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Discussion Starter #1
So, about 5 months after starting down this road (so many distractions and problems this year), I finished my project of pulling the engine from my 2001 Esprit, replacing the cam belts, and redoing the gas tanks. Everything is back together and I tried to start her up. Initially there was no fuel pump noise, and I noticed that the cutoff switch had gone off (must have bumped it somewhere). I reset that, and then she slowly sputtered to life. But it sounds like it's running on half the cylinders, missing and shaking.

I checked for error codes, and all I get is P1100 (Fuel Pump #1 Relay or Circuit Open). From the ODBII software I can turn the fuel pumps and off and they sound fine. So it doesn't seem like that's an issue, although I'm curious what exactly sets this error since I tried to clear it but it comes back. Am I misunderstanding the code?

Otherwise, the only thing that seemed like a potential error on my 'engine removal steps' list was that I had an engine ground wire on my list that I didn't find. But I think I must have wrote that down twice. I reconnected the ground straps to the gas tanks, and one strap from the engine to frame. There isn't a fourth ground, is there?

So with no error codes, I'm on my own. Any ideas what I did wrong? I didn't replace anything else except a few o-rings. Do I have to reset the ECU or anything?

Thanks
Rock
 

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P1100 is indeed a problem with the power to the relay for fuel pump #1 (the primary fuel pump), the ECU, the wiring, or the relay. That is the big clue as to what the problem is and you have to clear it up. Once you find and fix the cause the engine should run better. Follow the wiring from the ECU to the relay and you can try swapping the relays between fuel pump #1 and #2. If you can get the trouble to move (or go away) you found the problem.
David Teitelbaum
 

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Discussion Starter #3
Sorry for another delay. More cars have been causing big trouble. They're starting to beat me down.

A couple things on the P1100.
1) How does the ECU get feedback from the circuit to know if it's open? I can't find anything that would seem to serve that purpose in the circuit diagrams.
2) The secondary FP relay is different than the primary on my car. I guess since the secondary doesn't need both outputs, somebody put in a different relay. So I can't switch that relay into the primary, but I switched the primary relay with a different relay (since almost all other relays are the same) and didn't notice any difference.
3) When I run the car, I don't see the MIL light on when it's running now. I'm pretty sure it was the first time(s). However, if I clear the code, it seems to come back when using the "ODBII + Lotus Esprit V8" free software. But no check engine light. Does that make any sense?

Also, checking at the exhaust, it feels/sounds like the LH bank is running fine. The RH bank is clearly missing, probably running on two cylinders. So to me, that would indicate something that is specific to the RH bank and probably not a FP issue? Especially since the RH bank is first in line from the FP. Does that give anyone any ideas? Note that there are no other error codes from the ECU.

Thanks
Rock
 

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Something is obviously up with the fuel pumps. My guess is the fuel pressure is too low and that is why it is not running right. The error code is trying to tell you the ECU is seeing some problem with the fuel pumps so that is where you start. Maybe somehow the fuel pumps got mixed up and/or maybe you have a leak in the fuel tank. Other owners having similar symptoms had either a leaky hose or a loose hose clamp allowing the pressure to get lost. Get the right relays, make sure each pump is wired up and running correctly and check the fuel pressure. If that doesn't seem to help you might have to pull the fuel pumps. The ECU sees the relays so if you don't have the correct ones the ECU may not like what it is seeing. You may have had that error code all along but never looked because you never had an engine check light!
David Teitelbaum
 

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You need to buy a simple fuel pressure tester and there's a connection at the back of the Esprit V8 engine. Takes you 5 minutes instead of a days and weeks of guessing.
Autozone and advance auto sells them.
 

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I do not believe the fuel pressure testers from the "local" sources will fit. The fuel pressure fitting on the engine is a standard size but also in a not so convenient place. If I remember correctly an elbow adapter that also works on some Corvettes is required. A long time ago I had to order the adapter because I couldn't find one locally.
 

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I bought this from advance auto & used it a few times for my fuel pressure test. Behind the engine there is a Schrader valve ( i think that's how they called it) connection. That's all you need. If i remember, $27.00 complete.
 

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Discussion Starter #8
OK I'll check the fuel pressure. I can try to verify the electrical connection at the fuel pump is correct. I'd assume the connector can't be oriented incorrectly, but if it were then that might explain a low pressure issue and a FP1 circuit error (if it thinks it's turning on FP1 but it's really FP2 that is getting powered).

I can switch some other relay with the FP2 relay, but that oddball relay did work fine previously. It just switches from one output to the other, instead of switching the two outputs as a pair. But for the secondary FP circuit that only uses one of the outputs, that should be good enough.

I'll double check for leaks in the fuel circuit. I made a check initially when I installed the engine and ran the pump, and I didn't see any leaks then.

Do you know how the ECU sees the FP circuits? I don't see anything that connects from the FP relay outputs back to the ECU. Although it must do something since this error code exists.

