hornbm

Well after going through replaeign my fuel pump, (turned out that I had my positive and negative wires reversed) my engine finally starts and runs. The damn thing just wont idle though.

I know you are supposed to adjust the idle RPM screw at the top of the engine (S5 N/A) on a new engine and set the idle around 1500 RPM, but I turned the screw 360, and it was all the way in, it wont screw in any more.

I dont have my tach hooked up right now, so I used the tach on my timing light. I connected it to one of the trailing wires. And to keep it alive it had to be somwhere around 2000 - 3000 RPM.

One of my teachers said it sounded like it was running lean. He said ot could be a vacuum leak. I really doubt its a vacuum leak, because I just replaced all of the vacuum lines with silicone ones. The other thing in question is timing, I know mine is off, probably like 10 degrees. Could that cause it?

Also for reference, could someone check how many turns of the idle rpm screw from all the way in is around 1500? I have no idea where that idle screw is set now.

Is there anything else that could prevent the thing from idleing?

hornbm

I just thought of something, I dont have a neutral switch on my car, and I dont think my clutch switch is working right.

Could that prevent it from idleing?

Last idea is that I dont have 12v connected to that MT/AT switch in the ECU. Could that make a difference?

sonic7

iTrader: (1)

is it a automatic transmission? IS all you did was replace the fuel pump?

hornbm

no it is a manual transmission, and as for the fuel pump... I thought it was bad so I decided to test just the pump before I completely disconnected the wires, and then I noticed I had the wires reversed. Problem solved!

Keep is mind that this is a custom engine swap into a FB, so I had to do alot of custom work, so anything could be causing it.

The thing revs fine, it backfires occasionaly which tells me that I need to adjust my timing. Could bad timing prevent it from idleing?

The last idea is is it possible that I need to add a fuel pressure regulator? I know I have the ones at both of the fuel rails and I have one at the pump (its an inline pump) but the pump was from a GSL-SE which I think had slightly higher fuel pressure because of the higher flowing fuel injectors.

Amur_

My uneducated guess is that your TPS is dead... Do you have a spare one or one you can borrow that you can swap in?

hornbm

are you sure its not out of adjustment, or is there anyway I can test it? there aren't very many s5's around here that I could borrow or get a TPS from.

Oh I just thought of something else, I dont have my vent line connected to the motor. Could that be causing a massive vacuum leak?

BlackRx7

your timing could very well be not letting your car idle correctly, also how is the engine harness "modified?"

hornbm

lol you got me while I was editing.

But so could the vent line being disconnected from the motor be causing a vacuum leak?

As for the harness, it has been stripped of everything that doesnt have to do withe the EGI system. Like headlights and stuff. Otherwise thats it.

Amur_

What is a 'vent line?'

hornbm

Your fuel tank has three lines: supply, return, and vent.

Vent is what keeps your tank from crushing itself when you pump the gas out of it. Its also where you have your charcoal canaster connected.

Basically there is a little hole around the end plate ( i think) and that connects to your charcoal canister, which is connected to your vent line that is controlled by the cut and check valve.

I dont have my vent line connected at the engine and I dont know if it's a big vacuum leak or not.

BlackRx7

nope my vent line it wide open, thats not it....go over what you have checked and we'll go from there...

hornbm

lets see, I know the air flow meter is working that was the one thing that kept me from being able to start the engine, so I stuck a screw driver in it to hold it open and it worked, then I realised my BAC valve was not connectet to the air inlet.

When I put the vacuum harness pn I replaced all the rubber lines with silicone ones. I didt it hose by hose so I didnt mess anything up.

I have my air injection for my cat left open.

I dont have my acv silencer connected yet.

Heres one that might have something to do with it.... My custom s4 lower manifold. What I tried to do was put s5 acutators on there because I thought the s4 one required vacuum. Yeah it was a stupid idea but I left it like that because I have to keep it under 4k for the first 1000 miles, so the 6 ports wouldnt be doing anything anyway.

I have an s5 lower manifold ready to swap on as soon as I pass emissions. But to bolt on the s5 acutators I had to grind away some of the air passages for the old acutators because the s5 ones are alot fatter, I then plugged up both sides of he manifold with a bolt after removeing the metal air lines for the acutators.

