lost number 2 and 3 cyl - have spark

[McClendon-EspritSE]

1991 Esprit SE - USA Fuel Injected Turbo:

Car was running a little rough on idle, and always has stumbled on take off and throttle mash from a stop. Yesterday I was sitting at an idle at 80c degrees, all of the sudden it started running very rough. I checked all four cyl for spark. Pulled off plug wire 1, car almost died, pulled off 2 and 3, no change in idle but have a full spark to block. Pulled off plug wire 4 and it did the same as 1, almost died. I think for some reason I have lost fuel to 2 and 3. Is it possible that the two fuel injectors are tied together and I lost a ground to both of them at the same time? Is there a fuse that controls 2 and 3 injectors? Help!

[rogerch]

Do a compression check first, eliminate that as a cause.

[USAndretti42]

Does this car have 2 double-ended coils for the spark? If so, I would suspect you have lost the coil that sends spark to cylinders 2 and 3. Are you sure the spark is good to those cylinders?

[andydclements]

2&3 would indicate what Trevor said, they share a coil pack, alternatively, what Roger has hinted at, a cylinder head leak between 2 & 3, but if ity was sudden, my money would be on the spark being the cause.

[McClendon-EspritSE]

2&3 would indicate what Trevor said, they share a coil pack, alternatively, what Roger has hinted at, a cylinder head leak between 2 & 3, but if ity was sudden, my money would be on the spark being the cause.

My car does have the dual "twin-pak" coils on it. I can swap the coils and see if the problem moves to 1 and 4. My initial thought was that the coil was ok because of the foloowing:

With the car runnning (very rough by the way, only 1 and 4 are firing), I can pull each plug wire off one at a time. on 4 and 1 the car will try to stall (only then running on a single cylinder). When 2 or 3 are pulled off there is no change what soever. I can see a spark to the engine when I have the plug wire away from the spark plug. The wire tip will throw a spark at just about anything I get it near. So I asumed that the coil was ok. Maybe it is weak? I changed the plugs to eliminate that variable.

My thoughts keep going to the 2 and 3 fuel-injectors loosing power or logic. I checked my shop manual (Section MD Sheet 7b) and it shows the the 2 & 3 injectors tied to a single black wire and then heading to an IHC (??) tagged as "B"; and then heading off to the ECM, and the 1 & 4 injectors tied together with a black lead going to IHC (??) tagged as "A" heading to the ECM. Could an injector just stop working completely all of the sudden? Better yet, two at the same time?

I will try the coil swap this afternoon and see if anything changes. Any feedback on injector problems or trouble shooting is most welcome. I dont have any tools to test the actual injectors though.

Many thanks,

Charlie

[sanj]

You can get get an injector harness tester, aka "noid light" at most auto parts stores. It's basically a small lamp with two pins that plugs into the injector socket. It should light dimly if the injector is being pulsed. You are correct in thinking the two injectors share a common power source. If you obtain a noid light, disconnect both injectors before testing the harness. If it lights up, reconnect one, then the other -- it is possible for one injector to fail and bring down the other. If the noid light doesn't light up at all, suspect the harness or the ECM.

[McClendon-EspritSE]

You can get get an injector harness tester, aka "noid light" at most auto parts stores. It's basically a small lamp with two pins that plugs into the injector socket. It should light dimly if the injector is being pulsed. You are correct in thinking the two injectors share a common power source. If you obtain a noid light, disconnect both injectors before testing the harness. If it lights up, reconnect one, then the other -- it is possible for one injector to fail and bring down the other. If the noid light doesn't light up at all, suspect the harness or the ECM.

UPATE on 91 Esprit SE:

Replaced both coil-packs with the MSD units. Reset ECU, no change in the way the car ran. Still dead on 2 & 3. Plug wires are good, but I am still going to replace them with new, if anything just for me to know it has been done.

Pulled Chargecooler off and started in on the primary fuel injectors. Installed four new RC injectors (purchased from JAE.... Lots of help from Jeff and the gang).

Also noticed some dried out and broken vacuum lines under the Chargecooler, replaced all lines. Reset ECU. Fired the car up and she runs smooth as silk. I am pleased with the feel of the engine and the response of the RC injectors.

Next project is to replace the secondary injectors with RC units, install new plug wires and a set of NGK Iridium plugs.

The big project.... Need to replace the waterpump (it is leaking from the weep-hole), and while I am wedged under the car, replace all the belts (mainly the timing belt, not sure how old it is and car has 33k on it).

Lesson learned.... An old Lotus is a lot of work to own, but even more fun to tinker with, drive and just flat out enjoy!!!

[fjmuurling]

Great news, by the way IHC stands for Injector Harnass Connector.

Freek

[McClendon-EspritSE]

Thanks Freek....

Have you ever experienced this problem on your SE? Its nice to see some chat from a fellow SE owner, looks like you are on the other side of the globe from me )

I am a wee bit nervous about doing the water pump and the timing belt, but I guess its guys like us that keep the old Esprits alive. Talk to you soon I hope.

Cheers,

Charlie

[sanj]

I cane up with a trick for helping install the water pump in situ. Buy a couple of long 6mm studs with a hex opening and install them in the block in two of the water pump mounting holes. Put sealant on the mating surfaces, offer the pump up to the block, and the studs will help keep it in position while you put the other bolts in. Remove the studs and install the remaining bolts. Voila!

[fjmuurling]

Hi Charlie,

Nope I never had your problem before. (knock on wood). The belts are not t0o difficult to change, just follow the manual. For tensioning the timing belt I use an microphone and a program called Tune!It, works like a dream. Cambelttension for more more information.

Freek

Edited February 14, 2010 by fjmuurling