Fuel pressure gauge ..

[ChrisW500]

I have a 99 plate Chimaera 400 pretty much stock. Had a failed injector recently and have replaced all 8 with Omega 3 litre injectors. I want to have an in line fuel pressure gauge so I can monitor / adjust things going forward. Question is what side of the fuel system to fit it as per piccy in terms of the hoses and any advice / pictures of other gauges and adjustable FPR?



Thanks

Chris

[hoofa]

Mount in the return line to the tank

[ChrisW500]

Thanks A or B then?

[rev-erend]

B.

[Steve_D]

No
It has to be in the supply line to the regulator which will be A unless you have changed things (you mention adjustable pressure reg.).
B is the return line after the fuel pressure regulator so unless there is a restriction in the return line the pressure will be near zero.

The pump, if pumping against a closed line, will produce many bar of pressure and way higher than we need.
When pumping against the regulator it will be trying to pump as hard as it can but the reg. is releasing the pressure at about 2.5bar. So if you measure anywhere along the line between pump and reg. you will only see 2.5bar.
Steve

Edited by Steve_D on Thursday 21st October 08:45

[spitfire4v8]

My advice is to not fit a pressure gauge in the engine bay, they often aren't designed for continuous use (no matter what the ebay sellers will tell you) unless you get a very expensive one.
Much better/safer is to fit an electric sender and have the gauge in the car, they're popular for motorsport and designed to be permanently fitted.

However, you really shouldn't need to monitor fuel pressure all the time unless you think you might have an ongoing issue. Get the pressure tested (you have a serp engine so have the take off on the fuel rail for this purpose) and if it's faulty change the reg, if it's ok leave it all alone.

[ChrisW500]

Great advice all thanks… happy to leave it be but a quick question, given the new injectors would they be just fit a play then? They are in and the car is running fine with no discernible differences in running, tick over or power?

[spitfire4v8]

what flow rate are the new injectors? if they are the same, or very slightly higher, than the old ones then you will be fine.

[ChrisW500]

The Vauxhall Omega 3.0 injectors are quoted at running at 3.8 BAR though, and flow rate is quoted at 3 BAR.

[ChrisW500]

Also 470 ccm at 3 bar and is a 4 hole laminar injector

[Zener]

ChrisW500 said:

Also 470 ccm at 3 bar and is a 4 hole laminar injector

I doubt a factory 3.0 run of the mill GM motor would come fitted with that large/f;low rate inj TBH you set pressure and done no need to constantly monitor FP with a gauge

[spitfire4v8]

ChrisW500 said:

Also 470 ccm at 3 bar and is a 4 hole laminar injector

could do with a part number or a link to what you bought, that's pretty much double the std injector flow rate ...

[ChrisW500]

The spec is .........VAUXHALL OPEL CARLTON OMEGA SENATOR 3.0 24v C30SE FUEL INJECTOR 0280150413

[url]|https://thumbsnap.com/fPM7Xrk2[/url

These are in and work perfectly, no smoking or excessive fuel use that I can detect, plugs are burning at normal colour just wanted to set everything up to properly suit these injectors...

[spitfire4v8]

yep they are 205cc/min and 16ohm resistance . they are slightly lower flow than std by about 6 percent .. which coupled with the reduction in mixture from e10 might give you an issue if you use e10 that is. total reduction in mixture would be in the order of 10 percent from original on non ethanol fuel.

You might want to get the full throttle mixture checked on the dyno just to be safe. On part throttle the lambda control will sort that out anhyway.

[ChrisW500]

OK many thanks ... I will get it on the dyno in the next few days ... surprised that they are lower flow rates ... given they are 4 hole and more efficient than the standard rover injectors ... I certainly don't want it effecting the AFR rates at full throttle :-(

Edited by ChrisW500 on Thursday 21st October 16:53

[spitfire4v8]

yes whenever i get std injectors tested they come out around 220cc/min at 3bar test pressure. I use injectortune and mr injector who are respected reconditioners so i assume their rigs are fairly consistent. They both seem to produce the same kinds of numbers anyway.

[Zener]

That figures because @ the standard 2.5 BAR the stock Lucas inj's are around 185/195 cc