Posts: 942
If I'm understanding it correctly, GM module does more with its signals than the Bosch module (turning off the coil when ignition's on but the engine isn't spinning for example). I don't think a Bosch module will be as sensitive to run of the mill DeLorean electrical system fluctuations (I've never heard of OEM owners having to add capacitors to solve a misfire -- usually the reason is mechanical, such as a bad injector).
Bill Robertson
#5939
Location: Leonardtown, MD
Posts: 9,005
My VIN: 03572
Correct. The Bosch ECU already has capacitors built into the ECU for power filtering. One brand of the GM module I tested also did not have the "miss" problem so maybe it also has capacitors built into it. It was the AutoZone GM module that had the problem.Originally Posted by content22207_2
In any case, adding more capacitance will only improve the power feed to your ECU. What causes a problem in one car may not show up in other cars. It all depends on how the harness wires run and how good your connections are.
Posts: 265
I've been searching the forum for more detail on the ignition system and I came across one of Bill's posts from February. He said that the polarity is important on the coil so I took a closer look at the one installed in my car and I found that it did not match his description of correct installation.
Coil_Installation.jpg
I looked through the workshop manual and technical information manual and I cannot find anywhere the polarity is published for this. So far Bill hasn't steered me wrong... I don't know if this can cause fouled plugs but I swapped it around and fired her up and she still seems to be missing. I then pulled the idle speed motor in preparation to pull that cylinder 4 plug and the metal pipe was looser than the hoseclamp side and just slide out of the motor.
IdleSpeedMotor.jpg
Do I need to take the intake apart in order to reinstall the metal pipe? I want to relocate this thing like Bill suggested. I think I can just get some properly sized hoses and mount it elsewhere. Then while I was poking around I noticed this hose is just hanging out of the Control Pressure Regulator, it doesn't go anywhere and it has a hoseclamp on it at the Control Pressure Regulator so I'm wondering if it's supposed to be just hanging or should it be hooked up to something?
Control_Pressure_Regulator.jpg
Posts: 265
Also, I just noticed from this post I think my yellow wire (that goes to the 2.2uF cap) is incorrectly wired. It is currently hooked up to the negative terminal of the coil (with White/Slate), and looking at all the wiring docs it appears that it should be on the positive side (with White/Yellow). Would someone please confirm this for me?
Location: Leonardtown, MD
Posts: 9,005
My VIN: 03572
The yellow wire going to the 2.2 uf cap should be wired to the negative terminal of the coil. The case of that cap gets connected to ground which should be the metal plate of the "coil box".
Location: Florida
Posts: 2,371
My VIN: <2000
Club(s): (DCF)
Here's a picture of my coil wiring. I don't think it's been touched, but I can't be sure about that. I have an early car and it runs very good.
image.jpg
Based on this discussion, I'd like to find out if it's wired correctly as well.
Dana
1981 DeLorean DMC-12 (5 Speed, Gas Flap, Black Interior, Windshield Antenna, Dark Gray)
Restored as "mostly correct, but with flaws corrected". Pictures and comments of my restoration are in the albums section on my profile.
1985 Chevrolet Corvette, Z51, 4+3 manual
2006 Dodge Magnum R/T (D/D)
2010 Camaro SS (Transformers Edition)
Posts: 942
Page M:18:03 of the Workshop Manual disagrees, as does the overall wiring diagram at the end of the section -- both show the capacitor on White/Yellow (positive).
That capacitor is only to prevent clicking noises on AM radio, so it's not really critical in today's world.
Bill Robertson
#5939
Posts: 942
White/Yellow is positive (from the resistor grid). White/Gray or White/Slate is negative (to the ignition ECU).
Bosch coils can be a little confusing. Terminal 15 is positive. Terminal 1 is negative. On Page M:18:03 of the Workshop Manual, Terminal 1 and "WS" is negative.
Every aftermarket coil I have see is labeled + and -.
Ignition coils do not work well wired backwards. The more windings they have, the less well they work backwards (an MSD or Pertronix coil wired backwards will perform worse than a Bosch coil wired backwards).
Bill Robertson
#5939
Last edited by content22207_2; 07-07-2016 at 08:47 AM.
Posts: 265
Hi Bill, I saw that page but there's nothing on there to denote positive and negative terminals, nor terminal 15 vs. 1. There is a '1' next to the coil to label it as such but that's not for the terminals. Here's a screen shot from M:18:03:
IgnitionSystem.jpg
You and I are apparently using the same coil and the polarity is clearly stamped on the top. I'm just looking to verify which side within the car should be positive and negative with the manuals but they never seem to indicate...
Posts: 265
Thank you Dana, I can't tell looking at your picture which wires are which. I can see that 15 (+) is toward the bulkhead connectors and 1 (-) is toward the engine side but the white/yellow and white/grey both look just white. Can you verify which is which?
Thanks,
-Greg
Posting Permissions
Reply With Quote
Dave M vin 03572