Calavera 0 Posted April 26, 2013 Report Share Posted April 26, 2013 (edited) Hello together, at my Esprit Turbo SE (MY90) - I have a problem with the turbo boost - it takes in very, very late at about >5.000U/min then it raises to about 0.5 to 0.7 bar and the car pushes forward as it should. But with U/min under 5k the boost presure stays at a maximum of about 0.1 bar... We meanwhile: - changed the waste-gate actuator (new one) and checked the right position of it - removed the kat (exhaust) to see the open turbo - the waste gate valve sits perfect in its seat and the turbine looks good as well - don´t think there´s the problem. Do you have any ideas where to look at next? Is there any sensor to check which maybe takes effect at the turboboost which maybe is gone? I think I had a similar problem before when the engine was completely cold - sometimes I had no boost availible here to but the problem was gone just when the engine warmed up... so maybe any sensor which was not right fixed or was faulty is no gone complete??? Please help! Many thanks for any idea!!!! Calavera Edited April 26, 2013 by Calavera Quote Link to post Share on other sites
Gold FFM Sparky 2,954 Posted April 26, 2013 Gold FFM Report Share Posted April 26, 2013 Boost will be limited if temperature is low. Do you have Freescan? You need to check your coolant temp sensor. It could be numerous other things but your post suggests you should look here first. Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to post Share on other sites
Calavera 0 Posted April 26, 2013 Author Report Share Posted April 26, 2013 Hi - no unfortunaly no freescan - seems as if I should check out how it works ... Before I search all the documentation up and down - can you give me a hint where the coolant sensor sits? And thanks!!! Calavera Quote Link to post Share on other sites
Gold FFM Sparky 2,954 Posted April 26, 2013 Gold FFM Report Share Posted April 26, 2013 It's under the inlet manifold, roughly between ports 3 and 4. Quite difficult to get at but possible to change it with a deep socket. It's a GM part, so should be available from a decent parts store. Be very careful not to disturb any other cables whilst changing this. Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to post Share on other sites
Calavera 0 Posted April 26, 2013 Author Report Share Posted April 26, 2013 Thanks!!! will check it! Any other possible idea´s are welcome - cause I can test it not before next week (due to my neightbors Garage ) So if we once start would be great to check as much possible reasons as we can at one time... Quote Link to post Share on other sites
Calavera 0 Posted April 27, 2013 Author Report Share Posted April 27, 2013 Hi - do you think a broken actuator for the exhaust back pressure valve could have the same effect? @sparky - the sensor you mentioned should give the signal for it - right? As I read in the repair handbook the e.b.p.v. should open at water temperatures higher then 70° - so maybe the actuator is defective? Quote Link to post Share on other sites
Bibs 11,708 Posted April 27, 2013 Report Share Posted April 27, 2013 Wire the EBPV open, you don't need it to work and it's one less thing to go wrong. Is your cat in good condition too, no bits missing or blocking the core as you looked into it? Quote 88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport Evora NA For forum issues, please contact the Moderators. I will aim to respond to emails/PM's Mon-Fri 9-6 GMT. Link to post Share on other sites
Calavera 0 Posted April 27, 2013 Author Report Share Posted April 27, 2013 @Bibs - yes we will check it! The cat should be o.k. - no bits missing - but we didn´t look into when disconected... probably because the lambda sensor was fixed and we didn´t took it out completely - hmm - we better should... Quote Link to post Share on other sites
Calavera 0 Posted April 28, 2013 Author Report Share Posted April 28, 2013 @Sparky - would this sensor be the right one? I doubt about getting it here at a local GM seller... http://www.ebay.co.uk/itm/Intermotor-Coolant-Temperature-Sensor-Engine-ECU-Temp-Gauge-Sender-Unit-New-/360500089825?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Car+Make%3ALotus%7CModel%3AEsprit&hash=item53ef7ad3e1 Thanks a lot! Calavera Quote Link to post Share on other sites
Gold FFM Sparky 2,954 Posted April 28, 2013 Gold FFM Report Share Posted April 28, 2013 Certainly looks like the one! Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to post Share on other sites
Calavera 0 Posted May 20, 2013 Author Report Share Posted May 20, 2013 Hi guys, just want to let you konw that it was the backpressure valve... man! never thought it has such a big effect... Well after checking: - wast gate actuator (new one!) - correct closing of the waste gate in its seat - O2 sensor with freescan - temperature sensor with freescan the BPV and a leak in the pressure system was left to check... - when we activated the BPV manualy with running engine - the car became at once double as loud as before (had´nt the correct loundness present after the winter break) and while the following test-drive the boost gets in again just from 2000 revs up... Back on road again - yea! Thanks for you advice! Regards Calavera Quote Link to post Share on other sites
Calavera 0 Posted July 13, 2013 Author Report Share Posted July 13, 2013 (edited) Hello - just another question to all SE, S4, S4S or S300 Drivers... After fixing the backpressure valve my boot raises very fast again - but as I think maybe too high?!? If I kickdown the pedal the boost raises shortly up to 1,1 or 1,2 bar and then falls back to 1,0 or 0,8 depending if boost mode is active or not... I don´t know if that behavior is the same as before we changed the wastgate actuator and fixed the backpressure valve... Is this behavior normal or shouldn´t raise the boostmeter over the 1,0bar mark? If I press the pedal slower and constantly the boost goes up to 0,8 or 1,0 and stays there - the "overboost" only appears if I kickdown... - don´t want to damage the engine! Thanks! Calavera Edited July 13, 2013 by Calavera Quote Link to post Share on other sites
Vulcan Grey 257 Posted July 13, 2013 Report Share Posted July 13, 2013 Double check your wastegate adjustment. Though if boost rises too much, then the ECU should reduce boost to ~.65bar by the boost control freq valve. BTW, at my altitude of 5300ft+, my boost gauge pegs often. What is your altitude? Quote Travis Vulcan Grey 89SE My Lotus Photo and Projects Album Link to post Share on other sites
Tom Jorgensen 1 Posted August 12, 2013 Report Share Posted August 12, 2013 Hi Do anyone have doc. how to adjust the westgate. I think i might as well get to much pressure to early. Anyone have a FreScann log with all working fine. I have the SE version with 264 hp. Regards Tom Quote Link to post Share on other sites
rotaryspeed 7 Posted April 29, 2014 Report Share Posted April 29, 2014 My 1990 SE does the same thing, boost only up to 0,5 bar on the gauge, sometimes it goes a tad behind 0,5 bar. I will check the back pressure valve today as I ve seen that the vacuum port is not hooked up. Oh and its also very quiet ^^ Quote Link to post Share on other sites
rotaryspeed 7 Posted April 29, 2014 Report Share Posted April 29, 2014 So after work I did a quick check on the backpressure valve, its not hooked up and per default in the closed position. Going to fix this tomorrow, then its due for a photo shooting Quote Link to post Share on other sites
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