1.6K SS missfire

[Alan Bowler]

Help!

Getting cross with this now.

1.6K EU3 with verniers and SS ECU, intermittently missfiring under light load.

Seems fine when it gets going and the revs are up.

Very lumpy idle - always has been since I did the verniers, but now seems even lumpier.

If it had a dizzy, I'd be taking it apart - thats what it feels like.

Its got new Magnetron plug leads, & new plugs. I thought I'd found the

problem when looking at the contacts in the coil packs. Very corroded. I cleaned

them up but it didn't help. Am I right in that they just connect to the plug

through a very spindly spring? Seems odd, but I guess its the path of least resistance.

They don;t seem to quite meet the top of the plug so must be connected through the spring.

 

I checked the camshaft pos sensor is away from the other leads too.

And reset the ECU. Can't see any air leaks.

 

Any other suggestions?

 

Thanks

AB

[Mr Locust]

Check out the connections to the lambda sensor (exhaust), TMAP sensor (inlet manifold top) and throttle potentiometer (throttle body).

 

I used some draught excluder 'p' strip to form a waterproof seal on the edge of the plastic top engine cover which virtually eliminates moisture around the coil packs etc.

 

Ian

 

Green and Silver Roadsport 😬

 

Edited by - Mr Locust on 24 Apr 2007 21:38:29

[Delbert]

try your throttle position sensor , or rather the conection on to the loom.

 

Mine has been moissfiring irregularly for a while and this time undoing the connection and re doing it eliviated the problem.

 

Maybe somebody who knows what I am talking aboout will explain more

 

 

If at first you don't succed Sky diving is not for you

[Alan Bowler]

Thanks - checked these, and they looked OK to me - will have a closer look. The car did get a soaking before the problems started, so maybe some damp has got into one of the connections. Couldn't believe how bad the coil connections were though (and that cleaning them up didn't fix it ☹️). Also, I did manage to blow the ECU fuse on a hot start/click before the misfire started. I hope I didn't damage the ECU ☹️

 

Have noticed that the rev counter is erratic at high revs, but put this down to my piggybacked wiring for shift lights (which work fine and have been there a while), plus oil pressure guage erratic (have new sender, ready to fit). Could a bad earth somewhere cause this? Where would I look?

 

Thanks for any advice!

AB

[shn7]

Alan,

 

Welcome to the Seven Mis-Fire club. Been trying to sort mine on and off for a couple of months. Similar symptoms to yours though EU2 in my case. Mine started first time out after a soaking the month before evne though it's stored in the garage with dehumidifier running. I do suspect water got somewhere it shouldn't and has caused some corrosion. I've check pretty much all connections, replaced numerous bits and it still happens. It doesn't happen on full throttle so jst encourages me to make progress 😬. Has to be an upside to these things.

 

Steve.

West Sussex AO

Not forgetting Percy the Polar Bear

[Alan Bowler]

Steve,

😬 - Full throttle does seem to cure it. Maybe it needs a couple of track days

to help clear its throat properly. I'll have to convince myself its a highly tuned and

tempremental racing engine, and not a slightly upgraded metro shopper engine,

as I kangaroo through the villages.

AB

[Simon_hill]

Hi Alan,

 

Have you re-checked your cam timing? I recently swapped to a 1.8 from a 1.4, assumed I'd got the right timing and was convinced it was some electrical fault, but it just turned out to be a bit too aggressive timing. Again, it was under light load and especially when cold.

 

Simon

[Alan Bowler]

Simon,

Very good point. I moved to a SS ECU and adjusted the cam timing to be

slightly more agressive a few months back. I may have gone too far I guess.

I used Oilys suggestion, but he did qualify it as a "you could try", rather than

"use this". Seemed to work fine initially though.

 

I had thought that I could rule out this change, as it does "feel" like an electrics

problem. Engine just seems to die for a few fractions of a second.

 

Its def. worse when cold on light throttle as you describe.

Out comes the dial guage then. Worth checking the verniers haven't moved

too

 

AB

[Alan Bowler]

Adjusted the verniers/cams back a bit, checked connections for sensors etc., but its still not right. Any other suggestions?

Thanks

AB

 

[GTD]

With Peter Carmichael's and John Howe's help last weekend we established that my EU3 ECU was not allowing the engine to go into 'Closed Loop' and when we swapped the ECU for another one the engine immediately became smoother. Could you try swapping the ECU for another one tempoarily to see if that is the culprit?

 

G for Geoff here

[old captain slow]

As Steve says - The 7 misfire club. I've been trying to track mine down too. Changed the TP and going to try a new Lambda tomorrow if I can get the old one out. It's an EU2 1600KSS with verniers. Tends to f*rt when you accelerate tentatively. Foot to the floor is fine.

 

C7 CDW

[John Howe]

Picking up on Geoff's suggestion. If you are running on an Emerald and still have your Rover ecu - give it a try. The Rover items will not like the higher revs but should be kinder at start-up revs.

 

Not suggesting you run the car on it but rather use it as a means of elimination.

 

Are you sure you have no moisture in the Emerald - a night in the airing cupboard should cure that sort of problem - the Emerald that is, not suggesting you spend the night there.

 

JH

Deliveries by Saffron, the yellow 230bhp Sausage delivery machine

[shn7]

I'm seeing PC tomorrow so will report back after that.

 

Steve.

Sussex (West) AO

Not forgetting Percy the Polar Bear

[Alan Bowler]

Tried disconnecting the shift light, fixed a leak in the exhaust, disconnected

the TPS while engine running (revs climbed slowly - is this right?). Went for

longer blat and thought it was sorted - but no, kangarood'd back thru village.

As you say, foot to floor and its fine. Will spend a night in the airing cupboard

with the ECU (standard rover EU3 SS) - good idea.

Air filter has seen better days - fine black powder in the TB. Would this cause

such a problem? Will replace it anyway.

Many thanks for the suggestions.

Good luck with Peter C.

AB

[Andy Best]

Don't know if this is your problem. I had a similar symptoms last year on my EU2, after checking everything else I replaced the coil which cured it.

 

Andy

[shn7]

Already done the coil on mine ☹️

 

Steve.

Sussex (West) AO

Not forgetting Percy the Polar Bear

[Sheds Moderator]

Have you tried measuring the resistance of thre throttle pot while you move it? If it is full of crud it may give false readings along its range, while at WOT it will give a steady reading as the throttle pot is at the extreme of its travel and not dependent on the wiper. Fix is contact spray.