My Twin Turbo has a misfire on cylinder # 4. Me & Mikey Bean had a look today to try and resolve it, so far we've tried changing coilpacks, spark plugs, PTU, cleaned up coil pack connector, can hear injector ticking like all the others.

 

Where can I go from here? Can someone give me an idea of what to try next please? Got bits kicking around if I need to swap things like ECU etc. :shifty:

 

Any input would be most appreciated thanks :thumbup1:

Did you check the Cas unit?? dodgy connector maybe?

are you getting fuel from that injector is the plug wet when you take it out ?

might be a tempremental injector or blocked if its clicking as id imagine from experience that the plug should be wet if theres spark

the plug looked identical to the one from cylinder # 2, will try another CAS & ECU tomorrow methinks, after checking the coil pack connector for voltage :thumbup:

Do a compression test.

Do a compression test.

 

nooooo dont say that :(

mine was missing really bad a a couple of weeks ago, i took it to an auto electrician dreading it was guna cost a fortune. It turned out to be a loose connection on one of the coil packs. simple fix!

Ohm the injector, check your get spark plus fuel. If your getting both, compression test. If you have compression, fuel and a spark its merley not happening at the correct time.

thanks guys will get my teeth sunk into it tomorrow :yes:

Have you been doing anything to the ECU lately bud? May be a problem with the connector? i.e. over tight/not tight enough on the nut. Just a thought as it was the reason for my misfire.

No mate not touched the ECU at all, but I will check that cheers :)

Get a Volt meter on the coil pack connectors in case you have a break in a wire from the ptu. 1 Earth 2 signals. I cant remember the voltage so compare it to a known good pack. I had the same problem and it turned out to be the small return wire that had a break in the conduit and it took a life time to find.

Thanks tony had a check today but the readings were similar to another bank. My mate come round today and we took the coil pack & plug out and saw it sparking as good as another bank, so theres definately spark there. My mate said this means its a fuelling issue and suggested swapping injectors over, but obviously thats not a quick task on a Z unless I get the dremel out!

 

Is there an easier way to check the injector?

The only way is to dremel for an injector out Baz, and it is surprisingly easy....... Unless u want to do a plenum pull!!!

 

Reading ur thread matey, this sounds just my issues form a few weeks ago...... The result was an injector; But on bench test, the injector was fine.

 

Alz.

thanks Al, what was the fix for yours in the end? I want to do the dremel mod anyway so I can eventually get my 555s in.

I plunged in at 555 JECS................ :)

 

Alz.

Follow "Robo's" dremel mod........ Worked a treat for me matey.

 

Alz.

I see ur winning my balance bar on ebay Mikey......... ;)

 

Alz.

Answer my Q Al lol what was the fault with yours?

omg ... come on baz its not that late

 

JECS 550 @ $475 = about £300

JECS 750/850 same price

 

550cc http://conceptzperformance.com/Cart/description.php?II=3867&Car_Type=300&UID=2012051814281780.1.103.33

750cc http://conceptzperformance.com/Cart/description.php?II=3868&Car_Type=300&UID=2012051814281780.1.103.33

850cc http://conceptzperformance.com/Cart/description.php?II=3866&Car_Type=300&UID=2012051814281780.1.103.33

Edited May 18, 201213 yr by MarkDerby

Bazzie...........

 

On the car I had 1 injector not delivering. The screw driver test seemed fine on all injectors; they clicked away fine, all 6. 1 cylinder stayed dry, (no fuel). Bench tested all injectors and they all fired. Seemed strange.

 

Alz.

Not sure if u know, but u can bench test injectors with a 9V battery (the small square type). Get the injector out, attach 2 wires to each terminal on the batt, and each to the injector connectors, and the little beaut will pulse/click, if she is good. No pulse/click, then she is bad...... Information curtsey of "jimmer, Zed God".

 

Alz.

no didnt know that, thanks mate! :)

 

So what, you put them all back in and your car was cured?

No, took them out, bench tested them, all seemed fine, put them back and still 1 cylinder down. Swapped the injectors around, all seemed good for a little bit then, lost 1 cylinder again. Seems strange, as I thought it could not be the injectors as they seemed fine out of the engine. So I took the plunge and changed to JECS 555's.

 

Alz.

have you done an ohm test on the injecttor buddy? that will tell you the health of them i think its about 14ohms, look it up. if its lower or higher by a few point syou know the thing is fubar. save you having to start chopping it out.