Problems for me today in the beta LC



i set off from traffic lights, and it sounds like the car is running launch control. at around 3-3.5k revs, i get ignition cut rev limiter, which backfires out of the IM if you keep it up. driving around, it seems very down on power, so i think the computer was pulling ignition timing. i pulled over for a few minutes and checked all my sensors. the upstream 02 was a little loose, so i tightened it up and the car ran fine.



*continued on my way to uni*



sure enough, 5 minutes later, same problems again. i pulled into another car park and started thoroughly checking connections, disconnecting one sensor at a time and seeing what happened. the single wire connector next to the 3 wire crank angle sensor seems to be the culprit - disconencting it does nothing. that whole section of harness looks farked, the metal tab seems to have been cut on an angle. the actual electrical plug looked very tired, i think it has been heat treated by the exhaust. where the sensor wire re-joins the harness is starting to unravel as well.



i'm confused as to what it is though? there's the 02 sensor, what i presume is the crank angle sensor (with three wires connecting to it), and then about an inch to the left of the crank angle sensor is this? its just a metal tab coming out of the block, with one wire connecting to it. it seems to be the cause of my problem.

 

I'm going to guess at the engine oil pressure switch

 

thats the one. i replaced the metal tab with one from a spare alpha i had lying around. also cleaned the dirty wiring connector for the crank angle sensor, but no dice. it is still carrying on. is there anything else it could be? to be fair, i did wire up my tacho the other day, i cut the wire about 2 inches out from the ecm plug and soldered on an extension to connect to my instrument cluster plug. does anything else use the tach wire? or does it solely run from the ecm to the dash?



i'm going to try replacing the crank angle sensor and see if that helps the issue.

 

Did the bad running start when you installed your new gauge?

 

Yes it did start after i wired up the tacho, but not immediately. the car ran fine for a whole day (35ish miles) of driving, but in the evening it started to act up. at the moment it is very intermittent. it tends to behave when the car is cold, but once warm it will randomly act up. if you pull over and turn the car off for a minute or two (enough time to check the harness for any loose connections) it usually starts up and runs normally, but not for long. also the tachometer drops to zero/generally acts crazy when the car is playing up. i'm not sure if this -is- the problem, or whether the faulty crank angle sensor is sending an erroneous signal and that is what the ecu is 'seeing'. i have ordered new crank and cam sensors, so that might solve the problem through brute force.



its just the stock tacho cluster from a GLS btw.

 

To clarify: You have a beta swapped accent running the cluster from a car that came with the beta engine



You hooked up the tachometer on the swapped-in stock GLS cluster and the car began running poorly the next day



Yes?



If you don't have the cluster set up right then the CEL might not come on even though a code is set. DO you have a CEL and/or have you had a reader on it to see what codes might be set or pending?



If your car runs right after you undo whatever wiring you did to get the tachometer working, then you did it wrong. Sorry if that sounds obvious but sometimes it helps to point out the obvious

 

I second that, disconnect that tach an see if the problem goes away.

 

whoops, i'm sorry for not being more clear. the cluster is from the deluxe model of LC, with a tacho. it might be called the GS in the states? as it was, i only had the fuel gauge and speedometer working. to get the tacho working, i cut the rpm signal wire (pin 66) about two inches out from the ecm plug, then soldered a longer piece wire in place to connect to the back of the cluster. i just taped up the end of the remaining piece of tacho signal wire that went back into the loom.



unfortunately i cannot pull codes at the moment. a) the CEL isn't wired up and b) i don't think the diagnostic plug is wired up. three different scanners cannot connect to the car, so there are probably some important things not wired up that will allow it to run the full OBD-II caper.



but yes, in light of this, i think what i'll do is just splice the tacho cluster into the signal wire, rather than completely stealing the signal. the rpm signal might be used elsewhere?

 

Splice, do not cut-and-tape off, when you tap signals into important things like engine computers!

 

ok, so i fixed the wiring this afternoon. the connections are now spliced.



its made no difference. i started the car up, it ran fine while it was cold. i thought it was solved, but 10 minutes later: rev limit goes back down to 3000. then the engine cuts out completely and won't start. i did the usual trick of letting it cool down, then reset the ecu and limped it home.



i hope the new crank angle sensor fixes the problem. should be in tomorrow. thanks for everybody's help so far!