How screwed am I or what happed to my engine?
04-20-2024, 04:20 PM
#121
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Thread Starter
sorry but a lengthy post i just made has completely gone missing ?.... argghhhhh
i haven't the strength to re-type it all so a short note will have to do.
You really need to pull the E connector out of the block in order to see all the wires and make voltage and continuity test as in my video.
I didn't ask you if there is a immobiliser in place ...I only need to know if the fine black yellow or yellow black wires are formed into a small loop beneath the E connector block.
You have not mentioned terminal 87 ? this is probably the most critical terminal in the DME can. !
You need to check that there is 12v+ on Terminal 87 with the ignition on
Use your multimeter to check that terminal 85 is connected to ground .......It should be a constant ground ...ignition on or off..
If you have a ground on T 85 and 12v+ on T 86 then you should also see 12v+ on T 87 you need to check this.
The second DME relay solenoid comprises a switched 12v+ from terminal 30 within the DME relay can together with a ground that is made within the DME relay.
DO NOT connect terminal 85b to the chassis or bodywork . The ground for terminal 85b must only come from the DME never connect it to common ground . when the DME is happy that the sensors are providing the right information..it will ground terminal 85b and activate the second solenoid thus providing power to the fuel pump from terminal 87b.
Johnny
i haven't the strength to re-type it all so a short note will have to do.
You really need to pull the E connector out of the block in order to see all the wires and make voltage and continuity test as in my video.
I didn't ask you if there is a immobiliser in place ...I only need to know if the fine black yellow or yellow black wires are formed into a small loop beneath the E connector block.
You have not mentioned terminal 87 ? this is probably the most critical terminal in the DME can. !
You need to check that there is 12v+ on Terminal 87 with the ignition on
Use your multimeter to check that terminal 85 is connected to ground .......It should be a constant ground ...ignition on or off..
If you have a ground on T 85 and 12v+ on T 86 then you should also see 12v+ on T 87 you need to check this.
The second DME relay solenoid comprises a switched 12v+ from terminal 30 within the DME relay can together with a ground that is made within the DME relay.
DO NOT connect terminal 85b to the chassis or bodywork . The ground for terminal 85b must only come from the DME never connect it to common ground . when the DME is happy that the sensors are providing the right information..it will ground terminal 85b and activate the second solenoid thus providing power to the fuel pump from terminal 87b.
Johnny
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peanut (04-21-2024)
04-21-2024, 08:22 AM
#122
Burning Brakes
The next time you visit the car perhaps you could check and clean three important ground or earth points GPll GPlll & GPlV
GP2 and GP3 are located on the chassis rail ....and GP4 which should be adjacent to the Ignition amplifier,( if fitted ),which is bolted to the front wing
Check if terminals 85 and 85b on the DME relay socket are connected to ground with the ignition on.
Check there is 12v+ on DME relay terminal 87
Lastly check to see if there is a short black/yellow wire loop under E connector. You may be able to do this without removing the connector.
With these checks done and eliminated I'm sure that we will be a lot closer to finding the issue
GP2 and GP3 are located on the chassis rail ....and GP4 which should be adjacent to the Ignition amplifier,( if fitted ),which is bolted to the front wing
Check if terminals 85 and 85b on the DME relay socket are connected to ground with the ignition on.
Check there is 12v+ on DME relay terminal 87
Lastly check to see if there is a short black/yellow wire loop under E connector. You may be able to do this without removing the connector.
With these checks done and eliminated I'm sure that we will be a lot closer to finding the issue
Last edited by peanut; 04-21-2024 at 09:18 AM.
04-21-2024, 12:00 PM
#123
Advanced
Thread Starter
The next time you visit the car perhaps you could check and clean three important ground or earth points GPll GPlll & GPlV
GP2 and GP3 are located on the chassis rail ....and GP4 which should be adjacent to the Ignition amplifier,( if fitted ),which is bolted to the front wing
Check if terminals 85 and 85b on the DME relay socket are connected to ground with the ignition on.
Check there is 12v+ on DME relay terminal 87
Lastly check to see if there is a short black/yellow wire loop under E connector. You may be able to do this without removing the connector.
With these checks done and eliminated I'm sure that we will be a lot closer to finding the issue
GP2 and GP3 are located on the chassis rail ....and GP4 which should be adjacent to the Ignition amplifier,( if fitted ),which is bolted to the front wing
Check if terminals 85 and 85b on the DME relay socket are connected to ground with the ignition on.
Check there is 12v+ on DME relay terminal 87
Lastly check to see if there is a short black/yellow wire loop under E connector. You may be able to do this without removing the connector.
With these checks done and eliminated I'm sure that we will be a lot closer to finding the issue
85 has ground.
I hope I checked the correct ground points, I am attaching pictures of it.
The loop is intact (see picture)
04-21-2024, 01:45 PM
#124
Burning Brakes
Excellent at last we are getting somewhere! that's good work. 
As Sherlock said...'when you have eliminated the impossible, whatever remains, however improbable , must be the truth' ......not sure if that applies here but I always think it sounds right .
So the loop is intact ...good that means the the yellow/black 12v+ feed from the Ignition switch is directly supplying terminal 86 on the DME relay
Terminal 85 has a ground so that should now activate the first relay solenoid and switch 12v+ to terminal 87 to power the DME and Injectors and pressurise the fuel system
Next step is to work out why 87 has no voltage
i take it you did test Terminal 87 with the DME relay fitted yes ?
looks like the earthing point in the last image could do with a thorough clean to bare metal
As Sherlock said...'when you have eliminated the impossible, whatever remains, however improbable , must be the truth' ......not sure if that applies here but I always think it sounds right .
