Gutted - Camaro wouldn't start.

[F Body]

Quoting: Titsy

Can you make this happen by removing your bypass resistor, disconnecting the cable from the barrel and turning the key?

Don't why i didn't try that

Thank you oh titted one

[HardRockCamaro]

Based on what you've said so far...

You need 4 things for it to run:

1: Fuel - You can hear the pump but get hold a fuel pressure gauge, screw it into the fuel rail and check what pressure you have.  It's probably fine as you hear the fuel pump prime, but still, check it.

2: Spark - Are you getting a spark to the plugs?  Test it.

3: Timing - It's computer controlled so highly unlikely anything is wrong there.

4: Compression - Highly unlikely this changed while it was parked.


If you have all 4 of those then it has to run.

So you're either not getting fuel or you'er not getting spark.
I'd be inclined to listen to the GM guide, if your security light (assuming it works) is not lighting up to indicate a problem then I would assume the stock immobiliser is not a problem.  If you're hearing the fuel pump it's probably fine for fuelling.  Which means no spark.  If your ecu is going through all ignition on tests then it can't be dead.   So either the Clifford alarm is causing a problem (my gut feeling) or you have some other spark problem, presumably a dead coil pack.

[F Body]

Quoting: HardRockCamaro

1: Fuel - You can hear the pump but get hold a fuel pressure gauge, screw it into the fuel rail and check what pressure you have. It's probably fine as you hear the fuel pump prime, but still, check it.

Haven't got a pressure gauge and I doubt you could fit one easily because it's all shaped metal piping. May be I can crack a joint to see if fuel comes out

Quoting: HardRockCamaro

2: Spark - Are you getting a spark to the plugs? Test it.

Already done, I've got a dam good spark which hurts even when your wearing gloves

Quoting: HardRockCamaro

So either the Clifford alarm is causing a problem (my gut feeling)

Nothing showing on the computer diagnostics, although with the Concept 4 your can't interrogate individual components, you just get a status reading

Quoting: HardRockCamaro

or you have some other spark problem, presumably a dead coil pack.

Surely you couldn't kill all 8 coil packs at once, I'd at least expect it to fire even if it wouldn't run

[HardRockCamaro]

There is normally a valve in the fuel rail for you to screw in a fuel pressure gauge.

If you're getting good spark when it turns over then the coil pack(s) must be fine.

If you are getting spark and fuel I don't see how it can be an immobiliser...  
Beyond that there is only compression you can check.

Other than that it has to be a timing issue...

It would suggest perhaps a problem with the sensors feeding into the ecu, maybe the crank position sensor so as far as the ecu is concerned the engine isn't turning over?


If you're getting fuel, spark, compression and timing then it has to run.  It can't not run at that point.


Stupid question:  The starter is actually engaging the engine yes?

[HardRockCamaro]

Just re-read your initial post saying it is turning over and getting an rpm and airflow reading...

There is either no fuel getting in there (injectors not getting a firing signal or no fuel in fuel rail) or it's not sparking.
If you cant hear it trying to fire at all, just starter motor noise while it turns over then you're not getting fuel or spark imho.

Fuel pressure:


You really need a gauge, but without it you could let it prime and then press the valve in with the end of a small screwdriver.  As Mr H&S I'm sure I don't need to point out that it will shoot out at about 45psi and take your eye out.  Wear safety glasses.  Seriously.



Also, are you getting oil pressure?
Modern ECU's won't let you start the engine if they don't get oil pressure while cranking over.  Again I'd expect a fault code for that though...

[HardRockCamaro]

Also, you have checked all your fuses and relays right?

[F Body]

Quoting: HardRockCamaro

If you are getting spark and fuel I don't see how it can be an immobiliser..

Well I can't take a plug out to see if it's wet,
but there isn't any smell at all coming from the exhaust.
But may be the CATS wouldn't let anything past

Quoting: F Body

My next best guess is the BCM ( Body Control Module ) , this can either or both, stop power going to the starter relay,
mine cranks fine and/or disables the fuel injectors

The only way to actually tell if the BCM is sending the control signal to the
PCM is using an oscilloscope or the GM official VATS diagnostic computer

You also don't really want to change the BCM because :

1 / It's located behind the passenger air bag mounting right up inside the dashboard.

2 / If you replace the BCM it could be any of the 15 possible resistor values.

3 / Even after getting the correct resistor value/key it can still require the PCM to be re-flashed to work with it.

[F Body]

Quoting: HardRockCamaro

Also, you have checked all your fuses and relays right?

No haven't even looked at them

Fuses are easy, but there are loads and loads of plastic boxed relays

[HardRockCamaro]

Well look up what they are for and stuff like for the fuel pump (although likely working as you hear it fire) are ones to swap out with one for something less important while you try cranking it.

I'm convinced you are either not getting a spark or you are not getting fuel into the cylinders.  With both in there I'd expect to hear it at least try to fire...

If the immobiliser is kicking in (either stock or Clifford) then you can't be getting spark or fuel.  The immobiliser would stop either the fuel pump or ignition from firing, or both.

