2.3 Duratec

[duh]

Have had a 275 bhp Dutatec installed in my R400.Problem with misfire from day one.If you floor the throttle quickly you get all sots of backfires .Engine builder initially took back ecu and fuel pressure regulator,but found no problems.Next they spent a day with a lap top trying to tweek the ecu,but with no improvement and finaly the engine was taken out sent back to them to be sorted,but again no better.On start up from cold it runs on choke/cold start for approx 18 seconds,during this it revs clean as a whistle.I have put a very basic halfords emission tester on it which shows 5% when engine is warm,and when you rev it this figure drops to zero.If you squirt petrol down the throttle bodies again it revs perfectly.With my rather basic knowledge it suggests that it is very weak low down the rev range.Any thoughts please.

[Peter T]

It sounds like the mapping structure is not correct.

Using your halfords tester is frankly a waste of time, as it would be nowhere near quick enough to accurately check what is happening to your engine, so really you need to have an independant Lamda air fuel meter attached while you drive the car through it's rev range on the road. Even this is not perfectly usable unless you can log the data for any given loading or speed.

A rolling road session is the only real option to assertain if it is running weak. Are you sure that the missfire is not ignition related? you state that it was like that from day one? have you tried eliminating the obvious causes like swapping the plugs/coil/leads/crank possition sensor?

Also worth considering is the temperature sender as this could be giving false readings to the ECU regading fueling? Also check your throttle pot as a faulty unit will give the ECU false readings.

Have you also checked to make sure that your fuel pump can supply your engine with the correct amount of fuel and pressure?

I would eliminate all of the above first before you throw money on a session again to reduce costs.

What ECU do you run?

Is it a standard fuel pump?

Where the injectors new? or have they been checked and flow tested also?

Is your alternator and charging system pefectly adequate for supplying the necessary current that your electrical system needs, it might lie here also.

Lot's of things to check first but you might find the problem.

 

R500 Mango Madness

[Peter T]

PS, is your CPS screened? does it run close to another power source?

 

R500 Mango Madness

[Dobuy]

Yep, I agree with Peter, it is almost certainly a fuelling problem, due to the size of the throttle bodies and injectors required for big horsepower, they are quite sensitive to the need for proper mapping, especially at low revs.

 

Duratec SV, built in Dubai

[Jason Plato]

sounds like the accelaration fueling is wrong, so that when you snap open he throttle it hesitates.

 

After spending all that money on the 270 horses a good mapping session is a sound investment you need to put the engine under load and monitor fueling with a wide band lambda - this can be done on the rollers

 

 

 

 

 

here is C7 TOP

Taffia Area Rep

[Gambo]

I had a very simi;ar problem with my car when the throttle bodies were fitted. among other things incorrcet with the map , the main problem was that th ethrottle pot had not been properly set, it was reading site 9 on idle and had been maped like that( numpty mapper ) What was happening was that the car was idleing on site 9 then as throttle was added the pot would go site 10 then site 1,2,3,4etc, so as the revs rose the fueling was reduced I uploaded a generic map for a similar spec engine to mine from SBD and steve talked me through th eset up process, balance bodies, set up Throttle pot. the car ran very well. I then took it to the two Steves and they did the rest.

If you have a laptop you can connect it might serve you to to check that out. Might not be your problem, but could be somthing silly like that.

Best of luck sorting the problem. I bet a 275 duranail will be quite entertaining to drive 😬

 

RED 2.0 HPC 230BHP

[timbo]

 

sounds much like a fuelling issue. But why if it was 'acceleration' fuelling would it only rev cleanly for 18 secs after which it coughs and spits? Coolant/air temp will hardly have moved within 18 secs. I just can't seem to fathom why after 18 secs it pisses about??? that's what's scratching me! It can't be acceleration fueling ... Both cold start fuel & ign compensation will definitely still be active within 18 secs of start up... if not for another 5-8 minutes at least with a reducing compensation % values.

 

How has the engine been mapped.. what ECU are you using?

 

If it is an emerald you are using here is a very simply check to carry out. Add 20% fuel to all values across the map, all load & speed sites. (make sure you save the original map file first). How does it rev. If you have no access to this... increase the fuel pressure by 1 full turn on the fuel pressure regulator (remember to reference the original setting). (provided it is adjustable) See how it responds from there.... if a little better try one more turn. Please do not attempt to drive the car even if it improves based on these suggestions (they are only a quick test) .... I don't want to be responsible for a melted piston 😳

 

 

 

 

 

SV 2.3 Duratec and for the last time, no it is not a truck

[timbo]

 

sorry.. I may have missed something here... when you apply quick throttle action does it spit back on the induction side (weak mixture) or is it predominently exhaust backfire? hmmmmm... could be also be ign timing

 

SV 2.3 Duratec and for the last time, no it is not a truck

[duh]

Thanks for all the replies,many questions which i will try to answer.Ignition,checked-ok.Fuel pump standard R400 pump,but pressure checked and fine.Injectors new.Alternator new,checked-ok.When i apply quick throttle it mainly backfires through the exhaust with flames,and i have also seen it spit through the throttle bodies/air filter.Above 3500-4000 rpm it is perfect and balistic.The engine builders are flying up to Scotland in January to have another go at re mapping the ecu(mbe) but i have lost all confidence in them.I would rather not name them but they are certainly one of the best known.

