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P38 diesel won't start saga


pete3000
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History (scan down for solution)

About a month now since my brother bought a nice-ish P38 DT with 100k on. The jobs discovered so far.

New transfer box and gearbox/driveline fluids sorted out bulk of concerns, due to a seized viscous coupling.

However Saturday brought a new problem. Car refused to start after 30 seconds or so of cranking with 2-3 preheats.

Seen this fault two weeks ago but started on third go at -5 degrees. :huh:

We fitted a hot start kit after the usual 5-10 secs crank from warm at fuel stations, fixed the hot start issue.

But this was from cold, put battery on charge and went for a cuppa. :unsure:

Suspects were, glowplugs, blocked fuel filter, in-tank pump, underbonnet fuse box.

Saturday saw the fuse box out and dismantled as per rangerovers.net page. No real problems there apart from one or two iffy looking solder joints. Back together and still wont start, dn't wan't to cook starter motor so retire to dinner with rave cd.

Had bought glowplugs earlier and decided on sunday to change them next as they cost £28 ish.

Solution.

As soon as we got the intake manifold off, as per rave cd, the faults were obvious.

1). the spill off rubber hoses had become brittle and frayed, two were split allowing air into the system, the rest didn't look far behind so the lot were replaced, fixed with stanley knife and some diesel spill off tubing from motor factors 2 packs for £8.20.

This took a couple of hours as the rubber was so hard/brittle it had to be broken off the injectors with a knife,screwdriver without damaging the injectors (which cost £150 each).

2). The glowplugs were next up and came out with the help with of a 1/4 & 3/8 drive socket set with uj, a 12mm ring spanner (12 point). 8mm 1/4 drive flexi for the electrical nuts. 3 of the plugs were shot (100k miles) as three were lightly sooty but clean otherwise, the other three were really oily and showing no sign of heat, confirmed with a meter.

3). The jewel in the crown, MAP sensor pipe had dropped off. Couldn't find where a perished spill off pipe which had come adrift was missing from. The end was brittle covered in oil and bent over at an angle. The end was split also.

Looked on rave which offered there was a Manifold Abs Pressure sensor on the fuel filter. But no clue where the other end was from.

Looked on the maifold, then in the middle between 3&4 pipes was a pipe connection in a recess with oil round it, result. Pushed another length of spill off pipe on and put it all back together.

4). Time to bleed the air from the filter (air bubbles in clear pipe from the cracked spill pipes). 17mm and uj cracked union open and switched the ign onto pos 2. diesel and air escaped, tightened back up after air out.

5). Jumped in preheated once, fired up on second revolution.

Results.

engine revs much more freely, has more power, starts first go etc. In all very please for about £30.

Diagnosis, the air in the system probably stopped it finally once enough had got in, the first couple of time I had seen this it started after 30 secs or so of cranking. The MAP sensor though according to RAVE, has a fail mode of not letting you rev beyond 3500-4000 rpm, and reducing engine power by using a set of defaults. The annoying 1400-1600rpm vibration has gone also maybe because the ecm has started working on proper values enabling the antiknock feature. :) By not being connected it was in failover mode.

I'm happy that is was as cheap to fix. I have read horror stories of in tank pumps and injector pumps.

Hope it may save someone a few quid. :D

Pete

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