Engine misfire - fuel injectors

[Falco II]

After being in the garage for two hours I started up my beloved Elan - It did not run smoothly as normal. It is like it´s only running on 3 cylinders. Sounds like an ignition problem.
I then put in brand new spark plugs and brand new plug leads. same problem.

I then read in this forum, that it might caused by faulty fuel injector.

How do I find out, if my fuel injectors are faulty.

If it´s not the fuel injectors, do someone have a suggestion of another cause for the problem ?
All god suggestions will be appreciated

[Enright]

Here's a god suggestion - pray to Allah to fix it for you!

Oh alright, you want a serious answer? OK: Leave the spark plug cover off, the engine running, and in turn pull each lead off and put it back on.
If there's no change in the engine note, then you've nailed which cylinder is the problem.
But if it runs even rougher, then that cylinder isn't the problem.
If the problem is with more than 1 cylinder, and it's 1 & 4 or 2 & 3, then chances are a coil pack has developed a fault.

PS Put your location in your profile and another Elan owner local to you may spring up and help.

[Falco II]

Thanks for your reply Enright.

I have just checked - two cylinders are "out of order" - number 2&4 ?????

I will double check the connections to the coil pack.

Otherwise I will try to renew the fuel injectors. - is it possible to measure if those are faulty ??

[Brit-Car-Nut]

Both the injectors and spark plugs fire in pairs (spark waste) - BUT in different pairs.

fuel Injectors fire 1- 3 and 2- 4 while plugs fire 1- 4 and 2 - 3 so it would appear it is injector related.

More and more owners are finding the injector internal windings (coils) are breaking down under heat but somehow manage to keep opening and closing due to existing momentum. When you shut down the car and shortly after try to restart, it restarts on 2 cylinders because the coil isn't able to open the injector and the defective injector prevents it's mate from adding fuel too. Let it sit for a LONG time, the injector might start moving again, but the process repeats.

Cleaning might improve the defective injector(s) but the symptoms return soon and eventually, new injectors are the best solution.

[Falco II]

Hi Brit-car-nut
Thank you for your reply.

I have just sent you a PM

Best regards
Erik Grønning

[dkellis]

In my car's case it was a bad injector, #4. It would short at random times and take out #2 with it and the car would run on 2 cylinders and then randomly revert to normal. I was tearing my hair out, getting depressed, wishing I'd never bought the thing, and always hoping for normalcy. And then a wise old Lotus mechanic isolated the problem, I ordered replacement injectors, the mechanic installed them, and the car has hardly hiccuped since. (It is a Lotus after all!

The technique this mechanic used was to press a modified stethoscope on each injector in turn and listen for normal operation with the engine running. (Modified by replacing the little listening bell with a solid rod, fwiw.) The injector was in failure mode at the time and he easily identified the bad one.

I've had my car for about 9 years and the coil packs have never been a problem.

That mechanic also rewired the wiring harness by splicing in new leads to the injectors.

[Tyger]

I'm having this problem and just bought new injectors, but I can't tell how the heck to get the little clips off the injector wiring connectors. Anyone have any pics of one when it's off? I just don't want to break anything.

[Falco II]

Thanks for all your replies.

I changed the 2 fuel injectors and it worked .

I did have a hell of a work when fitting the new injector. Two times I had to dismantel it all, because an injecter was not dense. it turned out to be the clips holding the injector to the fuelbar. It dammaged the O-rings when I tried to press the injector in the fuelbar. BE VERY CAREFULL to move the clips away fro the hole to the injector, or it will cut slightly in the O-rings !!!!!

To Tyger:

I became an Expert to move the security pins holding the electrical jacks to the injectors. Press a small flat screwdriver close to the middle of the pin to make room for a small "pointy-tip" pliers at the side of the pin. I have attached a pair of pictures

juli14 006.JPG

juli14 007.JPG

[Tyger]

Thanks Falco! What exactly do you mean by "dense", though?

[Falco II]

Thanks Falco! What exactly do you mean by "dense", though?

Can not hold the pressure (Gasoline pressure in the fuelbar) - if the O-rings are damaged, then you will have a lot of gasoline vapor outside the fuel injectors

[HJ2]

Top tip:
Keep a fire extinguisher at hand when tinkering around with the fuel systems. I also use safety goggles, but then again i am the p.o.c. of all safety matters at work

[c4mun]

I've only had the car for a few days and suddenly no power. Discovered that it's not firing on cylinders one and three, so after carefully removing the injector electrics, the résistance of number three is very low compared to the other three.
I left the injector three disconnected and surprise surprise is now firing on three cylinders. Hopefully proving that I need at least one new injector. I understood that a low resistance on one injector would pull down the other one.
So now debating where to find the right injector for a turbo SE. Maybe I should replace all four?

