free hit
counters
ECU, Engine, Injector, Coils or something else - Engine/Ancilliaries - The Lotus Forums Jump to content
modifiedv8engines

ECU, Engine, Injector, Coils or something else

Recommended Posts

Engine, ECU, Ignition, efi fault.

Bit of a missive this one but here we go…..

3 weeks ago Esprit back on road, short test drive rattle/vibrating noise from engine, exhaust area.

Checked bearings on idler pulleys, checked heat shield, belt covers and a good check around exhaust and nothing obvious. Short low speed test drives (3) to double check and noise had gone.

 

Few days later, start car, fuel pump primes okay but slow to start. Runs on all 8 cylinder while reversing off drive way, Join highway and need to stop at junction about 250 yds down the road.

 

Move off from junction, accelerate and engine missing and down on one or more cylinders. Use a bit more throttle and intermittent misfire so back to base about 1.5 miles. Attempt to close drivers window and nothing. Stop engine and remove key, re-insert key and battery has insufficient charge to start warm engine.

 

Engine check light on,

Battery removed and on charge. Battery re-fitted and starts okay, not instant but engine cranksand fires up.

Use scan software to check for faults and none found but removed PIDs even theough there were not any, and engine check light off.

Reverse, back, then on to main road as before and at the junction, the mis-fire less than 8 cylinder situation.

Feather throttle and misfire clears and car runs fine. Engine up to working temp , covered about 10 miles at fairly high speed and no issues and in fact it went well, very well.

Thinking fault cured and possibly bad or discharged battery.

Few days later, nice evening so out for a few miles fun. Engine cranks okay ( thinking battery okay) starts and settles to idle speed just under 1000rpm.

Off side silencer popping, spitting and hand over silencer outlet indicating the 1 – 4 bank of cylinder has a fault. Continue to warm up and misfire, spitting still present. Stong smell of unburt fuel and a smoke haze from the 1 – 4 exhaust.

Leave engine to cool a bit and remove spark plug. Lead covers. Remove all 8 plugs to check for water ingress. All spark plugs rusty/rotten.

NGK plug not available locally so instead use some of the new iridium plugs. Install and still same misfire issue.

Old plugs, the rustly ones quite badly corroded externally ( car lives outside and no attempts with the Lotus gasket and Dirko sealant seal those covers – not the best design) Number 3 cylinder spark plug slightly sooted or probably better to say electrode discoloured.

 

What to do next ……..

Plenum removed, primary coils checked for resistance and all @ 0.6 ohms.

Secondary coils all checked out okay @ 11.69, 11.79,11.79 & 11.73 K ohms.

Remove injectors and number 3  injector shows some sign of discolouration when compared to the other 7 which all look pretty good.

Bit of a quandary as not completely sure if it’s the injector (all 8 are within the 12.3 – 12.6 ohm range) so doubt its those and since the coil packs, lead and new plugs are all okay bit stumped on what to try next other than the wiring to the injectors from the ECU.

So if anyone has the pin outs for the ECU or knows if there are 8 separate injector drivers or they are batched and smilar for the coils tht would save a lot of wasted energy.

After writing this lot down just had a though that may be the battery is faulty and probably the owner !

Any help much appreciated

 

 

 

 

 

 

 

   

 

 

Share this post


Link to post
Share on other sites
Upgrade today to remove Google ads and support TLF.

There are 8 separate injectors drivers and the coil outputs are paired - I can email you the pinout details if you PM me an email address.

I had a similar misfire problem recently that turned out to be the ECU.  edPlugged-in a spare proven ECU and the car runs perfectly.

Mike S


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

Share this post


Link to post
Share on other sites

Maybe check MAP sensor, fuel pressure regulator and fuel pump (these were the suggestions of my mechanic on a similar problem, I bought all three to replace since they are cheap parts and my car is almost 20 yrs old)

Share this post


Link to post
Share on other sites

Thank You for your advise/help and to Mike for the info.

Chances are Mike you are probably right so the next issue is testing and depending on the outcome, finding a ECU to borrow and verify. Having searched various threads on V8 ECUs it seems to be an issue getting these from the factory, and getting anyone to repair as I heard Blue Streak, Mike Haines Racing etc etc no longer could help. 

I use an Emerald K6 on a TVR I have so was considering one of those if my Esprit ECU ever went bad but recall only 4 coil drivers ( I think Esprit ECU only uses 4 with some spares) but doubt its worth the hassle as a new loom, rolling road etc etc and been down that road with the TVR

Esprits MOT expires today and it seems car has also .......what to do next .........?????

 

 

Share this post


Link to post
Share on other sites

Esprit Engineering offer an ECU repair service.  I would send the unit to Geoff to see if he can fix it.  If you can get a local owner to help with proving your engine with another unit, that would also give you piece of mind.

If it is the ECU and you cannot get your unit repaired, I have a stock of working units but they are not exactly cheap.


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

Share this post


Link to post
Share on other sites

Thanks Mike

I spoke to Emerald this morning while testing a couple of sets of injectors (which turned out to be good but crap injectors anyway according to Dave) and another company ( ex Lotus Engineering software guru) who are quite interested in providing a new ECU which will fit inside the OEM case. 

