1988 928 S4 No Injector Pulse
10-07-2022, 08:29 PM
#16
Track Day
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10-07-2022, 08:32 PM
#17
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I looked through my old saved scope signals and saw that I had previously seen iniector pulse. This has been a long time project so forgot I checked that in the past. However I currently don't. Bit of an odd one. Only things done since then are a new crank sensor and the plugs were re-insulated.
10-08-2022, 09:29 PM
#18
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Speed sensor output from EZK (pin 13) has a perfect signal. When checking the speed for EZK (pin 1 blue/white) the scope signal looks like the photo attached. I'll also attach the pinouts, maybe I'm getting the wording wrong. But I'm confused, speed signal to LH when checked at the green wire is fine, but the LH side is terrible which explains my injectors not pulsing. I fail to see how it can be different when it should be a straight connection between the two?
Am I just missing something massive?
10-10-2022, 09:48 AM
#19
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Had a look through your thread and in post 18 you state you are "confused" - whether you are or not remains to be seen- if you are confused nothing to be ashamed of- that is why we are here to help.
So let's try and see if we can reduce and hopefully eliminate any confusion there may be and hopefully not confuse you any more than you already may be.
First of all may I suggest a simple test that my help eliminate any wiring issues- starting position everything connected as normal.
1. Remove the LH relay [XXV] - test for battery voltage on pin 30- that should read same as full battery voltage- about 12.6 volts if your battery is in good nick as there is no load on the system.
2. Disconnect the battery, remove the LH plug, carry out a resistance check between terminal 87 of the LH relay socket and terminal 18 of the LH plug- it should read about 2.5 ohms [8 resistors in parallel of about 16 ohms each for the injectors plus the cap and wiring of up to 3 ohms for each circuit]. If the resistance is not as it should be then you need to determine why.
3. You say that the EZK output speed signal on pin 13 is "OK"- this would be the signal feeding into the EZK from the CPS across pins 13 and 6- but how are you measuring that given it is not possible to do so [or so I understand unless you have direct contact with the cores]? Can you post an image of this signal?
4. You then say you are monitoring the signal in pin 1 of the LH plug and presumably this is the signal on the image of your scope screen you posted which as i can tell bears no resemblance to what should be seen. Which other pin did you use for earth reference?
Not related to the above:
5. In post 8 you showed an image of a two pin connector- as Jim posted that looks like the idle speed positioner cable with a red and blue cable- this point did not converge. The idle will "sort of function" with this connector down. With no input signal the ISV has a default orifice that passes enough air to support idel on a warm engine naturally. Cold starts will be difficult without fethering the throttle and will stall if the pedal is not depressed a taad until the enigne warms up. Similarly switch on the AC and the car will immediately stumble and cut out- sound familiar at all?
6, The cable supporting ISV operation feeds under the rear of the manifold and connects to the ISV that sits towards the front of the manifold but underneath the connector block being rear most of the ISV position. If somehw there is a cable connected to it I have no idea what it may be- I suspect with the help of a small mirror you can look in there and you will see the connector block with nothing connected to it.
Trust the above helpful.
So let's try and see if we can reduce and hopefully eliminate any confusion there may be and hopefully not confuse you any more than you already may be.
First of all may I suggest a simple test that my help eliminate any wiring issues- starting position everything connected as normal.
1. Remove the LH relay [XXV] - test for battery voltage on pin 30- that should read same as full battery voltage- about 12.6 volts if your battery is in good nick as there is no load on the system.
2. Disconnect the battery, remove the LH plug, carry out a resistance check between terminal 87 of the LH relay socket and terminal 18 of the LH plug- it should read about 2.5 ohms [8 resistors in parallel of about 16 ohms each for the injectors plus the cap and wiring of up to 3 ohms for each circuit]. If the resistance is not as it should be then you need to determine why.
3. You say that the EZK output speed signal on pin 13 is "OK"- this would be the signal feeding into the EZK from the CPS across pins 13 and 6- but how are you measuring that given it is not possible to do so [or so I understand unless you have direct contact with the cores]? Can you post an image of this signal?
4. You then say you are monitoring the signal in pin 1 of the LH plug and presumably this is the signal on the image of your scope screen you posted which as i can tell bears no resemblance to what should be seen. Which other pin did you use for earth reference?
Not related to the above:
5. In post 8 you showed an image of a two pin connector- as Jim posted that looks like the idle speed positioner cable with a red and blue cable- this point did not converge. The idle will "sort of function" with this connector down. With no input signal the ISV has a default orifice that passes enough air to support idel on a warm engine naturally. Cold starts will be difficult without fethering the throttle and will stall if the pedal is not depressed a taad until the enigne warms up. Similarly switch on the AC and the car will immediately stumble and cut out- sound familiar at all?
6, The cable supporting ISV operation feeds under the rear of the manifold and connects to the ISV that sits towards the front of the manifold but underneath the connector block being rear most of the ISV position. If somehw there is a cable connected to it I have no idea what it may be- I suspect with the help of a small mirror you can look in there and you will see the connector block with nothing connected to it.
Trust the above helpful.