Rovergauge connection issues on Bowler Tomcat

Rovergauge connection issues on Bowler Tomcat

Author
Discussion

w4hsa

Original Poster:

13 posts

74 months

Saturday 17th April
quotequote all
Afternoon all, I am trying to establish why my V8 is overruling and filling the sump with petrol.

I put it in the garage for a couple of months (all fine) now it won't run if I switch the fuel pump on.

I've checked the for a shuck injector and they all seem to click as normal,. Fuel pressure is normal and return seems ok etc etc so to avoid loading the expensive parts cannon I have invested in a Rovergauge lead and downloaded the software.

Initially I tried the latest version of the software but got an error message and reading around people suggest that version 0.8.8 is the correct version for Windows XP. This is installed and runs, I have also setup the COM port and everything looks ok.

However when I hit connect the red led flashes on the USB plug as it should (i see a couple of fast green flashes) then nothing - it appears that the ecu is not responding back to the rovergauge software.

I have tested the USB lead by connecting the top and left pin which shows both leads flashing (as it should)

I have also tested the diagnostic connector getting 2.8 ohms on the top pin to the ground pin and 11.3 ohms on the lower right pin to the same ground (when ignition on).

Can anybody help? What am I doing wrong?

Cheers Andy

Poko

299 posts

136 months

Saturday 17th April
quotequote all
How's the 12v? Have you checked the pins providing power to the ECU?

If it worked before and only now you're having issues, I'd look at the power first - then check all the grounding pins

w4hsa

Original Poster:

13 posts

74 months

Saturday 17th April
quotequote all
Confident that ecu is getting power as the engine will fire and run but then if I switch on the fuel pump (manual disconnect) it over fuels.

Also I can feel the main relays clicking and here the ecu cycle the fuel pump building pressure before start.

s p a c e m a n

9,812 posts

115 months

Saturday 17th April
quotequote all
Try the android app? You'll need an adapter for the usb lead, they're a quid on fleabay, will rule out the lead and ECU.

https://play.google.com/store/apps/details?id=com....

Edited by s p a c e m a n on Saturday 17th April 18:11

stevieturbo

15,488 posts

214 months

Saturday 17th April
quotequote all
w4hsa said:
Afternoon all, I am trying to establish why my V8 is overruling and filling the sump with petrol.

I put it in the garage for a couple of months (all fine) now it won't run if I switch the fuel pump on.

I've checked the for a shuck injector and they all seem to click as normal,. Fuel pressure is normal and return seems ok etc etc so to avoid loading the expensive parts cannon I have invested in a Rovergauge lead and downloaded the software.

Initially I tried the latest version of the software but got an error message and reading around people suggest that version 0.8.8 is the correct version for Windows XP. This is installed and runs, I have also setup the COM port and everything looks ok.

However when I hit connect the red led flashes on the USB plug as it should (i see a couple of fast green flashes) then nothing - it appears that the ecu is not responding back to the rovergauge software.

I have tested the USB lead by connecting the top and left pin which shows both leads flashing (as it should)

I have also tested the diagnostic connector getting 2.8 ohms on the top pin to the ground pin and 11.3 ohms on the lower right pin to the same ground (when ignition on).

Can anybody help? What am I doing wrong?

Cheers Andy
Keep it simple.

Find out where the petrol is coming from. If need be, remove the rails/injectors from the engine and let them sit/spray into small jars for testing.

First unplug them all and key on to prime the system. Does any leak through the injectors ?
Then plug them back in and perform same test.

Then try cranking to see how much is sprayed from each.

Unless there is somewhere else it could be drawing fuel in ( sometimes a leaky FPR, can allow fuel to be drawn in via the intake vac reference if fitted )
But if it is leaking in via one cylinder...pull the plugs and crank it over ( disable ignition ) and see if any fuel/wetness is ejected from any one cylinder more than others
As well as inspecting the plugs.



w4hsa

Original Poster:

13 posts

74 months

Saturday 17th April
quotequote all
Thanks all for the help.

I intend to approach this as 2 faults,. 1 mechanical and 1 ecu readings.

I will explore more the fuel injectors and locate the fuel entry point and secondly investigate further why Rovergauge isn't giving me readings.

Cheers Andy

GreenV8S

28,860 posts

251 months

Sunday 18th April
quotequote all
You can check whether the injectors are being held open with a volt meter or attach a noid lamp to also see how much duty cycle you're getting.

You can also check whether the fuel rail will hold pressure with the pump off - if not, that suggests the fuel is going somewhere, perhaps through an injector that isn't sealing properly. It's not especially difficult to test them but does involve playing with petrol under pressure, which can be highly dangerous if you don't know what you're doing. There are places you can send them to for servicing for a reasonable cost if you don't fancy trying to DIY.

w4hsa

Original Poster:

13 posts

74 months

Monday 19th April
quotequote all
Ok latest update.

