Two years of intermittent hard starts, please help!

[DropTopKingM3]

ATB88 I had all the work done as I mentioned above and my car is still hesitating to start on the first try of a cold start. My friend Pat who did the work told me that a buddy of his tracked down the problem to a Vapor Leak Detection Pump. He wasn't getting any codes for it and when he replaced the unit it never happened again. Have you checked your evap system and lines? Maybe thats where we're losing pressure overnight?

[jet_dogg]

His problem is unique because it happens on warm starts. It's could possibly be vanos related due to what position the cams stop after shutting off the engine the first time,

I think most cold start issues are fuel related but I don't think it could be the ldp since I believe that almost always throws a code and is for emissions purposes anyway.

[ELEUTHERIOS]

Hello my friend ATB88 i read all your post and saw your videos. If you notice on the first video at 1:23 you put the key to position 2 before crank but i dont hear the fuel pump priming either the nedle of the gauge moving.Take a look and reply😀

[thegenius46m]

Here's a video of my cold startup problem. Ive had this issue for years now. So far I've replaced the fuel pump. I'm currently having the fuel filter, fuel pressure regulator, crank, and camshaft sensors replaced.

Try DMTL pump and vanos solenoid. Both of those when faulty will contribute to similar situations. Read this document on how the car carries out the leak detection test and then try to pay attention to every single start following and see if the issue starts to occur on the second startup when the criteria listed is met. If you do a lot of short trips that criteria can take multiple restarts to be met so what appears "random" isn't really random anymore. I think you have to drive for at least 15-20 minutes for it to count as a cycle.

[DropTopKingM3]

Try DMTL pump and vanos solenoid. Both of those when faulty will contribute to similar situations. Read this document on how the car carries out the leak detection test and then try to pay attention to every single start following and see if the issue starts to occur on the second startup when the criteria listed is met. If you do a lot of short trips that criteria can take multiple restarts to be met so what appears "random" isn't really random anymore. I think you have to drive for at least 15-20 minutes for it to count as a cycle.

Thank you for your contribution bro. I just had my vanos redone and I replaced the solenoid with one from Beisan. So I will go ahead and try the DMTL pump.

[thegenius46m]

Thank you for your contribution bro. I just had my vanos redone and I replaced the solenoid with one from Beisan. So I will go ahead and try the DMTL pump.

I wouldn't rule out vanos solenoid if dmtl doesnt fix the problem. Besian units are hit or miss. Went through 8 units before I bought a new one from the dealer.

[S54B32]

I’m very very sure that the dtml pump should not affect start up in any way. You can also unplug the purge valve, because when that fault code is present, ecu will not do leak test. Vanos solenoid should throw codes when the soldering points start to give up.

[M3_CJ]

My 2cents, currently having this intermittent hard start issue as well. I replaced my DTML pump due to fault code coming up and it did not solve my hard start.

[DropTopKingM3]

Ive already ordered the DTML pump so Im going to install that.. Im going to more than likely have my current injectors cleaned and tested and have new orings installed.

[jet_dogg]

Injectors always come with orings. I noticed people keep mentioning orings separately, was there instances where this wasn't the case?

I think I read somewhere here (maybe in this very thread) that clogged injectors were the cause of their hard starts.

[DropTopKingM3]

Injectors always come with orings. I noticed people keep mentioning orings separately, was there instances where this wasn't the case?

I think I read somewhere here (maybe in this very thread) that clogged injectors were the cause of their hard starts.

The cleaned injectors do come with orings. I’m just not sure what brand or type they come with. I’ve read posts where the hard starts were caused by injector orings as well.

[DropTopKingM3]

I reached out to a friend of a friend who’s a 25 year BMW dealership tech and showed him my video. This is what he said. I also attached a real oem diagram. I’m guessing it’s 15, 16, and 17. Cheap enough to try it out as the vacuum lines aren’t too expensive. I’m going to order the lines and replace them along with the DMTL pump which arrived today.

I started up my car tonight for the first time in about 2 weeks and it fired up on the first crank. This is puzzling lol.

[jet_dogg]

I reached out to a friend of a friend who’s a 25 year BMW dealership tech and showed him my video. This is what he said. I also attached a real oem diagram. I’m guessing it’s 15, 16, and 17. Cheap enough to try it out as the vacuum lines aren’t too expensive. I’m going to order the lines and replace them along with the DMTL pump which arrived today.

I started up my car tonight for the first time in about 2 weeks and it fired up on the first crank. This is puzzling lol.

This is funny, though I didn't have starting issues when I stopped driving the car these were on my list to replace regardless.

[DropTopKingM3]

This is funny, though I didn't have starting issues when I stopped driving the car these were on my list to replace regardless.

I agree. I figured since I'm doing a refresh anyway and the car is 20 years old they're probably very brittle and worn out. I may also do a smoke test once I'm done to see if theres anything else that needs addressing.

[jet_dogg]

I agree. I figured since I'm doing a refresh anyway and the car is 20 years old they're probably very brittle and worn out. I may also do a smoke test once I'm done to see if theres anything else that needs addressing.

That is never a bad idea. I've seen many rubber hoses deteriorate over the years.