubber on a rear axle bush.......

BTW, for Pat Primmer, I HAVE already checked the archives and FAQs etc without success. Thanks!

 

[JDana]

Have you drained the water seperator and changed the fuel filter lately?

Diesel fuel additive does work as does adding bio-diesel to your tank.

If these don't work you may be looking at some erosion of the injectors as the cause of you troubles.

 

[PEW]

Thanks for a very prompt reply!

The fuel filter was brand new but no, I haven't checked for water contamination. I will do that.

Bio-diesel? I haven't seen this on sale yet around here(we're in UK, BTW).

I just noticed that the label on the injector cleaner (Motorcraft branded, from my local motor factor) says the active ingredient is kerosene! If there is no more to it than that, I have just been ripped off.

If that is all there is in injector cleaner fluid, I will get a gallon of Jet A-1 from work and add some of that at each fill up from now on!

I'm sure it's not that simple.......

Paul W

 

[rmw]

Believe it or not, (I did not when I first heard it from one of my truck drivers) automatic transmission fluid works nicely. A quart in a tank full of diesel will gather up a lot of water, and disperse it so that it can work through the filter, and out of the system. I did my own test, and became a believer.

All additives are not created equal. I have seen side by side tests, and a US company named Standadyne was heads and shoulders above the rest.

There is an article in the current issue of Power Engineering, a Penwell publication on distillate fuel problems in fuel storage tanks at power plants, and all the issues apply to automotive diesel storage and distribution as well.

Be sure you are purchasing freshly refined diesel that is distilled for your seasonal requirements. In other words, don't buy from some "mom and pop" station that is still trying to sell last winters diesel from their tanks, because their diesel sales volume is slow. But from stations that have a lot of diesel customers and lots of fuel turnover.

If you suspect a water problem, change the filter again. Even a new filter can become quickly plugged if you have a lot of water.

Another diesel secret (hard to convince wives to go along with this) is to keep the tanks full. Don't leave the tank sitting empty overnight. Ever come out and see your auto all covered with dew?? Well the inside of your tank is just as wet as the outside of the car and the tank. Diesel does not have the vapor pressure that gasoline has, so it does not resist "tank breathing" like gasoline does.

The reason it starts well later in the day, is that because the innerds of the engine are still warm, and less heat of compression is lost to cold cylinder walls, as happens upon your first start of the morning. If it is balky, crank for a few seconds, and pause, then crank again. This lets the internal parts heat soak a little bit, so that they do not absorb so much heat as the initial crank.

Other than that, I don't know much about diesels.

rmw

 

[Metalguy]

Do your wife a big favor and get someone who knows what they're doing and REMOVE the injectors. Take them to a diesel engine service place that is capable of testing/rebuilding them. The engine will probably run like new then if everything else is OK.

 

[PEW]

Again, thanks for all the advice. This website is probably better than going to the garage as folks can have complete honesty here, with no reason to "be economical with the truth" for their own commercial reasons.

Good advice about keeping the tank full, I'll pass that on. The van's used for deliveries every day so a fair amount of fuel goes through it. It's filled at the local supermarket, which is often busy to the point of having to queue for a turn at the pumps so the bulk fuel doesn't sit there for long. We don't tend to have small "Mom and Pop" outlets in the UK towns anymore, the big supermarkets have taken over just about everything and the small filling stations were very early casualties.

I had a vague thought about ATF in the back of my mind somewhere, I have previously heard of someone using it neat, dribbled into the intake of a running petrol engine as an upper cylinder valve cleaner but realised this might result in a bent conrod or similar if attempted on a diesel, not that the intake ports are accessible anyway. I hadn't heard of it being used diluted in the fuel though and certainly didn't think it could take water with it. I no longer run a car with an automatic gearbox, so that is a good way of using up those couple of cans of ATF in my garage...I'd been wondering what to use them for.

Yes, I know if all else fails, those injectors really do have to come out and get serviced properly and they undoubtedly will. I'll get a compression leakdown test done too. However, in the mean time, the van is used 7 days a week, so to have it off the road causes a lot of inconvenience (and loss of shop revenue from deliveries) so it is worth trying additives if they can be effective, which is really why I asked the question.

I put in the Motorcraft additive last night, then brimmed the tank and gave the van a good 30 minute blast down the Motorway at full speed. I felt it did run a bit smoother afterwards and it seemed to pick up a bit better too so we'll see. I'll post the final diagnosis (from the florist)later when all has been tried!

