Fuel pressure going crazy

[spongebob]

Hi just been checking my fuel pressure on a M111 turbo conversion i e just done into my 190e.
Watching videos online other peoples gauges when off stay static then when started they bump up a little bit higher.
Mine goes to various numbers when priming then when running just goes completely nuts
Its running the stock tank and lines but with a brand new Bosch 044 pump and the stock regulator which i believe is around 3 bar

www.amazon.co.uk/photos/share/XSS79kNBagdGGzVZjhYHBP7ePPNzp443mGBgryXr3go

[carat 3.6]

Going to need more details on what you've done. What controls the pump? What fuel pump relay? Have you removed the pressure accumulator? What regulator are you using? Standalone ecu?

[kevins]

It should go to the set pressure on key on, (usually between 3 and 3.5 bar) and when the engine is idling it should drop by the manifold depression (generally around 0.7 bar), as you open the throttle it will vary between the two pressures.

If the gauge is not damped it will flutter at a high frequency as the injectors open.

[bmw2101]

have you put the reg on the feed line instead of the return?

[spongebob]

Sorry ive been on hol for the last few days.
I said in my original post its using the stock 190e lines which ive just connected the stock clk230 engine fuel rail.
So my guess is should be around 3bar.the clk ran fine from london to warrington before i pulled the engine.
The clk had no return line
Just a feed.
So my setup is original 190e tank with return removed.
Line out the Bosch 044 pump, filter and standard 190e fuel acumalator
New wiring and relay connected to base mapped emerald k6+
Line from pump the standard clk fuel rail
Thats pretty much it.
Car starts and ticks over ok on base map.
But fuel pressure is off the scale bouncing off the needle stop .

In my mind the setup is essentially the same as the clk230 had. Pump, line to rail and regulator. No return

Can the fuel pump be controlled to alter pressure through the ecu??
Its going in for mapping on Tuesday so could do with figuring out and sorting before if its something i can fix myaelf
Thanks

[carat 3.6]

Aug 15, 2020 13:17:23 GMT spongebob said:

Sorry ive been on hol for the last few days.
I said in my original post its using the stock 190e lines which ive just connected the stock clk230 engine fuel rail.
So my guess is should be around 3bar.the clk ran fine from london to warrington before i pulled the engine.
The clk had no return line
Just a feed.
So my setup is original 190e tank with return removed.
Line out the Bosch 044 pump, filter and standard 190e fuel acumalator
New wiring and relay connected to base mapped emerald k6+
Line from pump the standard clk fuel rail
Thats pretty much it.
Car starts and ticks over ok on base map.
But fuel pressure is off the scale bouncing off the needle stop .

In my mind the setup is essentially the same as the clk230 had. Pump, line to rail and regulator. No return

Can the fuel pump be controlled to alter pressure through the ecu??
Its going in for mapping on Tuesday so could do with figuring out and sorting before if its something i can fix myaelf
Thanks

Sorry but that setup is not going to work.

You need to get rid of the 190e pressure accumulator and connect the return line, use an earlier m111 fuel rail with the kompressor injectors swapped in.

[spongebob]

Thankyou. Ive ordered an aeromotive fpr kit. Ive been told the old m111 rails and regs are not much good for proper boost.
Ill run a new return line in thicker diameter back to the tank. Should work well then.
What caught me out was the clk having a tank based return or relief line whatever its called. With the actual rail just having a feed i didnt think the car would need a return line

Thanks for the help. Hopefully sorted by tuesday morning ready fir tuesday afternoon mapping session.
Nothing like cutting it close haha

[carat 3.6]

The m111 fuel rails are fine for big power, can certainly flow more fuel than the injectors you've got can use. It is a good shout to use a proper FPR though.

If your anywhere near Oxford I've got a few here you can borrow if needed.

[spongebob]

Ah right. I spoke to someone after you said that had done it and originally had the cast alloy rail and he said he swapped it out as it seemed to struggle.
He told me he modified the later CLK one and linked in an aftermarket fpr and its since seemed to be much better.
I'm not too clued up on the difference to be honest but as i already have 2 of the later ones and wanted a good fpr anyway ill just do the same.
I'm using 911 GT3 injectors which are 660cc as using emeralds calculation the original 290s would be pretty much on the limit of flow at 400bhp which is my target power for this step of the build.
I have a spare engine that i was going to strip and upgrade the internals properly to push for more in the long run.
Thankyou for your advice though as it steered me in the right direction.

[bmw2101]

out of interest where are you taking it to get mapped?

[spongebob]

Efi parts in Runcorn. They claim to be an emerald specialist so seeing as they're 30 mins drive and emerald is 4 to 5 hours for me i figured id give them a try.

With me all this is new and first time ive ever tried such a project so didnt want to pay to have the car taken all the way to norfolk to find ive done something wrong and they cant map it.
At least this way if ive messed up its not cist me much to find out haha
My plan is to get everything done and setup, findwhat works and doesnt and just get the car motd and useable then next year ill book it in with emerald themselves and get it fine tuned

[bmw2101]

Ah thought so, Chris is very good, when i was putting the b230 in my bmw, he told me to go for microsquirt, and he also agreed to tune it which that type of ecu not many people will. He is an emerald specialist, your car will be in good hands.

[spongebob]

Got the car sorted. Aeromotive fyel reg turned up 3 hours before i was due in for mapping. Nothing like cutting it close. Haha.
Chris did a good job on it. Hes advised me to swap my manual boost controller to an electronic one as I'm getting silly torque mid range but it dies off at the top.
But still he got just under 300bhp and 370lbs torque. Not bad from a second hand t28 on a 90 odd thousand mile engine that was cobbled together by someone who had no clue what he was doing(aka me) .
Its been a steep learning curve for me but now i know more ive got a few tweaks planned for it that should see me over 300bhp in and 1150 kg car. Should be a good laugh