Mercedes-Benz Forum banner

1 - 20 of 35 Posts

·
Registered
Joined
·
2,508 Posts
Discussion Starter #1
Could you take a look at these and see what you think? It is a little slow to crank and skips after return to warm engine after 15-30 minutes for restart.

I am thinking of replacing 1 injector at a time to see if it really is a leaky injector, but thought we may find an indication
plugs 09072019.jpg
from plugs on which one to start with.
 

Attachments

·
Registered
Joined
·
16,695 Posts
Replacing one injector at a time is futile. If the current injectors are 10 years old and/or have done 150Kmi/250K km they're as done as a thanksgiving turkey. Ditto on the injector cups and seals.

A healthy looking plug should look like #3 (counting from the left).

However, ALL your plugs look like you are dealing with oil fouling due to worn valve guide seals.
 

·
Premium Member
Joined
·
1,371 Posts
The ONLY semi-normal looking plug is #3 from the left. #1 and #2 look to be a tad fuel fouled, the black deposits indicate you aren't getting a full/clean burn in those cylinders. Those are the ones I'd suspect for bad injectors, especially #2. And ALL of them appear to have what looks like crusty, sandy, mineral deposits of some sort. Can't say I've seen that before, but it's not good. As Sbaert says, oil deposits maybe(I don't see a lot of gray ash or heavy black soot deposits on the ceramic post indicating oil)? If I were to guess, i'd look at water being burned, leaving that sort of grainy deposit.
How many miles on the engine/vehicle, what year/model, and could you better describe the symptoms?
Slow to crank... like something is impeding the rotation(water in a cylinder?), or takes 2-10 extra revolutions to fire up(low compression, poor fuel pressure?)?
Skips after warm restart... is it a quick tick, or noticable miss/loss of power? At what RPM? Idle? Wide open throttle?
I'm confused about the 15-30 minutes for restart. Is that when it skips, after you wait 15-30 min, or does it start skipping after you drive it 15-30 min after a warm restart?
What does the oil look like? How about the coolant?
What does the tailpipe look like? Do you see noticeable black, gray, or white smoke coming from the exhaust, either while on the highway, or upon starting?
Are you losing oil or coolant?
How would you describe your driving style? Aggressive, or driving Miss Daisy?
 

·
Registered
Joined
·
2,508 Posts
Discussion Starter #4
Appreciate your replies. 89 300E M103 straight 6. Over 300K miles, injectors and seals replaced probably at 140K and 7 years ago.

Valve job done further back, and coolant leak showing below head after that job, not wet, but white debris. It's been years like that. I do add a bit of distilled water occasionally, but there is always a hose or something to tighten or replace around these cooling systems, so it is hard to pinpoint a culprit here. I replaced the radiator last year and can show you some white crusty around the top of that now. So I don't know exactly where the coolant goes.

Slow to crank: after I drive it for awhile, then go into store or something for 15 minutes, then come back and start it up, it is hard to crank and skips at idle until I rev it up to about 2000 rpms and it clears the skip. It is a noticeable skip like it is missing on a cylinder. It cranks before 5 -7 seconds; it has never fail to crank in past 5 years - except when I had to replace the battery once.

Daily driver, normal to aggressive, oil is black and needs changing and tail pipe is black an sooty inside. Nothing noticeable around it though.

I took the cold start valve out of play a year or so ago, to see it that would fix it and it didn't. Still never connected it back up but it does not need it here in Georgia anyway. It was doing the same thing then and a couple of years prior. Still goes 0-60 pretty quickly at wide open throttle and always works; just have to rev it up after cranking it sometimes.
 

·
Registered
Joined
·
16,695 Posts
Do the injectors, cups and seals before delving deeper. Everything beyond that point is going to get more expensive.

The fact you have to add coolant now and then means you have a leak somewhere. No other way to put it. Head gasket, old hoses, you name it. Anything could be causing that based on that age and mileage of your car.
 

·
W201 Moderator
Joined
·
2,174 Posts
You never mentioned how much oil you are burning. I believe sbaert mentioned that first.
Those plugs look pretty similar to how mine looked after only 2K miles after a spark plug replacement when I was burning quite a bit of oil prior to the valve stem/seal replacement.

So how much oil are you loosing?
 

·
Registered
Joined
·
2,508 Posts
Discussion Starter #7
How much oil am I loosing. Hmmm. There is no telling, It has a rear seal leak, maybe a bit coming from the oil level sensor. I did the front timing cover seal so that is dry now.

How much am I burning. I don't think it's burning that much, due to the prior valve job.

But I do have to add a quart every 3 or 4 weeks. I have to clean catch pans I have under the car too.

The injector cups and seals are not a problem, tested with propane and no leaks. In fact, several years ago I used the propane test and there were leaks so I replaced seals, injectors... and that is about when the hard starting began really. The seals did not leak after that any more though, my thought was that the cracks in seals let the fuel dry after it leaked from injectors,and so it did not flood the cylinder and cranked perfectly, just a guess though, no proof.
 

·
W124 Moderator
Joined
·
12,585 Posts
The fuel pressure regulator can also cause hard "hot" starts. I had the same symptoms on the 300CE. Ran great etc but the hard start after sitting 15-20 min persisted. The new FPR solved the problem for me.

