SYCKDC23

Ok, so I have a 2001 gsr, but a friend blew my motor and we swapped in an obd1 gsr. The car wont stay idle, it goes up and down and eventually stalls out. Ive had the car checked out and everything was fixed except I had to get a obd1 p72. I got that but yet it still idles to zero and cuts off. The motor I bought didnt come with a crank position sensor.... Would this be the reason why I'm still having this issue?

b18c1ej1

if ur using an obd1 ecu than it doesnt matter about the crank position sensor...sounds like the timing is off...is the check engine light on?

SYCKDC23

if I hook up the obd2b p72 it threw 4 or 5 codes, but i fixed all of them but one, the one left is for the crankshaft position sensor, if I hook up obd1 p72 no codes at all and the car doesnt hesitate at all... with the obd2 it hesitates when pedals to the floor. even when i am driving with the obd1 p72 if I hold in the clutch the rpms go to zero and the car turns off. until i release the clutch.

Fabrik8

Yes, the engine you swapped in (the OBD1 engine) DOES have a crank position sensor. The sensor you're thinking about is the crank fluctuation sensor most likely, which is on OBD2 engines only, and usually only on USDM engines. This is NOT the same as the crank position sensor, though it is on the crank. The crank position sensor is still in the distributor.

If you want to use the OBD2 ECU, there are ways to bypass the crank fluctuation sensor, which I think just involves tying both ECU inputs to the crank position sensor in the distributor. You'll have to look that up to be sure, I've never done that before and I don't want to tell you the wrong thing.

SYCKDC23

crank fluctuation sensor... I looked it up to see what it looks like, and thats what my motor doesnt have, I have the part in my garage..... I just wish i could figure this shit out

Gold Eg

to answer your question NO. the fluctuation sensor will not single handedly keep the car from running. i ran an obd2 ls for a week with out it. yes it will DUMP fuel and could potentially wash the cylinders but it sounds more like a timing issue, given all the variables have been considered (fuel, spark, air, wiring correct, ecu, engine mechanical condition) if your engine won't idle check your compression and timing will usually reveal its face!! hope this helps!

mondyva

i'll give u a hint, it makes your motor go up and down really fast.....give up? you have to rewire the iacv

SYCKDC23

it does idle up and down fast, it just idles at 1000-1500 until drivien for a minute, then coming to every stop it idles to maybe 50, stutters for a few then cuts off... If im driving and hold in the clutch it will go down to zero and show that the car is off until i release the clutch

Fabrik8

Check the IACV wiring, clean the IACV screen, and check for cracked/missing/disconnected vacuum lines.

Does that engine you swapped in have a lightened flywheel?

SYCKDC23

yes, while doin the motor swap we instialled a 7.5lb fidanza flywheel. All vacuums have been checked.... how do I check this iacv? I have dsiconnected the sensor but it looks fine...

another thing, If I unplug the throttle position sensor, the car idles fine and never stalls out, but of course vtec doesnt hit. And gas milage is fuckin horrible. I have replaced the tps and still didnt fix it.