Long crank starting issue

[Renos]

Okay so ran a few more tests on it again.

blue62, I did run it again with obd2 and paid attention to more of the features. I already had as much info as I could up to get benchmarks.
So the temp gauge works for coolant on both obd and the dash gauges. Air temp sensor seems to work too. In 98 to 103 degree weather air temp was saying 130 in intake. Kinda high I think. Stock air filter.

I also wouldn't say it is a cold start issue. More like a hot issue. Cold starts often have the best start for us, it's the ones where we go eat somewhere or in a store and come back is when it struggles.

thstone, we disconnected the maf and seemed to have no change. A pain to start again after clearing codes and nothing better after that.

I have noticed the fuel trims at idle vary between +5 and -8 or -10. At cruise it settles out mostly around 7 to 10 positive. After the spark plug change I gained my performance back mostly. Not much hesitation but when I gas it, it pegs out at 25 lean side.

However I finished changing the driver side plugs. Middle tube, number 3 I think, had oil in the tube. A good bit. Enough it saturated the plug and coil even at connection point. Cleaned them up really good with electric cleaner spray and rags. Put new plug in and promptly ordered a new oem tube with seals just in case the tube is bad.
Engine was cold when I finished and car fired up right away with 2 turn overs, sputtered for a minute about 150 rpm lower till settling back up with the new plugs. Fired it up a few times after it warmed up to 145 degrees and again near 180. It didn't last long...but I noticed something.

When the car struggles to start, and finally fires, all the lights are off on gauge except our top issue, and cel. But the battery light comes back on and cuts off after a second or two.
So I curiously when get it tested as quickly as I could. Battery tested at 12.7 volts and 100% charge and healthy. For some reason I got the car with an h8 battery. Yeah.

So I has alternator tested after. Volts were at 13.8 volts or so and the "alternator tested good however the voltage regulator is failing."
Now I am not being ignorant of getting my fuel pressure tests going but given I go back to work today for a month i havent had the ability to schedule some involving tests like that at any shop... but this brings me to a question again.
How, if at all possible, could the voltage regulator affect the performance of the car with these starting problems?

And how is it the regulator is listed as failing when I have no real symptoms of it? Unless this starting issue is one of them.

[blue62]

Sorry I was thinking you had a cold start problem.
Every aspect of modern day engine operation and management is via electrical signal. You on your 2002 Boxster and I on my 2000 S don't give the engine fuel or even air. We just push a pedal that is connected to a potentiometer and the ECU does everything else.
So yes a failing voltage regulator could be the root of your problem. or at least a contributing factor.

So I would replace the voltage regulator first as it is a known problem.

If you still have issues.

I would still do a vacuum test with a proper vacuum gauge as that simple test can give you a lot of info on general engine condition. Vacuum leaks can cause a lot of tail chasing.

Also when you replaced you plugs did you check the condition of the coils??? No cracks??

Then:
I would do a fuel pressure and volume test next.

If you have disconnected your battery for any reason you need to recalibrate your throttle. (gas pedal).
If I remember correctly you reconnect the battery.
Turn the key on for 1 full minute ( do not start engine: do not touch the gas pedal).
Turn the key off for at least 10 seconds then start the car and let the computer re-adapt.

[Renos]

Originally Posted by blue62

Sorry I was thinking you had a cold start problem.
Every aspect of modern day engine operation and management is via electrical signal. You on your 2002 Boxster and I on my 2000 S don't give the engine fuel or even air. We just push a pedal that is connected to a potentiometer and the ECU does everything else.
So yes a failing voltage regulator could be the root of your problem. or at least a contributing factor.

So I would replace the voltage regulator first as it is a known problem.

If you still have issues.

I would still do a vacuum test with a proper vacuum gauge as that simple test can give you a lot of info on general engine condition. Vacuum leaks can cause a lot of tail chasing.

Also when you replaced you plugs did you check the condition of the coils??? No cracks??

