She Runs! Not Well :-( Help!

[Drfatz]

First off...WATCH MY VIDEO!

Second, I picked up a new MAP sensor as well as a new O2 sensor today just because at this point mine as well just start replacing all of the old sensors. Which leads to my next question, I picked up the generic BOSCH O2 sensor listed on the xreference sheet, and its only 3 wires instead of 4. The 4th wire on the stock O2 sensor looks like a ground, do we need this?

I installed them and then reset the ECU and IAC valve using FreeScan. Well I managed to get the cars idle to stabilize at around 1100 RPM and I can say it was terrible. The engine was shaking violently! I could literally smell raw fuel coming out the tail pipe. At this point I really believe she is not firing on all four cylinders, why else would it run so rough? I rechecked the timing this time lining the flywheel up exactly with the TDC mark and my cam dots were almost perfectly lined up (GO ME! )

When I get another set of hands around here I will pickup a fuel injector light and make sure they aren't staying open all the time and I will check to make sure each cylinder is firing.

I did check the spark plug wires but I mine as well ask a stupid question...Cylinder No 1. is the one closet to the firewall right?

...she still hasn't gotten the best of me, but its getting there

-Graham

[Paul93Lotus]

I did check the spark plug wires but I mine as well ask a stupid question...Cylinder No 1. is the one closet to the firewall right?

...she still hasn't gotten the best of me, but its getting there

-Graham

It's hard to tell that anything is wrong from the video....the Lotus does have a slight lope, and there will be a little bit of shaking, but definitely not violent to the point of feeling like a stall waiting to happen.

Yes, the #1 is closest to the firewall...just checked my car. But at the coils they are not 1-2-3-4

They are 2-3-1-4, with the #4 closest to the firewall.

Might want to double check at the coils.

I remember reading a post saying to stay away from a generic O2 sensor, and to only buy the Lotus one....which I naturally questioned. I have always thought they all operated the same except for the extra wire for the heater. What condition was your old one? Was it contaminated? Did you ever do a log before switching O2 sensors, and if so was there a change in the log after?

Have you double checked the large vacuum line that runs from the IAC area to the plenum? Are you sure the hose is clamped down tight, and there are no cracks in that hose?

You also mentioned that you have an aftermarket fuel pressure regulator. Can you temporarily switch back to the stock fuel rail / pressure reg. to see if there is a change. Possibly your fuel pressure is too high (despite readings)?

I'd have to say you need to start with the mods that you have installed first...they could be contributing to this idle problem.

Edited July 7, 2007 by Paul93Lotus

[Dermot]

Don't fit a generic O2 sensor. I have lost count of the number of people who have done this and ended up going back and getting a proper one. Get one from a Lotus especialist at least.

[rydning]

It should be pretty big diffrence when the O2 sensor is conected or not.

When its not my car did go rough.(way to fat)

[Drfatz]

Once I saw the O2 sensor only had three wires I opted to just return it.

I can't change my fuel system back to the old one, but I can adjust the pressure to whatever I want and I tried lowering and then raising it quite a bit and it made no difference.

I checked all of the connections to the IAC including the large hose, its fine and the clamps are tight.

I truly believe that I am only running on 2-3 cylinders at this point. That would explain the extremely rough running. It wasn't running that rough in the video because it was running at 1500+ RPM. Once I reset the IAC valve and it tried to idle around 1100 rpm all hell broke loose, it was like the engine was going to blow apart! Also running on 3 cylinders would explain the high engine load.

I have good compression which means my valves aren't stuck open and I just adjusted the valve shims so they should be opening properly. The only thing left is they aren't getting proper spark from the coils. Also I smell raw fuel coming out the exhaust which makes me further suspect one of more of the cylinders is not firing. Is it possible for some of the cylinders to be firing and not others?

-Graham

[Artie]

it certainly is possible for 3 cylinders to fire and one not. Pull the plugs one at a time or just arc the plug end lead to a chassis part for ground. Use a long paper clip jammed into the plug boot then ground it whilst trying to crank. See if all 4 are sparking. Next you can start the car, let it idle and pull a plug wire at a time. See if the idle changes as you remove one wire at a time. Use spark plug pliers so you don't get shocked. However, note that if one cylinder isn't firing, pulling the plug should be an indicator as the non firing cylinder should be wet with fuel and the plug should be wet also. Also, did you get a "noid" light set and check that all 4 primary injectors are firing. I'd also check the secondaries just to be sure they aren't sticking open and "dumping" fuel adding to the problem.

