At Track Car Won't Start - what to check? HELP!
 

I'm at the track at my car suddenly got a misfire I brought it in and turned it off and read the codes which were a series of misfires on cylinders 3, 4, 6. Also got a code on cylinder 4 for open injector circuit. After that the car won't start. It turns over fine and the tach needle bounces but it doesn't start.

P0204 injector circuit open 4
P0300 random multiple misfire
P0306 misfire 6
P0304 misfire 4
P0302 misfire 2

What should I check that would prevent starting? It has fuel, I looked at the engine related fuses and no obvious wires are disconnected.

The causes of a P0204 engine light code could be any of the following: Bad injector. This is usually the cause of this code but doesn't rule out the possibility of one of the other causes.
First, using a DVOM check the resistance of the injector. If it isn't within specs, then replace the injector. Check for voltage at the fuel injector connector. It should have 10 volts or more. Visually check the connector for damage or broken wires. Visually check the injector for damage. If you have access to an injector tester, activate the injector and see if it operates. If the injector operates, then you likely have either an open in the wiring, or a blocked injector. If you do not have access to a tester, swap the injector with another one and see if the code changes. If the code changes, then change the injector. At the PCM, remove the driver wire from the PCM connector and Ground the wire. (Make sure you have the correct wire. If you're not sure, do not attempt) The injector should activate Replace the injector

Thanks I got it started and the problem does appear to be #4 injector. Seems stuck open.

So now how to get at it? At least this one is on the back of the motor if we are talking about the back of the car. I can see if I can touch it but to you actually change it is going to be a big job it looks like.

a friend and more experienced 996 turbo owner said he changed his with motor in the car, by removing Y pipe and airbox, said everything was cramped but straightforward after that. Was this a stock injector or aftermarket? Sticking open is bad juju, can hydrolock a cylinder! saw that in a Subaru once, the starter had enough torque to bend the connecting rod and lunch the bearing all in one go.

It's stock. Once I removed power it stopped pouring in fuel.

A rennlist member donated a spare set. I'm good for the part, will install this weekend.

yikes, that's scary that it got hung open. best of luck.

is that your garage in your pic? looks sweet!

I've got the injector out on the bench, it measures 11.8 ohms resistance. So does a "good injector". So the failure doesn't seem electrical in the injector itself.

Yes it was puzzling at first. Thanks for garage props, I finally renovated it last fall after 12 years.

https://cimg5.ibsrv.net/gimg/www.6sp...b714fff3d.jpeg

How do you like the propane heater?

It works well for something small and portable. I gave up on the kerosene versions while ago for propane. Big open flame though so no fumes allowed when using!

That's my problem- fumes as I store gas in the garage I'm trying to heat= so its going to be electric I guess. Propane probably would be fine but I'm paranoid. Thanks.

I replaced the injector and the wires from the injector plug to the harness. They looked overheated and the insulating sleeve had melted a bit. Car started and ran great, did a test drive and no more codes. Problem solved for now.

I did drop the motor a small bit and it took a few hours to do this replacement on the passenger side. Here are the tools required to swap the injectors (less the wiring replacement tools) - I'm glad I didn't attempt this at the track.


https://cimg7.ibsrv.net/gimg/www.6sp...190272d55.jpeg

is that a wurth zebra flex driver? I love those things.

Yes indeed - excellent for hose clamps.