Then:
I would do a fuel pressure and volume test next.

If you have disconnected your battery for any reason you need to recalibrate your throttle. (gas pedal).
If I remember correctly you reconnect the battery.
Turn the key on for 1 full minute ( do not start engine: do not touch the gas pedal).
Turn the key off for at least 10 seconds then start the car and let the computer re-adapt.

Coil packs look brand new. In fact I noticed they are the updated coils with the thicker mounting holes and longer bolts.

I have a fuel pump coming in and the tube I mentioned had a leak, as well as the voltage regulator. I am still curious about the condition of my aos given I had some oil in the intake but didnt seem like much.
I could go ahead and try for another maf while at it. I will try to have the wife get these tests done given I can't do a thing for a month.

I did replace a fuel cap because of cracked seal and I guess it got my emission leak out but I still also worry about that fuel smell. I wonder if I have a combination of problems going on. Maybe the regeneration valve is failing or crank position sensor. Very confusion with this issue.

All I know is car running lean under acceleration and the crank issue is a major concern. I also noticed since we got the car that I have rpm hunt / bouncing in 4th and 5th gear from 1400 to 2200 rpm. Pretty often too. I would say every second or maybe 1.5 times a second. It jumps up maybe 100 rpm and back. Dunno if this is another contributing symptom but as easy as this car is to work on, it sure is complicated compared to my 2008 mazda mx5.

[blue62]

Originally Posted by Renos

Coil packs look brand new. In fact I noticed they are the updated coils with the thicker mounting holes and longer bolts.

I have a fuel pump coming in and the tube I mentioned had a leak, as well as the voltage regulator. I am still curious about the condition of my aos given I had some oil in the intake but didnt seem like much.
I could go ahead and try for another maf while at it. I will try to have the wife get these tests done given I can't do a thing for a month.

I did replace a fuel cap because of cracked seal and I guess it got my emission leak out but I still also worry about that fuel smell. I wonder if I have a combination of problems going on. Maybe the regeneration valve is failing or crank position sensor. Very confusion with this issue.

All I know is car running lean under acceleration and the crank issue is a major concern. I also noticed since we got the car that I have rpm hunt / bouncing in 4th and 5th gear from 1400 to 2200 rpm. Pretty often too. I would say every second or maybe 1.5 times a second. It jumps up maybe 100 rpm and back. Dunno if this is another contributing symptom but as easy as this car is to work on, it sure is complicated compared to my 2008 mazda mx5.

Yes you could have multiple problems going on. Things like lean under acceleration, RPM hunt, point to a vacuum leak. that would be my first place to look. second would be a lazy (slow) signal from the primary O2 sensors.


My method of diagnosing problems is to start with the simplest most basic things first, proof them out as positive (with no doubts) then move to the next thing on the complexity ladder.
Problems like yours always start by just looking in the engine bay with a flashlight for about a half an hour not even touching anything just looking for things out of place.
Like wiring that could be rubbing against metal or a cracked vacuum hose or?????

Second thing I do is a vacuum test it can tell you a lot if you know what your looking at with the reading and how the needle is acting.
Depending on what my vacuum test tells me that dictates my next step. I don't replace things like MAF sensors or any cam sensors or any sensor unless I know it is faulty. (It could be just faulty wiring attached to it). if there is faulty wiring most wiring problems are due to bad grounds.
So a long winded way of saying simplest things first go step by step up the ladder simplest to most complex.
Most problems are not very far up the ladder.

[Renos]

Well the fuel pump came in and my wife got help putting it in. She didn't do any tests or anything else I asked but she got the pump in and now her issues seem gone. Fuel trim running slightly rich from what I saw and she has one CEL up that is P0430, saying a catalytic converter is failing I assume.

So one headache down, another one to go.

Thank you guys very much for the help and advice. I would have done it myself if home and able but sadly work requires me away for a month at a time.