[timbo]

 

well at least they haven't walked away from the problem.. and I presume are taking all costs on the chin. That at least is a merit despite the problems you have. Good luck in January... keep us informed of the results. As Dave Jackson says... get the thing on a ro ro .. it is small money well spent. I gave Dave Walker a number of gold shekels Sept past... different motor compared against the 1st so so mapping session I paid for.... no extra power gains but totally different animal in driveability terms.

 

SV 2.3 Duratec and for the last time, no it is not a truck

[simonbell]

Is the R400 pump uprated........or just the R500 one?

 

If the R400 runs a std pump then surely ypu need the R500 one........as I understand it the std pump won`t be able to supply the fuel to an engine at that level of tune.

 

It sounds as though it is a weak mixture. When you start up the ecu has startup enrichment which falls off.....not sure it would nromally be as much as 18 secs.........after this it is running on the map. However there are sll correctons for air temp, coolant temp etc. I doubt it would be air temp sensor as they normally read hot in a duratec leading to extra fuel being added.......it is worth checking all sensors though.

 

My first port of call would be to ensure the fuel pump is up to the job. Presumably your engine builders have built and run the engine on a dyno to map it. The thing to do is look at what is different between running the engine on the dyno and running the engine on the car........again points towards fuel pump.........

 

Could be all manner of things like sensors, wiring issues.........but start eliminating the obvious things first.

 

Simon Bell - Caterham 7 Duratec R

I`ve seen the future.....and it`s powered by duratec Check out the website here

[timbo]

 

unlikely to be the pump Simes... "Above 3500-4000 rpm it is perfect and balistic" .. I wouldn't have expected this statement if the base line fuel pressure was questionable.....

 

SV 2.3 Duratec and for the last time, no it is not a truck

[Graham Perry]

BUT, I would still check the fuel pressure on the rollers under full throttle acceleration in case the pressure slowly trails off in that mode AND find another remote fuel pressure gauge as well in case theirs is not as accurate as the believe.

 

I might also be tempted to replace the fuel filter in case high fuel throughput during full throttle is stirring up some crap.

 

 

Edited by - Graham Perry on 30 Dec 2006 14:03:06

[duh]

I believe the fuel pressure has been checked a number of times and i certainly saw the pressure remaining contant with a gauge fitted and the throttle snapped open.When the engine was returned most recently the builder found that when run on the dyno the fault showed up.They did various tweaking to the ecu and commented that whilst not still instant under throttle it was better.I have found it to be even worse,and sometimes i can kill the engine under quick throttle.when the engine was first installed i tried to race at Croft.After exiting the hairpin with full throttle i was about one third of the way down the straight before it cleared.

[Paul McKenzie]

Being the owner of a carb'd VX dinosaur , I must admit to knowing little about injection...however has anyone checked fuel flow . I know you have the pressure, but that doesn't necessarily mean you have the flow if the system is partially blocked

 

Paul

[Gambo]

Duh, sorry to repeat my self, but has the throttle pot been checked 🤔, the more I read this thread, the more it sounds exactly what i had. Mine would give all sorts of grief at small throttle openings or large at low Rpms, but once the motor was up and running so to speak It would go OK.

 

RED 2.0 HPC 230BHP

[duh]

I am not sure if anyone has looked directly at the throttle pots.will ask the question,although the fact that neat petrol srayed down the pots cures the problem,suggests to me that this is not the problem.

[Tre Zarcoff]

I think he means the electronic sensor that tells the ECU how much the throttle is open

 

I like cream...

[duh]

Thank you for that mr piles.I would hope mr engine builder checked this,but who knows!

[millsn]

Having done the same thing myself -I'd second the throttle pot recommendation. I seem to recall that the info I was working to had been supplied incorrectly which led to my problems so double check your sources for the info you're working to then double check your connections.

 

Secondly, I had to make some major changes to the fuelling in my car to get it to work after using my engine builders map as a starting point. In my case I leaned it out with the usual extensive help from Mr. Steve "I did all this years ago" Foster!

 

Nigel Mills - My next car must have xenons

[Mickrick]

Any Joy Mr. duh? 😬

[duh]

The learned people who built my engine are now coming with lap top in hand on the fifth of feb to knockhill to attempt to solve the problem with a bit of remapping.I am not confident,time will tell.

[dannylt]

Could it just not be poor acceleration enrichment configuration? I had a big problem with this when I first got my car even though the engine ran fine with loads of power and the map was fine. Tweaking this is apparently a bit of an art and hard to emulate on rollers. Experience of the mapper counts! Each ECU does this differently, but Steve & Steve @ Track'n'road spent some time sorting my MBE. It used to cough & splutter on fast throttle opening as you say but after their treatment the instant response is enough to wheelspin - perfect!