Probably easier to stick with the Factory item for the time being but when those available are no longer available, alternatives will need to be found. 

Couple of coil packs ordered and once these are here I can fit and test ( those fitted look like the originals). 

 

 

Share this post


Link to post
Share on other sites

I have dealt with Emerald on a number of occasions when running k series engines and they were always fantastic at setting the car up 

Share this post


Link to post
Share on other sites

Agree with you on that, The Emerald team are all very good and the aftersales tech support is also very good too.

I spoke to Dave Walker (Emerald and regular tech writer for car mags) yesterday while having the Esprit injectors checked and he sees no problem with the K6 running the Esprit V8 engine. As this is a standalone replacement ECU, those who wish to tweak their fuel and ignition maps can do this along with any boost change requirements etc etc , and fairly sure 2-3 different maps can be loaded for different driving conditions. 

Mate of mine can make up adpater looms ( this is what I had made to use the factory hotwire loom on my TVR to take the Emerald K6) and with Emerald a few miles down the road, it may be a consideration for an alternative to the Lotus V8 ECU which is getting difficult and as Mike S will tell you costly to buy, repair and programme. I think Emerald have already supplied  ECUs for Exige S1 owners which is apparently a similar ECU to the V8 item but with a few add ons

Right.......New coil packs to fit, injectors, check resistance of ignition leads ( now I have the values 2200 ohms per foot for Magnecores KV85s) and reassemble and check fuel pressure.

Earlier buzzing noise which were assumed to be heat sheilds may well be the fuel pump as these are apparently known to go bad. Apparently the priming you can hear on our cars is the secondary fuel pump which is energized to run for a few seconds to keep it working as its only usually required very rarely ( 150 MPH or when conditions dictate). 

 

 

 

 

 

 

 

Share this post


Link to post
Share on other sites

Update and still not fixed.

New spark plugs, plug leads  checked for resistance, new coil packs, injectors flow tested and nothing untoward.

Wanted to verify if any of the above were faulty but seems not. And with the hot weather last week and rain over the weekend only just got round to testing fuel pump.

61 psi on energising pump and then drops 2 psi with ignition off.......after about 10 minutes fuel pressure decays to 45psi which is slightly below spec but anyone know or experienced this lower than spec value affecting engine running.

Would like to rule or cross this off the list before compression testing next ??

 

 

 

 

 

 

 

Share this post


Link to post
Share on other sites

Found it I think and all thanks to Peters V8 Esprit software

Fault Code P1101 ......fuel pump relays ( on order from Land Rover) Fuel Pumps ( I have new spares) or wiring fault........moneys on the last one but we shall see. 

  • Like 1

Share this post


Link to post
Share on other sites
34 minutes ago, modifiedv8engines said:

Found it I think and all thanks to Peters V8 Esprit software

Fault Code P1101 ......fuel pump relays ( on order from Land Rover) Fuel Pumps ( I have new spares) or wiring fault........moneys on the last one but we shall see. 

On top of all the other problems, I also had problems the engine cutting out (losing a cylinder)... So now that I ordered fuel pump I hope it solves the problem!!

Share this post


Link to post
Share on other sites

Worth checking the relays too.

Just changed mine and engine running marginally better @ idle speed however still the odd spiting sound from the number 1 # cylinder bank (cylinder 1,2,3,4). Maybe ECU finding its base setting but yesterday lambda test showed Bank # 1 voltages all over the place with fairly normal voltages on Bank #2.

As above, fuel pressure  below spec so with throttle applied, more fuel required and the spitting/misfire worse with a light smoke haze from Bank #1. 

Waiting for fuel pump seal to tank so once I have that can fit the new fuel pumps and see if that cures the problem.

 

 

Share this post


Link to post
Share on other sites

Did you check your secondary injector O-rings?  If you have a mild fuel leak from the secondary's, it would be consistent with your other findings.


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

Share this post


Link to post
Share on other sites

No sign of leaks from the secondary injectors (externally) and no fuel leaks other than from the dowty washers/banjo bolts on the rear of the plenum. These were replaced when fuel pressure was checked/tested.

Would have expected a greater decay rate in fuel pressure if the primary or secondary injectors were leaking but after 2 hours, 43psi pressure held steady would suggest a fuel pump problem ... perhaps.

At this stage however cant rule out anything so once I have the fuel pump/tank seal, I can change the pumps and filter at the same time and carry out a biopsy on the removed parts.

You might be right though Mike as the initial start, move off driveway...250 yards on road and then down on one or more cylinders, could be either fuel starvation or flooding as the misfire I had above idle speed would be similar if either conditions were apparent.  That said, the secondary fuel pump can be heard to prime on initial key commands ( ie before engine cranking - about 2-3 seconds) and while the engine is on fast idle (warm up), the engine appears to be behaving itself.

Application of throttle or thereafter when the lambdas have heated etc is when the spitting is most noticable.  