[Andy]

I would've almost sad this was identical to the fault we had on ours, except it wouldn't turn over at all.

That was the VATS module dying after what apparently was too many attempts at starting with a duff key. I'm wondering if with your original key that seems to have gone faulty and then this new key with quite possibly an incorrect resistance whether you've done over the VATS systems altogether.

I reckon it might be worth a call to Robin Gray at AutoPontiac as he had dealt with ours and had it fixed pretty sharp.

As Phil said though, it sounds like a case of the car not being used enough... i'm happy to use it as a daily

[F Body]

Quoting: Andy

That was the VATS module dying

Hence the reason I have a cheap backup plan :

GM VATS or PASSkey II Bypass Module For LS1 and LT1 may be worth a punt at £13.47 delivered  

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=220708329684&viewitem=&sspagename=STRK%3AMEWAX%3AIT\" target=\"_blank\" rel=\"nofollow\">http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=220708329684&viewitem=&sspagename=STRK%3AMEWAX%3AIT

[philoldsmobile]

ahh, thanks for jogging my memory. if VATS cuts in, the car wont crank at all.. so you can rule out VATS.

I'd start by checking the clifford, away from that, its anyone's guess..

[F Body]

Quoting: philoldsmobile

ahh, thanks for jogging my memory. if VATS cuts in, the car wont crank at all.. so you can rule out VATS.

The engine won't crank if the VATS module doesn't get the correct key resistance, however if the resistance is correct it will continue to crank, even if the module isn't sending the control signal to the PCM to fire the injectors

[philoldsmobile]

Its VATS then, it only has the key resistance as a trigger, so it either works or doesn't - if it cranks, its not VATS -  its an incredibly crude system.

this also explains why the vats bypass didn't work.

get a diagnostic computer on it, it will tell you a lot more about what's going on..

could even be an ECU failure...

[Titsy]

Quoting: Titsy

Fuel, Compression, Ignition...

Do you have all of these?

Are the injectors firing? they should have a constant 12v on one side when the ignition comes on, and a ground that is switched by the engine ECU to fire them.

Do you have fuel pressure in the rail?

Do you have a spark at the plugs?

Have you checked all of these?

[philoldsmobile]

I'd work through Titsy's list, as if an engine has spark, fuel, timing and compression, it has to run....

I think you can safely rule out compression, as loosing compression to all eight cylinders at once is beyond unlikely, and at this mileage wear is not an issue, so its likely to be fuel timing or ignition. on a V8 poor compression is normally either one or two cylinders (head gasket) or mega high miles. a V8 will start happily on 6 cylinders, so this is very unlikely.

low fuel pressure would likely cause at least a cough, as there is nothing happening at all, there is either no fuel pressure (pump?) or the injectors are not firing. as you say you can hear the pump prime, non firing injectors are on the hit list. there should be a schrader valve on the rail, even if you don't have a pressure gauge, you can do a basic check by pressing the core of valve in, if the fuel is at full pressure it should squirt as opposed to dribble out. (be careful, its probably about 30 - 40 PSI)

the other option is of course no spark, or timing completely out (crank trigger failure?), but in either situation I'd expect to be able to smell fuel through the exhaust after prolonged cranking.

I'd definitely be leaning toward the injectors not firing.....

you can often hear the injectors tick as they fire too, have a listen while someone else cranks it, if all is quiet there may be a clue there..

[F Body]

Quoting: philoldsmobile

I'd work through Titsy's list, as if an engine has spark, fuel, timing and compression,

Haven't had much time lately, did nearly 18 hours yesterday and it's going to be another couple of hours until I get away tonight ( currently in a meeting on my lap top )

[nick69]

How much fuel do you leave in the car when stored?

[F Body]

Quoting: nick69

How much fuel do you leave in the car when stored?

Full tank

[nick69]

If your not driving the car, the fuel WILL gel over time. Seen it many times. Just last week I dropped the tank of a friends firebird. He drives it like you and the tank had a load of gunge in the bottom of it.

Its usually helped along by cold weather too.
Have you managed to test the fuel rail pressure?

[F Body]

Quoting: nick69

If your not driving the car, the fuel WILL gel over time. Seen it many times

Well I drove it three weeks ago so don't think that's the problem

Whilst in the gym this morning I had an idea ???????

Why not crank the engine whilst spraying some easy start into the intake

If she fires it's 99% sure to be a fuel issue

[F Body]

Going to go through all the other test points today anyway

[F Body]

OK first of diagnostics :

OB2 says :



Crankshaft sensor is OK - cranking speed :



Ignition circuit is changing the advance ( ignition advance V rpm graph )



Moving onto the Clifford Diagnostics now

[F Body]

Quoting: F Body

Moving onto the Clifford Diagnostics now

Ah the quaintness of Windows 95







No fault codes or error messages :



Onto the fuel system fuses

[HardRockCamaro]

I'm not convinced your injectors are firing...

You could probably unplug one and test what signal it's getting with a multimeter...