'87 S4 won't start
He stays in touch, and quickly answered all my "silly" questions. 
05-13-2005, 08:48 AM
#17
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By the way Rich, the car is running FANTASTIC......too bad the back end ain't looking too good right now. Should be back on the road with a bruised behing but back by this weekend. 
My problem was stalling, but it always started back up.
My problem was stalling, but it always started back up.
Originally Posted by Rich9928p
Kevin,
I've had several '87 and '88 LH injection modules in recently for rebuilds. Sometimes LHs die quickly, other times they die in many slow ways - death by multiple cuts. The multiple cut death is the worst scenario, because the car can stall and leave you by the side of the road, and then start up later. Shops can charge a lot of money chasing things down. Many shops aren't aware of the LH failure modes and make kludge repairs, such as wiring around the fuel pump relay. Sooner or later the LH always dies, and the mess is larger than ever to clean up.
I provide pretty detailed diagnostic steps for checking out many of the other possible problem areas for no start in the diagnostic section of my website www.electronikrepair.com. One of the LH failure modes is to inject way too much fuel - I saw that with Brett's and JE's LH modules. That can cause other problems downstream. Also, more than one component failure can occur at the same time.
A quick way to tell if your LH is dead is to plug in a known good LH from a friend or regional buddy's 928 into your car. If your 928 starts up and runs great with the test module, you've diagnosed the LH quickly. I test LHs as part of my service.
I've had several '87 and '88 LH injection modules in recently for rebuilds. Sometimes LHs die quickly, other times they die in many slow ways - death by multiple cuts. The multiple cut death is the worst scenario, because the car can stall and leave you by the side of the road, and then start up later. Shops can charge a lot of money chasing things down. Many shops aren't aware of the LH failure modes and make kludge repairs, such as wiring around the fuel pump relay. Sooner or later the LH always dies, and the mess is larger than ever to clean up.
I provide pretty detailed diagnostic steps for checking out many of the other possible problem areas for no start in the diagnostic section of my website www.electronikrepair.com. One of the LH failure modes is to inject way too much fuel - I saw that with Brett's and JE's LH modules. That can cause other problems downstream. Also, more than one component failure can occur at the same time.
A quick way to tell if your LH is dead is to plug in a known good LH from a friend or regional buddy's 928 into your car. If your 928 starts up and runs great with the test module, you've diagnosed the LH quickly. I test LHs as part of my service.
05-13-2005, 10:24 AM
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Thanks for all of the input! I'm going to try testing the MAF and the problem areas listed on Rich's site. If that gets me nowhere, I'll get in touch with Rich regarding getting my LH checked/rebuilt. At least the car died at home...I'm just hoping I don't have to flatbed it to the shop! Also if there's anyone in the Ft. Myers, FL area that would be willing to lend me a brain for testing that would be super...
Now to search the archives on how to check MAF and remove the LH (obviously this is my first time dealing with these items!). Any quick links to info on this would be appreciated.
Thanks again.
Kevin
Now to search the archives on how to check MAF and remove the LH (obviously this is my first time dealing with these items!). Any quick links to info on this would be appreciated.
Thanks again.
Kevin
05-13-2005, 12:27 PM
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Kevin . . . I will be in your area in a couple of weeks. I can roll over in one of the S4's to do the swap. Our move date is 5/27. My guess is you want to drive the shark as soon as possible. But if your stuck know that help is on the way.
HTH
HTH
05-13-2005, 06:43 PM
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Ron, thanks for the offer...I just may take you up on that! I'll try a few other things but if I can't determine anything else I may wait till you're here, then try the brain swap to see if that's the cause.
I also have a fuel pump question...when I turn the key (just before firing the ignition), should I hear the fuel pump fire up? I hear a few relay clicks but that's it right now...I'll check the fuse and relay for the pump again, but maybe it's a fuel pump issue?
Thanks in advance.
Kevin
I also have a fuel pump question...when I turn the key (just before firing the ignition), should I hear the fuel pump fire up? I hear a few relay clicks but that's it right now...I'll check the fuse and relay for the pump again, but maybe it's a fuel pump issue?
Thanks in advance.
Kevin
05-13-2005, 07:41 PM
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Kevin,
Another check, is to see if there is voltage at the fuel pump, when you turn the key on.
Amazingly enough, I too lost my fuel pump! Serious coincidences going on here!
Something else you won't see, until you remove your intake, "dropped" vacuum connections. Maybe knock sensor wiring insulation, that has broken off, exposing wires..... Maybe your idle speed actuator has failed?
I also found the boot between the throttle body and MAF, has a 1.5-2 inch long through crack......
Another check, is to see if there is voltage at the fuel pump, when you turn the key on.
Amazingly enough, I too lost my fuel pump! Serious coincidences going on here!
Something else you won't see, until you remove your intake, "dropped" vacuum connections. Maybe knock sensor wiring insulation, that has broken off, exposing wires..... Maybe your idle speed actuator has failed?
I also found the boot between the throttle body and MAF, has a 1.5-2 inch long through crack......
05-16-2005, 06:01 PM
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Well, the car is now running! I checked and re-checked all related fuses and relays, checked that everything under the hood was connected properly (sensors, plugs, etc.). Verified there is gas in the tank, then popped off the shroud to get at the fuel pump and verified nothing has come loose.
At first the car started and ran for ten or 15 minutes then died (after a restart it ran a few seconds then died). Then yesterday all seemed well; fired it up two different times and took it for a few laps around the block and no issues. Today it fired right up and did fine on a few more laps.
So needless to say I'm happy it's running, but would almost prefer that I'd found something wrong as now I don't know if it'll happen again or not! The only things I found were:
- On the front two-pronged sensor that sits under the strut bar (looks like the one on the back of the intake - temp sensor?), the insulation on the connectors has worn off.
- On the fuel pump, one of the wires leading out is missing some insulation as well (so bare wire is exposed).
I don't know if those could be part of the problem or not, but at this point I'm thinking this is/was an electrical prblem with the fuel pump. If the brain were dead, as it appeared to be, I'd think it would still be dead? As of now, it's as if nothing ever happened...
Also, there is an access panel in the trunk, passenger side under the carpet; is this the in-tank fuel pump (checked this connection as well)? Will the car run only if both pumps are functional, or can it get by on one?
Thanks in advance for any thoughts.
Kevin
At first the car started and ran for ten or 15 minutes then died (after a restart it ran a few seconds then died). Then yesterday all seemed well; fired it up two different times and took it for a few laps around the block and no issues. Today it fired right up and did fine on a few more laps.
So needless to say I'm happy it's running, but would almost prefer that I'd found something wrong as now I don't know if it'll happen again or not! The only things I found were:
- On the front two-pronged sensor that sits under the strut bar (looks like the one on the back of the intake - temp sensor?), the insulation on the connectors has worn off.
- On the fuel pump, one of the wires leading out is missing some insulation as well (so bare wire is exposed).
I don't know if those could be part of the problem or not, but at this point I'm thinking this is/was an electrical prblem with the fuel pump. If the brain were dead, as it appeared to be, I'd think it would still be dead? As of now, it's as if nothing ever happened...
Also, there is an access panel in the trunk, passenger side under the carpet; is this the in-tank fuel pump (checked this connection as well)? Will the car run only if both pumps are functional, or can it get by on one?
Thanks in advance for any thoughts.
Kevin
05-16-2005, 06:17 PM
#23
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Kevin your car has only one fuel pump under the tank ,the thing under the black circle with a fuel line is the level sending unit and the return fuel line.