S4 LH and Fuel Pump relays won’t engage
02-21-2019, 03:28 PM
#16
Rennlist Member
02-21-2019, 09:31 PM
#17
Chronic Tool Dropper
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Stooopid stuff:
The fuel pumps and the injection relays get power via dedicated power feed wiring direct from battery positive in the boot. Those smaller red wires attach to the positive post with either an extended stud or a piggyback bracket with screws for each wire. Regardless, those connections MUST BE clean and tight. Else the pump will run weakly or not at all, and the injectors won't pull in since the LH relay isn't getting correct voltage. Further, the FP relay feeds the unfused heater in the oxygen sensor too, if you want to get deep into possible causes. Since you were undoubtedly fiddling in the battery well as an early part of the start effort, look again there and make sure the connections are all clean/shiny and tight.
The fuel pumps and the injection relays get power via dedicated power feed wiring direct from battery positive in the boot. Those smaller red wires attach to the positive post with either an extended stud or a piggyback bracket with screws for each wire. Regardless, those connections MUST BE clean and tight. Else the pump will run weakly or not at all, and the injectors won't pull in since the LH relay isn't getting correct voltage. Further, the FP relay feeds the unfused heater in the oxygen sensor too, if you want to get deep into possible causes. Since you were undoubtedly fiddling in the battery well as an early part of the start effort, look again there and make sure the connections are all clean/shiny and tight.
02-22-2019, 07:40 PM
#19
Burning Brakes
Thread Starter
Stooopid stuff:
The fuel pumps and the injection relays get power via dedicated power feed wiring direct from battery positive in the boot. Those smaller red wires attach to the positive post with either an extended stud or a piggyback bracket with screws for each wire. Regardless, those connections MUST BE clean and tight. Else the pump will run weakly or not at all, and the injectors won't pull in since the LH relay isn't getting correct voltage. Further, the FP relay feeds the unfused heater in the oxygen sensor too, if you want to get deep into possible causes. Since you were undoubtedly fiddling in the battery well as an early part of the start effort, look again there and make sure the connections are all clean/shiny and tight.
The fuel pumps and the injection relays get power via dedicated power feed wiring direct from battery positive in the boot. Those smaller red wires attach to the positive post with either an extended stud or a piggyback bracket with screws for each wire. Regardless, those connections MUST BE clean and tight. Else the pump will run weakly or not at all, and the injectors won't pull in since the LH relay isn't getting correct voltage. Further, the FP relay feeds the unfused heater in the oxygen sensor too, if you want to get deep into possible causes. Since you were undoubtedly fiddling in the battery well as an early part of the start effort, look again there and make sure the connections are all clean/shiny and tight.
still no love from this car!
i had read somewhere on rl that all three crucial relays can be jumpered, I’m considering doing that but I’m a bit nervous. probably shouldn’t be.
also, since the car ran hot, is there something, anything, that could have been damaged to affect the fuel pump or LH ability to receive the correct signals? what do they share in common?
if I pull all of the fuel injector connectors and test with a multimeter (battery connected and or disconnected) will I potentially find the problem?
Last edited by Shark2626; 08-01-2019 at 10:23 AM.
02-22-2019, 08:35 PM
#20
Team Owner
before you do anything else remove the bell housing and do a crank end play check.
Make sure to remove the rear pinch bolt and inspect the drive shaft to verify it is centered in the slot,
and the bolt is not damaged. reinstall the rear pinch bolt firt with a drop of blue loctite and torque to 66 ft/lbs,
then tighten the front pinch bolt after you have pried the flywheel to the rear of the car.
Next remove the intake tubes and put the engine to TDC ,
you can look down the cam cover vents to verify the timing marks are correct.
Inside each tube is a small V this will line up close to the indentation on the front side of each cam pulley.
any chance you can post a full picture of the CE panel in your car.
Also go and reclean all of the battery connections.
Make sure to remove the rear pinch bolt and inspect the drive shaft to verify it is centered in the slot,
and the bolt is not damaged. reinstall the rear pinch bolt firt with a drop of blue loctite and torque to 66 ft/lbs,
then tighten the front pinch bolt after you have pried the flywheel to the rear of the car.
Next remove the intake tubes and put the engine to TDC ,
you can look down the cam cover vents to verify the timing marks are correct.
Inside each tube is a small V this will line up close to the indentation on the front side of each cam pulley.
any chance you can post a full picture of the CE panel in your car.
Also go and reclean all of the battery connections.
Last edited by Mrmerlin; 02-22-2019 at 09:04 PM.
