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rally864 10-10-2012 07:27 AM

Car won't start!
So I just finished rebuilding my 2001 ZX3 with the Zetec. Went to fire it up and it will not start.The car will crank over but will not start. When you first turn the ignition on you can hear the fuel pump prime. I pulled the fuel rail off with the injectors still attached to see if we were getting fuel out the injectors and we are. There is 43 psi of fuel pressure. I also changed the fuel filter thinking maybe lack of fuel still no luck. There is good spark on all four cylinder as I put a new coil plugs and wires on also. We hooked it up to a code reader and it was saying that 1st o2 sensor had 0 voltage and at WOT the TPS was only reading 94% and at closed throttle it was reading 8%. I have checked the timing and all the marks are still on also. Also did a compression test with all good number across the board. When I picked up the car it had a bad piston in cyl 3 no sure what it was from. But I was able to get the car to run on 3 cyl before I tore it down. The oil pan is tapped which leads me to believe it was boosted at one point. Not sure if the ECU still has a boosted tune which could be not allowing it to start. As of now this is where I sit.

The rebuild was stock. I put stock pistons and everything back into it. The only changes are EGR delete, A/C delete, Cruise Control removed, a 65mm throttle body. Other than that it is all stock.

6SPD_soul 10-10-2012 09:17 AM

You say you have spark since all the ignition components are new, but have you used a spark tester to verify that you're really getting spark during cranking? The pigtail/wiring harness that plugs into the coil pack is known to give people problems and of course a no start condition.

Your TPS sensor readings are probably typical, and the offline o2 sensor is a secondary problem. The fact that you got good compression test results (or any compression for that matter) re-inforces that the timing is probably correct.

I think you need to get 100% positive that you're getting spark, an adjustable spark tester is the sure fire way to know.

And welome to FF, hopefully we can be of some help.

rally864 10-10-2012 09:37 AM

I did not use a spark plug tester I took the spark plugs out and grounded them to the head and was able to see the spark from each plug. Tested each on seperately.

6SPD_soul 10-10-2012 12:03 PM

I should have figured from your other tests that you actually saw spark and ruled that out, there are people that buy new ignition components and take it for granted that they are working. The fact that there is spark at all means the PCM is getting information it thinks is plausible from the crank position sensor, but it might be off enough to prevent running. One other thing I thought of is that o2 sensor is probably fine, they don't start working or influence AFR until they get hot and it takes a couple minutes of running, it'll read 0V until then.

It sounds like all 3 elements of a running engine are there and just not in sync somehow. If you did the compression tests with the throttle wide open, you effectively bypassed the idle air control valve and if that were stuck closed it might prevent the engine from firing. I'm just spitballing, you probably tried to start the car with a little throttle for good luck. The IAC could get sticky though depending how long the engine sat for.

Try unplugging the MAF sensor once, I've got a periodic no start problem in the winter and unplugging the sensor for starting has solved it in the past.

The fact that you had it running briefly on 3 cylinders makes me think there's nothing weird about the tune preventing it from running.

There are a lot of people here smarter than me that might have different ideas.

rally864 10-10-2012 12:19 PM

The engine was just rebuilt and put in about a week ago. I tried playing with the throttle while trying to start it and it would sound like it wanted to fire at WOT but just wouldnt. We also tried unpluging the MAF and didnt see a change in the results.

rally864 10-10-2012 12:56 PM

As I was turning it over I was playing with the throttle hopeing it would do something but very little change. I could get it to some what fire but it would stay running. We did unplug the MAF and try and didnt notice a change in it. We had 2 bad injectors so we swapped them out with new stock injectors. After comparing the two injectors on ones taken out of the car had a larger body i assume from when it was boosted.

rally864 10-10-2012 07:55 PM

So i swapped ecu's tonight and got the car to fire up. The car will idle fine but as soon as you go to give it gas it will bobble and if you floor it will snub it self out and shut off. But if you roll into the throttle an feather it you can get it to rev to 4500 and it stops right there. I have have 3 of the vacuum bungs plugged on the intake manifold along with the tube that went to the brake booster. when its reving at 4500 rpm its only at half throttle if you go past that it will die.

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