OK fellas my D5N serial # CAT00D5NHAGG02056 has about 3650hours. Im out of Pittsburgh PA and our weather is obviously cold this time avg 28deg this of year but not anything out of the ordinary like some fellas experience. Machine is on jobsite and not used all day every day. When operator attempts to start machine, he turns key and the diagnostics activate, the Heating element light on the dash comes on for a short period of time. Key is turned and machine turns over and over. He's telling me it's taking around 4 separate attempts for the engine to fire. machine just had a Cat 250hour full service performed by local dealer. My question is, what type of glow plug or heating element does this machine use? And is it possible that there's something that is malfunctioning? Current ambient Temps today are 35degs which is warm this time of year. Any advice or things to check on would be much appreciated. Nige you could probably diagnose this in your sleep. Thank you Joe
I'll leave the diagnostics to Nige. What I want to know is how long has it been taking 4 attempts to start? Are you sure it's correlated to the temperature? 35 F sounds warm to be experiencing any kind of starting issues like this for a relatively modern, relatively low hour medium sized diesel engine like this. My guess is it should start within 5 seconds down close to zero without any kind of heater. With short days and long nights, the night time low is more relevant to the temperature the block and battery will be when you try to start it. Has the problem been much worse on days after the really low night time lows?
C7 engine ?
At night it can get into the teens as far as temp. I'm wondering If the Air intake heater or the relay is malfunctioning. The machine starts fine after it warms up. Yea I'd say it's worse after we have machine sit after very cold nights. All this is very normal, what surprises me is that it's taking multiple attempts of cranking for 20 seconds as per the operators manual which yes I do own and possess.
I would stick a meter or test light on the intake heater stud and check for voltage with some one turning the key on. No voltage check obvious things first, fuse, relay. If it has power then check the heater like you would a glow plug.
I most certainly will. Appreciate it. Have you personally had any issues with cat engine with similar problem?
I’ve got a c7 in my work truck. It takes a little bit of cranking but I chalk that up to the 350k miles. It being a heui motor I would give a stiction emlimnator a try and steer away from roltella and long oil change intervals. Should see a difference
My Cats are around Pittsburgh, too. No issues with mine. Look at the water separator assembly. Is the shoulder of the drain plug contacting the water bowl (completely shut)? As for preheater, it's in the intake. Check for voltage at the red arrow location during preheat. I've changed quite a few relays for the grid heater.
I have a C7 in a F750. It's also a bitch to start. what stiction additive do you use? I'm definitely gonna buy some. Been considering this for long time now
My man thanks alot for the help. That is interesting. Just had Cleveland Brothers do a full PM on her. There is a chance the water sep might be slightly loose. Do you think that would cause a slight leak? As far as the relay, that's a 12 volt relay correct? Any chance you have part numbers for the coil and the intake heater? I have parts books. What model Cat Dozer do you have? Thanks again brother
Mine are all in 328D excavators. Everything on your machine is 24volt. I've had issues with the drain plug becoming hard to turn and have found them partially unthreaded (because they would go in no further), and, subsequently, air is introduced into the system before the electric priming pump. Again, the thumb wheel on the drain plug needs to touch the water bowl boss.
Copy that. I figured your parts diagram was of a different cat engine. I'll definitely double check the filter. Thank you sir.
I’ve used hot shots and arch oil. With far better results with the arch oil. This is my first winter with the c7 so I’m interested to see the results. All uses before were on high Milage 7.3’s
Them pictures are from a D5N AGG parts manual.
Those air intake heaters draw a lot of amps, check the relay, cables, connections, just like you would check a starter and battery cables. Use a volt meter and see where you get voltage when you have somebody turning the key. The battery voltage should drop a couple tenths when it's running, so you can do a quick check right at the battery. If the battery voltage is 25.5 to start, your operator turns the key and it drops to 25.3 for fifteen seconds, then goes back to 25.5, then the grid is working most likely.
Thanks for the tip.
Just to eliminate it from the diagnosis, what viscosity grade of engine oil did the dealer use when they last serviced it..? Was the problem there before it was serviced, or has the cold weather come in since the service was performed so it’s impossible to say.? Does it seem to crank over at the “right” speed when it’s having the starting problem, or does it sound “sluggish”.? I’ll have to leave others to come up with anything technical. I’m travelling and working off a phone that is nowhere near as smart as it thinks it is....
