idle problems

[Dirty325ix]

So I just put my engine in and it starts right away but does not run for longer than a few seconds I hear hissing from my fuel line. Could this be a symtom of a cracked fuel line

[Earendil]

So I just put my engine in and it starts right away but does not run for longer than a few seconds I hear hissing from my fuel line. Could this be a symtom of a cracked fuel line

Unless it's sub-zero, if you're losing enough feel to keep the car from running, you will smell it. I've personally seen my own M20 dump a lot of fuel from a line and still idle okay... though I'll admit to being heavily distracted by the fuel spray to take considerable note of how well it idled.

If you just installed the engine, and it fires up okay, my guess would be a massive vacuum leak someplace. Make sure that isn't the case first and foremost.

[DetailAddict]

+1... that happened to me after the stroker went in...

If you just installed the engine, and it fires up okay, my guess would be a massive vacuum leak someplace. Make sure that isn't the case first and foremost.

[dnguyen1963]

+2

[Dirty325ix]

I'll check it out tomorrow...I'm now thinking that the sucking noise I hear is like you say a vacuum leak and not the fuel hose because I see no gas spray and if there were a leak in the gas lines I guess it would squirt out and not suck in

[Dirty325ix]

So I was at the garage today and I couldn't see any obvious vacuum leak. So I fixed my fuel leak and now it seems as long as I'm gentle with the gas I can keep the car running as long as I want but the second I let off the gas the car dies down to 500 and dies
So I looked at the throttle cable and it was loose so I tightened it
This is the first time when I tightened it to much...it didn't die on it's own I turned it off

https://www.youtube.com/watch?v=LxvOz8UDdCg&feature=youtube_gdata_pl

Then I loosened it a little and have the same problem as bef
Second attempt

https://www.youtube.com/watch?v=7AGoH4lUqsI&feature=youtube_gdata_player

[Dirty325ix]

Oh and I just did a 5 speed swap and put a newer m20 in

[Earendil]

I'm coming at you as a guy that's never does a motor swap, so I don't know what the common failures there are, but...

1. Make sure you Idle Control Valve (ICV) is functioning properly. If it's stuck closed, you'll be starving the engine for air. The more common failure here though I believe is partially stuck open, or stuck wide open.

2. unexpected and negative changes in engine RPM in the transition to or from idle points to the Throttle position sensor. Now, a bad TPS will NOT cause the car to die, but it could conflate a problem with something else, like the ICV. The TPS is easy to test with a multi-meter, you can even do it from inside your car if you pull the cable to the ECU. You can find a pinout for the ECU cable on the internet and what the expected test values are. This info is also in the Bentley.

3. While you're doing number two, go ahead and check other sensors that can be checked with the car off and the ECU unplugged, like the coolant temp sensor. Not only does this check the sensor, but checking from the ECU plug will also make sure the wiring from the ECU to the sensor is intact.

I'd verify that those things first off. It seems likely that if there is no vacuum leak, that you have more than one bad egg, and a lot of things will cause the car to not start, or to run really shitty, but very few will allow it to fire right up and then die.

[Dirty325ix]

Can you get a vacuum leak from a valve cover
Yea I'm surprised how quick it starts up especially because it is very cold outside

[Earendil]

Can you get a vacuum leak from a valve cover

Like, if you don't have a valve cover?
Yes, yes you can.

The last bad vacuum leak I had was from the rear of the valve cover, from one of those two rubber "grommety things" (technical term).

A hole the size of say, the oil filler cap? That would kill or come close to killing the engine.

[Dirty325ix]

No I have a valve cover but got a wire caught in it while tightening it down and instead of putting a new gasket on I just loosened the bolts and yanked the wire out then retightened the bolts but I bet that the wire left a big imprint in the gasket

[Earendil]

No I have a valve cover but got a wire caught in it while tightening it down and instead of putting a new gasket on I just loosened the bolts and yanked the wire out then retightened the bolts but I bet that the wire left a big imprint in the gasket

Oh. Well that's not something I can make fun of you for :P
That might cause a slight problem, or add to the problem you have (if it were leaking) but it wouldn't prevent the car from running.

[Dirty325ix]

So I unplugged what I think is a idle cotrol valve(it is black with 1 wire) and now the car Idles fines. So is this broken or is the fuse out or did my 5speed wiring do this

[Dirty325ix]

Can you clean this because last time I had my car running(a year ago) and every thing worked fine and I would rather not waste money

[Earendil]

So I unplugged what I think is a idle cotrol valve(it is black with 1 wire) and now the car Idles fines. So is this broken or is the fuse out or did my 5speed wiring do this

Can you clean this because last time I had my car running(a year ago) and every thing worked fine and I would rather not waste money

It can be cleaned, brake cleaner or carb cleaner sprayed inside should do the trick. The door inside should swing easily enough, and when it's unplugged just (lightly) shaking it back and forth should get the door to swing around.

However, it sounds like the electronics is shutting the door during idle when it should be open. If it were stuck closed than unplugging it shouldn't have any effect.

I don't know (off the top of my head) if the ICV wiring can be tested from the ECU harness that I mentioned before, but you might see if it can be.
If it checks out faulty from the harness, then see if you get the same results directly at the ICV.

• Same results = bad ICV.
• Good and different results = Bad wiring.