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Saffron Yellow 05 Elise Turbo
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Discussion Starter #1
Alright, I'm getting to the point where I would be grateful for some input on what to check next.

I have a 2005 elise (turbo and standalone ems), which had been running well. I was driving on the highway, pulled into a gas station and filled up. Then the car wouldn't start. It seemed to catch once and then stall out before the RPMs really started to rise, and after that wouldn't catch at all it would just crank.

I dont believe it's bad gas, as I had multiple friends fill up at that gas station at the same time, also getting 93. I had the car towed back and have been trying to figure out the problem.

Things I've tried:
1) pulled the charcoal canister on the off chance it flooded. I did "top off" the tank (yes I know it's bad, it wasnt intentional). However there was nothing in the charcoal canister. This was the first thing I thought because it seemed rather strange it was running fine, and then wouldn't start after filling it with gas.

2) checked spark plugs, they're all good, and they do spark.

3) I can hear the fuel pump priming when I turn the ignition on, and I can smell the fuel after trying to start it for a while. So I think the fuel pump is fine.

4)) checked every fuse with a meter in the two fuse boxes in the engine bay, they're all fine. Those boxes hold the fuses for the fuel pump and injectors according to reading the forums and the manual, and since they're not blown that's not the issue.

5) replaced the crankshaft position sensor, this was probably premature, reading some posts led me to believe this might have been a plausible cause so I went ahead and replaced it. The tachometer does move when cranking, and i was able to connect to the ECU (Haltech) and see the rpm's get up to ~300 rpm, so I dont believe the crankshaft sensor is the problem. (Also, if the CPS was bad, it wouldn't even spark would it, now that I think about it).

6) checked the voltage of the injectors which was zero, even with ignition on. And my friend who read them while I tried to start it said it never got past 0.4. I saw a post that said it should read 12, and if the fuse is fine and theres no voltage at the injectors, it's probably the MFRU.

7) I have charged the battery completely with a trickle charger and checked its voltage and it seems fine. The car cranks fine, it just won't start.

8) I did push on the inertia switch and it felt like it clicked a little bit. Car still doesnt start though, and I think the fuel pump always primed, even before I was messing with the inertia switch so I'm not sure that it actually was tripped.

I have not tested the MFRU yet, that's the next thing I'm going to try. Does it seem plausible that it would just completely die like that with no warning and stand me?

Things I have not tried yet:

1) camshaft sensor
2) draining the fuel
3) front fuses
4) pulling the fuel rail
5) checking the ground straps

I guess the next thing to try is the MFRU but I would welcome any input on anything I've overlooked or would be good to try. I seems very odd that I filled up and it wouldn't start. I had no issues or symptoms that I noticed leading up to it. Now that finals are over I'm really hoping to get her back on the road, and I'll have a lot more time to dedicate to troubleshooting.

Thanks!
 

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Sorry to hear of your issue and it sounds like you've made logical PD steps so far. What year is you car? Have you put a code reader on it? It's almost sounding like an immobiliser issue. As people start to wake others will chime in but checking codes will be one of first things asked. Richard
 

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Check the ground strap , it could even seem ok at first inspection and still be bad !

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With the ignition on and engine off you should see 12V at the injectors.
Also, within your ECU you should be able to see the voltage of each injector, at least with my Adaptronic you can.
Does your ECU allow you to manually test each injector?
With the key on, do all of the other sensor outputs look normal?

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Sorry to hear of your issue and it sounds like you've made logical PD steps so far. What year is you car? Have you put a code reader on it? It's almost sounding like an immobiliser issue. As people start to wake others will chime in but checking codes will be one of first things asked. Richard
If he is hearing it prime and the starter kicks, those are the only two functions impeded by the immobilizer. Having had my fuel pump circuit fail on my immobilizer, I am typically prone to point a finger at it, but I think OP is right about more signs pointing to the MFRU.
 

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6) checked the voltage of the injectors which was zero, even with ignition on. And my friend who read them while I tried to start it said it never got past 0.4. I saw a post that said it should read 12, and if the fuse is fine and theres no voltage at the injectors, it's probably the MFRU.
That's a pretty big red flag if the measurement was done correctly. It is weird that what he read went from 0V to 0.4V; I would expect more of an all-or-nothing reading, but that's just a hunch. Fuses 6 and 7 are both controlled by that same relaybut different pins on the MFRU. Either way, I'd expect the hot side of those fuses to read similarly unless it is a wiring issue. If you are getting 12V at one and noth the other, it might not be a bad idea to temporarily splice the hot sides together and see if the problem is fixed.
 

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Saffron Yellow 05 Elise Turbo
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Discussion Starter #7
Thank you to everyone who replied. It's been a busy couple of months with covid and things getting moved around, but I wanted to share how the issue actually got resolved, as I hate the threads where the OP has the same problem as me and never posts how it was fixed.

There was actually an error on my part in the beginning. What I thought was the fuel pump running was not, I discovered this when I pulled the fuel rail and it was empty. (Won't make that mistake again haha)

I traced a lot of things with a multimeter - injectors, inertia switch, chassis ground, etc. And eventually narrowed the issue down to the last thing in the chain before the fuel pump, the immobilizer. I was able to test the fuel pump actually worked by jumping it.

It turns out what happened was the plug to the immobilizer went bad, it was allowing the proper voltage into the immobilizer, and the immobilizer was sending the proper voltage out, but something had failed within the plug, and the voltage was not coming back out into the chassis harness and then to the fuel pump.

Cut and spliced the wires together bypassing the plug and everything works. I'm still a little surprised it failed at the gas station and not on the road, but that's a mystery for another day. Hopefully this helps someone else in the future.
 

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As a person that searches old threads and gets frustrated at how many do not follow through on the resolution, THANK YOU for the follow up!!
 

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+1 on thank you for the follow up!
 
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