02-23-2019, 06:14 PM
#21
Burning Brakes
Thread Starter
before you do anything else remove the bell housing and do a crank end play check.
Make sure to remove the rear pinch bolt and inspect the drive shaft to verify it is centered in the slot,
and the bolt is not damaged. reinstall the rear pinch bolt firt with a drop of blue loctite and torque to 66 ft/lbs,
then tighten the front pinch bolt after you have pried the flywheel to the rear of the car.
Next remove the intake tubes and put the engine to TDC ,
you can look down the cam cover vents to verify the timing marks are correct.
Inside each tube is a small V this will line up close to the indentation on the front side of each cam pulley.
.
Make sure to remove the rear pinch bolt and inspect the drive shaft to verify it is centered in the slot,
and the bolt is not damaged. reinstall the rear pinch bolt firt with a drop of blue loctite and torque to 66 ft/lbs,
then tighten the front pinch bolt after you have pried the flywheel to the rear of the car.
Next remove the intake tubes and put the engine to TDC ,
you can look down the cam cover vents to verify the timing marks are correct.
Inside each tube is a small V this will line up close to the indentation on the front side of each cam pulley.
.
Last edited by Shark2626; 08-01-2019 at 10:23 AM.
02-23-2019, 07:11 PM
#22
Team Owner
i don’t have any experience with the car running,
I bought it this way as a project to build up over time.
the previous owner (my neighbor) told me that it started running rich and that that got worse until it overheated so he parked it, then no start.
I bought it this way as a project to build up over time.
the previous owner (my neighbor) told me that it started running rich and that that got worse until it overheated so he parked it, then no start.
NOTE If this is your starting info then what i would suggest is this.
Note this is for all 87 S4 on,
check the timing belt is timed correctly.
Next would be a crank end play check.
Next verify the battery is fully charged,
Next verify the 4 running relays are working.
Next would be to swap in another MAF
02-23-2019, 07:35 PM
#23
Burning Brakes
Thread Starter
i don’t have any experience with the car running,
I bought it this way as a project to build up over time.
the previous owner (my neighbor) told me that it started running rich and that that got worse until it overheated so he parked it, then no start.
NOTE If this is your starting info then what i would suggest is this.
Note this is for all 87 S4 on,
check the timing belt is timed correctly.
Next would be a crank end play check.
Next verify the battery is fully charged,
Next verify the 4 running relays are working.
Next would be to swap in another MAF
I bought it this way as a project to build up over time.
the previous owner (my neighbor) told me that it started running rich and that that got worse until it overheated so he parked it, then no start.
NOTE If this is your starting info then what i would suggest is this.
Note this is for all 87 S4 on,
check the timing belt is timed correctly.
Next would be a crank end play check.
Next verify the battery is fully charged,
Next verify the 4 running relays are working.
Next would be to swap in another MAF
if I can just figure out why the new fuel pump won’t run unless it is jumped and why the (rebuilt) fuel injectors are not firing. it starts with starter fluid (runs like crap, but it starts). I was wondering if I had a bad “out of the box” new bosch cps sensor, as has been noted by several owners on rl, but I don’t think it would start with starter fluid if that was the case.
Last edited by Shark2626; 08-01-2019 at 10:24 AM.
02-23-2019, 10:58 PM
#24
Chronic Tool Dropper
Lifetime Rennlist
Member
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If the alarm is tripped, you risk these symptoms. For grins -- close all the doors, hood, hatch. using the LONG alarm key (not the red valet key), cycle the driver's door lock to LOCKED, then UNLOCKED, then open the driver's door. If the alarm had been tripped, this should reset it.
02-24-2019, 05:55 PM
#25
Burning Brakes
Thread Starter
If the alarm is tripped, you risk these symptoms. For grins -- close all the doors, hood, hatch. using the LONG alarm key (not the red valet key), cycle the driver's door lock to LOCKED, then UNLOCKED, then open the driver's door. If the alarm had been tripped, this should reset it.
i have literally read about every no start 928 on rl that I could find to try to use their ultimate solutions, none have worked thus far. sadly there are many threads that just end with no update on finding the solutions. I did try the door unlock trick, and then went on to jumping the alarm control box to disable it entirely, no luck.
since I have the covers off of the key 53 relays I can close the circuit with a piece of plastic. I tried that a little bit ago with the non functional LH relay, key off & battery connected. I hear a single closing of something from the engine bay (passenger side I think) when I do that. what would engage when the LH relay is engaged? I kind of want to jumper it and the fuel pump relay and give it a go, your thoughts??
Last edited by Shark2626; 08-01-2019 at 10:24 AM.