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I have a1993 acura legend coupe that cranks and hard to start. I have verified that main relay is working and even got another and verified fuel pressure. When cranking the tachometer does not move. After multiple cranks the car will start and the tachometer will work. If I shut the car off I will have to repeat the multiple cranks to get the car running again. Is the ecm jumper plug tan on the 93 legend and attached to the top of the ecm cover in a blank outlet?
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While I don’t know about the jumper plug, what you are discussing is indicative of a bad crank position sensor (CKP). Without a CKP signal to the computer, there will be no RPMs on the Tachometer and either no spark or no fuel delivered depending on the manufacturer. I believe the CKP is in the distributor on your year Acura.
It will do exactly as you described, when the signal gets there, the car will start and the tach will work…
I pulled my hair out over this one on a Toyota one time when I found that the wire to the CKP was frayed by a belt… It was intermittent as well..
-Karl
Thanks. I don’t know if it is the cps or the ecm or something else and want to be certain before replacing parts.
Well, the ECM should be the last thing you replace after all else has failed…. Even Eric admits he has only done a couple of them when he was with Acura… I have seen very few go out in Toyotas in my experience FWIW..
I would take a good look at the CKP wiring and CKP…. Possibly backprobing it for any issues….
JMHO
Best of luck..
-Karl
If the ckp is bad will I get a code on the ECM?. The legend does not have a distributor and I need help with locating and changing the sensor that I have read is behind the trimming belt.
If it is behind the timing belt, it is a more modern version…Look around the crank pulley….
And no, if it is intermittent, you won’t get a code because it won’t start to give you a code…
FWIW That is the same type of setup I was dealing with on the Toyota which had the frayed line… I recommend to backprobe and check for continuity starting at the wires right on the sensor and going as far back as I could go.. Ensure there is not an issue with the wires… The CKS is essentially a magnetic pickup which sends the signal when the crank turns and meets a certain spot on the crank…
To find out more about it and see diagrams, you may try to get on the Autozone website and look under their REPAIR MANUAL section… It may be there, may not…
I also recommend ALLDATA DIY… You get all the factory stuff online for one vehicle for around $16-$17…. https://www.alldatadiy.com/
Sorry I can’t help more on Acuras/Hondas… Easier to do when the vehicle is in front of me… 🙂
-Karl
Update:. I found the correct jumper to read the odb codes. It was attached to the ecm cover in a blank plug and was tan in color. I got a code 6 which was a bad ect sensor. When changing the sensor to a new one I broke the sensor and had to get another. I can’t believe how little torque it takes to break the sensor. I tested the sensor before trying the installation by just connecting the connector and the car started without a problem. I will install a new sensor tomorrow and Test after the engine gets hot.
I also got a code 12 on the ABS light and will research what it means.
I am hoping my start problem is just a bad Temp sensor.
Change the ect sensor today and ran the car without any start problems. I can’t believe the Temp sensor would keep the car from running.
I know that a ECT sensor in a Honda can cause hard starts and poor performance, but a no start without any signal to the tach is what I find unusual… Computer must read as an out of whack temp and shut off the crank/spark plug signal for protection as near as I can figure…
Congrats on getting it running…
-Karl
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