Engine not running since changing water pump
 

Strange one this on my 2002 LS1 coupe.

All I have done is fit a new water pump. It was working fine before I started.
When I try to start the engine it fires and then dies. Can't keep it running at all.

Fault codes that come up are;

B0332 - Outside air temp sensor short to ground
B0337 - Inside air temp sender short to ground
B0361 - Left actuator short to ground
B0365 - Right actuator short to ground

Obviously I have managed to do something wrong. Trapped a wire? I can't see anything trapped. Any ideas where to look????

All I took off to fit the pump was the throttle body and hoses. :banghead:

Make sure everything is connected in terms of electrical. Of course it not the water pump thats causing this.

Looking at an '02 wiring diagram I see that both air temp actuators and both temp sensors share the same ground...it's a gray/black wire...look there for a possible short !! (most likely at the ambient air temp sensor...passenger side r/h corner by rad support)

Clear ALL of those DTCs and ATTEMPT to start the engine. When you go to CRANK and then back to RUN, re read the DTCs and post ALL that you see..
Bill

That's exactly what I have done.

I will look at that. But the code says the sensors themselves are grounded?

The only electrical connectors I disconnected were the MAF sensor and the two on the throttle body. All of which I removed for clear access to the pump.

did you reconnect the throttle body sensors though?... weird that no codes are thrown indicating the cause of the problem, the air temp sensors have nothing to do with your starting issue though so I wouldn't worry about that right now... is the car modded or stock?

Thanks for the ideas so far.
As suggested I have checked the MAF connection. Seems solid. Also tried without it connected. Exactly the same result. The engine fires for a couple of seconds then cuts out.

One other thing I tried was just disconnecting the battery again for a few seconds. Like a computer hard re-boot.

Now I am not getting ANY codes. But I am getting a "LOW OIL" warning on the dash. Even though it has plenty oil in. That could be because it's not running long enough to get oil pressure I assume??

Is there any way of electrically testing the MAF?

Any other things that might kill the engine after a few seconds? Like a bad O2 sensor or something???

The MAF is getting 0.5 volts on a yellow wire. Is this correct?

No !!...Yellow wire is your 5 volt ref (not 1/2 volts), pink is 12 volts and black/white is ground or earth for you !!...recheck both T/B connections and recheck that MAF sensor signal voltage and DON'T go there with a bad O2 sensor...LOL !!...Cheers !!!

Ah! my mistake. The reference ground I was using was no good. Found a good ground connection and got the correct voltages.

OK so what else is there.

I have a continuous warning about low oil level on the dash now.

When I fire the engine up I don't see any response on the oil pressure gauge in the moments before the engine shuts itself off again. Plenty of oil in the block.

Does the engine have an auto shut off function if it thinks it has no oil pressure??

NO! No oil pressure failure shut down.

I asked for the DTCs only because they help me (US) understand the ENTIRE state of health of the car. Something that is not important to you may mean something that helps me get you going again.

So,, Can you list all the DTC that are displayed????

Bill

It's strange that the car was running fine before you changed the water pump and had disconnected the MAF,TPS sensor and TAC motor if that is all you did disconnect. Once again check pin fitment on the TPS sensor and motor...and yes, let's see if you have any DTC's that are current. Also bad TPS can cause the start and shut down. Probably something simple but just need some direction !!

The four that I had before I disconnected the battery for a minute have come back now. But as historic. Not current. Listed in my first post. No other codes. Only a warning of low oil level and pressure.

I don't like the look of the wires going into the TPS sensor. Each one has a pinch where it has been pulled tight back over the edge of the connector. Is there a way to check these?

Here is a thing I have found. With the ignition on there should be fuel pressure right?

When I take the cap off the Schrader valve on the end of the fuel rail and press the pin in shouldn't I get fuel squirting out?

Nothing happens when I do this.

Yes, if the TPS was good I was going to suggest spraying some brake kleen or starting fluid into a vacuum line to see if the engine might run for a little bit longer to see if we have a fuel delivery issue. Yes, the fuel pump should have a 2 second prime when the key is turned on and you should see a little fuel squirting out of the Schrader valve...do that and see if you can hear the pump run for a few seconds....what you can do quickly without getting to involved is swap out the fuel pump relay with the horn relay...see if it runs and if not we can do a few things....will verify if maybe you have a bad pump relay !!...also check fuel pump fuse...#13 I believe or #15...it feeds the load side of the relay. If good we will have to see if we have a good feed to that fuse.