I still am pretty sure that that is a closed system so it should be fine. My brake booster is getting vacuum so dont think the manifold is leaking.

I also just put a breather K&N filter on the air inlet of my air pump as well.

The throttle mody adjustment could be all out of wack, as I never used the thing before. I the idle speed screw might have something to do with it, I have no idea what exactly it's set at right now since the thing wont idle. After about one 360 degree turn clock wise the screw will not turn in anymore.

Again timing could be off I think the light said about 10 degrees of where it should be. (leading 5 degrees and trailing 20 are the correct settings) The thing was back fireing, but only once every 20 seconds or so, and was pretty quiet for a backfire. That says timing has to be adjusted right there.

the last thing I could think of is could my fuel pressure be too high? I am using a GSL-SE fuel pump and the GSL-SE's fuel pressure was a little higher than the FC's.

hornbm

bump

sonic7

iTrader: (1)

first off... i see "Bump" written all over... what the frick is bump?

I also think it sounds like the tps, have you ohmed it out yet? If its bad, make me a reasonable offer and I will sell you one of my S5 TPS's... DID you leave ANY hoses off? I thought that bigger vaccum leaks caused the engine to not idle at all.... Definately check your TPS!!!

Rex_Roto 7

i dont know if this will help you out much but i once had a problem that sounded simular to yours. What the problem was that i forgot to install the fuel injector grommet at the end of the injector. I left them in my core and sent it out. This caused the same type of conditions that you described. I would double check that. Mazdatrix sells them cheap.

http://mazdatrix.com/c-6.htm

Hope this helps you out

AE_Racer

iTrader: (1)

"bump" the post to the top of the list, some people use "TTT" to the top...

ducetius

If you still have your ACV..did you check it out for internal vac leaks??

hornbm

Well my TPS was a little out of adjustmet but that wasn't it.

I figured it out, I have a big vacuum leak on my hands here. I tested the manifold manifold vacuum and it was only like 5 psi and my auto shop teacher said it should be around 20 psi.

Ok, I have a couple areas that could be causing the problem. First I would like to rule out the indavidual vacuum lines themselves. They are new silicone lines and they were replaced one at a time to ensure that the lines were put on correctly.

The fuel injectors.... my rear secondary injector feels alot looser than the front one. They can both turn around which I'm pretty sure is normal.

There is a very very small spot around the secondary injector that apears to be some gas that sieped out. The spot is very small but none the less it is still there.

When I installed the engine I put new o rings and grommets on all four fuel injectors. However I didnt get the gas line on the secondary fuel rail towards the rear of the engine secured on all the way. It was creating some resistance against that side of the fuel rail, but it felt fine once I bolted it down. But again the rear secondary injector mooves much easier than the front one. So I could have a pressure leak there.

The other possibility would lie in the lower intake manifold. The s4 acutators have been removed and there are s5 ones in their place. I had to grind some material off of the intake manifold to make them fit, but that spot just contained the air supply line to the old acutators and wouldnt be used anymore. So these lines are left open to the air and there are bolts put in the lines connecting them on the side of the lower manifold.

Anyway In my attempt to use the s5 acutators, I had to create a new back plate for the aux sleeve rods to turn agains because I needed to change the start and stop point of the rods. I removed the rods, and I couldnt find new seals for them and so I resued the old ones and re installed the rods with the new backing plates. It is possible that there could be manifold pressure leaking from there.

I tried using a stethoscope to find the vacuum leak(s) but since I have to keep the engine at such a high RPM, it's impossible to hear a leak if there was one. I also tried spraying brake fluid at some of the vacuum lines to see if the running condition improved. I didnt find the leak, but I still have many more spots to test and I wont be able to work on my car unitll monday.

What is the best way to find these vacuum leaks?

Amur_

My preffered method is to use a garden hose. Water's free, you don't have to listen for it and you don't have to worry about blowing yourself up.

hornbm

I have someone spray it on trouble spots and listen for engine improvement right?

Aside from that does anybody else know if my possible problems listed in my previous post could be causing a masive vacuum leak?

Amur_

Nope. Just set it flow slowly and move it from spot to spot around your motor. Let it run over joints, hoses, etc.

And your vent line is not causing this. My vent lines as they pass near the diff are rotted out and a section of the line is GONE and I don't have your problem. Yes, it will be repaired (after the S-AFC goes in. )