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I am so close to giving up and walking away

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I have a 1986 Lotus esprit G car. You might think that I am in the wrong forum, but I dont know what else to try, so I figured I would post this topic in both the Stevens and giugiaro room.

I am at my wits end. I read every article there is on Bosch k jetronic systems, and I think I read my lotus service manual 1000 times. I am getting so close to giving up and selling, but I really dont want to do that. I love this car, and would like to enjoy it one day. It is a year and a half old, and that day did not come yet. I think the bosch system seems to be rare, and nobody really knows too much about it. I need some experts.

When I got the car a year ago, it never really ran too well. I rebuilt the entire engine. It only had 27ooo miles on it. After rebuild, I got it to the point where it idled well, but the car was extremely slow on throttle response. I heard it is no rocket off the line, but this is really, really slow. You need to give it LOTS of gas while letting the clutch out in first. It has NO low end power whatsoever. I had an old ford escort 4 cylinder 1.8 litre many years ago, and that car was much faster when flooring it from a dead stop.

Lately, I just got done swapping the blue and red dot cam sprockets with the standard 104 green dot with the hope of restoring low end torque. Boy was I wrong. It is worse than ever. I know the cam timing is correct, I even used a degree wheel, and dial indicator to measure maximum valve opening points at 104 degrees! When the engine is running, I can point my adjustable timing light at the flywheel, and tweek it into TDC, then see the green dots perfectly lined up on the cam sprockets. Compression is good. I hit the gas, and blaaaaahhhhhh. This thing barely revs. It is much worse than before.

I think the mass air flow unit was running rich before. I think it is running even richer now. Not sure how cam timing could effect that.

I bought one of those air/fuel mixture gauges, and hooked it up to the o2 sensor (computer disconnected), and it was pegged to the rich side. As I leaned out the Bosch air flow sensor mixture screw, idle slowed down, but the meter never showed a lean condition. It never got off the extreme rich side. Then the engine would not run anymore.

Even when it is running, it just doesnt sound right to me. There is no crispness to the sound of the engine.

I dont know where to look next. The car is timed currently at 20 BTDC at idle. I heard that is the best timing for this car. Believe me, I tried 25,30, 15, 10, 5, 0, and is still sucked!

Plugs are black and sooty.

Could this be a bad ignition module?

I have tried everything. I have no clue where to go now.



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Back in the day as a VW mechanic the CIS system could be a challenge. Couple of suggestions..... 1) Find a good Volvo, Porsche or VW mechanic that has the know how and tools to troubleshoot. 2) Get the proper pressure gauges and if the Lotus manual isn't thorough on trouble shooting there are other manuals that will cover it.

If the car has sat for a long time or has had rust in the fuel system you might need a new fuel distributor. I recently did a job on a Delorean and it ran OK but once I replaced the fuel distributor it was much better. These fuel systems need to be absolutely clean. Any little bits of grime will cause all sorts of problems.

Good luck,


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I know the gauge is cheap, but it actually works pretty well. It has 15 led's on it, and it should at least get me in a close "safe" zone.

I am wondering if the lucas constant energy ignition module is bad. A lead off the coil to the block yields no spark over 5 mm gap. At 5 mm, the spark is orange. I am used to seeing blue on other engines. Maybe the amp is old, tired, and out of spec.

Interestingly enough, when I changed the cam sprockets to the green 104's, the idle speed fell dramatically to the point where a full adjustment of the idle speed screw could not hold it above 700 rpm! And the mixture seemed alot richer. If I am getting more compression with this sprocket, like I think I am. (valves closing sooner, rather than later like the red and blue dots) This should build more pressure in the cylinder as there is more volume to compress. If the spark was not good on the old compression, then it will be even worse on the higher compression, with a significantly less burn, resulting in less power (lower rpm's at idle), and a rich sooty barely burned mixture. Not to mention, when I floor it, it doesnt do much of anything at all. If you are patient, you might get it to 4000 rpm's in 6 seconds. I kid you not. It revved much faster with the old sprockets, and same timing.

Am I headed in the right direction here? Sounds logical.

I am getting a new ignition amp.

