Cold Start with Flooding
 

My turn for cold start issues... I got a '97 M-tech, M44 engine at the beginning of the summer, and it's been great to me. But since it's been dropping below freezing at night, my first start of the day is near impossible. It cranks fine, but seems to flood itself and just doesn't start. After letting it air out for 15 minutes, it manages to start, but with a lot to difficulty. The idle is LUMPY for about a minute, but will smooth out and run just fine. If there's any residual heat left, I can start it up easily for the rest of the day.

My Peake scanner only shows random misfires or a misfire on #3. I replaced the coil pack, wires, spark plugs, so ignition shouldn't be an issue. The battery is fine. Hoses are in good condition, and the intake boot from the MAF to the ASC throttle body has no cracks. The MAF is brand new. I am able to borrow parts from my other ti, a '98, which starts just fine.

Flooding on cold start, no helpful codes, runs fine when warm... Any suggestions?

what oil are you running?

It has been suggested to use a 5w-40 fully synthetic oil, which can sometimes sort the issues.

Otherwise, possible vaccum leaks under the intake manifold? CCV?

Could you possibly have a faulty injector that's flooding that cylinder?

Update
 

Thanks for your replies.

I'm using 5W-30 conventional oil. Castrol High Mileage, I think. On a student's budget, I'm not ready to make the jump up to synthetic. :wink:

No vacuum leaks, and all of the hoses are in good shape. I'm guessing that one or more of the injectors is dying, and the problem is worst when the air is below freezing for extended periods of time. The injector(s) must drain into the cylinders overnight, and when it's time to start, the DME sends an additional shot of fuel and wets the plugs. Still no codes, even with the rough start.

With 198,000+ miles on what looks like original injectors, I'll just replace them all. It looks like I'll have to take the upper intake manifold off, so I'll need a new upper gasket. Has anyone done this job before?

It's really easy to pop the upper half of the manifold off. There's a write-up on here somewhere. The fuel rail's really easy to remove as well. If you want to save some money you might consider sending the injectors to be cleaned and tested. It's about the same price to do that for four injectors as it is to buy one new one. I recently sent mine to Marren Injection, but a lot of folks use RC Engineering or WitchHunter as well. Whatever course you pursue just make sure you have new upper and lower o-rings for the injectors when you put them back in.

+1

And don't try to clean the injectors yourself. There's places that specialize in injector cleaning. Those things are calibrated and flow tested to match as a set. If you screw one up or replace just one, there's a good chance your car will never run right.

Thanks again for your responses. I just went ahead and ordered a set of remanufactured injectors from Pelican Parts, along with o-rings and a new upper intake manifold gasket. I just want my ti to run right in the cold, and I'll get some money back on the cores. NJ just got a good amount of snow, so this needs to be fixed soon.

I suspect that this is the reason the previous owner sold the car... At any rate, it should be fixed soon!

I agree there's places that specialize in injector cleaning.

An update:

I pulled the fuel injectors on Saturday, and I replaced them with rebuilt ones from GB Remanufacturing (through Pelican Parts). The old injectors were dirty! Unfortunately, it starts rich and lumpy for the first minute, and then it idles and runs fine.

So I've replaced the plugs, ignition coil, injectors, mass air sensor, air temp sensor (in the air box), and the pre-cat O2 sensor. Intake boots and vacuum lines all look good. No codes, except for the occasional random misfire.

It's certainly an issue with fuel delivery, but I'm running out of things that could possibly be broken, and funds to replace them. Any ideas? What about the fuel pressure regulator?

Are you getting any lights or codes? The remaining things to check could be the camshaft position sensor or crank position sensor. The cam sensor can be on it's way out for quite awhile before it dies completely so you might start there. I'm not sure if there's a test procedure for it or not. You'd have to check the Bentley manual. BTW, the sensor in the airbox is not the coolant temp sensor. That's the intake air temp sensor. The coolant temp sensor is on the side of the head underneath the intake manifold.

^ +1, CKS/CPS would be the next logical step. I'd bet on the CPS out of either of them.

Thanks again for your replies.

My mistake, the sensor in the air box measures AIR temperature.:rolleyes: (It's been edited) I feel like I've replaced or checked so many components, it's tough to keep track... But the coolant temp sensor appears to be fine, too.

Wouldn't a faulty CKS or CPS cause the car to run badly all the time? I'm not getting codes for the CKS or CPS, and the ti runs perfectly after the first minute or so. After the lumpy start gets smooth, it idles fine and runs fine.

There aren't any major cracks in any of the intake boots, and I carefully did the starting fluid test. No revving up, and I still have my eyebrows.

To recap:

Starts rich when cold, sometimes wets the plugs.
Replaced MAF, injectors, plugs, wires, coil pack, air temp sensor, upper intake gaskets, pre-cat O2 sensor.
No codes on CKS, CPS, idle air control, MAF, secondary air pump, fuel trim, O2 sensor(s).
Boots and hoses look good.

My last cam position sensor would occasionally throw a code for several months before I got around to replacing. Each time I reset the code and it stayed off for weeks to months. Other than the normal less-than-buttery-smooth idle of the car it didn't seem to affect the performance of the engine. My understanding is that the crank position sensor plays some part in activating the fuel pump, but my only experience with that was a bad sensor causing the pump to not activate. It sounds like you might have the opposite problem. My cold-start problem (difficulty starting and then feeling like it wasn't running on all cylinders) was completely resolved after replacing the injector vacuum lines, the cam sensor, and having the injectors cleaned. So, at this point I'm pretty much out of ideas. Keep us posted.

I've since headed back to school in PA with the new injectors, a new secondary intake boot (from the throttle body to the intake), and a new hose that runs from the boot to the injectors. Even with that nasty ice storm we had, the ti more willingly starts up. Still not super smooth on startup, but it still starts up every time it want it to. It's way better than it was, and there's no codes yet. At 25 °F, I'm sure most cars with 197,000+ miles would be tough to start. The crank position sensor never threw a code for me, and the problem isn't/wasn't that I'm not getting fuel, just too much fuel at start up. I'll keep you guys posted in a week or so. Now to get my CCFL angel eyes to behave in the cold... :rolleyes:

souders any update? i'm having the same issue.
thanks!