ARtie

[docf]

have you fit fresh spark plugs? Looking at that video the idle seems almost normal.. those fouled plugs wont clear themselves unless you take the car out and thrash it a bit. I think you've ruled out most things that would result in catastrophic failure so a nice little drive might be all she needs. Start with a fresh set of plugs if you haven't already.. that was the cause of my no start condition when i first got my car.

[Drfatz]

it certainly is possible for 3 cylinders to fire and one not. Pull the plugs one at a time or just arc the plug end lead to a chassis part for ground. Use a long paper clip jammed into the plug boot then ground it whilst trying to crank. See if all 4 are sparking. Next you can start the car, let it idle and pull a plug wire at a time. See if the idle changes as you remove one wire at a time. Use spark plug pliers so you don't get shocked. However, note that if one cylinder isn't firing, pulling the plug should be an indicator as the non firing cylinder should be wet with fuel and the plug should be wet also. Also, did you get a "noid" light set and check that all 4 primary injectors are firing. I'd also check the secondaries just to be sure they aren't sticking open and "dumping" fuel adding to the problem.

ARtie

Cheers Art. Honestly I am really hoping that one of the cylinders is not firing for I can't think of anything else that would cause this at this point. I have checked and or replaced all of the major sensors, I installed new plug wires and just put in new plugs (again). The timing is dead on, the valves have been professionally serviced and adjusted. Compression is excellent. ECU is brand new as if the S4s MEMCAL. If only I had the shift linkage hooked up (I have to run new cables and get a braket made up) I could take her out!

Tomorrow when I finally have another set of hands I will pull one wire at a time and see what the story is.

Thanks all!

-Graham

[98GT3]

Cheers Art. Honestly I am really hoping that one of the cylinders is not firing for I can't think of anything else that would cause this at this point. I have checked and or replaced all of the major sensors, I installed new plug wires and just put in new plugs (again). The timing is dead on, the valves have been professionally serviced and adjusted. Compression is excellent. ECU is brand new as if the S4s MEMCAL. If only I had the shift linkage hooked up (I have to run new cables and get a braket made up) I could take her out!

Tomorrow when I finally have another set of hands I will pull one wire at a time and see what the story is.

Thanks all!

-Graham

Just thinking out loud...........you haven't got a couple of the plug leads switched?....just a thought! Also it might be worth checking that, with all the memcal plugging and unplugging a pin hasn't got bent in the socket??? As I say just thoughts!

Phil

98GT3

[Artie]

I also watched the video and it sounds very normal, engine doesn't appear to be shaking violently. These engines are by no means Smooth! At idle I can hardly make out images in my rear view as the thing shakes so much. My engine makes a light popping noise at startup( suspect it's a little piston slap) but goes away once warm. What is the vacuum at idle?

Artie

[Drfatz]

I also watched the video and it sounds very normal, engine doesn't appear to be shaking violently. These engines are by no means Smooth! At idle I can hardly make out images in my rear view as the thing shakes so much. My engine makes a light popping noise at startup( suspect it's a little piston slap) but goes away once warm. What is the vacuum at idle?

Artie

Some good news.

I found out that it ran super poorly before because one of the spark plug wires was not totally installed and thus one of the cylinders was not firing. I checked all cylinders have spark which is good. I ran the car and it still ran a little poorly so I decided to change the IAC valve. Once I did that she seems to run almost normal! On occasion I hear a popping/hiss sound and the engine stumbles slightly when this happens. I believe that one of the one way valves in the vacuum lines coming from the intake manifold is malfunctioning (installed wrong?). I think what is happening is its opening up suddenly and releasing pressure in the intake causing the engine to stumble slightly.

What is the purpose of the black and white valves in the vacuum lines? Do they fail often and where can I get some? Also, what about the crankcase vent valve? Does anyone know of a cross reference for that part?

-Graham

[KENCO]

Some good news.

I found out that it ran super poorly before because one of the spark plug wires was not totally installed and thus one of the cylinders was not firing. I checked all cylinders have spark which is good. I ran the car and it still ran a little poorly so I decided to change the IAC valve. Once I did that she seems to run almost normal! On occasion I hear a popping/hiss sound and the engine stumbles slightly when this happens. I believe that one of the one way valves in the vacuum lines coming from the intake manifold is malfunctioning (installed wrong?). I think what is happening is its opening up suddenly and releasing pressure in the intake causing the engine to stumble slightly.

What is the purpose of the black and white valves in the vacuum lines? Do they fail often and where can I get some? Also, what about the crankcase vent valve? Does anyone know of a cross reference for that part?

-Graham

It really needs to have the computer reset so it will have a chance to re-learn everything that you are changing.

I would get they other issues sorted out, so you can get to a point that you can drive it on the road, and then re-set the computer.

[Artie]

Some good news.

