Club G40 Forum

Technical => Engine and Transmission => Topic started by: swiftg40 on November 03, 2009, 11:21:32 PM

Title: engine problem
Post by: swiftg40 on November 03, 2009, 11:21:32 PM
hello,
the engine on my G40 (converted GT) is being a bit strange, if i drive off boost it always drives fine also on boost is is fine (smooth with no noticable power loss) but if its boosted then is driven normally at around 1500 - 2500 rpm it's like the engine is being switched off for a split second but it can cause quite a jump, this can happen once or twice a minute, i can only say it happens when warm as i dont boost it until its warmed up, recently (last 200 miles) i have replaced plugs (w5 dp0) oe leads, complete distributor with hall sender, coil, lambda probe, blue temp sender, oil/filter, timing was checked at a garage (not by me) so i'm assuming they have done that right, co pot is 600 ohms, battery volts are 13.5v, cleaned points and re-done all earths in really thick gauge cable and earthed the manifold (lambda) point straight from battery, i dont really know what to do next i'm thinking ecu, cleaning crank case breather, one way valve.
the engine has 65mm pulley, r1 charger <2000 miles (boosts to 16 psi), jabba chip, front mount intercooler, de cat, de-wedged throttle body.

sorry for the long post guys but just giving as much info as i can
really appreciate any help as im not driving the car other than testing 
Title: Re: engine problem
Post by: Nick_S on November 03, 2009, 11:33:38 PM
Check the fuel pump relay (4 pin one by the ECU).
I had a similar problem and it was due to a water corroded relay.
Title: Re: engine problem
Post by: swiftg40 on November 03, 2009, 11:41:27 PM
hi nick, i've checked the terminals which seem clean but i suppose the relay could be buggered internally i'll get a new on on an see what it does
cheers mate
Title: Re: engine problem
Post by: swiftg40 on November 03, 2009, 11:46:40 PM
hi rae, all the ignition is brand new done less than 100 miles a complete dizzy hall sender an cap, plugs, leads an coil. car is still behaving the same  :(

i'll have a look at the belt timing
cheers
Title: Re: engine problem
Post by: swiftg40 on November 07, 2009, 05:10:49 PM
Put a new 4 pin fuel pump relay on and cleaned terminals in the plug   
had new timing belt fitted today and ignition re-checked to +6 degrees btdc
cleaned out auxillary air valve (choke)
cleaned out oil separator and the valve on top of it (these were removed from the car)
checked all vaccum & boost hoses for leaks (nothing found)
Car is still behaving the same
only thing i noticed was the valve on top of the oil separator i believe is meant to be a one way valve to vent off any crankcase pressure but i can blow though mine both ways
does anyone know if this is for sure a one way valve? if so some boost pressure may be getting in to the crankcase from the boost return???
Title: Re: engine problem...sorted
Post by: swiftg40 on December 15, 2009, 09:31:40 PM
evening all
tried another ecu, co pot...still no change
then changed the engine wiring loom and its run spot on for 3 weeks now...woohoo
cheers for the help anyway guys...one more happy driver again ;D
Title: Re: engine problem
Post by: hayesey on December 15, 2009, 09:33:42 PM
have you still got the old not working loom? 
Title: Re: engine problem
Post by: swiftg40 on December 16, 2009, 04:42:29 PM
hi mate, i've still got the old loom but am going to keep it in the G spares box incase i need anything from it in the future, do you need anything in particular off it?
Title: Re: engine problem
Post by: hayesey on December 16, 2009, 04:52:16 PM
no not really, just wanted it for spares like you do :D