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Discussion Starter #1
Hello - thanks for reading my post...I'm a desperate dude....

I have an '07 Exige S with a Charlie X Header tune, 2bular header, Griffen intercooler, custom flow injectors & PSE supercharger upgrade & rebuild. The issue is that the car runs very rich (10s & 11s AFR) and shows only 214hp at the wheel. The car is only used on the race track and burns 93 octane.

My question is where to begin the power loss diagnosis. I view the checklist to look like this based on 3 days of thread reading:

1. Check current boost levels
- Do I have to install a gauge - can I check with an off the shelf scan tool?
2. Check leak down #s
- Blow by in overflow cans in miniscule.
- Motor has 5k track miles - 13k total.
3. Check for O2 sensor codes
- The car has only an AIM dash in lieu of the OEM dash so no warning lights can show.
4. Check for play in the bypass valve.
- Initial visual inspection seems ok - there is a small (+/- .125 inch play in the valve armature)
5. Check for serpentine belt slippage and/or tensioner play.
- Seems taught and doesn't have dust or debris around or when whipped with finger.
6. Check for system leaks via smoke test.

I'm feeling overwhelmed on where to logically begin so I thought I'd turn to the forum to inquire. Does it make sense to start with:

A.) a scan tool and check for O2 sensor codes?......Or
B.) is it better to remove & replace serpentine belt?...OR.....
C.) do I take my skull halloween smoke machine out and blast some into the intake after the MAS and before the supercharger?


I"m on track again in just 7 days!!-eek--eek--eek-
HELP!!!!




And DO NOT like following these guys around when I should be in front of them :coolnana:
 

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Have you checked your plugs? Maybe you have a fowled plug, esp since it's running that rich. Check your charge pipe connections/couplers/clamps too.
 

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Hmm - I just went through this myself lledoux101 - could be a variety of things. For me it was a combination of fouled coil packs (check yours) - bad bypass valve actuator (does your supercharger whine like it should?) - loose couplers on the intercooler tubing - and for some reason my ecu tune went bad... This was also an 07 Exige. The ECU Tune was the one that really thru me off.
 

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Discussion Starter #5
OK - Thx Elige & Benjamin.

I have swapped plugs on dyne with new NGKs that are a setting cooler and LOST 1hp gaining 1ft-lb of torque. So that eliminates fouled plug variable.

Supercharger definitely whines I think - see here


Coil pack test idea is a good one. I have no idea how to do that - can you guide me? I figured I'd buy a low budget boost gauge and test boost today. If boost was ok, then I'll pull the ECU and send to Venom for a bench test. I always worry about how to keep tabs on those flashes.

Any other ideas or suggestions?
 

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Discussion Starter #6
Hauling out the old halloween smoke machine leads me to believe I DO NOT have a super charger system leak..


..and it kept the kids busy for 20 min after I looked it all over.

This leaves me with only a few possible causes left:

1. ECU
2. Slipping Belt
3. Spent Supercharger
4. Coil pack issues
5. Faulty by-pass valve

It looks like there is a little test host on the vacuum side of the bypass valve (see picture)....is it a place to test the bypass actuator? what would I be looking for there?
I'm wondering if I can use my compression test gauge to test boost level. Do I have to be under load?
 

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shay2nak
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Hmm - I just went through this myself lledoux101 - could be a variety of things. For me it was a combination of fouled coil packs (check yours) - bad bypass valve actuator (does your supercharger whine like it should?) - loose couplers on the intercooler tubing - and for some reason my ecu tune went bad... This was also an 07 Exige. The ECU Tune was the one that really thru me off.
How was the ECU bad? which tune did you have?
 

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You can't get a boost reading there. You're going to have to tap the passenger side intercooler pipe or the intake manifold for an accurate boost reading. (There is a pressure drop across the intercooler)

Hauling out the old halloween smoke machine leads me to believe I DO NOT have a super charger system leak..


..and it kept the kids busy for 20 min after I looked it all over.

This leaves me with only a few possible causes left:

1. ECU
2. Slipping Belt
3. Spent Supercharger
4. Coil pack issues
5. Faulty by-pass valve

It looks like there is a little test host on the vacuum side of the bypass valve (see picture)....is it a place to test the bypass actuator? what would I be looking for there?
I'm wondering if I can use my compression test gauge to test boost level. Do I have to be under load?
 

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How was the ECU bad? which tune did you have?
Stock Tune - It was very Odd - my car had lost a lot of power. First thing my tech noticed was the ignition timings were not advancing. He then noted I was due for a new ECU Revision. I'm not sure when but evidently Lotus had made an update at some point. He uploaded the new Tune - and my timings were again advancing... That took care of about half the problem - The rest was the Bypass Valve Actuator. The linkage (which is a primitive setup IMO) was out of alignment.

lle - Check this thread for coil pack info

http://www.lotustalk.com/forums/f25/coil-pack-arcing-77822/

Check this for bypass valve actuator

http://www.lotustalk.com/forums/f160/low-sc-boost-question-68461/

In particular make sure your linkage looks like the picture in post 18. Mine was way out of alignment which led to no boost.
 

