I think I have a leaking injector, but not sure.

[willfill]

For a little while now my car has been hard to start, taking up to 20 cranks of the engine to get going, and eventually stopped starting at all. I replaced the fuel pump relay a few days ago which fixed the starting problem and now the car starts fairly quickly.

However when the car starts, if it hasn't been started in a while, it runs really rough for a few seconds, and then dies. It will do this a few times, and sometimes I need to rev it to around 1500-2000 rpm for a few seconds to get it going, and after that runs fine. If I turn it off after it has been running for a while, and then immediately back on, it will start and run fine.

I'm thinking that it is a leaking injector, and what is happening is that when I turn the car off, there is pressurized fuel in the fuel line, and as I let the car sit, the fuel slowly leaks into the cylinder, causing the rough starts. The reason the roughness goes away after me revving the engine is because I have burned off all of this excess gas, and the cylinder is clear. This would also make sense as to why it doesn't happen when I start the car immediately after shutting it off, as the fuel hasn't had time to leak into the cylinder.

So I'm planning on buying some of the 17# M50 injectors tonight, but I just wanted to make sure that this is the most likely cause of this problem, is there anything else that this could be?

[Insanerhetoric]

Does is smoke at all after a cold start? If it's a stock b25 those 17# might be a bit of overkill if you're not chipped. The stock injectors are only 14# I believe. Pull your plugs and try to look down into the cylinder chamber. If you see one cylinder that is cleaner looking than the others, more than likely that injector is leaking.

[jlevie]

Let the car sit, then pull the plugs and watch while someone cranks the engine. If you have a leaking injector fuel will spray out. The other test would be to pull the inectors and rail and jumper the fuel pump relay to pressurize the system. A leaking injector will drip.

What you describe could be a leaking injector or something else, like intake leaks. Do the necessary diagnostics before replacing any parts.

[willfill]

Does is smoke at all after a cold start? If it's a stock b25 those 17# might be a bit of overkill if you're not chipped. The stock injectors are only 14# I believe. Pull your plugs and try to look down into the cylinder chamber. If you see one cylinder that is cleaner looking than the others, more than likely that injector is leaking.

I haven't noticed any smoke, but I'll check next time I start it.

[willfill]

Let the car sit, then pull the plugs and watch while someone cranks the engine. If you have a leaking injector fuel will spray out. The other test would be to pull the inectors and rail and jumper the fuel pump relay to pressurize the system. A leaking injector will drip.

What you describe could be a leaking injector or something else, like intake leaks. Do the necessary diagnostics before replacing any parts.

Well I just pulled the fuel rail, I couldn't really get it out from underneath the intake manifold, so I just got my neighbor to turn the key to the on position while I checked for leaks. I didn't notice any, but I was at a pretty bad angle so I may have missed it. I put it back together though, and now the car is running really badly. At idle it is rougher, the whole car vibrates a bit, and I took it for a test run around my block and at 3500rpm the engine just died for a second, rpms went to under 500 and I had to depress the clutch. I think I may have damaged one of the injectors while removing the rail, or maybe one just isn't in all the way, but they all look fine.

If I pull my plugs, and one of them is wet, is that a sign of a leaky injector? Because I remember a plug being very wet when I pulled them a couple months ago.

[jlevie]

Just turning the key on doesn't run the fuel pump to pressurize the rail. The engine must be turning for the DME to turn on the pump. But you can jumper the fuel pump relay.

Damage to an injector is a possibility, but an intake leak at an injector is even more likely given the old seals.

[willfill]

Just turning the key on doesn't run the fuel pump to pressurize the rail. The engine must be turning for the DME to turn on the pump. But you can jumper the fuel pump relay.

Damage to an injector is a possibility, but an intake leak at an injector is even more likely given the old seals.

I'll try jumping the relay today, I was under the impression that turning the key primed the system. I'll report back with the results.

[jlevie]

The pump only runs when the DME sees timing data from a rotating engine.

To have the rail where you can actually see what is going on, you first remove the rail, then the injectors, and re-connect the injectors to the rail. Re-installation is the inverse.