I installed a Delco D1927A ignition module on my 1993 Lotus Esprit which has a GM Quad 4 engine management system. I had a code 42 and after completing a diagnosis, results indicated the DI mudule was defective. With the new module I get a code 41, EST. After reading on the net, I've learned the generic ignition modules do not have a wire to one of the pins on the 6 pin connector to inform the ECM of speed control signal like the Lotus ones do, so you will always get a code 41 with a generic one. Given this, can you pleast advise me of the model # of the DI module Lotus used? Understanding this is not a GM vehicle, the engine management system is GM. Hopefully you can research this issue for me. The engine speed signal is used during setup up and tuning during development of the code, for some reason Lotus left it in. Other Delco equipped cars that use the same ECM don't use the speed signal. Thank you, Bob Frohwein 904 635-7118

You need to check for engine management fault codes, here is how you do that. Follow the link to check codes codes How to Get GM OBD1 Codes in Under 5 Minutes

A quad driver is a transistor in the engine control module ! GM OBD Trouble Code 26 GM OBD Trouble Code 28

Code 26 is for a problem with one of the quad drivers inside the engine computer, or the wiring harness, and code 42 is for a problem with the ignition module or the control.
You'll need a shop manual with the testing procedures for each code to proceed.

What engine ? 2.2 l or 2.4 L. You don't say if any codes are set. no P0303 - P0304 cylinder's 3 & 4 misfire ? or any other ? No the cam sensor wouldn't cause just two cylinders to misfire. The PCM triggers the ICM to turn on an off coil's to build up an collapse the primary voltage inducing the secondary voltage . This engine is equipped with a non-distributor ignition system called the electronic ignition (EI) system. The primary circuit of the EI system consists of the following components:
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Two separate ignition coils

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An electronic ignition control module (ICM)

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A crankshaft position (CKP) sensor

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Related connecting wires

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The ignition control (IC) portion of the powertrain control module (PCM)
Important: The camshaft position (CMP) sensor is only used for a misfire detection. It is not part of the ignition system. !
How to Test the Ignition Coils GM 2 4L Quad 4

Fuel filter,tune up,could be crankshaft sensor.

I do not know your vehicle but in that time frame a lot of cars used what is called a ballast resistor. During start it was shorted allowing the coil to output more power, once the engine came up to speed about two seconds the short was removed. Shorting simply means bypassing the resistor. I hope that helps.

US models such as my 1991 Lotus Esprit SE is to the left of the steering column at the bottom of the dash. Reach down and feel behind the dash there will be a rectangular pull or pivot which releases the hood.

Here is a code list for you. Remember this doesn't always mena a sensor issue, the problem can be in the wiring as well, or in the case of a lean code you may have an actual lean condition due to a vacuum leak at the intake or vacuum hoses or connections. I have highlighted your fault codes and added extra notes.
GM common codes for OBD1 (for vehicles made before 1995)
12 System normal
13 oxygen sensor circuit open
14 coolant sensor high resistance or shorted
15 coolant sensor circuit low or open
16 direct ignition system (DIS) fault in circuit
17 cam position sensor fault
18 crank or cam sensor error
19 crank sensor circuit fault
21 tps sensor out of range
22 tps sensor signal voltage low
23 intake air temp sensor out of range, low
24 vehicle speed (vss) sensor circuit fault
25 air temp sensor sensor out of range, high
26 quad-driver module (computer) circuit #1 fault
27 quad-driver module (computer) 2nd gear circuit
28 quad-driver module (computer) circuit #2 fault
29 quad driver module (computer) 4th gear circuit
31 camshaft position sensor fault
32 egr circuit fault
33 map sensor signal out of range, high
34 map sensor signal out of range, low
35 idle air control sensor circuit fault
36 ignition system circuit error
38 brake input circuit fault
39 clutch input circuit fault
41 cam sensor circuit fault, igntion control circuit fault
42 electronic spark timing (EST) circuit grounded
43 knock sensor malfunction or electronic spark control (ESC) circuit fault (ignore this for now)
44 oxygen sensor lean exhaust (make sure you no engine vacuum leaks)
45 oxygen sensor rich exhaust
46 pass-key II circuit or ps.pressure switch circuit fault
47 pcm-bcm data circuit
48 misfire diagnosis
51 calibration error, mem-cal, ecm or eeprom failure
52 engine oil temperature circuit, low temperature indicated
53 battery voltage error or egr or pass-key II circuit
54 egr system failure or fuel pump circuit low voltage
55 a/d converter error or pcm not grounded or lean fuel or frounded reference voltage
56 quad-driver module #2 circuit
57 boost control problem
58 vehicle anti-theft system fuel enable circuit
61 a/c system performance or degraded oxygen sensor signal
62 engine oil temperature high temperature indicated
63 oxygen sensor right side circuit open or map sensor out of range
64 oxygen sensor right side lean exhaust indicated
65 oxygen sensor right side rich exhaust indicated
66 a/c pressure sensor circuit low pressure
67 a/c pressure sensor circuit or a/c clutch circuit failure
68 a/c compressor relay circuit failure
69 a/c clutch circuit head pressure high
70 a/c refrigerant pressure circuit high
71 a/c evaporator temperature sensor circuit low
72 gear selector switch circuit
73 a/c evaporator temperature circuit high
75 digital egr #1 solenoid error
76 digital egr #2 solenoid error
77 digital egr #3 solenoid error
79 vehicle speed sensor (vss) circuit signal high
80 vehicle speed sensor (vss) circuit signal low
81 brake input circuit fault
82 ignition control (IC) 3X signal error
85 prom error
86 analog/digital ecm error
87 eeprom error
99 power management

