NO BOOST, LACK OF POWER, PLEASE HELP SOMEBODY

[4SPD]

help help help......
does anybody out there know what else i can try.Tried the actuater (WASTE GATE ROD) that sticks but moving freely no problem there i dont think.had mechanic look at it he was previously a lotus mechanic,but no joy. Really struggling to find problem. Diagnostic check with wire tells me code 13 lambda censor but hasnt got one.so totally stuck. when driving if feels just like when a pipe came off,but nothing off that i or mechanic could see.The more you accelerate the slower it seems to go where as if you are soft it picks up better

PLEASE CAN SOMEBODY HELP ME BEEN OFF ROAD NOW SINCE XMAS

[ailwyn]

1. Have you got an elanscan cable?
2. Have you got any Elanscan logs?
3. Have you checked the MAP sensor
4. Have you got a dump valve fitted?
5. If you have got a dump valve, have you tested it?
6. Does the heater vent selector work correctly?
7. When you should be getting boost do you hear any sort of hissing?
8. Was your mechanic able to check the car out under load, incase it's a leak that's only noticeable when the turbo is spinning?

[4SPD]

1/2) no im sorry i dont have either
3) no havent checked this and dont know how to
4/5)no it hasnt been fiddled with at all
6)the heating system seems to be working correctly (heat on windscreen very warm)
7/8) no hissing but the turbo seems to be spinning freely all the fins on the turbo are still intact .He listened to the engine only when it was standing but at full revs low revs medium .
I really appreciate the help as i havent had any luck on this problem various friends have tried to find the problem but with no joy.......
thank you

[ailwyn]

First thing you need to do is rule out an air leak, your best way of doing that is to get an Elanscan Cable which will allow you to hook up a laptop to the ECU.

That will then allow you to log all of the diagnostic data from the ECU.

Post a request here:

http://www.lotuselancentral.com/forum/v ... &start=260

I'm sure Geoff can rustle you one up in no time

Ailwyn

[ailwyn]

Update your profile with your location and there may be somebody local who can help out.

A.

[4SPD]

Good idea so if anyone has one i could maybe borrow it or something.
Thanks for advise. Would you post a message asking for somebody in my area to maybe lend me one or help me with one.

[4SPD]

or would you buy one instead and if i did could i plug it into my home pc or would it have to be a laptop.

[M100 TWO]

sounds like a blocked exhaust it will be either a collapsed cat or the main silencer this problem is not that uncommon
john

[ailwyn]

sounds like a blocked exhaust it will be either a collapsed cat or the main silencer this problem is not that uncommon
john

This was my thought but no O2 sensor should equal no cat to collapse.

[ailwyn]

or would you buy one instead and if i did could i plug it into my home pc or would it have to be a laptop.

You'd be better off with a laptop as the leads for the interface are not very long, and I'm sure Geoff would make you a longer one if requested, I'm not sure what the quality of the signal would be.

Cost of the interface is a reasonable £20ish, but check the thread I lined to for the actual price.

Ailwyn

[4SPD]

Just changed full exhaust to stainless steel one as thought might be problem.Replaced it all the way up to the front manifold down pipe and there wasnt a cat on the previous exhaust either.I doesnt run badly and sounds sweet just lack of power and the boost gauge going threw the roof.

[ailwyn]

just lack of power and the boost gauge going threw the roof.

Does it take off then lose all power with the check engine light coming on? If the boost gauge is going north and your then losing your power it sounds like you are suffering from overboost.

[4SPD]

no the power is more constant like it picks up in first like norm al then when the turbo should kick in i sound like it is,it doesnt.in hhigher gears when accelerating it seems to slow dont with more pressure and be better if you are light on the throttle.that might just be in my head though also back fire rev hard release pedal pops once

[ailwyn]

Did your mechanic check the engine base timing?

[Doug]

could it be a degrading signal from the TPS (throttle position sensor)? if so yes I agree you need an ElanScan to diagnose -- or pay up and have it checked at a Lotus dealer . . .

[gtm100]

Has this question been posted elsewhere? It sounds to me like fuel starvation, possibly blocked filter, I'm no expert so I don't know the answer.

[GeoffSmith]

From connecting up ElanScan, you've identified the fault code is 4800. This is showing that you have had a low MAP (Manifold Absolute Pressure Sensor) reading and overboost (the wastegate has not been able to control the boost). These would present as codes 31 and 34 with the paperclip test, so could quite easily have been confused with error code 13.

As I see you've had a new exhaust (what diameter?) I suspect you're experiencing 'boost creep'. Basically, with less resistance from a larger diameter / freer flowing exhaust, there is too much pressure across the turbo which the wastegate cannot control; the level of boost starts running away and when it hits just under 1 bar, the ECU cuts off the fuel to save the engine from possible damage. I've had this myself and have almost hit my head on the steering wheel several times as it is so violent. There is a distinct lack of power for about 10 seconds and the warning light on the dash should be on. After this time, the light goes out and normal service is resumed.

There are esentially two ways of countering this - lighter right foot / keeping an eye on the boost or to open out (port) the wastegate. The latter is the long term solution and the job is discussed here.

It would be worth doing an ElanScan log and posting it up here for us to have a look and hopefully confirm what I suspect.

Geoff

[GeoffSmith]

Reference your log here, it is a classic case of overboost and fuel cut off at about 245s into the run. So what exhaust ahve you put on?

Geoff

[ailwyn]

I've looked through you ES data (posted in the interface thread) and my uneducated guess would still be for a sticking wastegate.

You're hitting 1bar boost @ ~50% throttle, but at that point your wastegate duty cycle is 0%, which if my understanding is correct, means that the wategate is shut.

The highest the wastegate duty cycle goes is 27.34%, I compared this to Paul.P's ES runs from a few months ago and his was hitting 80%.

Your coolant temp at that point of 108.5 seems high also.

Anyone else have thoughts on this?

Ailwyn

[GeoffSmith]

As Ailwyn says, your coolant temperature is high (I presume the fans were cutting in and out) so your thermostat may be stuck. You could let us see a log of a run from cold until the fans kick in to confirm this.

The boost does look rather high for the throttle positions so the wastegate may be sticking.

[Ailwyn, from what I can tell, the 'wastegate duty cycle?' only comes in when you take your foot off the throttle and is typically 20-30%. Looking at Paul's, his does look rather high!]