Turbo questions

[RichK]

Hi,

I have an 89 1/2 Esprit which I just bought about 2 months ago. When I received the car, it had just had the computer and injectors replaced.

When I got it, it immediatly started throwing a low voltage code for the injectors. I researched the computer and found it to be a stock computer, however the injectors that were put into the car were high voltage saturated types and the old injectors (which were included with the car) were the low voltage peak and hold type. I replaced the saturated injectors with the proper OEM injectors. The check engine light no longer appears, however the turbo does not spool up when I hit the gas. It will operate when I hit 5000 rpm, but not before then. I am not sure if this was occurring before the computer/injector episode, but my mechanic (not a Lotus tech) says that there appears to be no enrichment coming from the injectors on the plenum. Apparently there is no voltage going to those injectors.

Any ideas of what to do next?

Thanks,

RJK

[plumdeplakmuis]

Maybe first check movement on the wastegate valve, and actuator setting.

[USAndretti42]

If your car is a 89

[Qavion]

\"It will operate when I hit 5000 rpm,\"

Hmmm... Sounds like the wastegate is partially open (when it should be closed).

It could be an electronic problem, but we can look at this later.

I have had a (not unusual) problem where the spindle which supports the wastegate (flapper) in the turbo has moved sideways... and the flapper is hitting the sides of the turbocharger housing (and not allowing the wastegate to close, thus not building up pressure until the revs are high).

Here's my old turbo showing the displaced flapper, not covering the turbo bypass hole (as seen from the exhaust side)..

In some cases, this can be fixed by hitting the end of the spindle (relatively gently) with a hammer to move it back into place (but there is no room to swing a hammer unless you remove the boot floor or the turbo). And this is not always a permanent fix. The spindle can migrate again. It\'s the bush which supports the spindle which actually moves (I have had to have this bush welded in place).

Some folks have had problems with wastegate actuators (especially the capsule). If you are very, very careful, you can disable the wastegate actuator capsule by disconnecting the black vacuum tubing (effectively locking the wastegate shut) to see if the turbo builds up pressure at lower rpms. Note that it will do this very quickly. The last time I tried it, I broke traction at the rear wheels even using the accelerator gently If you remove the vacuum tubing from the capsule, you will probably also have to block the vacuum tubing which comes out the side of the pipe which is between the turbo and your inlet manifold (just below the orange tubing, if I remember correctly). If pressure doesn\'t build up, you know the problem is not electronic, but either a problem with the wastegate or the actuator/capsule.... or something worse... missing turbo blades.

Note that you will damage the engine if you keep the accelerator to the floor with the wastegate disabled.

Also note that the capsule is rather fragile. Don\'t rotate the rod going into the capsule. Don\'t use large tools to try to move the wastegate mechanism. If you have inflatable lumber supports on your seats, you can use the air pumps from these to activate the capsule for test purposes.

Anyway, I wish you luck At the moment, I believe you have two separate problems rather than one (It does sound like coincidence).

Cheers.

Ian.

Edited November 8, 2008 by Qavion

[RichK]

What about the issue of my mechanic not being able to measure any voltage at the plenum injectors? He took it out for a ride with a meter attached and did not get any current under any condition.

Rich

[Qavion]

I'm wondering if the correct ECU was fitted. Do you know if the part numbers were the same? By "stock", do you mean Lotus part?

I recall the circuit for the injectors being quite complex. There may be other bits and pieces using the same fuses/relays. I'll check this out when I get home (currently at work). You can do resistance checks on the injectors to see if they are in the correct resistance range. Note that the (2) secondaries have a different resistance from the (4) primaries.

Cheers.

Ian.

Back home again....

Rich, I have to be cautious giving advice here, as I'm not sure what setup this "89 1/2 Esprit" has, but the Chargecooled version and the S4 have a secondary injector "resistor" inline with the secondary injector circuit (I assume these are the injectors your mechanic is talking about). The resistor will be a plug-in module in the relay compartment aft of the engine. Try plugging/unplugging this (I recall it's grey in colour and larger than the relays). If reseating doesn't work, try replacing it. I'm sure your local autoelectrician will have something like this. These resistors have been known to fail.

On the Chargecooled version and the S4, the secondary injector circuit also goes to contacts on the fuel pump inertia switch (also located in/on the boot relay box) but the switch only affects the pump, not the injectors)... but check that none of the wires going to the inertia switch are broken/loose. Also check the wires on the fuel pump relay (if you can find it). It won't hurt if you reset all the relays in that compartment.

Hopefully I'm not sending you on a wild goose chase (and your car is similar to mine).

Cheers.

Ian.

[RichK]

OK,

Thanks for the ideas and help. I'll start checking these things out.

Rich

[Qavion]

Also, Rich.. Make sure that the hose which runs from your turbo to your inlet manifold (or chargecooler as applicable) is not loose. I had a problem where the pressure would start to build up normally but never reach maximum. One of the clips on the hose appeared tight (as I was screwing the nut on the jubilee clip), but really wasn't. When the pressure built up in the hose as the turbo started spooling up, the air would begin leaking out.

Sometimes the simplest of problems can have you searching in all the wrong places

Cheers.

Ian.