Just a suggestion out side of the ambient temperature . If the pulse from one of the position sensors is not picking up extended crank time will result. Also scanning live data would tell you if injection command pressure is equal to measured pressure. Check the suction orings and suction piping to hpop esp if measure pressure is low when cranking cold. On initial start up measured pressure must momentarily exceed command to fire.
Nige cat used DEO ULS 10w 30 oil. Shes been a bit cold blooded. Last winter I used the machine regularly and we had to charge or jump the machine, But the batteries were old and Since replaced those. Cranks fine with a slight sluggish response after multiple attempts as expected. When machine went in for service, Fired up fine but the weather was also unseasonably warm in Pittsburgh PA. Service was done Nov 4th. Starter was replaced when I bought the machine with 3400hrs.
Unfortunately I don't have the gauges to check fuel pressure. I'm trying to avoid taking machine back to Cat for cost purposes. The suggestion you're making, wouldn't that cause a consistent difficult start? Once it fires up and warms up a little, runs fine. A previous post had a suggestion about the water separator being lose causing a vacuum issue which could be relative to what you're suggesting.
I was only making suggestion of common extended/ no start conditions thatth have experienced with the C-7. By the way I was speaking oil injection pressure not fuel pressure. As mentioned earlier , do you hear the grid heater solonoid activating When key on, it will activate with out going into the start position. It is simple diagnosis as it is no different than an old Ford starter solonoid. Power to the solonoid is provided through a breaker, activation of the solonoid(exciter) comes from the ecu.
Not trying to get to technical but I have found position sensors with abnormal wave forms when cold. It is just my personal method of diagnosis to not get pigeon holed into idea that one issue can't be the problem because it would also do this or that. Usually if there an ambient temperature issue causing a no start, it will create fuel smoke untill it eventually fires off. Is it smoking during the multiple attempts to start?
Yes the machine is puffing white smoke until it fires from what I was told from my father and the operator who normally runs machine. They worked on the machine looking For anything outta the ordinary.
The grid heater needs to be checked for continuity as well as voltage at the stud. If there is voltage the key needs to be turned off and see what the resistance from the stud to ground is. If there is no continuity it is burned out and probably falling apart and going through the motor. Our D-6n with a C-7 did that and ate almost the entire heating element before it got mentioned. Seemed like a lot of metal to go through the motor but so far so good a few thousand hours later!
Holy ****! I have a C7 on my truck as well. I'll have to check that as well. Any idea what the resistance should be? Do you know if this style grid heater is used on a 2005 C15?
Thanks for the clarification. In that case I’m with everyone else who has pointed a finger at the air induction heater. The operation of that had to be confirmed before doing anything else IMHO. Regarding your question about the C15 that would be application-dependent. What is it installed in.?
Thanks Nige. I will send the boys to the machine first thing tomorrow to check voltage. Would you happen to know what the resistance should be on the grid heater?
Any resistance is good, shouldn't be very many ohms, probably less than 15. If it is an O/L on the meter (open circuit) that is bad. They make a big difference in starting when the weather is what you are describing and the first thing to check and eliminate. From there it gets expensive like the heui pump and injectors and wiring harness under the valve cover that will make it start like you are describing. The performance of the heui pump can be checked with ET. If it has been run with extended oil drain intervals much it could be the problem but you should be good for a few thousand more hours before those things are an issue. Also like partsandservice says there could be other factors. I have seen a faulty temperature sending unit cause the same problem. It thought the motor was hot when it was cold so it wasn't kicking the grid heater on. I noticed the temperature on the monitor showing it was hot when it was cold, changed the sending unit and it fired right up. I have never seen a grid heater on a C-15, we have several in trucks of that vintage. But that doesn't mean they aren't out there
Thanks alot. What your saying makes sense. I had a DT466 International have hard starts and we had the injector pump rebuilt and it fires up almost as soon as you touch the key! I guess once we check the heater and fix or eliminate the problem I may have to look at the heui pump as a possibility.
After you check the grid heater for continuity and resistance, you might check the amount of time that it is on. I don't know what it's supposed to be but there was a lot of problems on skid steers for awhile where the grid heaters were only on for a few seconds. It wasn't enough time to get the proper amount of heated air to enable the engine to start.