PW

 

[drwebb]

FWIW, Kerosene is the diluent and not the "active ingredient" (regardless of what the label may say), which is probably some sort of amine-containing polymer. Variations of the same chemistry are often used in ATF as a dispersant, so there may be some basis to that recommendation. I can't speak to diesel applications, but I have seen reliable data demonstrating in-tank gasoline detergents can equal bench-cleaning of EFIs. The difference is that it may take a full tank of gas (i.e. several hundred miles of driving) to achieve this, while the benefit from the bench procedure is immediate. Also, the detergent must be used at the recommended "clean-up" dosage to remove pre-existant heavy deposits, which is 3-10 times the "keep clean" dosage designed to prevent the accumulation of new deposits.

There is very little a mechanic can do for $10 or less, so I think trying a quality injector detergent is a very cost-effective first shot at general drivability problems.

 

[rmw]

I forgot to mention that when I change filters, in order to keep that "stinking diesel" off of my hands, I fill the filter with ATF. It is doing double duty. Keeping my hands from reeking of diesel the rest of the day, and giving the fuel pump and injectors a good cleaning. It is the dispersants that keep sludge from building up in an automatic transmission by keeping them in suspension that gives the beneficial effect to water, et al in diesel fuel systems.

A lot of what I put in the filter gets returned to the fuel tank anyway as part of the fuel pump circuit.

But metalguy said it right. Take care of the wife.

rmw

 

[Metalguy]

Some/most injectors have internal springs that prevent the fuel from spraying below some level of pressure. Doesn't seem to take too long before the springs weaken/set and the injector sprays at too low pressure, without fine atomization.

I've seen SO many fairly new cars, including expensive ones, pouring black smoke. Probably this problem or dirty air filters.

 

[JDana]

I should also have suggested

http://www.tdiclub.com

They have a ton and a half of information there.

 

[rmw]

Metalguy,

The springs have a decent life, and any 'relaxation' is figured in on the initial setting. They are set in a range, and like anything else, some get set towards the low side of the range, or below, depending on how diligent the technician who sets them is.

Having said that, I have had several sets of pickup truck injectors set to my standards, by a willing technician (the shop owner) who set them to the very 'tip top' of the range, plus a little safety factor, that would not violate his obligation to his standards, and incur him any risk of damaging my engine.

It makes a difference in the performance, and the smoking. I took a turbo off of an 85 ford to move it to an 89, and with the injectors set thusly, upon returning it to otherwise stock service, wondered why I had bothered with the turbo addition.

I, too, have noticed the smoking diesels, especially an expensive model german car from several years ago, and I think they just had a poor design. They all smoked, until the universal use of turbo's came into vogue.

Some of it may have been operator error. See my comments of today in a thread titled Turbocharger idea, comments?

rmw

 

[Metalguy]

RMW,
I went to the other thread and read your (and others) replies. Excellent points!

My personal "small" diesel experience is limited to an International Harvester 1586 tractor (turbo) I had for a while. I bought it for a pretty low price because it needed a new/rebuilt HP fuel pump. While I was at it I pulled all 6 injectors out and had a good shop in Phoenix check them. All 6 had low pop-pressure or whatever they call it. It ran real well with the rebuilt pump and injectors.

But I've been here in northern Italy for 5+ years now, and have been "black-smoked" by damn near every diesel in Italy. Since I am usually on one of my motorcycles, I guess I have developed a deep hatred for Rudolph's engines. Fortunately my riding suit is an Aerostich Racecrafter (heavy nylon), so I am able to wash it in a big washing machine I bought ($1,800 please!). It was either that or buy a bunch of hand grenades.
Anyway, after thinking about it, I agree that nearly all of the heavy black smoke from newer diesel cars (including M-B's, BMW's and of course nearly all Fiat's) is produced at low speeds when the drivers apparently just mash the pedal. Since nearly every big car here has a turbo, it makes sense that it's simply a case of too little air until the boost builds. I'll have to look closer, but I suspect that M-B's that have the CDI (gear-driven vane blower) don't have the problem. Having had a few rides in one of them by the usual lead-footed Italian driver, I must say the throttle response was very good-remashing after the one time he had to take his foot off the pedal for a second or too!

 

[rmw]

Metalguy,

The term 'low pop pressure' is very meaningful to me. Not only is the quality of the atomization affected, the injection timing is as well, as the injection starts sooner with low pop pressure, rather than later, as in the case of 'high pop pressure'. Horsepower in a diesel is a function of injection timing among other things. I once owned an 18 wheeler that had a 350 (nominal HP) diesel in it, and there was also at the same time, a version of the same engine that was a 400 (nominal HP) and the engine was identical in every sense but the turbo housing, the pump delivery rate, and the injection timing.

Now, I recommend you do some PM on your washing machine, as you are going to need it. For an eye opening read, google the following; "F-T Diesel" and/or "Fisher Tropsch" and/or "GTL" or "gas to liquids".