This is code 12 and it means "System Normal"
Here is the complete list of fault codes for your Buick
GM common codes for OBD1 (for vehicles made before 1995)
12 System normal
13 oxygen sensor circuit open
14 coolant sensor high resistance or shorted
15 coolant sensor circuit low or open
16 direct ignition system (DIS) fault in circuit
17 cam position sensor fault
18 crank or cam sensor error
19 crank sensor circuit fault
21 tps sensor out of range
22 tps sensor signal voltage low
23 intake air temp sensor out of range, low
24 vehicle speed (vss) sensor circuit fault
25 air temp sensor sensor out of range, high
26 quad-driver module (computer) circuit #1 fault
27 quad-driver module (computer) 2nd gear circuit
28 quad-driver module (computer) circuit #2 fault
29 quad driver module (computer) 4th gear circuit
31 cam position sensor fault
32 egr circuit fault
33 map sensor signal out of range, high
34 map sensor signal out of range, low
35 idle air control sensor circuit fault
36 ignition system circuit error
38 brake input circuit fault
39 clutch input circuit fault
41 cam sensor circuit fault, igntion control circuit fault
42 electronic spark timing (EST) circuit grounded
43 knock sensor
or electronic spark control circuit fault
44 oxygen sensor lean exhaust
45 oxygen sensor rich exhaust
46 pass-key II circuit or ps.pressure switch circuit fault
47 pcm-bcm data circuit
48 misfire diagnosis
51 calibration error, mem-cal, ecm or eeprom failure
52 engine oil temperature circuit, low temperature indicated
53 battery voltage error or egr or pass-key II circuit
54 egr system failure or fuel pump circuit low voltage
55 a/d converter error or pcm not grounded or lean fuel or frounded reference voltage
56 quad-driver module #2 circuit
57 boost control problem
58 vehicle anti-theft system fuel enable circuit
61 a/c system performance or degraded oxygen sensor signal
62 engine oil temperature high temperature indicated
63 oxygen sensor right side circuit open or map sensor out of range
64 oxygen sensor right side lean exhaust indicated
65 oxygen sensor right side rich exhaust indicated
66 a/c pressure sensor circuit low pressure
67 a/c pressure sensor circuit or a/c clutch circuit failure
68 a/c compressor relay circuit failure
69 a/c clutch circuit head pressure high
70 a/c refrigerant pressure circuit high
71 a/c evaporator temperature sensor circuit low
72 gear selector switch circuit
73 a/c evaporator temperature circuit high
75 digital egr #1 solenoid error
76 digital egr #2 solenoid error
77 digital egr #3 solenoid error
79 vehicle speed sensor (vss) circuit signal high
80 vehicle speed sensor (vss) circuit signal low
81 brake input circuit fault
82 ignition control (IC) 3X signal error
85 prom error
86 analog/digital ecm error
87 eeprom error
99 power management

CODE 42 Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.
During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then "tells" the ignition module via the EST circuit.
An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.
The conditions for setting this code are:

• System in BYPASS mode but the ignition module is still controlling timing
  - or -
• Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec.

Typical causes for this code include:
1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM


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