STILL having cold start issues....fuel pump?

[tsi1991awd]

Alright this has been an ongoing problem for the past month or so. Its been cold out in the mornings before I go to work (leave at 6am)....it usually takes 4-5 tries before the car will start. For the past couple of days its taken longer. Then this morning I thought that it would never start. It took literally 5 minutes of trying to get it to start. Every once in a while it acted like it was going to start but it never did.

When it finally did start, it idled as normal when it warms up (2000rpm) and then fell to 1500 like it was dieing....and then died altogether. I started again and it fired right up. I held the throttle at 3000rpm for about 10 seconds and then it idled at 2000 and slowly went down as the car warmed up (as normal)

I made a post about this a while back and everyone said it was the CTS. So I changed the CTS and it still has this problem. I changed the fuel filter, and it helped for a couple days and then started doing the same old thing.

There are no fuel leaks...I've let the car idle for 30 minutes and monitored it and not a single drop of fuel anywhere.

I'm thinking it may be the fuel pump, but I'm not sure. As I said, this is on a cold start, after sitting for about 8 hours. I have a hard time starting in the morning before work and after I get off of work. Usually it is a bit warmer after work so it starts a little easier...but it also does not sit for as long. Most of the time my car is sitting for about 12 hours, but its only 8 hours when I'm at work.

I'm not sure what the deal is...when I try and start it, it sounds exactly like if I pulled the fuel pump plug. It doesn't fire up, just keeps trying. That's what makes me think its a fuel delivery issue.
I read on a VFAQ for FPR install that there is a fuel pump check right by the battery...you put alligator clips on the wire and put it to the battery and the fuel pump comes on and pressurizes the fuel system. Can I do this and then fire the car up? If it fires on the first try, I think I found the culprit.....BUT, still, why would only cold starts effect it like that?

 

[tsi1991awd]

OK, so I just went out and put the ignition to ON and then tried to hear the fuel pump whirring and didn't hear anything...so I went to the battery and used the fuel pump check connector.

I went around to the back and heard the fuel pump. I also heard a hissing noise coming from the engine bay. I listened good and it is coming from the fuel injector area. I don't know if it is only one of them or all of them. There is no fuel leaking, but I know this is a big boost leak. I can hear the hissing all the way from the side of the car.

Now it all makes sense....since it has a leak, the fuel system is losing pressure. HENCE why it is always hard to start when the car has been sitting for 8+ hours. It's not a COLD START issue, per se, but it is an issue when the car has been sitting a while.

When I did the fuel pump check, the car started up with NO PROBLEMS, on the first try. I am almost 100% certain this was due to the fuel pump pressurizing the system. Now for my next question....what do I need to do for the seals?

 

[thebird_19]

Get new ones. Or if you can afford it, upgrade the injectors all together.

 

[tsi1991awd]

I just picked up a set from the dealer. $9...was thinking of going to HD for some grommets, but decided not to half ass it. I have read some people experienced leaks after a few days and some people have not....don't want to risk it.

Can't believe it was $9 for some hot wheel tires though

Can't upgrade the injectors at the moment....but oh well. When I install the new lower seals, should I put them in the head first, or on the injector first?

 

[markmakeitso]

When you put the key in to start do you immediately turn to crank? The fuel pump should prime the system, then hold pressure until you start the engine. Try turning the key to on and waiting a couple seconds to listen for the pump priming. The hissing might be an injector slowly leaking fuel into the engine, which would explain the leakdown and also why you don't see any fuel leaking.

What is your fuel pressure with the engine running? A bad diaphragm in the FPR may cause similar problems, and that should show up during engine operation too.

Long shot here, but the caps in your ECU could be bad, which sometimes causes problems with the fuel pump relay activating. 1000Q should have good info on the caps, I've seen the packs on the 'bay, or some joker around here used to SASE them out.

I find it easier to put the lower seals in the intake first then gently line up each injector. Make sure you don't pinch off any of the top O-rings, those are actually the tricky buggers.

 

[tsi1991awd]

The fuel pump comes on for a second when I turn the key to ON. I replaced the injector insulators, then did the fuel pump check again. I still hear a slight hissing noise. I'm wondering if that is due to the fuel moving around in the rail or what??

I checked for leaks at the FPR and fuel inlet hose, and there are none. Checked for leaks at the injectors, and none.

Not sure what's up....only time will tell if this cured my hard cold start issue. Either way, the insulators I pulled out were hard as a damn rock, so they needed to be replaced anyways.