I, for one, and being in a majority of one, believe that the world out there that is awash in Natural Gas, and that has absolutely nothing to do with it but flare it, Quatar, UAE, et. al. come to mind immediately, is catching on to the concept that they can take their currently useless resource, convert it to liquid fuel, and put it on a boat and ship it anywhere in the world.

California already loves F-T diesel, because it has no sulphur, and hence, no SO2, So3. Lots of stuff on the web already about that.

But, Europe is, as your washing machine knows, already hyped on Diesel, for a variety of reasons much too invovled to go into in this rant, and the F-T diesel is a natural follow on, since there is a finite limit to the world's supply of straight run #2 distillate, and cracked distillate.

I am just trying to figure out how I, as a practicing Engineer can get in on the cutting edge of this technology, and it's applications.

rmw

 

[enginebob]

Some answers to these questions may be helpful in trouble shooting.
How many miles on the engine?
Did the seller have any records of service that has been done?
Does it smoke?
What color?

 

[PEW]

EngineBob,

The engine had around 38,000 miles on it when the vehicle was first obtained and the problem apparently hasn't improved or got worse over 12,000 miles. We have the full computer printout service history with the vehicle fro mthe UK Post Office who owned it from new. This shows it was serviced in accordance with the recommended intervals, and in fact there is a daily log that the previous Post Office drivers had to sign and write up any defects.

It smokes a little whitish grey smoke after it first fires up and runs, but once running it doesn't smoke at all.

The Ford owner's manual indicates that cranking the engine for up to 30 seconds from cold is normal after pre-heating the glow plugs; this seems a long time compared to other diesels I have driven.

The phenomena hasn't improved by use of the injector cleaner additive. I have one more bottle of this stuff to run through the tank. If there is no change after that, I intend to get the vehicle looked at by a specialist.

 

[enginebob]

Some diesel engines are very tempermental to the quality of fuel used. And since I'm in US, fuel in UK maybe different.
The cetane of fuel for winter time maybe a lower value than winter time there. And could cause starting problems. Since I'm not familiar with the different emssions standards there, the injection pumps may be different than a US model. There could be some kind of mechanical problem too. Trouble shooting with out having it in front of you is a very difficult thing to do. It could be any number of things causing it. Check those glow plugs first. Second a compression check.

 

[Majik]

I am in the diesel engine business and work on them every day. if it is sluggish to start do the following. Make sure the glow plugs are new and they are working. Doesn't matter if it's 90 outside or 30.. it needs glow plugs to start. Second it sounds like low milage for a diesel engine to have low pop pressure on the injectors (they usually last 100k miles) but that's step two in the diagnosis. Most mechanical diesel injectors are a tip which atomizes the fuel. Those really need to be cleaned or replaced. They wear but shouldn't be worn in your milage. The spring weakens and allows the fuel to spray early and not as atomized. It has kinda the same effect as advancing the timming on your ignition in a car. If they get weak enough they will melt a piston. I make my living replacing those pistons NEVER use ether on a diesel well unless your a certified ether professional around diesels. While those injectors are out getting cleaned and checked. Do a compression test on all the cylinders. You can't do the test till you remove the injectors so you might as well do it the same time. You should have atleast 350psi of compression. (yes you need a diesel compression tester. your gas car one will not work) addittives might and might not work... they are sketchy at best because most spend their time removing gunk and film that builds up on gas fuel injector tips where gas sprays out at around 35-45psi. Diesels usually open at around 1900psi so there is usually no film on the tip but the tip just wears from the impact of opening and closing..

 

[PEW]

Thanks again to everyone for taking the time to reply!

I think quality control of UK fuel is pretty good these days, more and more cars are using it rather than petrol (gasoline). I certainly had no problems with my own diesel car using fuel from the same sources. The difficult starting fault is the same, winter or summer.

When my wife first bought the van and complained of hard starting I replaced all the glowplugs. To be honest, it appeared that the ones I was removing had very few miles on them so I kept them as spares. I confirmed the power supply was working properly. It made no difference. There is also a fuel pre-heater in the engine bay, that also seems to be working properly.

A while back the starter motor solenoid stuck and stranded my wife. I was away working so she called out the RAC breakdown service who immediately got the car started by hitting the solenoid (he also showed her where to tap the solenoid, which saved her from further emabarrassment a couple of times until I fitted a replacement motor). In the mean time, she took it to a garage near her shop and left it with them for half a day to troubleshoot the starting problem. I rang them to discuss what they were checking. They said there wasn't a fuel heater fitted! Oh yes there is! It seems to work. I won't go back to that garage, I'm only an amateur but I worked that out for myself...

From the advice I've received here I think it's either:

Injectors, compression, or an air leak on the fuel inlet side.

Hopefully these can be checked this week. I'll post up the result!

Thanks again.

Paul W