Prado Conversion: 2LT-E to 2LT - CAS problem - UPDATE

CaribooPrado · 03-29-07, 05:42 PM

Finally an update and a few more questions regarding my LC conversion from a
2LT-E to a 2LT.

I needed to replace the engine in my 1990 Prado EX5 and ordered a used engine from Japan. Received a wrong engine twice and after months of searching and waiting I've decided to go with the 2LT. At the time it seemed like a good idea and the only real problem was the missing hole for the Crank Angle Sensor (CAS) or Crankshaft Sensor.
After the conversion, the engine was running fine, but with limited power. As I've learned on this forum it was running in limp mode because of the CAS not giving a signal to the computer.
I've found a couple links and pictures of a set-up where the CAS is mounted so it's pointing to one of the pulleys.
A small piece of metal is triggering the signal or to be more precise, is producing the AC current.

I've found a welder and learned how to weld and started fabricating a bracket to hold the CAS in place. Welded a small, rectangular piece of metal to the pulley. The set-up pretty much matches the original set-up. The size of the metal trigger and the distance from the sensor to the metal piece. I've actually mounted two sensors - one is hooked up to the computer/engine. The other one is hooked up to an oscilloscope I've borrowed to see if it's producing a consistent wave. It is. The pulse width is 71 ms and its 13.3 Hz. The voltage is roughly 1.4V.
Resistance is 22.88 Ohms.

So here's the problem: It works, but not all the time. I start the engine up and no check engine light comes on. I can drive for a while in first or second gear. Full power, uphill the turbo kicks in and all is fine. Then the check engine light comes on and I can feel the engine running in safe mode with less power. Unless I slow right down the light stays on. So, its on and off roughly 50% and I can not find a rhythm to it. It doesn't really seem to be related to speed or anything else. Sometime the check-engine light comes on at 3000 RPM, sometimes sooner.
I've been playing and adjusting the setup for two days now and it does get better, but its not perfect.

What else can I try? Should the set-up work? Isn't the fact that it runs for a while without the check engine light a good indication? Is there anything else that could cause the problem?
I'm running out of time and really need my vehicle, any suggestion for a good mechanic who can solve my issue? I'm in the BC Interior but would travel to Kamloops, Vancouver even Calgary if I'd knew someone can get the LC running for me...

I'm attaching a few pics showing the CAS set-up.

Thanks for your help in the past with this! Sorry for the long post.

Deep Thought · 03-29-07, 08:12 PM

I'm not an expert on these engines, but if it runs fine and then after the engine "heats up" there is a problem it may be the proximity of the sensor to the trigger. The heating up is causing expansion in the metal and the sensor may be moving far enough away from the trigger to stop it working. Also the trigger may be a magnetic material. I'm sort of shooting blindly in the dark here but it might give you a direction to look.

Regards
D.T.

CaribooPrado · 03-29-07, 08:23 PM

Quote:

Originally Posted by Deep Thought

the trigger may be a magnetic material.

Thanks Deep Thought! That's a good point, will have to look into it!

dhula · 03-30-07, 05:15 AM

Have you tried fitting both sensors and driving till the problem occurs. The one set up to read to the oscilloscope (which you'll need in the car when your driving of course) may give you more info.

A couple of other guesses.

Is the trigger piece to short or too long perhaps.

Is dirt/water/road grime interfering with the signal

Apart from that I can't suggest anything cause like DT I'm no wiz at things electronic

CaribooPrado · 03-30-07, 08:36 AM

Good suggestions. I've been experimenting with the length of the trigger piece and adjusted the width, lenght and height. It's quite the process as I have to take the pulley off every time and adjust the whole set-up. There are slight differences, but I think I've got the trigger just right. At least there is no more improvement.

I should try and rig it up so I can get a reading from the oscilloscope while driving. Since both sensors are mounted it should be easy...
thanks!

brownbear · 03-30-07, 02:15 PM

Is the pick up close enough? When I set up a mag pick up on aircraft for prop balancing I set the mag pickup about 1/10 of inch away.

brownbear · 03-30-07, 02:17 PM

One other question, if this engine is 2l-t why does it need any of these electronic controls? Did you not get the 2l-t injection pump? Are you trying to adapt the E one?

I would rather just have a non electronic engine in there. One screw to tune to fuel and adjust the boost to max number.

CaribooPrado · 03-31-07, 02:48 PM

Hello Brownbear, yes I'm trying to go with the EFI...

... AND I'm happy to report the LC is running excellent now. After 7 months and so many comments that it will never work with the EFI, it's running really good.
Yesterday I've modified the pulley with the sensor trigger, so that I can adjust it (turn it). Take a look at the picture, its pretty straight forward. Once I had that done it was a matter of trial and error until the check-engine light wouldn't come on. I will go for an extended test-drive now, but so far so good. Turbo kicks in, no check engine light at any speeds or RPM's.
I've got my favorite toy back in time for spring to explore the BC back country and get to work in 'style'. Yeah!

Thanks again for all your help, this forum is awesome. I've learned tons through this conversion process, from engine basics to welding...

cheers,
Tom

brownbear · 03-31-07, 07:01 PM

Do you run pyro and boost gauges? If not, I would suggest you do. As this is a completely different from stock set up, you want to ensure non of the parameters are exceeding hurting your new engine.