I removed the fuel rail complete with injectors, disconnected the plugs (so they wouldn’t open) then cycled the fuel pressure pump.

Fuel pressure registered and not a drip from any of the injectors, all sealed as they should be.

I then reconnected the injector plugs and repeated, they all fired as they should.

So leaking injectors can be crossed off the list.

GreenV8S

28,860 posts

251 months

Monday 19th April
quotequote all
Does the fuel rail hold pressure with the pump off?

Max_Torque

16,905 posts

184 months

Monday 19th April
quotequote all
A failed diaphram / seal in the manifold referenced fuel pressure regulator can in rare circumstances leak fuel into the inlet manifold! Remove the presssure reference line, run the pump, and see what happens!

w4hsa

Original Poster:

13 posts

74 months

Monday 19th April
quotequote all
Fuel pressure drops slowly once the pump has been turned off.

Pressure reference line? Is this the return pipe?

stevieturbo

15,488 posts

214 months

Monday 19th April
quotequote all
w4hsa said:
Fuel pressure drops slowly once the pump has been turned off.

Pressure reference line? Is this the return pipe?
No, the line to the intake manifold from the top of the FPR.

I would also still try cranking the engine over with some jars to collect fuel from each injector, to do a sort of basic flow test, just in case.

But a ruptured diaphragm in the FPR as already said is another possibility.

Max_Torque

16,905 posts

184 months

Monday 19th April
quotequote all
w4hsa said:
Fuel pressure drops slowly once the pump has been turned off.

Pressure reference line? Is this the return pipe?


The small metal pipe facing forwards in that ^^^ pic is connected to a short length of rubber hose and to a similar metal stub pipe sticking out of the inlet plenum base.

Max_Torque

16,905 posts

184 months

Monday 19th April
quotequote all
If you have an early 3.5 injection with the flap meter and cold start injector, check the cold start injector as well!!

Overfuelling in the sump could also be due to simply running very rich, and the excess fuel condensing on the bores and running down past the rings and into the sump.. Over fuelling can be caused by a number of issues obviously!

w4hsa

Original Poster:

13 posts

74 months

Monday 19th April
quotequote all
If the fuel pump regulator had a bad diaphragm wouldn’t fuel be visible in the vacuum pipe from the plenum?

Max_Torque

16,905 posts

184 months

Monday 19th April
quotequote all
w4hsa said:
If the fuel pump regulator had a bad diaphragm wouldn’t fuel be visible in the vacuum pipe from the plenum?
yes, and normally pnuematic side of the reg is obviously full of fuel too!

w4hsa

Original Poster:

13 posts

74 months

Monday 19th April
quotequote all
Vaccum side of fpr is dry.

I think the next place to look is the spark side of things - make sure everything is in order.

Just realised, I fitted ngk bpr6es resistor plugs last time so will revert back to previous set.

What are symptoms of air flow meter taking a dump? Longer injector pulse eg more fuel?

Edited by w4hsa on Tuesday 20th April 06:35

GreenV8S

28,860 posts

251 months

Tuesday 20th April
quotequote all
Overfuelling so much it won't even run suggests there's a huge amount of fuel going in, and I think you've ruled out gross problems in the injection mechanism itself.

If you have the flapper system with a cold start injector, you'll want to disconnect that. It's supposed to be controlled by the thermotime switch but this a reputation for being problematic on TVRs and can leave to massive overfuelling. It isn't needed in the UK climate and is routinely left disconnected to avoid these problems. Disconnect it and see whether that helps.

If that doesn't help, measure the fuel pressure with the engine running. If you've lost the manifold pressure reference signal then you would see peak pressure all the time, instead of staying relative to manifold pressure. That would cause overfuelling under light load.

w4hsa

Original Poster:

13 posts

74 months

Tuesday 20th April
quotequote all
Sorry should have filled in more details to help possible diagnosis.

It’s a standard 3.9 v8 from a Range Rover running the standard Hotwire airflow meter.

GreenV8S

28,860 posts

251 months

Wednesday 21st April
quotequote all
Is it running with lambda sensors?

Check the coolant temp sender circuit resistance across pins 7, 25 of the ECU plug when disconnected from the ECU - you should see about 2500 Ohms at 20C.

Check the tune resistor circuit resistance across pins 5, 27 of the ECU plug when disconnected from the ECU - you should see about 4kOhms for a catted car or 450 Ohms for a non-cat.

Check the fuel pressure drops when the engine is at idle. You may need to unplug the.injectors and run it on cold start to get it to run long enough to measure.