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Jeffbeck

Start, Run, Stall... Repeat!

89 posts in this topic

I have come across an interesting problem. Which has proved to be more expensive than I imagined....Back in July, the smart CDI would fire up, run for about 10 seconds then stall out if you didn't keep on the throttle. With the accelerator to the max, the RPM could only get up to 3100. This has been the saga since summer:1. Check Turbo - creates boost ok, boost leak found on intake to sensor line. Replace and reset. Same condition. 2. Check for clogged exhaust, loosen exhaust to muffler bolts, retest. Same condition. 3. Check EGR, found stuck partially open. replace and retest. Same condition. 4. Perform injector balance test... Failed, 2 of the three injector quantities are maxed out in opposite directions. Cleaned and Swapped injectors to see if the quantities follow. Same readings a before the swap. 5. Perform compression and leak down test. Compression at 400,390,420psi (way too high), leakdown 20-35%. 6. Remove intake plenum, tons of carbon build up (1/2 the diameter is coked oil)7. Remove head and inspect. Multiple valves not sealing and look burnt. Tons of carbon build up on head and in piston cups. High evidence of oil aeration and blow by. 8. Remove engine, disassemble, and inspect. Piston secondary compression ring is installed wrong side up on each piston (chamfer up), pistons heavily carbon deposited with burnt oil. 9. Send block out for machining. Replace pistons, rings, pins. Replace cylinder head. Since I am into it now... timing gears, chain, tensioner and sliders, all new orings and gaskets. 10. Install the rebuilt engine, hand crank until oil is pumped through all the oil galleries and turbo. Cycle the key to prime the fuel system and purge all the air by opening up the injector fuel rail lines. Start car, runs for a 5-10 sec then stalls out. 11. Re-purge the fuel system, retest, same result. Check rail pressure 300BAR, ok. Check the injector quantity, will stall out when the system begins to lean out the mixture (only notable on two cylinders). Pull the injectors, 2 of the 3 are wet and 1 is black with carbon but dry. Swap injectors around, same result, but does not follow the cylinder the injectors were swapped with, and is not the same cylinders as before (good numbers on cyl #1, so moved injector to cyl#3... but then #2 shows good numbers!). 12. Spray a little brake clean in the intake and start the car, runs a bit longer. Injection quantity goes to zero, spray more brake clean and it stays running. If I push the accelerator pedal the car revs up (not going to push it too high because of engine needs to be broken in still). Seems to stay running, idles smooth, injector quantity levels out and seems within spec. I shut it off and restart, it stalls out like before. Feel totally lost, not sure what to do or where to start next! Has anyone else had this symptom? Any ideas?

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There's not enough information.How many km were on the car? Was it running well before this problem began? Did you buy it as a non-running car? Had someone tried to rebuild it before you got it?Why was the compression too high if the rings were installed upside down?Why would all the valves show burning? Was there carbon buildup on the stems?

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I suspect a fuel supply problem. Start by checking low pressure fuel system by teeing in a pressure gauge in supply to high pressure pump. Fuel pressure should be 2 to 2.5 bar. Also chech for adequate flow.

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8. Remove engine, disassemble, and inspect. Piston secondary compression ring is installed wrong side up on each piston (chamfer up), pistons heavily carbon deposited with burnt oil.

Fitting piston rings with chamfer on the inside diameter up is pretty much standard. See info from Hastings below:

http://www.hastingsmfg.com/ServiceTips/com...nstallation.htm

Posted Image

Above photo, although poor, shows piston from a Smart OM660 diesel engine. One can clearly see that chamfer on second compression ring is fitted with chamfer up.

The other thing I would check out to home in on your stall issue is view live data from rail pressure sensor plus read off any fault code. I suspect rail pressure cannot be maintained at required pressure hence engine control unit does what it is taught to do and that is to shut down engine.

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I would replace the fuel filter.Your post doesn't say where you are located?Partsource has fuel filters available.See my technical wiki on how to replace and part number. (Max is doing some work on the site and it moved somewhere, p.m. me for part no.)Canman

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The link above that CruiseCarter posted is wrong.It is for European smarts, our fuel filter is in the belly panel under the drivers seat.Max is trying to recover the wiki.I will post a link when it's available.Canman

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What do they have in place of the aluminium in-line fuel filter forward of the right hand rear wheel arch? A straight connection piece or is the pipe continuous all the way from the the large filter under the floor pan?