It just seems strange there are no other error codes. I would have expected a misfire error code, or a lean error code. And you are right in that I never checked for errors before, so the P1100 might have existed previously. But the manuals say that the P1100 will set the check engine light, so it's weird that the light is not on now if the error is still active.

Thanks for the ideas.
Rock
 

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OK I'll check the fuel pressure. I can try to verify the electrical connection at the fuel pump is correct. I'd assume the connector can't be oriented incorrectly, but if it were then that might explain a low pressure issue and a FP1 circuit error (if it thinks it's turning on FP1 but it's really FP2 that is getting powered).

I can switch some other relay with the FP2 relay, but that oddball relay did work fine previously. It just switches from one output to the other, instead of switching the two outputs as a pair. But for the secondary FP circuit that only uses one of the outputs, that should be good enough.

I'll double check for leaks in the fuel circuit. I made a check initially when I installed the engine and ran the pump, and I didn't see any leaks then.

Do you know how the ECU sees the FP circuits? I don't see anything that connects from the FP relay outputs back to the ECU. Although it must do something since this error code exists.

It just seems strange there are no other error codes. I would have expected a misfire error code, or a lean error code. And you are right in that I never checked for errors before, so the P1100 might have existed previously. But the manuals say that the P1100 will set the check engine light, so it's weird that the light is not on now if the error is still active.

Thanks for the ideas.
Rock
If you somehow have wiring reversed between the primary and secondary pumps it should not matter as they are basically the same type (volume/pressure) pumps and are plumbed in parallel with the system. Your P1100 code can only be caused by an open circuit between the ECM and the primary fuel pump/injector relay which would not allow the engine to run at all as this relay supplies power to not only the primary pump but the injectors themselves. This must be some sort of ECM fault, or the ECM simply doesn't like the current draw it is seeing across the relay coil (too high a resistance) which could be caused by a poor contact internally in the relay or at a harness connection.
Furthermore, a fuel pump issue would not make one bank run differently from the other as they share a common fuel source. Your running issues are probably from some another source. Have you verified the cam positioning on the poor running bank as the belt was just changed?
 

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OK I'll check the fuel pressure. I can try to verify the electrical connection at the fuel pump is correct. I'd assume the connector can't be oriented incorrectly, but if it were then that might explain a low pressure issue and a FP1 circuit error (if it thinks it's turning on FP1 but it's really FP2 that is getting powered).

I can switch some other relay with the FP2 relay, but that oddball relay did work fine previously. It just switches from one output to the other, instead of switching the two outputs as a pair. But for the secondary FP circuit that only uses one of the outputs, that should be good enough.

I'll double check for leaks in the fuel circuit. I made a check initially when I installed the engine and ran the pump, and I didn't see any leaks then.

Do you know how the ECU sees the FP circuits? I don't see anything that connects from the FP relay outputs back to the ECU. Although it must do something since this error code exists.

It just seems strange there are no other error codes. I would have expected a misfire error code, or a lean error code. And you are right in that I never checked for errors before, so the P1100 might have existed previously. But the manuals say that the P1100 will set the check engine light, so it's weird that the light is not on now if the error is still active.

Thanks for the ideas.
Rock
If you have a problem with the plumbing inside the tank it will not be easy to see unless you remove the fuel pump assembly. The both pumps are plumbed in parallel so if there is a leak between them you won't have enough pressure. This is just a guess but there have been other cases where others had a similar symptom and it turned out to be a problem inside the tank. They didn't have error codes or engine check lights either. The ECU can see the current draw of the relays (or lack of) and if it isn't within the correct range it logs an error code. That error code doesn't light the check light. I guess for starters the best thing to do is check the fuel pressure first.
David Teitelbaum
 

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Discussion Starter #11
Have you verified the cam positioning on the poor running bank as the belt was just changed?
Now you sound like my brother in-law. :) I'll have to check that also, but I'm 110% sure that the cams were not off. I literally checked the positioning (and tension) 3-5 separate times before I put the engine back in, because I was so paranoid about it. With that said, if I didn't know better I would suspect the cam timing also. But I'll never believe I screwed that up. Even if it turns out to be true, I still won't believe it. :)

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Now you sound like my brother in-law. :) I'll have to check that also, but I'm 110% sure that the cams were not off. I literally checked the positioning (and tension) 3-5 separate times before I put the engine back in, because I was so paranoid about it. With that said, if I didn't know better I would suspect the cam timing also. But I'll never believe I screwed that up. Even if it turns out to be true, I still won't believe it. :)

Thanks
Easy enough to check. Did you use the "Lotus" cam alignment pins or an equivalent to verify positioning?

Back on the subject of fuel pressure,
If you had a split/leak in the delivery line (in tank), there would be enough fuel pressure generated upon start up for about three seconds to overcome any pressure loss (at least to idle properly) because the secondary pump runs for this length of time each time the engine is started to exercise it.
If the engine starts and does not run well for this first few seconds it is not fuel pressure related as if it the leak was so bad that the secondary pump running didn't mask the issue upon start up it would not idle at all.
 

