RonD.

Cold start, idles where set at 900 rpm, responds to light revs,returns to smooth idle WB AFR reads cold idle low 14's, as engine warms on idle only, AFR keeps creeping up to 16-17's, All of this with-in 5 minutes of cold start, idle stumbles, searches eventually stalls. Restart will not idle or respond to rev input stumbles at 3-400 rpm eventually stalls or I shut it down. Fuel Issue? Injector(s)? Has New ICV, TPS set correct, 0 vacuum leaks,new 3 Bar FPR,recent fuel filter change,Plugs, wires cap rotor, slight upgrades Super 48, Dual Port, 3" no cat, Russ Berry(RIP) custom chip. Never in 2+ yrs. 10 k with mods did this car skip a beat. Including on the drive 30 miles to Porsche shop for new headers and motor mounts. I can't believe that adding headers would affect my tune like this could it? Shop smoke tested it found no leaks. Dicked me around said if I could leave for 3-4 weeks they could take a look at it on my dollar since the work they did could not have caused my issue, said it ran perfect on idle in the shop for header heat cycles and to where they moved it in lot for my pick-up. When I asked if they road tested it they said they didn't WTF. I trailered it home. I honestly can't believe they could have done anything or should have for what work it was taken there for.

Please Help

Thom

Did they possibly damage the lambda sensor and/or its wiring when they replaced the headers, assuming they needed to drop the cross-over pipe?

If the lambda sensor is fine I would look at the coolant temp sensor feeding the ECU.

RonD.

Crossover pipe was not removed but I'll take a look. Can you tell me where the coolant temp sensor is located. Also, I forgot to mention plugs were pulled during diagnosis number one plug was burning lean other 3 fine a little on the rich side but typical appearance for my tune. Shop did install all new plugs. Did not change issue. Motor mounts were installed at the same time as Headers( All new studs, hardware, gaskets) absolutely no leaks. Motor mount replacement couldn't cause any of my issues?

RonD.

Dave at LR suggested the DME temp sensor could be issue. Is that the one deep down below front spark plug area?

Chapman951

yes underneath the intake manifold. Forgot if you can reach it without removing the intake manifold. But a faulty or disconnected one of those can cause a no start issue

RonD.

Is there coolant involved when removing?

Chapman951

it’s high up on the engine. Maybe the highest part? I would seriously doubt much or any would be lost.

RonD.

Located 2 sensors below intake manifold right below the thermostat area. One is slightly lower and further back has 2 spade connectors Is this the sending unit for water temp gauge? 2nd sensor is slightly above sensor one and closer to thermostat housing i.e.: towards the front of the motor and has a blue connector Is this the DME temp sensor? If so, On my car the Blue connector is on the connection wire it unclips the same way as the TPS or AFM connectors do after being unplugged 19 mm deep socket will remove it. When I search for replacement sensor they all come with a blue 2 prong plug on the top. So will my blue plug connect onto the replacement sensor blue connector ??? I ask this because after seeing multiple identification pictures of DME temp sensors with plug disconnected but sensor not removed from engine they all have the blue connector on the old sensor. Mine when disconnected there is no blue connector on the sensor as I've said the blue connector is attached to a wire which I assume goes to the DME. Is it possible there are 2 different styles for connection point to the sensor???

Just to be clear issue is not starting It starts idles fine for 5 minutes +/- then acts up as stated in my original post.

Chapman951

Unless the DME temp sensor is actually loose, I would not suspect it to be the culprit.

Tom M'Guinn

Did the car ever run right after having the header and motor mounts replaced? If not, I'd say it's on them to diagnose. Testing the DME temp sensor is easy enough though. You also might just disconnect the O2 sensor (barrel connector at back of intake) and see if you get a richer mixture. It's most like a sensor (O2, temp, AFM, etc.) or a leak, but the possibilities are endless (harness issues, DME solder joints, fuel pump, FPR, etc.). If the easy things don't reveal the issue, you'd want to check the fuel pressure at the rail (and confirm the FPR line is connected and has no gas in it). Unless/until a mechanic actually fixes the problem and tells you what he/she did, I wouldn't fully rule out leaks or anything else based on what someone else told you.

http://www.clarks-garage.com/shop-ma...9.htm#dme-temp

RonD.

Thanks Thom

The search continues

Ron D.

RonD.

Could this be a Fuel Pump? I started car today with doors closed stereo off and there is a moaning kind of sound coming from hatch area. Never made any noise other than the sound of Fuel Pump turning on when you turn the key prior to my issue. I just realized I've been hearing this moaning sound since this issue started but I always had the windows down drivers door open so sound was faint. Today I clearly could hear it. Uncovered the pump started car had my adult son listening to the pump and noise was clearly coming from fuel pump. My son said it sounded like it was laboring and moaning was oscillating. Does this at cold start when idle is fine and gets worse as car starts stumbling until stalling.

ElRicardo

Following this thread it is hard to tell, but the very last post sounds like a clogged/blocked in-tank strainer, plugged up or failing pump, or finally a blocked fuel filter. If you never changed the fuel filter do this anyway, it’s cheap and easy. While you are at it, and hopefully your tank fuel level is very low, remove the fuel pump shield and check your pump for obvious fouling. Then, and this needs to be done carefully, remove by unscrewing the in-tank strainer and inspect. All 3 of these steps will spill fuel, but greatly so if there is a lot of fuel in tank, so be prepared. Please google the in-tank strainer before just putting a wrench on it.

hope this helps!

RonD.

Correction on last post. I assumed the fuel pump was that part accessible inside hatch. That is actually where my son was hearing the moaning and groaning. Which is pretty much above fuel pump. Do you know any info on fuel pressure on the fuel rail? Was told to start there could show if issue is fuel related by hooking up a gauge to the end of the rail? Then start looking into fuel pump, filter, etc. Any chance that increased heat from headers could cause some sort of vapor lock in the rail? I'm spit ballen here, this is driving me crazy!

Thanks for your advice,

Ron D.

Chapman951

yes I run a fuel pressure gauge off of my fuel rail. Purchased from Lindseyracing.