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The connector is there, but no filter...we have the bracket for the in-line filter thoughpost-11642-1382306430_thumb.jpg

Edited by stickman007

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I have a fuel filter here anyways, so I will check the pump flow and low pressure lines at the same time. The high pressure side stays at 280-320 BAR even when it begins to stall out.Thanks to everyone for the input! Will keep you updated!

Edited by Jeffbeck

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Please don't kill me for saying so but step 14 is not required. As Smart142 previously mentioned, the fuel system is self bleeding. From the first key turn, you will hear the air fart back in the fuel tank. The water sensor has a passage thru it that goes down to the bottom of the filter. When you open the bleeder, water is drained from the bottom of the filter, if there is any, that is!

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Thanks Turbomar,You are correct, step 14 isn't necessary.If there was any sediment in the fuel tank or line bleeding the filter would remove the sediment, however by not bleeding the line the sediment would get trapped in the fuel filter, which is its job.So bleeding the fuel filter is optional.Canman

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When I pulled the fuel filter I noticed metal sparkles in the bottom of the drain bucket. I cycled the key and found that the fuel pump would run good and pump out alot of fuel.... however, but the 5th key cycle I found that the fuel was foamy and when running continuous the flow would cut out briefly (but the pump was still running). I pulled the fuel pump and found bigger metal chunks in the fuel pump cartridge, all the lines looked good and held pressure in the tank. It is likely the fuel pump, but it is possible that the metal chunks are interfering with the one way value that allow fuel to flow into the pump cartridge. Will get one on order and let everyone know how it goes!

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I'll check high pressure at idle on mine and post result tomorrow.

Thanks!I am still surprised that the high pressure shows up despite the lower pressure side cutting out/adding air...

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What do they have in place of the aluminium in-line fuel filter forward of the right hand rear wheel arch? A straight connection piece or is the pipe continuous all the way from the the large filter under the floor pan?

The hose loops towards the drivers side under the seat area where the larger fuel filter is located.

post-13373-1382319013_thumb.jpg

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, but the 5th key cycle I found that the fuel was foamy and when running continuous the flow would cut out briefly (but the pump was still running).

The metal chunk are not usual but about the flow reduction after 5th cycling of ignition switch, I believe that it's normal. The fuel pump unit got a bottom bucket with a limited flow inlet valve. If the fuel level is under the pump unit bucket, the fuel can only reach the fuel bucket strainer by this low flow valve. So after the 5th cycling, I think that it's enough to empty the fuel in the bucket. Then if you want more fuel from the pump outlet, you must wait that the fuel cross the low flow flap and fill up the bucket again. This observation cost me 423$ (fuel pump). Yeap, my old fuel pump was good. The new one did the same! <_< Hope it help and avoid that you waste a 423$ for low pressure fuel pump!Dom

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Low pressure feed pump runs continuously when engine runs. Rail pressure at idle is around 235 bar. Rail pressure goes above 300 bar when cranking engine to start. Low pressure supply to high pressure pump should be 2 - 2.5 bar. 3rd pumping element in high pressure pump is enabled during start but disabled at idle. The wee connector on the high pressure pump is for the 3rd pumping element solenoid. Below thread shows the internal workings of high pressure pump:

http://www.smartz.co.uk/showthread.php?161...-Cdi-2002/page2

Edited by tolsen

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You may want to inspect the wiring harness and sam connectors. It seems very strange when you move injectors around the fault goes to different ones, suggesting perhaps the resistance of the wiring harness is too high. Many a dealer have run into harness issues with the engine/transmission after replacing many parts, only to scrap the car in the end or send it off to a more "knowledgable" mechanic with time to fix things. What do the clear fuel lines look like on the engine, full of air or just fuel? Are all the hoses on the engine in good shape (they seldom leak fuel, but can leak air into the system). After all this work have you had the injectors serviced? I am sure a local rebuilder can clean them up and test (new tips are not avalable but cleaning and testing can go a long ways). If you have the required pressure at the fuel rail it seems strange that fuel supply is the problem unless there is lots of air. So many variables when replacing engines it can be really frustrating!Where are you located?

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Here in Vancouver, Fred Holmes fuel injectors thought they could get parts from Bosch and had no trouble with mine. It was only testing and flushing some low-mileage used ones for storage, get the diesel out and clean test fluid in. Stores better like that. The guy sure thought the injectors were very normal and no problem working with them and getting parts.

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Hi Alex, could you pm me his contacts? I have a set of injectors from my parts car that I would like to get it tested and stored. How much did it cost you?

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