1994 P38 4.0 V8 problems revving

CompassVL · Oct 23, 2011

Evening. I`ve bought an early P38 today with a suspected BeCM problem. Putting this aside, the first issue I`ve noticed is it doesn`t want to drive! It`s an auto, and seems to rev well enough when not in drive. As soon as you`re in drive, it only seems to want to rev upto about 2500 rpm, and has no power at all. It seems to be the same on petrol or LPG, but maybe a touch worse on LPG if anything. I know it`s been stood for a few weeks, so wasn`t expexting it to run too well on gas to start with, but thought it`d be fine on petrol. It could have a slight blow from the exhaust, but can`t see this causing any isses.

I`m a total novice with P38`s I`m afraid, so any help would be appreciated. I`ll be taking a look at the MAF and other fairly obvious causes tomorrow, but was wandering whether this was a common problem and if anyone else had encountered it?

Cheers in advance.........

rasheed · Oct 23, 2011

you sure its a p38? reason i ask is they only came out late in '95 and you're saying '94.

CompassVL · Oct 24, 2011

rasheed said:
you sure its a p38? reason i ask is they only came out late in '95 and you're saying '94.

Thanks for the reply. Yes, it`s definately a P38. It`s a 1994 (M) plate. If my memory serves me correctly, they came out post September 1994.

rasheed · Oct 24, 2011

no idea about gas tbh but on petrol if it does that its bascially fuel starved, either running too lean or a problem with the fuel supply.

if you have access to diagnostics you can check for fault codes and if there aren't any you can at least reset the ECU adaptive trims. worth doing once you change the air and fuel filters and clean out the mass airflow sensor, the throttle position sensor and the throttle stepper motor, check your plugs and leads (do they "glow" in the dark? if so the insulation is gone) and if you really want to get picky you can test fuel pressure at the rail. there is a valve there like a bicycle tire valve but you'll need a guage and someone to tell you what the pressure should be as i don't know. lastly check the primary and secondary winding resistances on the ignition coils. Eightinavee, one of the members in here once helped me out with those values so happy to pass them on. 0.8 ohm primary and 13000 ohm secondary.

CompassVL · Oct 25, 2011

rasheed said:
no idea about gas tbh but on petrol if it does that its bascially fuel starved, either running too lean or a problem with the fuel supply.

if you have access to diagnostics you can check for fault codes and if there aren't any you can at least reset the ECU adaptive trims. worth doing once you change the air and fuel filters and clean out the mass airflow sensor, the throttle position sensor and the throttle stepper motor, check your plugs and leads (do they "glow" in the dark? if so the insulation is gone) and if you really want to get picky you can test fuel pressure at the rail. there is a valve there like a bicycle tire valve but you'll need a guage and someone to tell you what the pressure should be as i don't know. lastly check the primary and secondary winding resistances on the ignition coils. Eightinavee, one of the members in here once helped me out with those values so happy to pass them on. 0.8 ohm primary and 13000 ohm secondary.

Fantastic. That`s a great help thanks. i`ll get onto this list the the next couple of days.

1994 P38 4.0 V8 problems revving

CompassVL

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rasheed

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CompassVL

New Member

rasheed

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CompassVL

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