only 1 cylinder firing

[Funfettie]

Hi there,
So weird issue i have going on. I just tried to start my project car and only cylinder 4 is firing. The manifold pipe is warm on cylinder 4, and the rest are cold. All 4 cylinders have spark, and great even compression. Anyone have a good way to check is the injectors are firing correctly? I just had them flow tested, and they are in good working order. Injector resistor pack maybe?

Thanks!

 

[V8srslow]

Could do injector balance test, psi should drop 1 psi as they open. Sounds like u have electrical issue. PCM or transistor perhaps. Coils good? Engine light comes on while ignition first on? And resistor pack is possible.

 

[cisco818]

Could do injector balance test, psi should drop 1 psi as they open. Sounds like u have electrical issue. PCM or transistor perhaps. Coils good? Engine light comes on while ignition first on? And resistor pack is possible.

He has spark so the coil pack is good. You could be right about the pcm. Make sure your r injectors sent plugged up.

 

[LiquidX]

You could pull the spark plugs and turn it over and check to see if the piston tops are wet. Quick verification that the injectors are in fact firing. Then you can go from there. Do you have a 1G or 2g CAS?

Are the plug wires new?

 

[NSRT4]

Take the intake manifold off and just pull it up to where you can see the runners then take the coil plug off then have somebody turn the key to see if they're firing. Make sure there is nothing by the head intake posts that could get sucked up in the engine. You can also get a voltometer and see if they're actually getting power at the connectors.

 

[Funfettie]

Wires are brand new Taylor 8.5mm's, 1g Green top CAS, Has spark on all 4 cylinder. (pulled the plugs out and verified this) PCM is the little black box that sits next to the coil pack in its stock location, correct? They are all plugged in, and the harness looks alright.

What voltage should they be getting when firing? I assume just probe the plugs with a voltometer and see if it reacts?

Thanks for the quick replies!

 

[V8srslow]

My bad thought only had spark on 1 cylinder. The PCM is the main computer and is behind the centre console. U might be looking at the power transistor. U can get noid lights that plug in to injector plug and light up when they open. Need to narrow it down. 2 wires for injector 1 is constantly power from ignition and the other is ground controlled by PCM and grounds when PCM says it time to open injector. If u test only use high resistance multimeter or could damage PCM.

 

[Funfettie]

I think you mean ECU? I have never heard of a PCM..? I think either the wiring got messed up, or power translator died somehow? Anything else that could cause this weird issue? time for a new engine wiring harness maybe?

 

[Funfettie]

alright! fuel is back on all cylinders. Redid a compression check, 120 across the board. WTF is going on? I think the cams are causing low comp. leak down tests are at 15-20%

 

[NSRT4]

did you degree the cams?

 

[Funfettie]

^Nope :/ I really should have.. I think the cams are too big also.. BC280's are a little large for my power goals. Thinking about stepping down to a set of kelford 272's