The indicator light is on for at least 10 or 15 secs. I'm assuming in order to adjust that time you'd have to use the ET software.
I don't remember there being an adjustment at all. Most applications that I've seen those heaters on, the timing was around twenty to thirty seconds. Maybe someone here has access to specs for that.
Not sure about the timing either, I don't ever remember seeing a place on ET to set it, I guess I have never looked either. Does your machine have the override switch that you can manually control it like ours does? If so you can try use it for 20-30 second like John C says.
Here are the specs for the heater. One thing I would check is that apparently there is a ground strap between the heater and the engine block. find it and make sure that it is making a good contact at both ends. Based on what's listed below (and V/I=R) the resistance appears to be very low, about 0.25 ohm which doesn't sound right to me. But the 86A current draw is correct if the power output of the heater is 1.892Kw and the supply voltage is 22V DC. 22 VDC 86A ± 10% 1.892 kW
Here's something from the O&M Manual. Note that the requirement for the AIH to energize is determined by the ECM. What if the Intake Manifold Air Temperature or Coolant Temperature Sensors were reading wrong, or not reading at all..?
Here's something from the SysOp that suggests to me that the problem could well lie with the heater itself, or the relay, etc.. It appears as though if either of the critical sensor signals are open/short circuit the heater will activate by default. At least that's the way I'm interpreting it.
Nige First of all thank you very much for this. Wow that's great information. I'm assuming access to this material must be privileged and you obviously have and we're a highly skilled tech with Cat. Is there a fee to be able to access this portal if more info is needed? Upon reading this info I agreed that the white smoke would definitely be a good indication of a failed relay, heater, poor ground on strap, or possibly one or both the two sensors could be bad. I've already had to replace the hydraulic temp sensor with your help last year. The water temp sensor seems to work fine but I will also check the inlet air temp sensor. Very very helpful Nige. Thank you
I think you should contact to heymccall. IIRC he registered on a web site somewhere from which can get Cat information such as you're looking for. It may have been AVspare but I'll let him respond on that.
If I remember correctly, the "heater" indicator light will stay on the specified time whether or not the heater is working. If it's warm, then the indicator light will not come on. this was NOT on a D5, but I'd guess the function is the same, any glow plug or grid heater I've seen has only had the light come on when needed. 10-15 seconds should be plenty at 30 after a low of 20. I bet the battery voltage won't drop one bit, indicating the heater is not flowing current for whatever reason. If it's heating, but not long enough, just turn the key off and cycle it again. Don't get too far into the weeds until you try the simple stuff.
OK fellas. Did the diagnostics as you all suggested. Checked the voltage at the relay. Had 24v. Then we checked voltage on either side of the relay. Neither side of the relay had voltage with key on or off. Across the relay only voltage on the hot side. Nothing once key was turned on. Relay is definitely bad, ordered new relay from cat. Now checked the continuity of the wires that feed the relay. Didn't make sense that the feed wire had to come from either the starter or batter directly. Thanks to Nige I was able to use the schematic to find how the heater is fed. Hot wire comes from the starter. Problem was when we looked at the wires on the starter there was only 3 wires hooked up. According to the schematic there should be 4. I followed wire around back of the engine and sure enough the feed wire wasn't hooked up to the starter. So even if the relay was working properly which it wasn't, there was no voltage to feed the heater. To diagnose the heater itself I used a jumper from the starter to the heater cable that's on the open side of the relay. As soon as we powered up the heater and waited about 15sec and turned the key the motor fired up instantly! No white smoke whatsoever. Going back to machine tomorrow to install new relay. Thinking we got the problem resolved and I'll know for sure tomorrow. Just wanted to say how much I appreciate any and all you guys on here that reached out to help. It's amazing how generous people on this site can be. There is a few members on here that are known notoriously for their expert opinions. I am humbled and all I can hope is to learn and help another poster in need in the future! Thank you fellas very much. God bless.
One thing to be said - a new replacement relay will be a darn sight cheaper than a new air inlet heater...!!
And easier, those heaters can be a pain. I agree with what you said about the people on this forum and the help that has been given here on a regular basis. There is no other place like this on the internet.