gilrob Posted April 20, 2023 Share Posted April 20, 2023 2006 smart cdi, replaced engine but can’t get it running! I’ve tried two sets of injectors, 2 crank sensors, confirmed that injection rail pressure demand and actual reading match (300bar). Confirmed turbo is free wheeling and not causing back pressure, removed intake piping to ensure no restrictions, the crush washers on the injectors are new and confirmed not leaking, it’s in a heated garage so glow plugs aren’t the issue. I’m not getting any black smoke while cranking, engine will run if introducing a separate fuel source (ether), so compression is good. Anyone have any other ideas Quote Link to comment Share on other sites More sharing options...
Willys Posted April 20, 2023 Share Posted April 20, 2023 Have you checked to see if there is a signal at the injector..? Did you attach the engine ground strap? Did you mess with the ECU or it's wiring? Are you using the original ECU that was in before changing the engine or are you using the new engine's ECU because that will not talk to your speedo or SAM. Quote Link to comment Share on other sites More sharing options...
450ken Posted April 20, 2023 Share Posted April 20, 2023 Where did you get the new engine ? also don't use ether without disconnecting the glow plugs they will detonate ether and then you will be buying another brand new engine. My guess would be you are not getting fuel from the injectors. Maybe somebody can remember but there apparently are 2 plugs that can accidentally get swapped when reconnecting wiring. Quote Link to comment Share on other sites More sharing options...
gilrob Posted April 20, 2023 Author Share Posted April 20, 2023 Ground strap is attached and I am using the same ecu, can’t thing of any plugs I saw that could be switched, what should a read at the injector plugs? Should be a pulse signal? Quote Link to comment Share on other sites More sharing options...
450ken Posted April 20, 2023 Share Posted April 20, 2023 Maybe pull an injector and have it piss into a pop bottle to see if you are getting any fuel at all I don't think you are. If you are getting any fuel at all it usually shows as White Smoke which is hot unburnt diesel fuel thats why it can sting your eyes. You may need a Star machine to sort this out if your mechanical engine timing is correct. Quote Link to comment Share on other sites More sharing options...
gilrob Posted April 20, 2023 Author Share Posted April 20, 2023 Would be nice to check if I’m getting fuel but not sure how to set it up in a beaker and still have the lines connected. It’s not smoking what so ever which leads me to think there is a fuel issue. The question is just why Quote Link to comment Share on other sites More sharing options...
gilrob Posted April 20, 2023 Author Share Posted April 20, 2023 If the crank sensor is reading and registering rpm is that enough to suggest it’s functioning as it should? Quote Link to comment Share on other sites More sharing options...
Leadwing Posted April 21, 2023 Share Posted April 21, 2023 Can you hear the fuel pump running?? That problem has been experienced by a few members. Quote Link to comment Share on other sites More sharing options...
Willys Posted April 21, 2023 Share Posted April 21, 2023 To check if the injectors are actually sending fuel through them simply put injectors into a water bottle and cycle ignition and watch bottles to see if the fuel is coming out of nozzles. Research bleed back testing of the injectors also, This is done by attaching clear hoses to drain back fittings to see if one or more of your injectors is simply sending too much fuel back to the tank. All injectors should be very close to the same amount of fuel over a specified time...? Not sure it can be done efficiently if the engine isn't running as I haven't tried it yet..? But was told this is possible to trouble shoot injector issues..? Beware of the amount of pressure being put into the fuel system as do not break the lines open as the fuel will inject itself into your skin in an instant. The injector signal is a pulse as in similar to spark plug signal in a gasoline engine. Hmmmm...? I did buy a machine or tool off Amazon that shows this but haven't used it yet...but it is available....and reasonable priced...it is an osciliscope type tool. I am told that the crank sensor either works or doesn't.....and have replaced both of mine, one because it was needed the other just because I had the engine on the bench and didn't want to deal with a possible replacement while engine was in the car...augh!!!!! Learned that lesson the first time...lol. Quote Link to comment Share on other sites More sharing options...
tolsen Posted April 21, 2023 Share Posted April 21, 2023 From memory voltage pulse to these injectors is about 70 V DC. Think you need an oscilloscope to check as far too high voltage to risk using your tongue. Timing could be off if someone has messed with this engine before you. Although it should be evident how flywheel and its spider is to be fitted, I have in the past seen this done wrong so worth while checking before fitting engine in car. Easiest way to tell if injectors are being pulsed is to disconnect a leakage hose on a single injector and look for pulsed leak whilst cranking engine. Quote Link to comment Share on other sites More sharing options...
tolsen Posted April 21, 2023 Share Posted April 21, 2023 An interesting paper discussing diesel fuel injector leaks: https://download.atlantis-press.com/article/25901675.pdf Quote Link to comment Share on other sites More sharing options...
Mjolinor Posted April 21, 2023 Share Posted April 21, 2023 2 hours ago, tolsen said: An interesting paper discussing diesel fuel injector leaks: https://download.atlantis-press.com/article/25901675.pdf That's a noodle baker. Quote Link to comment Share on other sites More sharing options...