Sent from my XT1710-02 using Tapatalk
 

·
Premium Member
Joined
·
10,096 Posts
Those plugs look bad as far as fowling, but that gold color from the poor pic obfuscates a better judgement call. Color is everything in reading plugs. Replace all the injector seals again. The reason I say this is because I pulled the injectors out of my old TE which were only a few yrs old and put them in my present TE. I had done all the seals and cups. The new seals were hard as rock just after a few yrs. The seals by comparison in my present TE were soft. Suppliers are obviously scrimping on O-ring/cup seal material.

On the face of it, it looks like your stem oil seals are possibly hardening too......I would do the injector seals first, put a new set of plugs in and then pull after a few thousand miles for examination.

Kevin
 

·
Registered
Joined
·
2,508 Posts
Discussion Starter #10
Thanks guys, this is a pic without the gold tint.

I will test for leaks around the seals again after I change out the first injector.

I was thinking of going pure millennial and asking for the test procedure for fpr, but I will search first. I know it is here and have probably read it a few times by now. I have the gauges, just need to use them.
plugs2 09082019.gif
Will post it up later probably.
 

·
Premium Member
Joined
·
10,096 Posts
Much better pic....as was said, the plug third from the left is the only one that looks close to a normal burn. All look to have some degree of oil fouling.

I think after you pull a few injectors you might find the seals are not supple and soft as they should be. And I wonder about the valve stem seals, even though they were probably replaced with the head work (hopefully). But it's a good idea to check out you FPR as well.

As Steve said, the injectors only have an estimated life of 100,000 miles, so it's your call there.

Kevin
 

·
W201 Moderator
Joined
·
2,174 Posts
Yeah, a lot of us are in denial when it comes to oil burning. One does not lose much oil thru leaks generally unless there is a big puddle of oil under the car. So most of the oil is burnt. Burn evenly in the cylinders, you will not see smoke coming out of the tail pipe either, I never did down to 1 quart / 400 miles.

So how many miles do you drive every 3 weeks. 300-400 miles?
 

·
Premium Member
Joined
·
10,096 Posts
Wow....I've always consider a quart every thousand miles to be a borderline litmus into maybe determining where the oil is going. A quart or less every 3-5K is a gift from MB in their older cars.

As far as oil on the ground....you'd think old British cars were puking up their guts every time they are parked. Oil on the ground, especially concrete always looks worse that it really is. Pour an entire quart on concrete and compare that to your oil spots.

Kevin
 

·
Premium Member
Joined
·
1,371 Posts
Wow....I've always consider a quart every thousand miles to be a borderline litmus into maybe determining where the oil is going. A quart or less every 3-5K is a gift from MB in their older cars.

As far as oil on the ground....you'd think old Brittish cars were puking up their guts every time they are parked. Oil on the ground, especially concrete always looks worse that it really is. Pour an entire quart on concrete and compare that to your oil spots.

Kevin
Ha, ha, ha... That's how you know Brit cars and Harleys have oil in them, when they are spotting the cardboard/floor under them.
I've seen vehicles that had so much oil pouring out the rear main, it made the clutch slip on a stick shift, and another time the oil coated the tranny and drive shaft back to the differential.
 

·
Premium Member
Joined
·
1,371 Posts
So this is what
Thanks guys, this is a pic without the gold tint.

I will test for leaks around the seals again after I change out the first injector.

I was thinking of going pure millennial and asking for the test procedure for fpr, but I will search first. I know it is here and have probably read it a few times by now. I have the gauges, just need to use them. View attachment 2603530 Will post it up later probably.
So this is what plugs look like from a 300K mi Benz!
That is a whole lotta deposits, how many miles on this set? 20-30K?
 

·
Premium Member
Joined
·
10,096 Posts
Ha, ha, ha... That's how you know Brit cars and Harleys have oil in them, when they are spotting the cardboard/floor under them.
I've seen vehicles that had so much oil pouring out the rear main, it made the clutch slip on a stick shift, and another time the oil coated the tranny and drive shaft back to the differential.
I remember reading in a car magazine a zillion yrs ago....when asked why their cars leaked so badly they said almost all garages there have dirt floors and so it's no bid deal....lol!


Kevin
 

·
Registered
Joined
·
945 Posts
I serviced mercedes for 30 years and never changed any injectors i only found one duff injector and that was in a new set i fitted and that one had a manufacturing fault .The set i just changed in my 30 year old M103 engine were all good after 30 years of use . But i had extra cash and no other jobs outstanding to do on the car before i sell it ,, Runs just the same with the new set that i have fitted . I would give the old ones to cbc if i was closer to him ..along with a new set of seals and o rings the holders dont wear .
 

·
Registered
Joined
·
945 Posts
All cars will leak oil at some time or other . Only to be expected as they get older with hot summers and cold winters.Take a look around the final drive of any rear wheel cars you will be very lucky if you dont find an oil leak at that point .
 

·
W124 Moderator
Joined
·
12,585 Posts
I'm pretty sure the plugs cbc is using are Denso T20EPU's. No gasket, tapered seat, non resistor..

Jayare

Sent from my XT1710-02 using Tapatalk
 
1 - 20 of 35 Posts
About this Discussion
34 Replies
10 Participants
Real1shepherd
Mercedes-Benz Forum
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!
Full Forum Listing
Top