• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Boost Control Solenoid/EVAP?

pski920

pski920

New member
After starting my car, it stalls after about 5 sec. It just cuts out, and if i rev it as it stalls out, i can save it for a sec. and then it stalls again. I used a high quality scanner on my car and it flashes a P1646 code (Boost Control Sensor). Is this a typical result of a bad BCS? Or is it flashing this code due to another problem? Has anyone run into this problem before? I've looked online for a sensor (or switch) to see what it looks like because i am not sure where it is located. I think it is in front of the SC and behind the front valve cover and has a harness going into the left of it and a vaccum line running out of the right. Any help would be appreciated greatly!
 
Last edited:


Re: Boost Contorl Sensor

Um, there is no Boost Control Sensor on these cars.

P1646 is for the EVAP Vent Solenoid control circuit, which is the one back by the gas tank. I wouldn't think that would be causing your problem.

What year is your car? Could be the fuel pump resistor.
 
Re: Boost Contorl Sensor

the scanner read Boost Solenoid/5v ref. C/ EVAP Vent Circuit. i thought it was sensor, but i meant solenoid. it wouldn't cause it to stall suddenly after 5 sec? what could it be? i tried pulling the MAF sensor to see if it worked, and it still stalled. and i cleaned the idle control valve too. my car is a 1998.
 
Last edited:
Thanks Scimmia, I think that's what it may be after finding out some info from a friend. He told me exactly what you told me, but when you responded I couldn't find anything on where this resistor was. Do you know exactly, and possibly a part number?
 
Thanks, I'll try it tmw. since the weather here in Upstate NY BITES! I'll let you know how i make out, and i got a resistor for 35 dollars from my cousin who works for a gm dealership. is that a good price?
 


Sounds about right, but I've never had to deal with it directly; the L36 never used the resistor, and GM quit using them in the L67 after 2000 anyway.
 
ahh, they actually realized thier problem and dealt with it. amazing. i appreciate your help and i will get back to you and let you know how it turns out tmw.
 


Thanks guys, I replaced the resistor and it worked. Also, when I got the part, it came as the relocation kit as well. So I mounted it to the firewall (since it will prob. happen again). haha...thanks again!
 
sorry guys but if u bend pin 85 the car dies isnt it like 87b tht needs to b bent??? and we are talkin about relay 14 in the engine compartment fuse box correct
 
all tha does is make your fuel pump work harder in high mode, the resistor controls the pump while the car is running.
 
ok youve lost me my car doesnt have a resistor... it has a 5 pin relay which has 2 seperate numberings on it... so the diagram on the relay referrs to a pin labeled 85 and i flip it over and look at the referred pin and said pin is labeled 87 wtf???
 


A 97-03 GTP has a resistor. It's located down behind the window washer container in a pain in the neck place. If you have a speed control relay in your fusebox... bend the pin. Searching on pump resistor will net you a picture or two. I would link you..but this pos I'm using isn't all that good.
 
ok... so i tried the pin 85 to no avail... fp doesnt even prime ill look for the resistor later as the car still runs... and now my ltfts are at zero all the time... i despise electronics for the time being
 
You must log in or register to reply here.
Back
Top