Mp9 intake with non-mp9 injectors

[Kurosaki_ZA]

A quick summary of my vehicle: I have a 98 Polo classic that use to be a 1.4i up until June this year when the motor blew and my mechanic had an AGG engine laying in his garage. I bought it from him and he dropped it in. I still have the 1.4i intake, injectors and computer box fitted on the 2L 8v engine. I've been having many problems with it since doing the conversion. The car jerks alot at times and is not very uniform with the power output except when I put flat. I've spoken to several car guys and everyone has a different opinion. Some say I should run a dicktator with my current setup. Others say I should get a 2L computer box.. and that's why I've decided to come to this forum.

I recently bought a 2l intake manifold that came with the fuel rail and injectors but was not mp9. During last week, I had the injectors taken out of the manifold and fitted on my mp9 manifold but it did not work. The mech who did it suspects its because the intake that the injectors are coming off of are not mp9.

Can someone please advise me what my next steps should be? The car rides well in general and has good power (didn't take it to a dyno yet) but i feel like it can push out so much more.

Any advice and help would be appreciated.

Thanks guys

[PapaJo]

Why did you not just go with the injectors in the 2l manifold with the 2L manifold adding the 1.4 map sensor to intake.

Did you measure the injector resistance to ensure it is the same as the mp9 injectors in terms of resistance of the injectors.

2l injectors are likely larger cc than the 1.4 injectors. This may cause an issue if you still run the 1.4 ecu and overfuel.

Your 2 options would be to reflash the 1.4 ecu with a 2L file or get Dicktator installed. Dicktator would likely be less of a headache and be more tunable than a reflashed ecu.

Did you check fuel pressure?

[Kurosaki_ZA]

The 2L manifold is a short intake and not mp9 so no place to put on the map sensor.

I'm not sure how to measure injector resistance but the one thing we did do when the 2L injectors were fitted was to see if the computer box was sending a pulse.

So even if I fit the 2l injectors to work, I'll still have to either get a dicktator or get my box flashed? My plan was to get a dicktator now during December but due to budget constraints I could not.

I have an adjustable fuel pressure regulator installed and it's currently set to 3bar. When the 2l injectors were fitted and we started it the first time, the pressure shot to 3bar like it usually does but almost instantly started dropping to zero as we tried to start the car.

1 thing I can also point out is that when we sprayed some petrol in the throttle body the car started and idled for a few seconds before switching off. It was after this that we checked if there's a signal being sent to the injectors, which there was.

I'm based in PE and I heard a dicktator is like almost R6k for everything. That's what put me out as my main plan was to get my freeflow installed, which I did, and to get rims

[PapaJo]

A std Dicktator should cost you in the region of 3k. If you buy and get it fitted, maybe 4-6k.

As you have srtarted and pressure drops straight away to zero, there is something seriously wrong. Is the fuel pressure regulator installed on the return line after fuel rail towards tank side?

If installed after fuel rail towards tank on return line, it means you had permanent 12v on injectors resulting in injectors fully open and spray maximum fuel into each cylinder.

Fit fuel rail outside of manifold and check that you get pulsing injectors with a fine spray when you crank the motor. I would recommend to let injectors spray into some sort of container and take all necessary precautions to prevent a fire hazard when doing this. Remember safety first as you don’t want any fires while performing this test.

With a bit of work, a flat file, drill bits and tread taps a suitable place for the map sebsor can be crafted on a filed flat surface (usually on the end square) if you are handy enough with hand tools. Alternatively find someone that can wekd up a piece of aluminum flange on manifold where you can fit the map sensor if you want to stay with mp9. No need to do this if you choose the Dicktator route.

[Kurosaki_ZA]

This is great advice. Thank you.

The FPR is sitting in my engine bay to the left by my cone filter. I think its connected before the fuel rail.

With no dicktator installed, If I had to just take the 2l manifold as is with the injectors and fit on my 2l motor, can I expect to have issues with the map sensor not being connected? Or is there a way to "delete" it?

[PapaJo]

This is great advice. Thank you.

The FPR is sitting in my engine bay to the left by my cone filter. I think its connected before the fuel rail.

With no dicktator installed, If I had to just take the 2l manifold as is with the injectors and fit on my 2l motor, can I expect to have issues with the map sensor not being connected? Or is there a way to "delete" it?

Your fpr should be after the fuel rail on the return to tank. Your fuel route should be from hp pump into guel rai, out of fuel rai to fpr and from for to return line on tank. That is the only way to have fuel rail and injectors pressurized.

You will need the map sensor. As a suggestion / idea you can possibly install a t-piece on the steel nipple that connects to the brake booster from intake and try to fit the nap sensor in one port on the t-piece. That is if you can craft a type of adaptor to t-piece to mount the map sensor to it. This might not be ideal, but worth a try.