ST20V Unable to Time Engine+ Cyl 2 Not Firing

[Plelz]

Car - 1984 KE70

motor / part in question - stock 4age Silver top 20v + Razorback ECU and loom

problem - Cylinder 2 not firing.

-When plug lead from cyl 2 is removed from plug it fires a blue spark (strong??).

-When plug lead for cyl 2 is removed when engine is idling, nothing changes. When any of the other plug leads are removed when idling the engine slows to a stall.

-No timing mark seen when timing light is attached to cyl 1. No ignition signal when timing light attached to cyls 2 and 3. Only signal on 1 and 4. When the timing light is placed on cyl 4 lead I can see the timing mark at 15 degrees BTDC at idle.

-Static timing (CAS, crank and cams) all ligned up perfectly.

-Plug leads checked. Problem persists when leads are on different cylinders.

-Plugs (all of them) are black and smell like petrol (over fueling??)

-People have suggested it could be a valve issue or a compression issue on that cylinder. I have checked all of the vaccuum hoses on the ITBs. Everything is where it should be. Engine idles well, revs up okay (only bogs slightly). Someone also suggested that I check that there are no clogged holes in the throttle body for that cylinder.

occurs/started when (if applicable)- has been happening since i got the motor running.

Any help would be much appreciated

Kind regards,

[Matt]

Swap the spark plugs between cylinders if you haven't already to see if the problem moves cylinders. Could be a cracked plug, but unlikely.

I'd also swap the injectors to see if the lazy cylinder changes. If you have spark on the lead , then it should transfer into the cylinder, which leads me to think it would be a fueling issue... You'd expect the problem cylinder plug to be dry and definitely not black.

When you are timing these and any 4age engines, make sure you bridge the terminals in the diagnostic box. T1 & E1.

As for over fueling, that is another issue that I'm not sure what the problem would be. Measuring the fuel pressure might help as I've seen quite a few of these fuel pressure regulators fail.

[Plelz]

Cheers for the help Matt.

Bridge the terminals?? What does this involve??

I will try swapping injectors but I would be very surprised if it was the injectors because all of the plugs come out black. Over fuelling may be closer to the mark. The bosch pump may have killed the standard fuel pressure reg.

[Plelz]

It seems like it is a weak spark as it is only picked up by the timing light sporadically. I have new coils, new plugs and new leads on it so am unsure of what it could be.

[Matt]

Could also be a blocked return line too...

[Plelz]

Its getting fuel because it runs/revs freely. I am just not getting a spark signal on the #2 cylinder plug lead. Plus the plugs are black as hell.

[Matt]

Have a look at the dizzy cap , the carbon in the middle should be a few cm
long. have seen a couple where it is gone almost completely

[Plelz]

Does not have a dizzy cap. It is just running a crank angle sensor (CAS). Which is the base of the distributor. It has 2 coil packs which are run from this. Does that make a difference. I wouldn't think so... ??

[Matt]

Nah it should be ok, i was thinking stock ecu for some reason... But yeah re-read your post and tbh i wouldn't focus your time on the spark. You have identified cyclinder 2 as being lazy, but when u swap the leads between the 2 the issue doesn't swap cyclinders. Says to me it isn't the spark.

How have u configured the spark in the ecu? Batch / wasted / sequential etc.

I'd run a compression test and compare the results between cyclinders.

As for it running rich, could be high fuel pressure / something unrelated to cyclinder 2.

[Aussie_XLR]

Plez, I know it might seem basic but can you hear injector no2 ticking?? and is it opening in the correct sequence as the iginition timing. I have had experiance where the injector plugs have been put on the wrong cylinder. The engine will still run even if the injector timing is 180 degrees out but it runs ruff.