I have been running my MAP signal off of a vacuum log connecting my Triple sidedraft carbs. I was also running my PCV valve thru that log. . I pulled my vacuum line off of my MS3xX unit and oily water/condensation came out of the hose-A BUNCH.
I have cleaned it up as well as possible but timing is still erratic.
I had also just finished installing a MSD 8920 tach adapter to get my current driven tach to work. When I fired it up in the garage the tach worked good. I took the car for a spin and noticed bad detonation. When I hooked up my laptop I noticed very high ignition timing -even at idle. I have attached a datalog.
I thought I wired the tach adapter wrong or something and disconnected it from the system completely, but timing is still erratic. That's when I pulled my vacuum line off of my MS3xX unit and found the oil.
I"ve cleaned it up as well as possible but timing is still erratic.
I had the MAP Daddy4 bar preinstalled with the unit when I purchased it. Now there is two ports on the sensor, can I try the other one?
Bad MAP sensor cause erratic spark timing?
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Bad MAP sensor cause erratic spark timing?
Steve
1971 Datsun 240z 3.2 L6 1975 EFI intake plenum 60mmTB with 42lb Bosch injectors
MS3x 3.57 Ignition LS1 coils running full sequential
!983 Nissan 720 MS2/3.57 ported efi 26lb Bosch VW 4 tower ignition wasted spark
1971 Datsun 240z 3.2 L6 1975 EFI intake plenum 60mmTB with 42lb Bosch injectors
MS3x 3.57 Ignition LS1 coils running full sequential
!983 Nissan 720 MS2/3.57 ported efi 26lb Bosch VW 4 tower ignition wasted spark
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- Experienced MS/Extra'er
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Re: Bad MAP sensor cause erratic spark timing?
I haven't verified timing because I need to go get a timing light, my old quit.
I will add that if I pull up my timing table, it shows the right timing for that rpm, but my gauge cluster shows at least 10-15 degrees more. 30 degrees at idle, but it doesn't sound like it..
I also changed over to fixed timing to try , and it sometimes gets stuck on crank timing(10 degrees), vs. the 15 degree fixed setting. If I blip the throttle it will go up to 15 and stay there.
I will add that if I pull up my timing table, it shows the right timing for that rpm, but my gauge cluster shows at least 10-15 degrees more. 30 degrees at idle, but it doesn't sound like it..
I also changed over to fixed timing to try , and it sometimes gets stuck on crank timing(10 degrees), vs. the 15 degree fixed setting. If I blip the throttle it will go up to 15 and stay there.
Steve
1971 Datsun 240z 3.2 L6 1975 EFI intake plenum 60mmTB with 42lb Bosch injectors
MS3x 3.57 Ignition LS1 coils running full sequential
!983 Nissan 720 MS2/3.57 ported efi 26lb Bosch VW 4 tower ignition wasted spark
1971 Datsun 240z 3.2 L6 1975 EFI intake plenum 60mmTB with 42lb Bosch injectors
MS3x 3.57 Ignition LS1 coils running full sequential
!983 Nissan 720 MS2/3.57 ported efi 26lb Bosch VW 4 tower ignition wasted spark
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Re: Bad MAP sensor cause erratic spark timing?
You seem to have 2 ignition tables operating in an additive fashion.
Find the Manuals up top under Quick links: Manuals.
Cheers Luke
Cheers Luke
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Re: Bad MAP sensor cause erratic spark timing?
Could you elaborate? I know I have 2 tables available.
Steve
1971 Datsun 240z 3.2 L6 1975 EFI intake plenum 60mmTB with 42lb Bosch injectors
MS3x 3.57 Ignition LS1 coils running full sequential
!983 Nissan 720 MS2/3.57 ported efi 26lb Bosch VW 4 tower ignition wasted spark
1971 Datsun 240z 3.2 L6 1975 EFI intake plenum 60mmTB with 42lb Bosch injectors
MS3x 3.57 Ignition LS1 coils running full sequential
!983 Nissan 720 MS2/3.57 ported efi 26lb Bosch VW 4 tower ignition wasted spark
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- Experienced MS/Extra'er
- Posts: 368
- Joined: Wed Mar 05, 2014 3:33 pm
- Location: Bloomington Indiana
Re: Bad MAP sensor cause erratic spark timing?
Thankyou for the clue. I see what you mean. I thought I was choosing between two different tables and I was using #2 as an additive. Hope I didn't hurt my motor.
Next to see if my MAP sensor is fixed.
So much to learn. I'm glad I am cutting g my teeth on a NA motor or I would have blown this thing up already.
Next to see if my MAP sensor is fixed.
So much to learn. I'm glad I am cutting g my teeth on a NA motor or I would have blown this thing up already.
Steve
1971 Datsun 240z 3.2 L6 1975 EFI intake plenum 60mmTB with 42lb Bosch injectors
MS3x 3.57 Ignition LS1 coils running full sequential
!983 Nissan 720 MS2/3.57 ported efi 26lb Bosch VW 4 tower ignition wasted spark
1971 Datsun 240z 3.2 L6 1975 EFI intake plenum 60mmTB with 42lb Bosch injectors
MS3x 3.57 Ignition LS1 coils running full sequential
!983 Nissan 720 MS2/3.57 ported efi 26lb Bosch VW 4 tower ignition wasted spark