I found out that it ran super poorly before because one of the spark plug wires was not totally installed and thus one of the cylinders was not firing. I checked all cylinders have spark which is good. I ran the car and it still ran a little poorly so I decided to change the IAC valve. Once I did that she seems to run almost normal! On occasion I hear a popping/hiss sound and the engine stumbles slightly when this happens. I believe that one of the one way valves in the vacuum lines coming from the intake manifold is malfunctioning (installed wrong?). I think what is happening is its opening up suddenly and releasing pressure in the intake causing the engine to stumble slightly.

What is the purpose of the black and white valves in the vacuum lines? Do they fail often and where can I get some? Also, what about the crankcase vent valve? Does anyone know of a cross reference for that part?

-Graham

Thats great news, remember these things are very lumpy at idle. They have very low compression and create little vacuum so they like to try and stall on cold start(at least mine does) The check valves(one way black and white) valves are part of the turbo control system as well as the emissions canister iirc. Check that you can blow air thru one way but when you suck air thru the same side it should not. If they don't work this way, ie air goes both ways, replace them. You can get new valves from Lotus or Autozone has several in the red "help" section. I've fitted one of these on my RX7 and have had no problems.

Artie

[Drfatz]

More info

I managed to get the clutch adjusted and put her in first gear so I could just drive down the street. Well she drove YAY! BUT not very well. The engine seemed okay at idle, but when I put my foot into it at all there was a lot of hesitation and stumbling. It seems to me that the car is running much to rich still and I can't figure it out!

I went out to get a noid light and of course NO ONE has it. I even went to five different places and the best I could get was NAPA would order one for $80! I decided I might try and put a stethoscope up to the injectors and see what happens.

I had a question about the fuel pressure regulator. I mounted mine after the fuel rail and then ran the return line from the regulator to the tank. Some one told me that I should mount it BEFORE the fuel rail. This makes no sense to me, but he did say that if you set it up like the way I have it (ie after the fuel rail) the car would run to rich

What else would be causing the car to run to rich at this point? I have checked everything I can think of and then re checked it again! All vacuum lines have been triple checked. The only thing left are the one way valves in the vacuum system. Sensors are new and calibrated. I pulled the connectors for the secondary injectors and it made no difference.

Suggestions welcome (unless your going to suggest I check the vacuum lines again!)

-Graham

[Artie]

PM Karvamore, he had a fuel system put on his car as I recall with FPR and stainless lines, he could direct you how the regulator goes. Find his sig and his site is listed with a link, you can see pictures of his setup there. Did you freescan log your drive by any chance to see what the sensors are reading? IE MAP, O2 etc. Seems there is discrepency between throttle opening and fuel delivery, perhaps adjusting the idle screws would be of help. PM Vulcan Grey as there are a set of adjustment screws that need only be adjusted by "trained" professionals but I am unfamiliar with those and their location. They are somehwhere by the butterflies. Perhaps they are just opening too far and fast?!

Artie

[Drfatz]

I checked Karvamore's site and his setup is almost exactly what mine is except he has smaller secondary injectors. I am beginning to wonder if maybe the secondary injectors are firing and there is just to much fuel going in. Perhaps I will take it around the block again tonight with the secondaries unplugged. I am still running the stock S4s chip at the moment and not the custom WC chip yet. The secondaries open at 3K? I am wondering at what point the computer starts to read the programed fuel and timing maps.

As far as screws are concerned the only one I see is the throttle stop screw and who knows if that is correct or not. I will have to look around and see what I can find out.

BTW in the small amount I drove the car so far, ITS A BEAST! Also the new Lotus suspension feels super sweet

-Graham

[rydning]

I checked Karvamore's site and his setup is almost exactly what mine is except he has smaller secondary injectors. I am beginning to wonder if maybe the secondary injectors are firing and there is just to much fuel going in. Perhaps I will take it around the block again tonight with the secondaries unplugged. I am still running the stock S4s chip at the moment and not the custom WC chip yet. The secondaries open at 3K? I am wondering at what point the computer starts to read the programed fuel and timing maps.

As far as screws are concerned the only one I see is the throttle stop screw and who knows if that is correct or not. I will have to look around and see what I can find out.

BTW in the small amount I drove the car so far, ITS A BEAST! Also the new Lotus suspension feels super sweet

-Graham

Nice that you have good progress now.

You should realy invest in a wideband lamda like this.

http://www.innovatemotorsports.com/xcart/p...=261&page=1

That will save you a lot of work and you know whats going on.

Or at least borow one.

I have tuned my engine so its AF 12,5 at the hole register above 0,1 bar boost.