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Discussion Starter #13
Easy enough to check. Did you use the "Lotus" cam alignment pins or an equivalent to verify positioning?
I used the Lotus crank positioning tool, but not the Lotus pins, I used a 16penny nail with the tip squared off. It's almost exactly 4.2mm. I checked the cam positions again, and thankfully for my sanity the pins lock in when the crank positioning tool is aligned. So cam timing is correct.

I checked the fuel pressure, and it is 58psi with either fuel pump running. Drops to about 51 when pump stops. So this should be fine also. This was checked with engine off and pumps controlled by the ODB software. Is there any need to check it with engine running?

So far so 'good'. What do you guys think?
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Rock
 

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Verify your plug wire positions on the coils for the right bank (that is if you even disturbed them). Beyond that there may be a good chance that you have a faulty ECU. I had an ECU go bad on my S4 with no warning, out driving with a few fellow Lotus owners and stopped for lunch. Tried to start the car after we came out of the restaurant and it would just shudder and die. Ended up having a cold soldier joint on the ECU.
 

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Discussion Starter #15
There were two plug wires that I'm not 100% sure I checked (although I'm 80% sure) when I took them off. The front two on the RH side. But unless someone installed those two reversed to the coil (i.e. numbered 2,1,3,4 instead of 1,2,3,4 from front to back) then they are on correct. I checked when it ran poorly and they are ordered 1,2,3,4 on the plug side.

Is there any easy way to determine that they are hooked up to the coil correctly without removing the plenum? I'm reluctant to disturb more areas than I have to right now. I did try to use a timing light to see if 1&4 fire at the same time (since I guess they should fire as a pair) and although it's hard to be sure since I can't find any good marks on crank for these plug timings, it does seem like they are in sync, as are 2&3. So I think the plugs are correct, but I would like to be more certain. I hesitate to ask this last question because it sounds terribly stupid and dangerous, but on the Esprit, what is the danger if I just swapped plug wires 1&2 on that side? Would they be timed to cause trouble or blow back through the intake, or would this be a risk-free way to test if they are reversed?

The ECU is definitely an expensive thing to try. Unless anyone has a spare they want to lend me. :) So I'd rather try to verify any other possibility first.

Thanks
Rock
 

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You can swap them around and try starting the car, shouldn't cause any damage to anything. I just wouldn't try spooling up the boost that way if they are wrong.
Do you have a non-contact IR thermometer? You might want to start the engine from cold and crawl under, measure the manifold temps at the exhaust ports to determine exactly which cylinders are actually firing. This might narrow things down a bit.
The plug swap might be the key though so try that first.
 

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I replaced my coil packs and plug wires recently. I have a July 2000 build Esprit. I've attached a layout of my wires for reference. The coil packs have small numbers stamped on the base of each of the four terminals, however, I used the original layout instead with no problems.
 

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Very unlikely (and it would be a BIG coincidence) that the ECU has a problem. That is the LAST thing to consider. Use that IR thermometer and make sure each cylinder is at the same temperature. If any aren't that is an indication that it isn't working. Could be crossed ignition wires, bad plug, unplugged coil pack, etc. 58 psi is on the low end but certainly enough. If you messed up the cam timing the sensors would keep the motor from starting but you would have bent valves. Are you sure you connected all of your ground wires?
David Teitelbaum
 

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Discussion Starter #19
If we're confident swapping those 2 plug wires won't cause trouble then I'll try that. It would be the easiest solution, although I'd be surprised. I'm not a fan of getting under the car when it's running, but I can try the IR gun and see which cylinders are causing trouble.

The ground wires are the one area on my engine removal list that didn't add up. As I mentioned in my first post, I had two engine ground wires on my checklist, but I could only find one when reattaching everything, and I could only remember one. Is there a second one? I think I made a mistake on my list, but that is rare for me. I'm usually slow and careful.

I also replaced all the plugs when it wouldn't run right, but no affect from that. And all 4 RH wires were driving the timing light, so the coil seems OK? Could the plug wires be broken if the timing light is being driven? I could try to ground the plugs and watch for spark, but I always seem to somehow get shocked when I try that even though I'm always holding the plug boot.

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Discussion Starter #20
I swapped wires 1 & 2 with no affect. I don't see any easy way to get to the header runners even with the IR gun, as there are heat shields and the turbo in the way.

But, I did unplug each of the four wires in turn, plugged it into a loose plug, and grounded the plug. To my untrained ear, it sounded the same each time I started it. And each plug was sparking. So it kind of feels like the issue is not a dead cylinder or two, but I'm not sure what to make of it yet.

Can I disconnect the spark plug wires and just leave them disconnected/open? I do this on other cars, but I don't really know if that's a good idea and the Lotus is generally more sensitive to hamfisted stuff. I'd be curious to disconnect multiple plugs and see what it sounds like.

Thanks
Rock
 
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