[lotusflasherman]

I've only had the car for a few days and suddenly no power. Discovered that it's not firing on cylinders one and three, so after carefully removing the injector electrics, the résistance of number three is very low compared to the other three.
I left the injector three disconnected and surprise surprise is now firing on three cylinders. Hopefully proving that I need at least one new injector. I understood that a low resistance on one injector would pull down the other one.
So now debating where to find the right injector for a turbo SE. Maybe I should replace all four?

That's a good topic for debate on any component.. One school of thought says "If it ain't broke, don't fix it", and the 'belt & braces' reliability men will say 'if one has failed and the others are the same age, change all of them".

I sit on the fence and say 'Buy four and only change them when they need changing'. Good idea to keep records of what's new & what's old - sometimes the new one fails before one of the older ones and it avoids racking the brain thinking "I'm sure that's the newest one...."..

[dkellis]

To c4mun:

I got my RC Engineering replacement injectors from JAE in 2010. They have worked perfectly since.

JAE part number E-6574-100-HP. Flow rate tested at 320 cc/min.

John Callahan ("Brit-Car-Nut" on this site) knows a lot about Lotus parts, including injectors.

Dave

[Ian T]

I replaced my injectors as a set from Rockauto - postage was very reasonable and they arrived quickly.

While I agree with Phil about not replacing things unneccessarily, I changed mine out as a set for two reasons - one I wanted to be sure that all injectors had exactly the same flow rate and the comparison between old and new wouldn't be possible without actually measuring the flow myself (or sending them away) and secondly, more simply, because it's a slightly fiddly job getting them out as said above and doing the job once meant I could put the whole set into a 'known good' state and move on to other tasks.

The RockAuto ones appear to be spot on - as advised by John (BritCarNut) who knows more than many of us about this.

If it helps, have a look at my project car thread - I wrote up some of my fiddling with the injectors and took some photos as I went. Here's a link: viewtopic.php?f=79&t=23531

I ultrasonically cleaned and kept my old injectors - could have kept using them really, but seeing as I had already bought replacements when I cleaned them, I fitted the new ones instead.

[Ian T]

I've found the Rockauto details from my original order:


ULTRAPOWER -- MFI559 -- Fuel Injector (8409.91.0000) -- £ 19.91 each, I bought 8 for £159.28 plus VAT

[lotusflasherman]

I replaced my injectors as a set from Rockauto - postage was very reasonable and they arrived quickly.

While I agree with Phil about not replacing things unneccessarily, I changed mine out as a set for two reasons - one I wanted to be sure that all injectors had exactly the same flow rate and the comparison between old and new wouldn't be possible without actually measuring the flow myself (or sending them away) and secondly, more simply, because it's a slightly fiddly job getting them out as said above and doing the job once meant I could put the whole set into a 'known good' state and move on to other tasks.

The RockAuto ones appear to be spot on - as advised by John (BritCarNut) who knows more than many of us about this.

If it helps, have a look at my project car thread - I wrote up some of my fiddling with the injectors and took some photos as I went. Here's a link: viewtopic.php?f=79&t=23531

I ultrasonically cleaned and kept my old injectors - could have kept using them really, but seeing as I had already bought replacements when I cleaned them, I fitted the new ones instead.

So did I - I had mine cleaned too but I kept my old injectors in the engine Had them cleaned first and then didn't buy any new ones as that sorted it. Scholar Engines are just up the road from me, well, 17 miles is just up the road in rural Suffolk, and they provided the cleaning service. I went there as Scholar was THE Formula Ford Engine to have in the 70's so thought they might do a good job, and they did. Cheap too.

[lotusflasherman]

I've found the Rockauto details from my original order:


ULTRAPOWER -- MFI559 -- Fuel Injector (8409.91.0000) -- £ 19.91 each, I bought 8 for £159.28 plus VAT

8 ? You didn't tell me you'd got a V8 in yours... How did you get it in?

[Brit-Car-Nut]

It's a shame that those injectors are now obsolete and the FJ559s are getting expensive again (and hard to find).

There was a guy on eBay selling the NON-Turbo Isuzu injectors (high Impedance) as Turbo (low impedance) injectors and not willing to correct his mistake. He used the FJ559 part number but when measured, they were 12 ohms compared to the 2 ohms expected. You need to know the supplier since the two different injectors look identical. An owner in Canada is "discussing" the facts with him now.

[Ian T]

8 ? You didn't tell me you'd got a V8 in yours... How did you get it in?

I think it just gives it that 'je ne sais quoi' we're all looking for.

I posted deep in that linked thread that I ran the shortest ever group buy and bought a set for Martyn (Maz_R) at the same time.

I think I told you at Brands that I bought my Elan while looking at cars that would scratch my V8 itch...