stevet Posted March 11, 2008 Share Posted March 11, 2008 Hello all, I've got a "y" reg 4.6 p38. It's been gas converted (multipoint not sure what make). It runs fine for normal everyday use but when you want to push it on a bit or overtake on "A" roads it seems to run out of power at 3200 revs, it will creep a bit higher but not much. 90mph on a motorway tops and it doesnt make any difference wether its on petrol or gas. An AA patrol has checked it out with his Vixen Unit and no fault codes have been found. Any ideas please. ta steve Quote Link to comment Share on other sites More sharing options...
steve_d Posted March 11, 2008 Share Posted March 11, 2008 If it's doing it on both fuels then I would look to ignition. Have you checked to see if the igniton advance is working both mechanical and vacuum? Steve Quote Link to comment Share on other sites More sharing options...
stevet Posted March 11, 2008 Author Share Posted March 11, 2008 If it's doing it on both fuels then I would look to ignition. Have you checked to see if the igniton advance is working both mechanical and vacuum?Steve Thanks Steve. next daft question, where am I going to find the ignition advance. In my mk1 cortina days it was on the distributer, the HT leads on this v8 disappear round the back of the engine so i assume the distributer is there out of sight. steve Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 12, 2008 Share Posted March 12, 2008 If Y reg is about 2000 (?) I would think that it doesn't have a distributor, it will probably have the Thor engine which has the ignition controlled electronically by the ECU and has four coils stuffed around the back of the head so you have to take the engine out to change them (slight exaggeration but not much!) I have no idea how the gas system would tell the engine ECU what to do with ignition though Quote Link to comment Share on other sites More sharing options...
Escape Posted March 12, 2008 Share Posted March 12, 2008 All p38a's have distributor-less ignitions. The 4.6 should easily reach 110 mph, mine tops out at about 112 and I also feel it is lacking power (upgrade in progress). Have you tried changing the air-filter, sparkplugs and ignition leads? How about fuel consumption? Does it also lose power in 3rd gear at about 3200 rpm? Greetz, Filip Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 12, 2008 Share Posted March 12, 2008 There you go. I have never seen under the bonnet of a P38 just going on the D2 engine. The only P38s here are stinky old diesels. Quote Link to comment Share on other sites More sharing options...
Escape Posted March 12, 2008 Share Posted March 12, 2008 The only P38s here are stinky old diesels. Even those should be able to reach 100mph without issue. (must be carefull of my posts, people will start thinking I'm a speedfreak ) Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted March 12, 2008 Share Posted March 12, 2008 The Vixen is not the best piece of kit to read that one with .......... there are some errors that it will ignore ............a bettter non rover tool is the Snap on Modis ................there also might be some run errors that are cleared at idle, or below a certain rpm when the ECU sees the correct parameters ............... Being as you have an after market gas system installed, the reasons for loss of power could be numerous ................ first area to check is that the auto box is shifting correctly ? .............. also when stationary, will it free rev to past 3200 ? ............ you should be able to blip it to 5K The P38 El Capitiano will be along shortly .......... watch the Sparkes fly Ian Quote Link to comment Share on other sites More sharing options...
stevet Posted March 13, 2008 Author Share Posted March 13, 2008 Thankyou all for the ideas. New plugs have been fitted, leads checked and all ok. There is a slight hesitation when changing up from 3rd to drive, when stationary and in neutral revs freely to over 5000. Its not really a loss of power its more like it runs out of power just when you need it, the higher up the gears you are the worse it gets. 1st fine, 2nd ok, 3rd hmm, Drive forget it. If I was happy to poodle along I wouldn't know any different. ( I don't do poodle ). I'm thinking of having it re-chipped/mapped but don't to do that if there is an underlying problem, so any advice you Guys can give me will be invalueable. ta steve. Quote Link to comment Share on other sites More sharing options...
disco_al Posted March 13, 2008 Share Posted March 13, 2008 auto box fluid running low maybe? not sure on slush boxes as i personally don't like them - but that's me..... Quote Link to comment Share on other sites More sharing options...
stevet Posted March 13, 2008 Author Share Posted March 13, 2008 Thanks Disco Al, I can find the Oil dip stick but where's the autobox fluid dipstick or hasnt it got one. If it has'nt got one does it mean crawling underneath and putting the oil in one hole till it leaks out of another. I'd get a haynes manual but I dont think they do one for my car. Anything you can suggest is helping me. ta steve Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted March 13, 2008 Share Posted March 13, 2008 Where are you? If you fill in your location, someone might be able to pop in and have a shufti? Quote Link to comment Share on other sites More sharing options...
stevet Posted March 13, 2008 Author Share Posted March 13, 2008 Stourbridge, West midlands. Quote Link to comment Share on other sites More sharing options...
paintman Posted March 14, 2008 Share Posted March 14, 2008 Sounds like you need to get a proper diagnostic done. Quote Link to comment Share on other sites More sharing options...
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