Low idle/ dogging at cold start.

Can somebody explain why the MAF controls anything when the car is running cold? I thought those electronics come into play once the car is running in open loop when the thermostat opens.

When was the last time you did an oil change? Did they use the right grade? My oil pressure gauge registers within a second, it seems kind of long for the pump to be priming. I would question the check valve in your purflux filter as well.

 

I plan on buying some MAF cleaner tomorrow...so I just give a few blasts on that thin white sensor within the housing? Seems pretty simple.

ALSO: I am also considering changing the fuel I use (Exxon to Sunoco) and maybe adding an injector cleaner. Does anyone have a suggestion for an injector cleaner that is safe for the car and will not make my fuel system explode? Thanks...I have heard a few suggestions on brands before but would like to use one that is certain not to do any damage to the car whatsoever

 

the oil was last changed about a year ago or five thousand miles ago. I have to periodically top it off because I have an oil leak from the main oil line. I use the correct 5w30 Pennzoil with the Ferrari logo on the bottle. I plan on doing a full oil change within the next couple of weeks. Where is this check valve you speak of? I would love to check that out

 

Its built into your oil filter, was that replaced a few months ago as well?Check it and be sure Date codes are on the top of filter.

 

can I take the oil filter off when the car is cold? Or will oil spill everywhere? If I do get it off can I access that check valve?

 

I use Shell 93 in all my cars. I drank the kool aid.

On additives SoCal has recommended a double dose of BG44K added to a 3/4 full tank (additive first then gas) but that is not really available retail.

Techron concentrate plus is another good one and is rebranded and sold through dealers like BMW and MB. You can try doubling up on that one.

The advice given by SoCal is to be prepared to burn off the whole (3/4) tankfull right after adding the cleaner for maximum benefit. You've got to really work the engine, redline pulls, and prolonged running at high RPM.

Change the oil. 5,000 miles is my personal limit on my "normal" cars.

DaveRocks has a great step by step write up you can use.

Notwithstanding oil filter problems, I'd do the italian tune up first and change the oil after.

 

CORRECTION: my oil is 5W/ 40, not 30.

 

I cleaned the MAF and took out the idle control valve for a quick inspection. Haven't started the car since, but I am sure it will dog as usual.

Here is a question for the forum:

Can 5W/ 40 oil be so thick at cold temperatures that it causes the engine to dog when I reach full oil pressure?

A more important question since I doubt that oil viscosity in 40 degree weather is the real issue. None of my other cars do this:

SO: WHAT POTENTIAL ISSUES can make the car dog at cold start GIVEN THAT IT TAKES 2.5 -3 seconds for the oil pressure gauge to move, and when it does, this is exactly when the dogging STARTS.

Bad oil sender unit?
Bad check valve in the oil filter?
A clog in an oil line?
A seal bent or broken in an oil line?
Old oil? 4800 miles, getting changed as soon as my filter arrives via UPS.
Oil too thick at 40 degrees? No, it took 3 seconds in the summer too, it just didn't dog.

What do you think?

 

Iac issue or coolant temp sensor issue (there are two,one for the gauge and one for the Motronic) or maf/iat sensor issue. Those would be my guesses. Bad or leaky fuel injectors would make it difficult to start or generate a misfire on one or two cylinders, not affect the whole motor after it had already been running ok. Could also be something killing a cylinder bank (limp mode) when cold like the cat ecu's.

Now that I think of it, that's similar behavior to when one of my cat ecu's crapped out, it'd start fine but then 5 or so seconds later I'd lose the right bank of cylinders. It wouldn't clear up if I revved the motor, though. No warning lights or anything. I unplugged the cat ecu and no more issue, but now I have constant slow down light.

 

I had SDL often when I first bought it 1 year ago, but my SDL has gone away, more or less. It flickered once in the summer, and that was it. Haven't seen it since. I have a 1448 bypass valve code, and not sure why. The valve sounds like it is fully functional. The code pops up after an ECU reset, but I just clear it with my OBD code reader and it doesn't come back. I used to get a cat temp code too, but that seems to have gone away as well.

 

I was getting no sdl when the bank would shut off, the flickering and then no light would seem to point to a cat ecu issue. Unplug it (it's easy) and see what happens.

 

Maf is used when cold. Open/closed loop is in reference to oxygen sensor feedback.

 

I had an idea. I'm out of my depth on this issue in general so forgive me if its a dumb one.

What if you tried cranking the motor with the fuel/spark cut (so it wont start) so as to build up the oil pressure prior to actual start.

Then quickly reconnect everything and start. If it truly has something to do with oil pressure than the dogging should start immediately. That's my theory anyway.

 

Great idea badabing . he should not depress the fob immobilizer and attempt a start to build oil pressure.

 

Thanks guys, good ideas. I'm going to try and prime the oil pump first by not disarming the immobilizer. Its a 1997 5.2 so I'm not sure if it'll work but I'm going to give it a shot. if that doesn't work I'm going to try to unplug the cat ECU. Is that the one that's on the right hand side all the way in the back close to the ground or is it the one that's on the left side at the top of the engine bay and is visible?

 

Brian- When mine starts doing that, I dump in a couple of containers of Techron and it works wonders. 6 container case is only $25 on Amazon. Injector bleed-down, who knows? When a double start works perfectly, like yours does, the Techron helps or cures the problem.

 

Thanks brother. I'm going to order some of that. A double restart used to solve the problem but now I have had to do as many as four restarts to solve it!!! The fact that the problem is getting progressively worse and is basically constant at every cold start tells me something but I'm not sure what. What does it tell you guys? I'm going to go read up on Techron and injector bleed down.

 

I was thinking about this a bit: What I do every time I start is turn the key forward until things turn on....I wait about 6-7 seconds and then start the car. When I do this, I see the oil pressure move up a little bit, but I still have the same problem with the dogging when the oil pressure FINALLY kicks in 3-4 full seconds AFTER the motor is running.

2 Question: Would it make a difference if I tried to turn the key with the car still immobilized (not hitting the button on the fob) VS just turning the key forward, waiting and THEN starting? Is this the same thing? I don't want to try this yet since I cannot drive the car due to salt and 6 inches of snow at the garage door.

2nd question: Is my car being damaged because the oil doesnt pressurize for 3-4 seconds? As if to say...am I basically shredding my cylinders because of delayed oil pressure? This worries me.

Thanks guys...all feedback is welcome and appreciated. This is my dream car, and this is an awesome forum. I have learned TONS from your help. I want to keep this car for a long time...so solving these bugs is uber important!