Willys Posted April 21, 2023 Share Posted April 21, 2023 Hmmmmm....??? That whole paper is useless unless you have the equipment and math skills to use the formula....ffs. I remember those types of math matical brain twisters etc etc when doing mechanical eng. degree.....back then I could mess with it but now it hurts just trying to read the paper...lol. It basically is explaining to you that injectors wear out and leak....lol. Quote Link to comment Share on other sites More sharing options...
450ken Posted April 21, 2023 Share Posted April 21, 2023 No sense over thinking it just piss test it into a water bottle it's getting fuel or not getting fuel. What about you geniuses out there can you put an induction coupling on one injector wiring and detect a pulse of voltage ? If there is no pulse of voltage when you turn over the engine the injector is not receiving voltage so the search would narrow. Quote Link to comment Share on other sites More sharing options...
Mjolinor Posted April 21, 2023 Share Posted April 21, 2023 14 minutes ago, 450ken said: No sense over thinking it just piss test it into a water bottle it's getting fuel or not getting fuel. What about you geniuses out there can you put an induction coupling on one injector wiring and detect a pulse of voltage ? If there is no pulse of voltage when you turn over the engine the injector is not receiving voltage so the search would narrow. Yes you can, it works well but you have to put it round one wire Quote Link to comment Share on other sites More sharing options...
450ken Posted April 22, 2023 Share Posted April 22, 2023 Maybe there should be a sticky prioritized thread on this we have had several people with this really difficult problem to solve. What do you check and what order do you check them ? Can you separate the injector wiring for an induction coupling to verify signal pulse voltage rule this out and look at fuel ? Quote Link to comment Share on other sites More sharing options...
Willys Posted April 22, 2023 Share Posted April 22, 2023 What I have done is do a continuity check on every wire in the engine bay....all checked out perfect. Just another thing to rule out imho. Also opening up ECU and peeking inside for anything strange and also corrosion issues also on the pins. I also checked before each connection and after it as in before the crimp to the pin and the pin itself. That took days! Quote Link to comment Share on other sites More sharing options...
gilrob Posted April 23, 2023 Author Share Posted April 23, 2023 Everyone is mentioning injecting into a bottle, how do I hook up the lines in a way that it’s possible Quote Link to comment Share on other sites More sharing options...
Mjolinor Posted April 23, 2023 Share Posted April 23, 2023 Generally it is not easy, if you google "spill test" and "leak back test" you will see how to do that and that can provide you with some useful information. In order to test if the injector is actually injecting you need spare injector pipes and a safe way to keep the injector in the glass bottle while you whirr the engine over. Do not use plastic as it will just blow holes in it. Do not allow the injector to spray into the surrounding particularly anywhere near you as it will kill you if it hits your skin directly. I do not think that your problem is at that end of the system. I am leaning towards the ECU not telling the injectors to fire. If they were firing you would have signs coming out of the exhaust in the way of smoke or smell. Disconnect the glow plugs and give it a quick blast of ether, see if it bangs like it should. Not for long and not more than once. I have never tried it but it may be possible to use a neon screwdriver to see if there is a signal on the injector wires. It is very close. I believe the Smarts use eighty volts and that is just about the voltage a neon will fire at. It would be interesting to try that on a runner to see if the neon does flash, a job for when I have nowt else to do methinks. Quote Link to comment Share on other sites More sharing options...
Mjolinor Posted April 23, 2023 Share Posted April 23, 2023 Have you measured cranking revs. If they are not enough then a diesel will never start. Generally speaking 150 RPM is an absolute minimum and you really should get over 175. Quote Link to comment Share on other sites More sharing options...
Willys Posted April 23, 2023 Share Posted April 23, 2023 Just as a silly suggestion, make sure injector plugs are all the way clicked onto injectors...yes it happens....doh...lol. After changing around my injectors I noticed it was very hard to get the connectors firmly clicked onto the injector plugs....? Quote Link to comment Share on other sites More sharing options...
gilrob Posted April 23, 2023 Author Share Posted April 23, 2023 Plugs click, getting around 300 rpm while cranking Quote Link to comment Share on other sites More sharing options...
Willys Posted April 23, 2023 Share Posted April 23, 2023 16 hours ago, gilrob said: Everyone is mentioning injecting into a bottle, how do I hook up the lines in a way that it’s possible You can undo the lines and reattach just the feed end of the line to the rail and rotate the line so you can attach injector at any angle away from engine....as suggested do not allow spray get near your skin when you spin the engine over. A few sprays of fuel into the atmosphere won't kill the human race off any quicker than they think we are doomed already...imho. This not something I recommend officially of course, but it may help you see if you have a dead injector? BEWARE!!! Quote Link to comment Share on other sites More sharing options...
tolsen Posted April 23, 2023 Share Posted April 23, 2023 There is an easier way to confirm if an injector is firing. Just use a screwdriver or a mechanic’s stethoscope. Quote Link to comment Share on other sites More sharing options...
Willys Posted April 23, 2023 Share Posted April 23, 2023 20 minutes ago, tolsen said: There is an easier way to confirm if an injector is firing. Just use a screwdriver or a mechanic’s stethoscope. down the glow plug hole looking for a wet screwdriver or hearing the spray...? Quote Link to comment Share on other sites More sharing options...
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