Range Rovers Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
57 Posts
Discussion Starter · #1 ·
My Callaway(GEMS) now has another issues. If I drive it for awhile, park it for 45min+, then go to restart, it will rev to about 1000 and quickly drop to about nothing and then die. We thought it was the throttle position sensor going since it will run if it is disconnected. It revs about right, but has hard shifts for 1st and 2nd gears. Also gas mileage suffers badly.

I have tried 2 different MAF's without any difference.

Does it make sense if it is the crankshaft position sensor that it would run by disconnecting the throttle position sensor?

Thanks.
 

·
Registered
Joined
·
118 Posts
If it is the crank sensor you won't have any spark, so disconnecting the TPS wouldn't effect it. Fuel pump running as it should?
 

·
JACK'S GRANDAD
Joined
·
9,259 Posts
Test the TPS and go from there. The TPS does control the tranny too, so that may be a clue right there.

Martin
 

·
Registered
Joined
·
5 Posts
Sounds like classic fuel starvation and the exact same thing happened to me.Try the fuel filter first. It's an easy replacement and is tucked away near the driver's door opening. BTW, how many Miles/km's does your car have? If it's 100,000m/160,000km it could be the fuel pump giving up.

The CPS tends to cut out the engine when the CPS gets hot and then after the CPS cools down, the engine will restart and continue, it's an intermittent fault that doesn't get registered on Nanocom etc- easy test for this is to poor cold water over the CPS (bottom left hand side of engine block) after it stalls and if it restarts normally you have a CPS issue.

Jonathan
 

·
Registered
Joined
·
57 Posts
Discussion Starter · #5 ·
Thanks everyone.

Poleonpom, if it a fuel starvation issue, does it make sense that it will run by just disconnecting the TPS? That is the part that confuses me. The TPS is brand new and I had the dealership reset adaptation.

It does have 94k miles and I am not sure when fuel filter was last done.

Thanks for all the help.
 
G

·
The point is the CPS/CKP may fail altogether - and then the car won't start, or it can fail intermittently -in which case it will start but run badly: Without a steady CPS/CKP input the engine/ECU is not sure where it is of course, and so when/how to fuel etc...... in which case it 'best guesses' (and so can ignore some sensor inputs to an extent).

Just try that cold water test and replace... (relatively) easy & inexpensive to do !
 

·
Registered
Joined
·
5 Posts
Hi there,

Must admit, doesn't sound now like the fuel starvation or CPS fault that I suffered, however, if there is petrol flow resistance due to a blocked filter, then the 'sensors' maybe trying to compensate for restricted flow. Also, your mileage is about right for impending fuel pump replacement, so it could mean your current pump is not delivering the volume it should - the car tends to get a little ratty in its running prior to the pump giving up completely.

I've also read somewhere that before shifting gears, the car automatically reduces the revs between gears to limit wear on the gearbox, I'm not sure what part of the RR system controls that, but I'm thinking that you have a 'balance' of sensors issue here. My first step would be to eliminate the 'mechanical' delivery of fuel and measure the rate of petrol flow from the petrol pump to the fuel system which you can do by attaching a pressure gauge to the 'tyre valve' connection that you'll find on the fuel rail near the plenum chamber, from memory it should read 32psi (with ignition on), but double check this figure. This will then tell you if the 'physical' elements in your fuel system are delivering as they should and, if they're not, whether the 'electrical sensor' elements are trying to compensate.

Let's see if that brings any results first.

Jonathan
 
1 - 8 of 8 Posts
Top