Technical question on ECU re-mapping
 

Hi all, trying to help out somebody i met who has a 300 bhp punto turbo..... problem being is that in order to get more power he needs different fuel injectors, he sourced some from an integrale/hf turbo but when the garage fitted them the car would not idle atall.

Would the car need re-mapping as the injectors have been changed? im guess that the car needs to be remapped but other people said that the ecu should have a seperate map for engine idle?

just wondering what the next step would be, has anybody solved a similar problem??

thanks in advance

moz

Writer/Researcher Rapid Cars Magazine

The map is based on the standard injector size. Assuming he's put bigger injectors in, then of course it should need remapping. As at any setting for the old injector, the new injector will let more fuel in, hence the lack of idle, it's either cold fouling or flooding. Has he tried an fse power boost valve to raise the fuelling towards the top end?

No offense intended but I would have thought the owner of a 300bhp Punto would already have had extensive modifications including remaps, injectors, turbos etc and would have a comprehensive history of all non standard parts. Fuel injectors open and close and allow fuel to flow for a defined period of time. Any change in injectors would require a full remap and you should select a suitable CC injector depending on requirements.

ok, more info the car capacity has been increased to approx 1500 cc, the whole engine rebuilt with parts sourced from italy, turbo size increased (2 sizes up). gas flowed head, performace cam, lighten/ballance crank...its had the full monty $$$

the actually bhp is around 200/240bhp, he wants 300 but the standard injectors arnt good enough. when the injectors were changed the car didnt idle atall and revved to around 4k.

I wasnt present at the time but he has asked me to see if i could find out any usefull info for him. I do think the car must have a full remap but confusion surrounds the idle. I dont know the exact spec of this car but have tried to paint the best picture as possible.

many thanks

moz

When I changed the ECU on my car I had to change the fuel injectors as part of the package. For reasons too long to go into we started the car on the new ECU with standard injectors in and it refused to idle or run over 4,000 revs and it was a struggle to even reach 4000 revs.

With all this work on the Punto the ECU must have been remapped or piggybacked at some stage to modify the timing, fueling etc. If he wants 300bhp just adding more fuel wont provide the results unless the boost is being turned up and on standard rods, pistons it may be a costly error. I would suggest a decent standalone ECU and mapwork as a starting point which may provide ample gains in itself and then consider the next upgrade knowing the ECU can be altered to suit. 300 BHP through the front wheels will certainly be entertaining. I snapped a few driveshafts on my old Uno with uprated power and I know the Uno's and Punto's are prone to throw gears under heavy boost so be warned that parts could start breaking on a regular interval.

Good luck and keep us updated.

Sell it, buy a Fiat Coupe turbo, add

Chip 30 quid
Bleed valve 25 quid
Decat 89 quid
K and N 40 quid
Hybrid Turbo 500 quid

Theres your 300 bhp Fiat.

Failing that speak to any tuner and get them to match the injectors, may find that bigger ones are available that fir straight in.

How will he get that extra power down though? Has he put in a new diff? Will the gearbox cope?

The whole engine is fully rebuilt to sum race spec, its already has a programable ecu, the engine can take more power/run more boost but the injectors are the only part of the car which havnt been modified.

Yes it has a new diff, gear box is standard.

Well the cars a bit of a project/one off as there arnt many running such a high spec (so the owner told me)

I bet once its finished it would murder a fiat coupe, remember punto weighs 1000kg.

If he has a programmable ECU then it is simply a matter of gettig someone who can program the ECU to go in and change the settings for the injectors to those for the new ones. It will not be a full remap, just a matter of changing a couple of settings. Of course, if he is planning on running more boost then it is going to need to be mapped for that anyway.

I can't actually believe a garage would fit bigger injectors and expect the car to magically run on them. I assume he has checked that the fuel rails, FPR and pump can all supply this extra fuel.