Spluttering under acceleration

[petros]

Strange fault with the car. Once the engine is hot and I put my foot down hard she splutters and coughs. Easing off the pedal stops the problem and she runs normally.Just fitted new.. ecu, coil, a f m, leads, shrouds, plugs, fuel pump, regulator and dissie cap. Any one ever come across this before ?

[bigd1877]

I'm having the same problem with my cerb, took her in to Gatwick they sorted the problem for about 2 days!!!
its really starting to pee me off HELP NEEDED

[GreenV8S]

petros said:

Strange fault with the car. Once the engine is hot and I put my foot down hard she splutters and coughs. Easing off the pedal stops the problem and she runs normally.Just fitted new.. ecu, coil, a f m, leads, shrouds, plugs, fuel pump, regulator and dissie cap. Any one ever come across this before ?

Yikes, you seem to have changed all sorts of things, and any of them being out of spec could cause problems like this. Or maybe the reason you changed all that is that you are trying to fix a problem by guesswork and haven't guessed the right thing yet?

Guessing at the problem not an approach I recommend. You need to get somebody to monitor the fuel mixture and spark strength under load and see what is going wrong and then track the problem back to the component[s] that are causing it. It's no rocket science but it requires tools that the average DIYer won't have access to, and a detailed knowledge of the inner workings of the engine management system, and experience in recognising and tracking down problems helps too. For problems like this, getting an experienced specialist to sort it is usually the best bet.

[that daddy]

Did you change rotor arm when you did cap,hope you fitted NGK plugs.also theres 2 push together spade terminals running in front of plenum related to low tension circuit,check these are clean & tight also the one,s going onto the coil,if not close up with pliers or crimp on some new.hope this helps with your problem.might not but good luck...

[that daddy]

Green v8s your right there no substitute for a scope to check KV, voltages etc,less costly in the long run.

[FunkyGibbon]

when mine did something like this it was the ignition amplifier.

FG

[petros]

changed that as well but could be duff.

[griffter]

petros said:

Strange fault with the car. Once the engine is hot and I put my foot down hard she splutters and coughs. Easing off the pedal stops the problem and she runs normally.Just fitted new.. ecu, coil, a f m, leads, shrouds, plugs, fuel pump, regulator and dissie cap. Any one ever come across this before ?

Did you replace everything like for like? ie you haven't got resistive leads, shrouds and plugs for example? Or the whole lot unresistive? IME you want at least one, preferably two of these to be resistive. Normally the leads and shrouds - unless these are replaced with ACT shrouds, which are non-resistive. Standard plugs ar B7ECS - non resistive.

When you refitted the ignition amplifier did you use heat conductive paste between it and the distributor / mounting plate?

Is the vacuum advance module loose?

Crap / air in the fuel line? Blocked fuel filter?

Does this happen at any / all revs? Or does it kick in at certain revs like a rev limiter? Can you put your foot down engine cold and it's OK?

Was the a f m new / recon / second hand? Is it for the TVR (Jags / Saabs use the same) and is it calibrated?

[rfisher]

Email me if you want to hire a fault code reader for £10 per week.

[petros]

Thanks Robert, had a fault code reader on her, only three times has a fault come up, 1) tune resistor out of range. changed. 2)throttle pot out of range.changed. 3) a f m out of range. changed. with the right one.

[scottiesland]

Hi.... I have the same problem with my Chimaera its a 96 4.0... its only got 15,000 miles on the clock.... it splutters quite alot especially when it heats up..... ive taken it to tvr barnet on a number of occasions and they could not find any problem with it.... when you hit about 3 thousand revs and try and put your foot down it holds back!! then kicks in... like some sort of power band!! then when i come to a stop at the lights and try and pull away it really splutters and backfires, and has problems pulling away, not all the time but it is getting worse!!!
I have tryed changing the leads and spark plugs....worked better for a day then went back to normal!!!!!
Its really getting to me now....cause i cant sell the car in this condition...can anyone advise me on what i could do to sort it out?

Cheers
Scottie

[GreenV8S]

Take it to somebody who knows what they are doing. That behaviour indicates you have a major problem during closed loop operation, and I would have thought any decent specialist would have no trouble tracking it down.

[john p]

I've had a very similar problem with my Chim,it seems to have cleared now,the last things I done were to move the position of the HT king lead,it was making contact with the coolant tank and other leads.I also checked the connections on the ecu and relays in footwell.The annoying thing is I don't know if it was any of these that was causing the problem or if the problem will come back.

[that daddy]

Oh it isnt the dreaded magnecor king lead problem by any chance if thats whats been fitted,just a fault,dont want to slate there products but.....

[jsr]

scottiesland said:

Hi.... I have the same problem with my Chimaera its a 96 4.0... its only got 15,000 miles on the clock.... it splutters quite alot especially when it heats up..... ive taken it to tvr barnet on a number of occasions and they could not find any problem with it.... when you hit about 3 thousand revs and try and put your foot down it holds back!! then kicks in... like some sort of power band!! then when i come to a stop at the lights and try and pull away it really splutters and backfires, and has problems pulling away, not all the time but it is getting worse!!! I have tryed changing the leads and spark plugs....worked better for a day then went back to normal!!!!! Its really getting to me now....cause i cant sell the car in this condition...can anyone advise me on what i could do to sort it out? Cheers Scottie

I'm no expert, but is 3000 ish revs a key rev for the lambda sensors (dont know whether they monitor the oxygen in the exhaust gases below or above this figure, but it is definitely a crucial point for the sensors)

[scottiesland]

Thanks for all your advise......I'll give some of the things mentioned a go and let you know the outcome....cheers

[scottiesland]

Hello again............Can anyone recomend what type of spark plugs and leads to put on my Chim?

[David H]

scottiesland said:

Hello again............Can anyone recomend what type of spark plugs and leads to put on my Chim?

For spark plugs you'll need NGK B7ECS

Plug leads you can go for a few option but make sure you get something that will stand up to the heat. Alot of people go for Magnecore but I've also heard good things from other leads including Morosso. Do a search on ebay (seems a bit lacking on there at the moment, give it a few days).

When you do buy the leads, make sure you get the extenders for the ends. The best place for these is probably ACT www.actproducts.co.uk/ignition.php

[chassis 33]

Plugs. NGK B7ECS

Leads. Pays your money takes your choice. I ran a set of Lucas eBay specials for a while on the racer, then tried some Magnecors that came with my LPG disco to see if they made any differece to the spark. A crude test admittedly, earthing a spark plug on the plunum box and seeing if there was any visible differece. There was, so I knabbed the ones off the disco and that was that. Whether they made any difference to the power I've no idea the cynic in me says I doubt I'd notice it in the right foot if it did and I probably wouldn't go and spend 80odd quid on a set. Like I said pays your money takes your choice.

I'm getting to know the folks at my local rolling road quite well, I'm tempted one day, once I have some cash to burn to hire it for the day and just try different things like leads etc to see if the rollers can tell the difference. Just out of idle curiosity, nothing more.

Regards
Iain