Edited by markd
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try taking her to a good shop and let them have ago at it . maybe a good Porsche shop the early 1978-81 928's used the Bosch k jetronic systems. good luck jp

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K-jet, despite folks not being overly in love with it, is actually a very reliable and good system. When tuned up it will run with very little trouble... but the trouble is that that once monkied with it can be a teadious thing to deal with.

Based on your description, your fuel system may be okay. If you backed out the mixture screw to lean and you were still rich it is possible that your fuel dist unit has been tampered with. But... I would set the screw to center and start over before I messed with it. Black and sooty spark plugs may not be a bad thing as the k-jet system with a turbo will run rich (you want this as a sudden lean condition under boost can be a problem).

20 d BTDC is way way to high for an HCI k-jet car and will kill your power and motor eventually. You need to set the time at 15 d BTDC (with all the vacuum lines off the dist). Once time is set, set the idle but remember to disconnect the TPS (throttle position switch). Also, make sure there is not a lot of free play in the throttle cable.

If the car will start, listen to the injectors with a stethescope (or coat hanger) and make sure they are buzzing. The tone can be different, but they should buzz consistantly. If not, there is a possible pressure problem or a bad injector problem. On the bulkhead side of the fuel dist unit you will find a little valve held in place with an electrical connector. It is the pressure regulator valve - also called a kricket valve - and it needs to be buzzing like a kricket (hence the name). This little bugger can cause all sorts of issues if going bad. Too rich, too lean, inconsistant running, low power, etc...etc.. etc... If it is not buzzing consitantly at warm up and steady with throttle it is either bad or it is getting a bad signal from the O2 (lambda) sensor. Remeber this thing opens and close at near light speed so it can easily fail after age sets in. Look in your records for O2 sensor replacement also... if it is old I'd get a new one.

With the time and idle set, blip the throttle a couple times and set how it tachs. At this point, at least the settings should be acceptable with the mixture possibly off a bit... but not a show stopper. Just be rich and not lean! If you still have your original D45 dist unit intact... start checking you spark quality first. It is much faster and easier than checking fuel flow.

The shop manual has a page with a flow chart and step by step ignition system checks. My car is an 88' and therefore the manual is also... but this is found on page 14 section MG in my book. If you find and issue anywhere in line with the electrical side it should be easy enough to replace the problem part.

Once the ignition has been gone through, check your RPM relay and Fuel Enrichment module. Either of these crapping out will cause a good idle and a crap throttle responce...

Now, I may have forgoten some little bit here, but I thnk I have covered it. So, onto the easy (well sort of) fuel stuff. Check the relays for the fuel pumps in the ignition box. Check both fuel pump fuses. If good, get under the car and check both fuel pumps are running. They buzz when a stethescope is held against them. Now, the fuel accumulator going bad could also cause a similar issue to what you noted above. I am not sure you can "check" it... If in doubt I just replace it (it is one of the only times i'd replace just to see if it helps).

That should get you through the easy stuff. If your fuel dist unit is bad it will require a specialist to repair/rebuild it. However, this would be very very rare compared to the other stuff...

Good luck,


Edited by Autocross7

"If you feel that you are in total control of the car, well, your just not driving fast enough". Jimmy Clark

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PM'd ya... and your thread in the g-car forum... has some great info!

Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

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Guest bharper

This is off the cuff, but redid a porsche 928 cis a few years ago, and it was really pretty easy to tune.

I expect you do have the allen bolt in the cis plenium to adjust the fuel to air mixture. On mine, I just hopped in the car with wrench in hand, and adjusted the mixture until the car ran the best.

Biggest thing that can hose you on the cis would be friction in the pivot shaft that the air plate arm is hooked to. I cleaned the heck out of mine, and put it back with just a thin film of synthetic grease, and adjusted the pivots for no play, but no friction either. I could rotate the cis plenium off the car and the plate and arm would stay almost stationary. If the plate and arm is laggy, mixture will go all over the place.

just a few thoughts on the cis....


Edited by bharper
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I would check your spark! Orange and not very strong sounds bad to me. I had similar engine running conditions on an old mg. Simple engine with simple SU carbs but couldn


"Belief is the enemy of knowing" - Crrow777

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Here is a really good one.



I have the LC1 on my car and am now on my 3rd unit in 8 months!!! i have been left stranded twice my this unit failing and have had to pay for AA cover that I didn't have which cost me a small fortune.... If you want to use wideband buy a KMS unit as these are far superior but to me your problems sound fuel related...

