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1995-2002 Range Rover P38A
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Discussion Starter #1
Morning all! I am in the midst of trying to put our 97 GEMS back on the road after 3 years with the engine out.
Symptoms that i am fighting
Starts fine (hot and cold), idles fine (a little bit of surge, but nothing bad).
Once hot (or closed loop, I can't tell.. but think it is the hot), engine will NOT rev above 2500-3k RPM, unless i press the gas peddle well above 1/2 travel. Can feel the engine shuddering like a very soft rev-limiter. Happens when under no-load, and when in gear driving (all conditions)
Prior to getting hot, engine runs great all the way up through revs.

Recent work: engine out, new bearings/seals (heads left alone). Fuel pump & sender (brand new yesterday). Fluids are all topped off. No sign of oil in coolant/coolant in oil. coolant system not appearing to be overly pressurized.

No check engine light (have only run for 10 minutes at a time, up/down driveway)

Items verified:
Fuel pressure prior to start: 35psi
Fuel pressure when @ idle: 30-35psi
Fuel pressure when revving engine: 28psi (stays there throughout rev range)

Crank Sensor: Have not pulled, but doused with cold water after symptoms started. no change in behavior
Coolant temp sensor (green): unplugged, no change in behavior
Manifold? temp sensor (lower intake manifold, to AC Compressor side of green sensor): unplugged, no change in behavior. Does have damaged insulation, but is not shorting
Mass Air Sensor: unplugged, engine immediately died, would not restart
Throttle sensor: unplugged, engine would start, would not rev
Knock Sensors: unplugged both, no change in behavior
Cam sensor: have not checked anything here.
Alternator: Output voltage @ idle: 13.3V, Output voltage @ 2500rpm: 13.3V
Cats: tapped on side of both, no rattling noises observed.

maybe related, maybe not: there is a tic in the lower-end (somewhere). have not isolated, but it seems to be there when warm.

I do not have a rovacom/etc yet, did not want to spend the $$ if i was not keeping the rig. I do have a generic OBD2 scanner for basics.
Multimeter is at the house i just moved to (rover is 3 hrs away). I am only able to work on it weekends, and this needs to be done and gone by August 22.

Any thoughts or suggestions for next move?

Thanks all

Nate
 

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Sounds like it could be blocked cats but a generic OBD sensor will be able to show any faults, you don't need dedicated diagnostics for the engine. Can it do live data? If it can, see what the lambda sensors are showing when you try to rev it.
 

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1995-2002 Range Rover P38A
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52 Posts
Discussion Starter #3
Sounds like it could be blocked cats but a generic OBD sensor will be able to show any faults, you don't need dedicated diagnostics for the engine. Can it do live data? If it can, see what the lambda sensors are showing when you try to rev it.
Good point, I will give it a look. first, i'm going to snake a camera down into the cat(s)... i thought I had checked them for blockages before I put the engine back in, however... squirrels & mice DO love to pack nuts & such in everything here... once they are off, I can fire up and see if the problem stays with or not, and plug in for diagnostics.
 

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Fire it up with no cats or exhaust, if it revs, you know that's the problem.
 

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1995-2002 Range Rover P38A
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52 Posts
Discussion Starter #5
Fire it up with no cats or exhaust, if it revs, you know that's the problem.
Yup, just did that. same exact issue. Once the engine came up to temp, it would not rev above 2500-3k while driving. (neighbors loved me i'm sure) got pics of the honeycomb while i was at it just to check. everything looked good there (no obviously plugged or melted)

working on getting my scanner up and running.

-Nate
 

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Green temp sender is the one that feeds the temp gauge on the dash, the other (grey?) one tells the engine ECU to adjust the mixture for cold running. If is open circuit, it will report -40 degrees C to the engine ECU so it will run OK when cold but the mixture will be way too rich once it warms up. See what the scanner reports as engine temperature.
 

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1995-2002 Range Rover P38A
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492 Posts
fuel pressure at 28 psi is to low it should be 37 to 38 psi and be stable at all times. if revving it in the driveway reduces the pressure to 28psi , how much do you have under load , not enough i bet. its starving for fuel.
 

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1995-2002 Range Rover P38A
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Sounds as though it could be the fuel pressure regulator. A mad as says, should be 38 psi and should increase as the manifold vacuum decreases so under load it is 40 psi or more.
 

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1995-2002 Range Rover P38A
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Discussion Starter #9
awefully odd that it is only happening after warm though.

one more thing to check out however, appreciate it (In between dropping the fuel tank 3x, and repairing all the rear brake lines, while moving out of the house, I haven't had the time to go through RAVE enough on most of these troubleshooting items).

Thank you all for pointers.

-Nate
 
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