So the loop is intact ...good that means the the yellow/black 12v+ feed from the Ignition switch is directly supplying terminal 86 on the DME relay
Terminal 85 has a ground so that should now activate the first relay solenoid and switch 12v+ to terminal 87 to power the DME and Injectors and pressurise the fuel system
Next step is to work out why 87 has no voltage
i take it you did test Terminal 87 with the DME relay fitted yes ?
looks like the earthing point in the last image could do with a thorough clean to bare metal
Last edited by peanut; 04-21-2024 at 01:53 PM.
04-21-2024, 02:39 PM
#125
Advanced
Thread Starter
Excellent at last we are getting somewhere! that's good work.
As Sherlock said...'when you have eliminated the impossible, whatever remains, however improbable , must be the truth' ......not sure if that applies here but I always think it sounds right .
So the loop is intact ...good that means the the yellow/black 12v+ feed from the Ignition switch is directly supplying terminal 86 on the DME relay
Terminal 85 has a ground so that should now activate the first relay solenoid and switch 12v+ to terminal 87 to power the DME and Injectors and pressurise the fuel system
Next step is to work out why 87 has no voltage
i take it you did test Terminal 87 with the DME relay fitted yes ?
looks like the earthing point in the last image could do with a thorough clean to bare metal
As Sherlock said...'when you have eliminated the impossible, whatever remains, however improbable , must be the truth' ......not sure if that applies here but I always think it sounds right .
So the loop is intact ...good that means the the yellow/black 12v+ feed from the Ignition switch is directly supplying terminal 86 on the DME relay
Terminal 85 has a ground so that should now activate the first relay solenoid and switch 12v+ to terminal 87 to power the DME and Injectors and pressurise the fuel system
Next step is to work out why 87 has no voltage
i take it you did test Terminal 87 with the DME relay fitted yes ?
looks like the earthing point in the last image could do with a thorough clean to bare metal
should I test everything „from below“ with the relay in place?
04-21-2024, 04:01 PM
#126
Burning Brakes
You only need to check terminal 87 to see if it has 12v+ with the ignition on and the DME relay in place.
We know now that the first relay 85 & 86 is activating . We just need to confirm 87 hs=as 12v+
If its too awkward or risky to pull the fuse relay board to check from underneath then put a piece of thin wire into terminal 87 before plugging in the DME relay but be very careful where the end of that wire is as we are hoping it has 12v+ on it when you turn the ignition on so make sure the wire cannot short out any other DME relay terminal.
We know now that the first relay 85 & 86 is activating . We just need to confirm 87 hs=as 12v+
If its too awkward or risky to pull the fuse relay board to check from underneath then put a piece of thin wire into terminal 87 before plugging in the DME relay but be very careful where the end of that wire is as we are hoping it has 12v+ on it when you turn the ignition on so make sure the wire cannot short out any other DME relay terminal.
Last edited by peanut; 04-21-2024 at 04:06 PM.
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peanut (04-25-2024)
04-28-2024, 08:33 AM
#129
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Thread Starter
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peanut (04-28-2024)
04-28-2024, 09:16 AM
#130
Burning Brakes
ok thats great news . now we are getting somewhere.
With 12v+ at Terminal 87 of the DME relay the DME should now internally connect pin 36 to ground which should supply a ground to Terminal 85b of the DME relay
[Note : one of my schematics shows DME terminal 35 should supply the DME relay terminal 87 not 36 ]
When Terminal 85b is grounded by the DME the DME relay's second solenoid switches 12v+ from T30 to T 87b .
Now power is supplied to the fuel pump ,injectors, sensors ignition coil etc .
At this point provided the DME is receiving the information it is expecting from the sensors the engine should fire . There The pump should run and there should be a spark at the plugs .
If this doesn't happen then the next step is to check all the sensors and I'll make a list and check sequence .
With 12v+ at Terminal 87 of the DME relay the DME should now internally connect pin 36 to ground which should supply a ground to Terminal 85b of the DME relay
[Note : one of my schematics shows DME terminal 35 should supply the DME relay terminal 87 not 36 ]
When Terminal 85b is grounded by the DME the DME relay's second solenoid switches 12v+ from T30 to T 87b .
Now power is supplied to the fuel pump ,injectors, sensors ignition coil etc .
At this point provided the DME is receiving the information it is expecting from the sensors the engine should fire . There The pump should run and there should be a spark at the plugs .
If this doesn't happen then the next step is to check all the sensors and I'll make a list and check sequence .
Last edited by peanut; 04-28-2024 at 01:07 PM.
05-01-2024, 07:25 PM
#131
Burning Brakes
So far we have done a sequential check and have not fiddled with , or adjusted anything randomly nor have we replaced any components in the vague hope that it might suddenly resolve the issue so we are in a good position to solve this non start issue and it hasn't cost you a cent
If the engine still has not got a spark at the plugs when cranking then we need to test the Engine Temperature sensor , the Air Idle Valve, the AFM and some other components to make sure that the DME is receiving the correct information it expects to see in order to pulse the injectors and generate a spark at the Ignition Amplifier.
If the engine still has not got a spark at the plugs when cranking then we need to test the Engine Temperature sensor , the Air Idle Valve, the AFM and some other components to make sure that the DME is receiving the correct information it expects to see in order to pulse the injectors and generate a spark at the Ignition Amplifier.
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500 (05-02-2024)
05-02-2024, 11:38 AM
#132
RL Community Team
Rennlist Member
Rennlist Member
I don't have anything useful to contribute to this thread, but just wanted to express how educational I am finding it. Not only in terms of the specifics, but also the overall process of working through a careful diagnosis and not jumping into scatter-shot parts replacement (which is easy to do, when you THINK you have an idea of what the issue may be... I have been guilty of this many times...)
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peanut (05-02-2024)