Old ford CVH engine on the RS turbo and XR3i were K jetronic so there should be plenty good mechanics out there with a good knowlege of the systen also VW and Porsche used it, 924 and 928 used it as did the 1.8 gti golf...

I hope you get this sorted and start to enjoy your car mate, stick with it as your retun for a good working car will be more then you'll get for a broken car less the repair bill....

Good luck

Mark :2guns:

Mark MacKenzie  Elise S2 135 Sport 

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This is just off the cuff,but if you have a MAF (mass air flow) sensor and this is faulty it will have the same symptoms. They tend to give up slowly, i had one go on my Porsche Boxter and i didn't realise until i was struggling to overtake Vauxhall Vectra's and the like, eventually the take off was very slow and even then it was only when the car felt like it had hit the rev limiter at 5k RPM that i took it in! When the car came back with the new MAF fitted, it went like a 911TURBO!

They are usually quite cheap $150 or so and could be why you are stuggling to get the mixture to be constant!

Worth a try before you sell such a beautiful car!

Good luck my friend



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OK, while you are getting advise on the fuel side, here are a couple of electrical ideas - Unlikely to be the CI module, as they tend to be either working or not working. (Its simply a switch, its not generating the spark). Ditto for pickup except that they can suffer from intermittent connections where the wires flex - however these are not your symptoms. Can you have a look at your coil and identify what numbers it has stamped on the base? I was wondering if it has been substituted by a non-CI type?

NB If you do decide to replace the amp, there is no need to replace the whole (very expensive) Lucas module, you can take the base off and replace the main module (a GM part!) and capacitor very cheaply and still readily available.

good luck Steve

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Hello Mark

don't give up just yet, i'm gonna do something for you as a one off.

Our Factory Training man Tony is one of the most knowledgeable bods anywhere and i'm gonna ask him to give you a couple of hours and see if he can help you.

As you prob know i'm one of the Aftersales gang at the factory and i've had the ok from the Head of Aftersales to do this.

So pm me your details and lets see what we can do.

He may 'f' a few times but trust me thats a good sign!

Look forward to getting you fireing on all 4.


Parts Supplying Lotus God

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I used top have a Mercededs 450 SEL and it had the 4.5 Litre V8 and K-Jetronic Injection. Maybe an Mercedes Dealership will have some experience also.



"Laugh" and the world laughs with you - "Cry" and you just wet your face...

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Before you repace ytour ignition parts take note that a misfiring engine will show up as running lean on an oxygen sensor no m atter how rich the mixture setting is. The misfiring cylinder is not burning the fuel so air and liquid fuel go down the exhaust and the sensor picks up on the extra oxygen.

However, that's a fantastic offer from Lotus. I cannot imagine any other manufacturer offering such a service for an owner of a 20-year old car. Hats off to Gooner.

S4 Elan, Elan +2S, Federal-spec, World Championship Edition S2 Esprit #42, S1 Elise, Excel SE


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You guys are great!

Thanks Gooner, I really appreciate it, but I have awesome news! I fixed it today.

I rebuilt the Lucas ignition module with the gm ignition part inside, and a new condensor. I replaced the coil with a new one , and the damn thing works!

For the first time in my life, I blipped the throttle, and it actually revved!

Took it for a spin, and it was awesome.

If you where all here, I would buy a round of beers!!!!



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I have always believed in 'if you want to know your car backwards, work on it yourself.'

Once learnt, hopefully never forgotten. Perseverance... Now go and enjoy it :2guns:

And if in the UK and it all goes to crap, take up the amazing offer from Gooner. (I still can't believe I read that!!) I have had holdens for years and they would never even think about what Gooner just said.


Edited by ramjet

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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Ahhhh Lucas......say no more.

Robert Costa
1984 Turbo Esprit
Very Black!
2004 Lotus Elise
Quite Green! gone :-(

1977 S1 Esprit, in bits

1998 Lotus Elise S1, Azure Blue
Sydney, Australia

“The parts falling from this car are examples of the finest British craftsmanship”

Recommended procedure before taking on a repair of Lucas equipment: Check the position of the stars,kill a chicken and walk three times clockwise around your car chanting:" Oh mighty Prince of Darkness protect your unworthy servant.."

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