Only at light cruise (belowe 0 boost or vacum) and idle do I use AF 14,7

You can easily tune your engine changing the extra injectors and with fuel pressure to get it right at the hole rpm/boost register.But I belive you will be find starting at 3 bar fuel pressure with vacum line off like the stock fuelpressure.

Edited July 10, 2007 by rydning

[docf]

IIRC the secondary injectors dont fire until 75% throttle and 9psi of boost.. unless they are broken which sounds unlikely. The only advantage of mounting the fpr after the rail is that excess fuel runs through the rail and back to the tank.. helps keep fuel temps down. Other then that you are just venting away excess fuel.. you could even mount the fpr on the fuel pump outlet and it would still work.

[Drfatz]

IIRC the secondary injectors dont fire until 75% throttle and 9psi of boost.. unless they are broken which sounds unlikely. The only advantage of mounting the fpr after the rail is that excess fuel runs through the rail and back to the tank.. helps keep fuel temps down. Other then that you are just venting away excess fuel.. you could even mount the fpr on the fuel pump outlet and it would still work.

Thanks guys! For a wideband O2 do I need another O2 sensor mount on the exhaust?

Currently I am beginning to think it might be a bad O2 sensor. Or that it may be a dyeing coil. Is it possible to have spark from the coil, but have it be weak and not give good ignition? I have checked and each cylinder has spark.

The only two things that are not brand new are the coil and the O2 sensor.

I am glad the FPR is not installed improperly because that is something I really did not want to remount

-Graham

[Vulcan Grey]

I am glad the FPR is not installed improperly because that is something I really did not want to remount

-Graham

Wait so are you saying that the fuel pressure regulator is not bypassing the excess pressure back to the tanks?

So whats at the end of the rail? Just a big hose going back to the tank? I guess I don't get it.

Seems to me that you have to have the fuel pressure regulator as the last restriction before the fuel returns to the tank... Otherwise you have a restriction (regulator) then a bunch of small holes (injectors) and then a big hole (return to the tank)... which would be a large pressure drop and would make the primaries pretty useless. Sounds like your secondaries are the only ones getting any fuel pressure... If I'm understanding your setup correctly.

BTW, funny story.

I was helping a friend with his Esprit once (shall remain nameless) and he had the blue race chip, bigger secondaries, higher pressure sport 300 pump, sport 300 higher pressure regulator, and he had mistakenly put in a 3BAR MAP sensor. Well the car was running like crap, it would idle fine but couldn't take any load at all. it would just start bucking and had no power at all.

We started to diagnose (he hadn't told me about the 3bar MAP yet) and so we checked spark, seemd fine, so we checked the injectors. I pulled the primary rail complete with injectors and placed some paper towels under the injectors to see if I could see if they were creating wet spots.

So I cranked the car to get the injectors to fir a few revs, and the car started and ran!!! It idled just fine... no injectors!

Then we remembered the secondaries... Yes they do run even at idle (well at least with all that extra pressure).

So we replaced the MAP with the original 2BAR, and put the fuel injectors back in and the car ran fine. Shot 6 ft flames though...

Edited July 11, 2007 by Vulcan Grey

[docf]

The only two things that are not brand new are the coil and the O2 sensor.

the coils are plain old GM dis coils.. i bought mine from summit but I've seen them at pepboys and autobarn. Made a noticeable difference in low rpm smoothness so you might as well just replace them.

[Vulcan Grey]

Graham,

Did you see my reply above about your regulator?

I just looked at the picture you posted

and it looks like this will not work.

The pressure drop after the regulator, due to the fuel return line, is much too large, and the primary injectors will not see the required pressure.

The regulator should be the last restriction before th return to the tank.

Edited July 13, 2007 by Vulcan Grey

[Drfatz]

I guess I'm confused. Currently the regulator is the last point before the tank return. The fuel goes from the tanks through the rail and then to the regulator and finally returns to the tank. I believe it is the last restriction before the tank. It is setup the same way the stock pressure regulator was setup...I think

Actually I thought about the MAP sensor, I will have my old one and it is easy to change. Although the car was just picked up to head off to the bodyshop for awhile so it will be two weeks or so until I get to work on her again :crybaby:

-Graham

[Vulcan Grey]

I guess I'm confused. Currently the regulator is the last point before the tank return. The fuel goes from the tanks through the rail and then to the regulator and finally returns to the tank. I believe it is the last restriction before the tank. It is setup the same way the stock pressure regulator was setup...I think

-Graham

Oh sorry, I thought I read that you HAD put the regulator before the rail. But you were just saying that someone had told you to do it.

[Paul93Lotus]

I would search Karmavore's old posts ...from what I remember he had problems with his set up, and it may have been the fuel pressure regulator.