problems with lotus esprit chargecooler turbo

[dave j gtt]

to cut a long story short . the car runs, has lost driveabilty, when heavy right footing it , it dose not reacte under load.

it has had dump valve fitted for couple of months against my wishes. i have binned mine

was stalling and throttle was not reacting at low revs. car still went under load

mam struggled down to lotus event down south and had pluged in and came back with no probs except intermitting miss fire now and agin.

so it was having this prob and mams husband changed the sparkplugs. he is not stupid just not really clever on turbo engines, he is very very good with the dirty jobs

still a prob , i removed dumpvalve and half the prob was sorted.

now since mam fooking off away and changing the plugs the car wont rev freelly under load with or without dump valve.

so i wonder change back to old spark plugs that reved under load ok.


am going to add more and update tomorrow. mam is unsure to listen to me or husband who just wants to break and test everything but the simple stuff first.


now it has no dump valve on now " he wants to put back on without even checking the rubber inside. , the old spark plugs all had nice burn colour
so have to put them back on surpose and see if any difference.

just mam needs advice from niether me or him hahalol argue city my house i tell you ! cant sit back and watch a good car ruined to just be able to say told you so
, am worried as it was the balls when was running right.


also am going to let the mother read and form her own opinon keep it clean

what other thing could a split dump valve diafram cause ??? couple of probs happened at the same time " could just of well happened"

going to check all vacume pipe tomorrow.


something that might help any helpers http://www.lotusespritworld.com/MaintenanceMods.html might have to copy and paste,

cheers regards dave

for any help, but would perfer just sensaibe posts from peeps who can help me explore futher the prob or problems.

[dave j gtt]

[DaveAVT]

Could be countless things, but very unlikely to be plugs if the car appears to be running on all 4 cylinders off load. You'd know if it was running on three.

Check if the vacuum pipe that supplies the dumpvalve also supplies the MAP sensor. Check this pipe has no splits in it, or blocked (ie blow it out)

If the MAP sensor pipe is damaged, or leaking, it will run very very rich low down off boost (ie bog down and rough) but then be fine on boost.

Check you havent got any boost leaks elsewhere. Is the boost gauge still going to where it used to?

Somewhere in the bay there is also some kind of Amal valve which controls the two levels of boost. When you do a standing start in an Esprit, and rev it above 4k, it runs a bar of boost, in first and then lower in the rest of the gears (and normal driving). This valve might be faulty, you just need to watch the gauge and see what its reading.

[DaveAVT]

Also, if the vacuum pipe that supplies the dump valve DOES supply the MAP sensor, then its advisable to change this, and not just have it tee-ing off.

[dave j gtt]

dave , it now dose not want to boost up at tall under heavy throttle, will build up slowley but wont when you floor it.

boost gauge is not showing same levels of boost as it dose not want to go it holds back like a fuel starvation or total loss of spark / map

just hope sumat hasnt melted inside

from a simple prob a couple of weeks ago " dump valve" would not listen now i fear it might be too late.

going to do a comp test on it later or prob tomorrow now.

cheers mate

[Ian S]

Does sound like fuel starvation.

Maybe it's sensing there's no boost and not supplying fuel.

[dave j gtt]

thanks ian was thinking along the lines of that, and a weak plug as i have been advised by a certain somebody via Pm, top bloke

will update tomorrow further when i have time for another play .

[DaveAVT]

Check for boost leaks etc, even if you run a car very lean, or back off the fuel pressure, the turbo will still spin up, its just the car won't go very fast, but it still makes the boost.

Check the actuator rod hasnt come off the end of the wastegate housing, or the rod is stuck..

[DaveAVT]

Did you check the things I told you to check? I.e, the map pipe?

Your not going to have lost compression, then got it back by fiddling with a dump valve, then gone again.. so no point in checking the physical engine.

Is the car running on all 4 cylinders?

[dave j gtt]

Check for boost leaks etc, even if you run a car very lean, or back off the fuel pressure, the turbo will still spin up, its just the car won't go very fast, but it still makes the boost.



Check the actuator rod hasnt come off the end of the wastegate housing, or the rod is stuck..

1 - turbo will not spin up to max boost. it will build up slowly if throttle is built up gentally.and not getting the massive surge of boost it should

2 - going to cheack the rod moves freely tomorrow

[dave j gtt]

Did you check the things I told you to check? I.e, the map pipe?

Your not going to have lost compression, then got it back by fiddling with a dump valve, then gone again.. so no point in checking the physical engine.

Is the car running on all 4 cylinders?

1 - lots of new pipes on order


2 - no am saying running without a correctly working dump valve , could have caused probs so mayby if worth testing to make sure more testing isnt going to cause more damage

car is running on all four but once under load somthing is a miss.....

[dave j gtt]

this is the car british racing green

this is its last outing


right think am getting somwhere now i disconected the battery reset the ecu. and things are better.
took it out for a drive before i reset the ecu got up to temp and was crap, then i reset the ecu and the it has impoved quite a bit.
just a few other lotus related probs i think ,ideal speed valve playing up. tps throttle position sensor. and boost control valve.

some more things to replace and reset the ecu again and all hopes are it will be better again with new (tps) going to replace some vacume pipes. the code and engine reading program "freescan" to check it has no more faults . it was coming back with 24 (ideal speed) and 35 (throttle position sensor)

it is defo a lot better now after resetting the ecu as it learns and adjusts to suit and assist the running of the car .
so with leaky dump valve and crap plugs it had learn to run with them, so was even craper when i fixed the leak and had new plugs.

[dave j gtt]

- found leaky pipe on the "map" pipe,

- found leaky "boost transistor" pipe, any one heard of one of these

throttle cable isnt seated correct or staying in the same place, its changing adustment

runs alot better just need "windows 98" to play "freescan" to cheack all sensors and for faults.

[DaveAVT]

- found leaky pipe on the "map" pipe,

- found leaky "boost transistor" pipe, any one heard of one of these

throttle cable isnt seated correct or staying in the same place, its changing adustment

runs alot better just need "windows 98" to play "freescan" to cheack all sensors and for faults.

Im good aint I

Boost transistor is probably that solenoid valve I was talking about..

[dave j gtt]

theres more to it than just a leak but yeah you helped cheers mate,

[dave j gtt]

car still dose not want to run - 100% but i have made progress

[DaveAVT]

Have you checked the plugs and cleaned/checked/replaced the lambda sensor?. If you have a leaky MAP system, it will run very rich at idle and part throttle and soot up the plugs and sensor.