Hard starts - worse the longer it sits

[Mike1261]

This issue has existed since we bought the car 2 years ago:

First start of the morning is rough and idle RPM can't come up on it's own. A blip of the throttle clears the issue and the rest of the day (even if I stop and start it later on) is fine and starts right up immediately even if the engine is let to cool.

If I leave it for a couple weeks between starts, it takes some extra cranking and is even more stumbly, but it clears itself and everything is good again.

We just had the car parked for 3 months. To make sure the cylinders didn't fill with any kind of fluid over 3 months I popped the spark plugs out and cranked it to clear out the cylinders. Nothing came out.

Then when I went to actually start it, it took several minutes of cranking attempts to get it to come alive.

During the cranking, it didn't seem to be sparking at all. The engine was just turning, and I thought maybe the ignition system was F'd. But eventually it started to try and fire, but couldn't quite catch. And then finally after another minute or so of "almost" starting, voila it started and we had lots of blueish smoke and some whiteish smoke.

My #6 cylinder is slightly low on compression, and a while back my #6 plug was so fouled that the car was rendered immobile. All the plugs look good right now though and have a good 5K+ miles on them.

The white smoke and lack of spark made me wonder if perhaps I had a head gasket leak and the pressurized cooling system was pushing coolant into the cylinder.

I relieved all the pressure from the cooling system one night, started it to clear the cylinders, then left it overnight. In the morning the car started right up. But knowing it could be fluke, I repeated the same thing 2 nights ago, just started it up, and it was back to hard starting/needing a throttle blip to bring the RPM to a stable idle.

I was hoping it would crank right up and I could go buy some Bar's Head Gasket Repair to throw into the radiator and fix the issue. But I'm not sure that that's my issue at this point as the system wasn't pressurized so probably not able to push much coolant into the cylinder.

I don't know if it's leaky valve stem seals and oil is getting into the cylinders, or leaky injectors flooding the cylinders, or something else entirely. I haven't completely ruled out head gasket coolant leak, but I don't seem to have the other telltale signs that go along with it. No bubbles in the radiator, no loss of coolant, no overheating, no sludge in the engine oil etc.

All I know is a simple fact: The longer it sits the worse it starts, and when it sat for months it didn't even try to fire the cylinders until it "cleared" whatever was in the cylinders causing it to not fire.

What am I missing??

[crystalworks]

Is your fuel pump original?

[Mike1261]

Originally Posted by crystalworks

Is your fuel pump original?

I'd be shocked if it wasn't! Is that something that makes startup progressively worse the longer the car sits?

If there's insufficient fuel on initial startup I suppose that could explain the inability to bring itself up in idle. And perhaps a weak pump would take a while to build pressure if the lines are drained from sitting?

[crystalworks]

^ That, coupled with lower voltage supply on a battery that had been sitting. Might take the pump a minute to really start pushing. You're at a mileage where the pump is likely to start giving you problems as well.

[Mike1261]

Originally Posted by crystalworks

^ That, coupled with lower voltage supply on a battery that had been sitting. Might take the pump a minute to really start pushing. You're at a mileage where the pump is likely to start giving you problems as well.

The battery was brand new as the (less than 2 year old) AGM H8 battery was 100% dead after sitting 3 months. The battery charger said "No Battery Connected" and a multimeter confirmed an internal disconnect inside the battery. Go figure! Bought the battery in Canada so can't even get a replacement under warranty haha.

Is there a port I can connect a fuel pressure tester to on these cars? I have a test gauge kicking around somewhere.

[crystalworks]

There should be a Schrader valve at the front or on top of the fuel rail.

A weak pump might not really start giving enough fuel pressure at starting voltage, but gets going enough at 13.5+v after running voltage.

Just a theory though, you're right to do diagnostics. I'm the type who enjoys using the parts cannon method of elimination. Especially on original parts.

[andrewwynn]

My wife's car has been having similar symptoms. I replaced the 185,000 mile fuel pump no change. Checking the pressure it wasn't perfect so I'm thinking it's the FPR. Once it gets over the initial hard start it's fine. After sitting about 6-8 weeks took at least 8-10 cranks at least 8-10 seconds each.

The main candidates are crank sensor and FPR.

Money has been stupid tight with me getting half hours and wife's getting zero hours since mid March due to cv19 so I have not been able to order the parts yet though I did start it after a week of resting and it started after a long single crank.

I left the pressure gauge on and it did drop to 40 psi almost immediately and did not seem to hold add it's supposed to so primary culprit is FPR .

[crystalworks]

Yep. As I said I'm a parts cannon guy, so I'd do fuel pump, filter, and FPR all at the same time. Would leave injectors alone though.

[andrewwynn]

Filter and FPR come in one piece and depending on age fuel pump good for about 5000 hours. If you are close to that it's worth replacing.

I got burned buying a premium pump that was DOA and with how stupid easy (3/10 difficulty) to replace pump I just bought an Amazon cheapo pump for like $75 that has a 1 yr warranty. I did have to replace one once under warranty but I just sent a pic of the serial number and they sent me a replacement right away.

[Mike1261]

I'm thinking it's most likely fuel pump and a faulty check valve from what I'm reading.

I'm struggling to find information on where the FPR is located on these cars. Some resources suggest it's built into the filter, and others show it requires removal of the fuel rail to access and resembles a GM/Ford style thermostat in shape. Kinda.

Where is it?? lol.

I'm quite excited at the prospect of finally fixing this issue. I suspect it's also the reason for the random stalling the car used to have (not so much lately) that occured when driving very slowly (like gas station speed) after driving for hours on a highway. And apparently it can also be responsible for the occasional smell of gas.