Member Since: 19 Jan 2017
Location: Maastricht
Posts: 3
D3 4.4 V8 LPG: Rough idle on cold and compression loss.
I am running a 2004 D3 HSE 4.4 V8. I bought it 2 years ago with 150K km on the odo and then installed a Prins LPG system. Now on 215K km.
Approx. 40K km after installation of the LPG system the engine started to run rough on cold idle and the engine MIL came on. No issues when warm, although the MIL stayed on.
Issue is getting worse now, with the message 'Engine in reduced power mode' (or something like that) and occasionally a flashing engine MIL on cold idle. But when I start of with cold engine and do not have to run at idle, I don't get this 'reduced power mode' message.
Once warm (say after 1 mile) the rough idle is over. Also, when in 'reduced power mode' I do a restart once warm, power is all back again and I can run on idle forever without getting rough or in 'reduced power'.
Because vehicle is always starting on petrol, but for the rest it is running on LPG, I suspected the fuel injectors for contamination. A dope to the fuel helped a little so I removed the injectors for testing and ultrasonic cleaning. One injector was faulty so it was replaced with a new one. Others were like new after cleaning. But the issue was not solved.
Then I searched the internet and found the issue valve seat erosion.....
Well....then I checked cylinder compression (cold engine) and this are the results:
Bank 1: 9, 9, 8.5, 9.5 bar (that's approx 130, 130, 125, 140 PSI)
Bank 2: 6.5, 9, 2.0, 7 bar (95, 130, 30, 100 PSI)
So that is not looking good.....
But why is the engine running fine when warm??? Or am I just imagining I have all 300 horses still running in front of me?
Is it really valve clearance? Or could it be something like carbon deposit build up? Or is that wishfull (?) thinking?
What would be the next steps, before taking the heads off for a rebuild?
Thanks in advance for any advise,
19th Jan 2017 10:45 pm
michele
Member Since: 07 Jul 2009
Location: gelderland
Posts: 216
The Engine in reduced performance, can be dirty throttle body, the rest I don't know.
20th Jan 2017 12:44 am
yaxman
Member Since: 02 Jan 2015
Location: pontyclun
Posts: 433
Bang some new ngk iridium spark plugs in it. New air filter. Get the lpg filters replaced and reset all the tolerances. Then see how it runs. Probably needs a good service.
Mine was running like a 90 year old running a marathon. Was quick. Good aervice and we was back in the game.
20th Jan 2017 12:53 am
Joel_NL
Member Since: 19 Jan 2017
Location: Maastricht
Posts: 3
I used the NGK iridiums before but at the last order I received the Champions instead! I prefer the NGK's so these are ordered now but I guess new champions can't be the problem.
Filters etc are new, vehicle is more or less serviced per LR guidelines with original parts.
Throttle body is cleaned. Done that before and yes that made a big difference! Amazing how so little contamination on the throttle body can cause such poor running and stalling issues.
Next step it getting the NGK iridium plugs in and get an IID tool to reset all the codes. For now I will leave the heads on.
21st Jan 2017 9:25 pm
Alphamale
Member Since: 28 May 2014
Location: Belfast
Posts: 496
While it does seem as though you have some VSE, as indicated by your compression readings, it is not likely to have been caused by the LPG as it's been in for such as short time. My '05 V8 had LPG from new and only needed work done in the last year, I did a full head job and had the valves cleaned and lapped and the tappets adjusted. When I finally removed my heads there were no signs of severe VSE and all I really needed to do was to fit new injectors and adjust the tappets.
How does the car run with the LPG off? I found that mine ran perfectly on petrol and if I had been paying attention I'd have realised that my problem was really the LPG injectors, they were found to be clogged and needing replaced, but by then I'd just finished a full top end rebuild.
You should also check the tappet clearances as they can cause reduced compression if they need adjusting. Mine were really bad and something else I should have fixed before doing the head job.
So your next course of action should be to see how it runs on petrol only. Then check your LPG injectors are clear and finally check the tappet clearances. If the tappets need adjustment it can be done without removing the heads but it's not a home mechanic job.
Last edited by Alphamale on 22nd Jan 2017 12:46 pm. Edited 1 time in total
21st Jan 2017 11:10 pm
yaxman
Member Since: 02 Jan 2015
Location: pontyclun
Posts: 433
Get away from champion plugs. As far away as possible.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
