E46 330ci Hard Starting Problem

[1rft2]

Hard Starting [sometimes] Does anyone have any experience with correcting a recent hard start problem with a E46 330ci. Cold OK, but hot long crank to start, [symptom - it seems rich] then it clears and runs OK. I can help the start by applying some throttle. Also in some idle manouvers, like parking it wants to hunt for correct idle. I'm thinking idle air control solenoid could be sticking or coked up. Any advise. Regards Bob

[Eugene]

Originally Posted by 1rft2 Hard Starting [sometimes] Does anyone have any experience with correcting a recent hard start problem with a E46 330ci. Cold OK, but hot long crank to start, [symptom - it seems rich] then it clears and runs OK. I can help the start by applying some throttle. Also in some idle manouvers, like parking it wants to hunt for correct idle. I'm thinking idle air control solenoid could be sticking or coked up. Any advise. Regards Bob

First thing that comes to mind is that your engine isn't holding fuel pressure via a leak in the system; 1) by leaking/sticking fuel injectors, thus flooding your engine after shut off and making it harder to re-start. This would explain why holding open the throttle helps it to fire up faster + the hunting idle as the engine is trying to determine stoich 2) would be that the check valve in the fuel pump isn't holding pressure which would make it hard to start but probably unlikely.

Try running some Seafoam or 2 through the fuel system + intake to see if it dissolves any deposits in the system, mainly the injectors which might hold them open. If that doesn't help I would hook up a fuel pressure guage, shut the engine off, then see if it holds pressure after time. If it doesn't, pull the spark plugs to see which of them is covered in fuel, and you found your leaky injector.

[1rft2]

Thanks Eugene. Recently I have done some preventative maintenance recently, as I bought this car with over 100K miles on it, like removing the injectors for cleaning, and installing new spark plugs, along with a new air filter. Yes you could be right as I recall this problem wasn't present before I had the injectors cleaned. I'll get a fuel pressure gauge and start with a bleed down check. Regards Bob

[Eugene]

Originally Posted by 1rft2 Thanks Eugene. Recently I have done some preventative maintenance recently, as I bought this car with over 100K miles on it, like removing the injectors for cleaning, and installing new spark plugs, along with a new air filter. Yes you could be right as I recall this problem wasn't present before I had the injectors cleaned. I'll get a fuel pressure gauge and start with a bleed down check. Regards Bob

Keep us updated and let us know how it goes.

[1rft2]

Hi Eugene. Since I read your note I've done two things : a] I removed the fuel rail leaving fuel lines attached but with the electrical harness removed and laid it on top of the engine. Then I cycled the key on/off several times 2 hours apart to prime the fuel system - no leaks on any injector. b] then I put it all back together and got the engine hot installed a fuel pressure gauge and again cycled the key on/off to prime the fuel system. Pressure drop after 2 hours 55psi down to 40psi. I did this twice then tried to start car. Engine exibited problem so I shut it off quickly and pulled the plugs. Insulator on #1&2 seemed a little darker but none of the plugs were wet. Put it all back together and have only tried it twice since, no problem each time. Time will tell.
Regards, Bob

[1rft2]

Hi Eugene, are you still monitoring my concern. Anyway the car seemed fine for a few starts after I found some SeaFoam and ran a can thought the car while on a recent 1,000 mile trip. Lately the problem seems to still be there. I can live with it, but I was considering pulling the throttle body off and checking it for coking around the throttle plate, and freeness of the shaft bearings. Though once running the throttle response seems fine. Idle hunting during parking maneuvers is still anoying.

Regards, Bob

[Godwin]

Take it to a BMW specialized shop that is equipped with the GT1 device.. It plugs into your ODB2 port and go around for a drive with your service advisor.. The GT1 has a logging function and it will be able to tell you what was going on when there is the idle hunting issue etc.

[Jono-vision]

My experience with a hunting idle has been vacuum leaks have you checked ALL your vacuum hoses yet?

[1rft2]

Godwin Thanks for your guidance, but I think I have my problem diagnosed. Last night after supper I decided to take the throttle body off for an inspection, and in the process I discovered that there is a branch [30mm dia.] off the top of the main air inlet duct, where it attaches to the throttle body, that has a bellows section and in it there were several cracks with openings [2mm x 15mm] in the root section, age deterioration. I plugged them with some silicone sealer, checked today and the sealer has adhered securely so I'm going for a ride shortly and see if that is the root cause. Allowing extra air to enter the system without passing through the mass air flow sensor could upset the ECM etc. especially the idle hunting when parking, over compensation. Regards, Bob

[1rft2]

Jono-vision
You may be right on. While I was replying to Godwin, I now see your post. Yes I did discover some vacuum leaks, plugged them temporarily with silicone sealer, as noted in my earlier post, and the test will be conducted shortly.
Regards, Bob

[Jono-vision]

Coolio! hope you git er dun!

[1rft2]

Jono-vision The test with sealer fixed the problem, so I went and purchased a new air duct piece [$25] and installed it. Cured all my concerns. Thanks for your tip !

[axel]

how can i replace this airduct that you said caused all the problem with the hard start? is there a diy for e46 (with photos)?

[1rft2]

Don't have pictures BUT, take extra time after you remove the air cleaner box to remove the divider around the power brake unit, then take off the inlet manifold diverter valve [black box above throttle body]. This will give you access to the two [2] gear clamps holding on the inlet duct. Have fun.