My understanding ( and please correct if Im wrong) was the secondary fuel pump primes or is activated to ensure its ready to meet demands when required at increased rpm or high road speeds. When conditions dictate, the secondary pump receives a signal from the ECU to introduce more fuel so not sure how this would impact slow running at idle speed or say > 2000 rpm when the pump is not operating or at least cant be heard to be running.

Doubt the seals are expensive but if available would be foolish not to change those as they appear easy to get too.

 

 

 

 

 

 

 

Edited by modifiedv8engines

Share this post


Link to post
Share on other sites

All injectors are hanging off a common rail.  The secondary fuel pump/injectors are indeed only playing a part for higher engine loads, but the dual O-rings seals are notoriously poor and if you have even a low level leak, that fuel is going to an impact.  It a very easy one to check and discount.


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

Share this post


Link to post
Share on other sites

Thanks Mike, need to get those O rings ordered and installed.

Been mulling this one over and since the fuel pump delivers fuel to all injectors, then the misfire would likely be on all 8 cylinders. The right bank or Bank #1 is where the P1101 fault code has been identified but not completely sure how to check for ignition sparks ( removing fuel relay, plugs checked in turn, cranking etc) to determine if indeed its number # 3 cylinder thats at fault since on initial start, the engine runs okay. Meaning........ to check for sparks would no doubt show all was/is okay as there is no problem getting the engine to fire up.

The P1101 code could well be  a bit of a "Red Herring" but I can report with the new relays fitted, less cranking and eaiser to start ........so not much making sense but will take your valuable advise and try the easiest first.

 

Share this post


Link to post
Share on other sites

Remove fuse B3 (fuel pump and injectors) and remove the plugs to check for spark


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

Share this post


Link to post
Share on other sites

Thanks Mike - 

If you have ever had ( sure you and most have) the ingress of rain water into the spark plug wells, where there is a spitting type misfire @idle, this is very similar to the symptoms Im experiencing with my engine, and that was my initial diagnosis as this has occured many many times. 

Sorry if this is getting a bit tedious and boring .......

So if we assume there is fuel leaking into the plenum from the secondary injector(s), this might be burnt off/consumed when the engine first fires as rpm is something like 1300 - 1400 rpm at that point. Once the engine speed reduces, any surplus fuel still present would likely cause over-fuelling as the sparks are unable to ignite the richer mixture and the spitting etc etc occurs. Could be a secondary injector or secondary fuel pump malfunction as per P1101on Bank#1

A light smoke haze from cylinder bank #1 exhaust ( aftermarket exhausts by the way) would further indicate excessive fuel  

But correct me if im wrong .........the O rings are to prevent air leaks. A jacked up rpm would normally occur in this type of situation with an air leak or have i missed the point here. 

Nothing to be lost from changing the secondary O rings but it may be the secondary injectors that are leaking ?

To confirm this possibly block off/remove the secondary injectors or disable the secondary fuel pump if possible as that pump circuit  is only for certain conditions .......unless both pumps run simultaneously for some other reason.

Bloody hell.....this is getting complicated

 

 

 

 

Share this post


Link to post
Share on other sites

When switching out the primary fuel pump relay be sure to get the correct type as there was TSB about changing it (and the ignition relay) for a Siemens relay due to the ECU's inability to drive the coil of the original specification relay under certain conditions.

Share this post


Link to post
Share on other sites

The secondary injectors are fed fuel from the side and the o rings prevent this from leaking past the injectors into the plenum. If the o rings fail you will either leak fuel to the outside or the inside of the plenum since the fuel pressure will be greater than the air pressure at either side.

cheers

-Chris

42_05a.gif

Share this post


Link to post
Share on other sites

Much appreciate the explanation about the secondary injector function Chris and point noted about the relay too SB.

The fact that the secondarys seal or in my case, possibly are not sealing ( as Mike also suggested) , would I reckon cause the strange engine running condition im experiencing. No fuel leak externally from those seals but with the car sat about for months etc etc a likely culprit.....

Cheers for that and will post my findings once fitted.

 

Share this post


Link to post
Share on other sites

Quick update.

Secondary injector O ring seals arrived via Strattons' late this afternoon.  Subsequently fitted and although the old O rings were loose on the injector, new ones installed and no improvement. 

Was hoping ( ...praying actually) this would cure the problem but unfortunately not. Something else to cross off the list so next job is fuel pumps to remove. Expect Ed China of Wheeler - Dealers could swap this in around 10 minutes but spent double that time just removing the ECU mounting bolts, which are a bit tight for access near the inner rear wing.  

Looks like a pump/tank removal tool will be required or something fabricated.

Report back when theres more news.

 

Edited by modifiedv8engines

Share this post


Link to post
Share on other sites

I'm sure Mike Sekinger sent me a link to the pump ring removal tool but I'm stuffed if I can find it. Mike, do you still have the link or remember the name of the obscure tool?

cheers

-Chris

PS Mike, if you can remember the thread you posted it in the first time that would save me going mad. 🙂

Share this post


Link to post
Share on other sites
  • Like 1

1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...