Redtop running on 3 cylinders after engine change

[fix]

Hi ive sold a redtop dizzy type to a lad who'd put it into his car as his engine was naffed.

The engines are both dizzy type with the same ecu numbers etc so everything should have been straight forward but for some reason the new engine only runs on 3 cylinders.

He's tried swapping everything he can over like both dizzies,leads,inlet but it just always runs on 3.His mate said he thinks the cars over fueling.


Can anyone think what could be wrong?

Thanks

[meritlover]

depends how his mate assumed it was over fueling, if he pulled the plug out and it was wet then it would be if its not firing/sparking.

do the simple stuff, stick a timing light on the duff cylinder and check it IS actually flashing/sparking.

if it is then petrol down the plug hole and see if it runs sweet for a few secs on 4 before drying up. if it does, then check the injectors, if its no different, do a compression check. and tell us how he got on.

[fix]

Cheers for the reply,he's checked theres spark on all the leads.I think he thought it was over fuelling just from how it was running.I dont know what a timing light is

Yep good idea to put petrol down the plug hole.I think he's tried the injector rails from both engines.

Compression should be fine the engines run fine ever since i had it,its never not fired on the 4th.We ran the engine the same day it was taken out.

[meritlover]

a timing light is a xenon or neon type 'strobe lamp' that you connect between the plug and the lead/coil/distrubutor. everytime there is energy for a spark it flashes, normally you aim this at the crank pulley to check your static timing (when the light flashes on the marks, you know its firing at the right time)

no flash = no possibility of a spark.

so check coil pack/coil/trigger wiring.

they can be bought for about £10 and are a very useful fault finding tool to have.

have you determined what cylinder is the duff one? when its running pull each plug lead off and if the engine note/speed doesnt change, thats the duff cylinder. if it changes on all cylinders check the static timing, as it may be waaaay retarded and just sounding lumpy.

Meritlover

[fix]

Yep that sounds like a good tool to have! I havent spoke to the lad in a couple of days,he hasnt rang me so might have sorted it out.At the end of the day i know the engine was fine before i sold it so it really should be something.

It was definately the cylinder nearest the passenger side when looking from the front,i assume thats the 4th

[meritlover]

yes no 4, no 1 always being at the side of the timing belt.
even if you dont have a timing light, if you just get a known good plug and stick it on the lead and earth the plug onto the block or head, you should see it sparking

[fix]

Yep he's done that he said all 4 leads are sparking

[Paul]

must be a fuelling problem then.

[Adam]

Dodgy injector

Low compression

[meritlover]

yup,

fueling or compression

is the plug wet with fuel when it comes out?

[Philsutton]

My money is on injector number one and the plug / wiring to it being at fault.

[Paul]

Try pushing the black loom box down hard onto the injector?

Figure out if fuel is getting through the injector or not.

[fix]

Thanks for all the replies like you all say first thing is to check if fuel is getting to the cylinder,if not then you think it would be the injector.Ill let you know when ive spoke to him ive left him a message to phone