P Poor flatting between rpm

[zircon450]

Owned for two weeks.

Between 1200rpm and 1500rpm my Chimp 450 seems to be hunting / plug lead fail / plug / coil ???

Surely not down to 97 RON fuel from BP rather than Optimax.

Car has just been bought, stood in PSSC's for some time.

Anyone think its poss fuel filter crap, rust, dodgy injector ?

Also where the FAQ list is the must clean valve chappy aka the FAQ Chimp list ?

If anyone says HGF I'm going to the pub !

[shpub]

Clean stepper motor time...

[M@H]

www.tvrsseries.com/steppermotor/steppermotor.htm

[GreenV8S]

zircon450 said:

Between 1200rpm and 1500rpm my Chimp 450 seems to be hunting

You talking about idle speed, or the engine doing a kangaroo impression driving at low speed / part throttle?

[zircon450]

Thanks for coming back guys.

Link to stepper motor clean is tip top.

The kangaroo effect is there (but not severe) it is like holding the throttle pedal at say 1200rpm and you get the feeling a plug lead or the coil is breaking down, or a plug or something.

I did have to fill up with 97 ron BP unleaded so not sure how much difference that would make. The car does this from cold through to normal temp, so don't think so.

Wondered where the fuel filter was located, as the car was clearly standing for a while before I picked it up and filled up, thought it may have picked up some crud from the fuel tank.

Have reseated all plug leads, from coil to plug shield and checked plug shields, seem ok.

Will deffo try the stepper cleanup, although the idle is ok at 950ish rpm, if a little slow to drop down.

Been around V8 Rovers for a fair few years, so no novice as such, just new to this vehicle, bit of a steep learning curve already.

Any other ideas chaps, more than welcome your comments.

Bob

[david beer]

Try disconnecting the vacuum advance pipe, cured mine and many others, some will pooh pooh it though. A very large engine "modder" insists on it.

[zircon450]

Hi Dave,

Will have a look at that, but just don't recall the problem being there when I first picked the car up.

Did drive it like a pansy though to start with.

Also looked at the Mod-Wise linky you have.

Bob

[Zircon450]

Tried the removal of the vacum pipe, possibly worse, certainly no better.

Refilled with Optimax, no change after a good lengthy drive.

Presume stepper motor clean next, but isn't that more or less just to do with tickover problems ?

[ggt]

check the coil, rub your hands underneath the coil, if you feel oil then it is knacked, this was a problem with mine, hope this helps.

[zircon450]

OK so.

1) Stepper cleaned per previous posts. No Change.

2) No Oil from coil - no change.

3) Removed heat shield spark plug covers - leaking spark everywhere, some even loose on plug leads !!!!

4) 1 X set 8mm Magnecors on the way from ACT (TIM) with plug covers.

Will post again - on Monday after new leads arrive.

Thanks Tim for quick response, thanks also for link to Tim's ACT website guys.

EDIT

Plug leads (as promised) arrived from Tim at ACT , and went off again via DHL as no one was here to sign for them.

Got home from work to find the usual "you were out" card so telephoned DHL and was told to email them to get another delivery date and address to send to.

Also told that their email system was down ! Muppets.

I asked if this was the real DHL delivery company and they said yes !

So, Tim at ACT did his bit, DHL are crap, and I dont have my plug leads yet.

Bob

>> Edited by zircon450 on Sunday 20th February 09:16

>> Edited by Zircon450 on Sunday 27th February 17:23

[Zircon450]

Me again guys, still not happy.

Removed all spark plugs, reset the gap to .033" , most were there or there abouts.

Fitted the new heat shields from ACT together with the Magnecor ignition leads.

Certainly a lot better than it was.

QUESTION.
Does the extra 1 point of 98 RON Optimax fuel really make that much difference from BP Ultimate 97 RON ?

[M@H]

Zircon450 said:

QUESTION. Does the extra 1 point of 98 RON Optimax fuel really make that much difference from BP Ultimate 97 RON ?

Not to the Rover V8 in standard Tune.. no. You could put 95 RON in a lot of Chims and they still wouldn't pink either..

Cheers,
Matt

[peteA]

Removed all spark plugs, reset the gap to .033" , most were there or there abouts.

Can you get/has anyone fitted the multi electrode type of spark plug?

these are supposed to give a better / stronger spark plus they don't need the gap setting.

wondered if they were available for the RV8 / TVR engines.

[s4s280]

Bob here again, started this thread as Zircon450.

Still can't get the car sorted out by myself, and after all your posts back I feel commited to solving this myself.

Searched the archives A LOT - hence the time lag coming back.

Think I'm coming round to dizzy or ignition amplifier probs.

First port of call was the dizzy as my Lotus Excel has just given me a lot of grief in this area (broken reluctor ring).

I sucked the pipe, and waggled the vac advance module. Oh dear, not tight, but not hanging off as I have read on PH.

First question
"Should they be totaly rigid mounted to the dizzy body or should there be any movement at all ?"

Peter et al ?

[GreenV8S]

Should be solidly mounted, no play at all. Check both screws are tight, with one loose it'll still be fairly tightly held by the other.

[S4S280]

Cheers Pete, I'll have a close look at this after work.

sorry about the time lag - had to do Le Mans :-)

[s4s280]

Oki Dokey, on tightening the left hand screw holding the vac module onto the dizzy body, completeing the ssuck/hold vacum test, and now road tested it.

NO CHANGE, not a chuffin thing, has got Optimax fuel in, and am now running out of ideas.

One observation.
I had fitted a new coil from Tim at ACT, and low and behold, one of the terminal threads appears to be "leaking" fluid. So I changed the coil back to the original one.

Ignition off, I unbolted the coil clamp and heard what sounded like the stepper motor whiring. Touched the coil back to earth, same sound. This was followed by the ign amp moving from engine earth and causing the same effect. Did it several times, same results.

Wouldn't have expected the circuits to be live with the ign off, some part function of the imobiliser ?

Also, on the feed wires to the coil, there appears to be a what I am assuming is the ballast resistor block, anyway I can test the values.

Anyway, I'm thinking of trying the green resistor route on the ECU for a short run, just to see how the engine "feels". What was that part code again ?



>> Edited by s4s280 on Friday 1st July 13:42

[gavnn]

I had the same problem with my Chimaera hunting arround low revs for yrs, took it to TVR who told me thats how they are mate "its a Big engine what do you expect"?" after some yrs I found it to be the spark amp on the side of the distributor, put a new one on runs beuatifully, not for long though (day or two, keeps blowing, I think the ballast resistor is nt dropping the voltage back from the starting voltage and am now looking into that.