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Best way to Compression Test the cylinders

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  #21  
Old 08-22-2015, 07:54 PM
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Originally Posted by caymandrew
It does have the o-ring seal. I've over heated a valve before in and different car, a six cylinder, and although it drove rough, I was still able to start it and get it to a shop on the remaining 5 cylinders. This one is driving me crazy. It's starts and stalls. I can spray starter fluid and it'll rev to 2k on start up and stall. I've replaced the fuel pump and the fuel rail and injectors. Spark is good, air is good, I'm totally stumped. Let's say I have a ring issue in cylider 3, would start and stall be a normal symptom?
Even if some of the cylinders are down on a compression test it should still run, rough maybe, but continue to run, I think you have other issues also. If the #3 rings are letting by it should run as well, maybe rough as a dog, but still run whatever. Don't use Easystart it ain't good and it'll mess up your engine starting normally, OK for diesels but not petrols. I have used it to fire up my old BDA race car engine for starting on rare occasions but that was a slightly different scenario running at 12:1 comp: ratio with twin Webber carbs and a very tight newly built engine.

It sounds like you have either sparks breakdown under load, possibly wires, or fuel starvation under load. I don't know enough about the Rover V8 engine electronics to comment on those but I'm sure some guys on here will have good knowledge. Let us know how you get on with the engine.
 
  #22  
Old 08-22-2015, 07:56 PM
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Have you considered the MAF?
 
  #23  
Old 08-22-2015, 08:15 PM
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Originally Posted by june82000
Have you considered the MAF?
That also crossed my mind but this guy has already sunk a bundle into his truck by the sounds of it, another $125 is maybe a bridge too far.
 
  #24  
Old 08-22-2015, 08:30 PM
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Originally Posted by OffroadFrance
That also crossed my mind but this guy has already sunk a bundle into his truck by the sounds of it, another $125 is maybe a bridge too far.
There's one on Fleabay right now for $22 with free shipping. Item # 271960092360. I think it's the right one...
 
  #25  
Old 08-23-2015, 12:09 AM
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I wouldn't waste money on another MAF right now. Even if your MAF was dead your truck should still run. It would run like crap but it should still stay running through default settings I believe.

1) Have you checked the fuel pump relay and fuse yet? You can just swap both the relay and fuse out with a known good fuse and relay really quick to test it out.

2) I know you've changed out almost all of the fuel system but have you confirmed you have fuel pressure at the rail yet? You can hook up a gauge at the schrader valve and test that really quick also.

3) Can you keep the truck running if you give it gas or will it die right away no matter what?
 
  #26  
Old 08-23-2015, 07:29 AM
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Originally Posted by R0VERGUY
3) Can you keep the truck running if you give it gas or will it die right away no matter what?
good point, it could be something as simple as the IAC.
 
  #27  
Old 08-23-2015, 08:16 AM
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Originally Posted by R0VERGUY

1) Have you checked the fuel pump relay and fuse yet? You can just swap both the relay and fuse out with a known good fuse and relay really quick to test it out.

2) I know you've changed out almost all of the fuel system but have you confirmed you have fuel pressure at the rail yet? You can hook up a gauge at the schrader valve and test that really quick also.

3) Can you keep the truck running if you give it gas or will it die right away no matter what?
Replaced the MAF
Replaced the Fuel Pump
Replaced the Rail and Injectors.
Coils are only a couple years old
Wires a couple years old magnacore 8mm
new NKG plugs
I have spark at each plug
Replaced the IAC
Swapped out fuel relay
Replaced the TPS
Replaced the CPS

Tested the voltage at the fuel pump I'm getting 5v, MAF 5v, IAC 5v, does the same thing with MAF plugged or not. Starts and stalls no matter what I do with the gas peddle.

The only thing I have not done is tested the Fuel pressure because I could not find the fitting on the rail until I removed the upper intake to replace the rail, now that I know where that is I will test next. This one really has me stumped!
 
  #28  
Old 08-23-2015, 08:46 AM
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I mention this all the time but have you ruled out vacuum leaks?
 
  #29  
Old 08-23-2015, 09:14 AM
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Originally Posted by caymandrew
Replaced the MAF
Replaced the Fuel Pump
Replaced the Rail and Injectors.
Coils are only a couple years old
Wires a couple years old magnacore 8mm
new NKG plugs
I have spark at each plug
Replaced the IAC
Swapped out fuel relay
Replaced the TPS
Replaced the CPS

Tested the voltage at the fuel pump I'm getting 5v, MAF 5v, IAC 5v, does the same thing with MAF plugged or not. Starts and stalls no matter what I do with the gas peddle.

The only thing I have not done is tested the Fuel pressure because I could not find the fitting on the rail until I removed the upper intake to replace the rail, now that I know where that is I will test next. This one really has me stumped!
-Well if you find you have good PSI at the fuel rail and rule that out also I'd have to start looking at the ECU, bad fuse box, or something electrical. Is this the Disco that sat in the mud for 5 days in the middle of nowhere?

-Have you confirmed that your inertia switch hasn't popped up and are you sure your ECU isn't in immobilized mode or something? Is the red light on the dash flashing fast or anything like that?
 
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  #30  
Old 08-23-2015, 11:04 AM
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Originally Posted by R0VERGUY
-Well if you find you have good PSI at the fuel rail and rule that out also I'd have to start looking at the ECU, bad fuse box, or something electrical. Is this the Disco that sat in the mud for 5 days in the middle of nowhere?

-Have you confirmed that your inertia switch hasn't popped up and are you sure your ECU isn't in immobilized mode or something? Is the red light on the dash flashing fast or anything like that?
Forgot to mention I replaced the ECU as well.
When I unplug the inertia switch no fuel or start at all.
No red light on the dash.

What's the best was to test for vacuum leaks and yes, it sat in a river door high water for 5 days.

Here's a video

http://vid1209.photobucket.com/album...psq31lzrlg.mp4
 

Last edited by caymandrew; 08-23-2015 at 11:10 AM.


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