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You haven't really described any problem?? 202 wHP was what my stock Exige S made.

It runs rich ... at what load point (manifold pressure and rpm) does it run rich?

If I were to hazard a guess (based on the limited info), I'd suggest a VVT problem ... either cam gear or VVT solenoid(s) since the car runs/idles ok, just low on power. Do you hear/feel the cams kick in when they switch over?

Did the car always make 214 wHP or did it make more wHP at some point? Assuming you test on the same dyno?

Rob
 

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Discussion Starter #11
thx for the coil pack link Benjamin, I'm on it.

Robains - if you believe this link - it would say that 'the problem' is the missing 49 rwhp that is advertised.

The transport company had to jump the car and blew up the battery switch in the process. I wonder if that could have 'flashed' the ecu?

I'm calling Vision Function today for some help.
 

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My under standing is that 11s AFR is correct for wide open throttle.

what do you have for AFR at
wide open throttle=
idle=
cruise=
 

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I would take what's "advertised" with a grain of salt ... other than not getting the power you think you should be getting, how is the car actually running? Idle good? Any hesitation? Do you feel/hear the cam switchover?

So far you really have not stated any problem other than you feel it's not making as much power as "advertised" ... that's not really "a problem". I know people that advertise 400 HP, but in reality it's more like 340-360 HP.

If a coil was bad, you would know it immediately, it would hesitate and misfire and be very obvious.

Everything is fused so no it wouldn't "flash" an ECU - it would blow the fuse first. Have you checked all your fuses? It's possible the VVT fuses blew which would allow the car to run "normally" but you wouldn't get any advance and hence lack of higher rpm power.
 

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Discussion Starter #14
Hi Robains - even if the actual hp is only 245-250 it's still almost a 10% deficit. VVT works fine, your comments on the coil packs make sense but I'll check none the less.

I just spoke with the Vision Function guys and they helped me understand that the tune CANNOT corrupt. If it does, the car won't run.

In conversation though, we did put together that the car's hunting at idle means a vacuum leak, which could also mean a boost leak, which would also potentially run rich as the ECU looks to cover the unmetered air.

Need that boost gauge as well as a leak down and compression test - asap.
 

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You need fuel oxidiser and heat for a fire (air fuel and spark).

If your compression is good, then spark advance may be worth knowing?

Once you determine that airflow is not limited on the intake side, then have you checked the exhaust?
Is the 11:1 A:F ratio normal (?) and could that put too much heat into the CAT?
 

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Please tell me how you know the VVT works fine?

Assume you found NO blown fuses?

Idle hunt can also be tune related and doesn't necessarily indicate a vacuum leak, BUT a leak down and compression test is a good idea.

Another possibility is that you wiped a cam (you can check that by removing the valve cover and visual inspection).

Do you know if your knock sensor is functional with the VF ECU tune?

It's not a belt slipping, you'd feel that under accel as hesitation.
 

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lle - are you sure the vacuum lines are correct feeding your bypass valve actuator? I'm assuming it was done on purpose, but my lines are setup differently.
 

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Discussion Starter #18
Hi Benjamin - where does the blue/white end plug into...or does it plug into anything? mine does not. If nothing, then mine is just doubled over.

Robains - I think the blip @ 5200rpm in the power line shows the vvt kicking in. Note the rich AFR & remember my rear bumper turns black in 20 min on track.

Rec'd my 2 bar pressure sensor from AimSportline yesterday and having a bung welded in the passenger side supercharger tube today. Hopefully I'll be able to post boost numbers tonight.

Compression test showed these numbers (cylinder 1 being pulley side of motor):

#1 - 210lbs
#2 - 207lbs
#3 - 220lbs
#4 - 200lbs

Next up:

* Boost level survey.
* Cam whipe inspection
* Leak down test (I'm a little worried about cylinder #4 compression level).
 

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Have you pulled the spark plugs ... take a picture of them (all) and post (close up pic).

Based on your dyno, looks like it could be leaned out (and smoothed out) some, but it's not crazy rich except when it starts to hit 7800 rpm -- did you stop the run at 7900-8000 because of valve concerns? Either way, your dyno AFR's aren't so bad that it's taking away 40+ wHP ... but would be nice to know what happens from 7900-8500 rpm.

What size pully 3.2"? (aka stock size)
 

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shay2nak
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are you close to a dealer? Get a Lotus Scan3 tool and check for octane scaling. Your issue could be ECU is pulling timing as in my case. Still searching for a solution as I have no mechanical issues.
 
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