I've got a 97 Disco, bought it from a guy i know, he had it as a 2nd vehicle. Runs good, until you get it up to about 55 - 60mph and then it starts acting like it has a governer on it......it cuts out and then comes back. Builds a little speed and does it again. The guy i bought it from says he called around and was told that the fuel pump was weak and couldn't keep up at that speed. That cant be right, can it? Any info will help.....Thanks

 

What's the fuel pressure at the injector rail?

 

Could be one of two things:

Fuel pump/filter/fuel pressure regulator - there is a schrader valve on passenger side fuel rail, should be 32-34 PSI when truck is running.

Vehicle Speed Sensor - on transfer case - when it starts going out, it begins to limit the top speed the vehicle can achieve. Normally that would be like 115 mph. But as it gets worse it will start doing it at 40 - 50. The RAVE tech manual download will show you exactly where these are. Not sure if you can clean the VSS, but you may improve the connections. It is not cheap, might check with uased parts source (dismantler, or you pull slavage), The VSS tells the ECU how fast you are going, the ECU starts killing spark to cylinders one by one to get you to slow down. The Rover is in charge, don't ever forget it!

I'd bet on the VSS, fuel would have been more RPM related.

 

or more load and rpm related. the injectors will obviously be open longer under load and require the fuel pump to work harder.


if it bucks the same at full load/high speed at low vehicle speeds as it does at full load/high speed at higher speeds, then id say it sounds like the VSS...

 

Thanks for the info. I put it in body shop today.....gonna make her pretty before I take her out and try to brake something. I'll try some of yalls suggestions when I get it back and let y'all know if I figure it out. Thanks for the help guys.

 

You must have plenty of money to throw away. Who ever heard of making a pig pretty before you take it to the mudbath........

No matter how pretty you try to make them, underneath they are still a pig.

I would rather spend my money on things that really matter. And with a Discovery, It will give you plenty of opportunities to do that!