No Start 87 S4 auto
05-13-2016, 03:26 PM
#1
Rennlist Member
Thread Starter
No Start 87 S4 auto UPDATE..Its Alive..Kinda..
Well, I get to start my own "No start thread"
* Engine installed
* New engine harness
* Rebuilt fuel injector harness
* New Speed reference sensor (CPS) Could be suspect
* Grounds cleaned under hood and double grounds to engine.
** Prior to engine pull my ECU (or whatever the fuel system brain is called) died. Currently I have another one known good. (Car ran with it) Could this have gone bad?
* Have good fuel pressure---Tested at end of rail via switched relay jumper.
* No spark on either bank --- via noid light.
* Tach needle jumps.
* Good relays for IV ignition, XX fuel, XXV LH.
* Not sure about electronic ignition XVI..I don't have a new one yet.
A little premature posting but cant get to car today and tomorrow.
Looking for a plan of attack..wanting to see who wants to play along..
Questions before I dig into WSM..Cant access until Sunday..Limited search availability too.
Things gonna do first
1. clean grounds at battery post and CE panel..they look good but I will clean em anyway.
2. Get a new battery..current shows good voltage, but I have had a low battery (Dead cell) give me headaches before with a show of good voltage.
3. Test for voltage at ignition modules. These are original AFAIK
4. test for signal coming from ECU.
5. I dont know how the ign coils get grounded from the bond that goes to the engine..The coils are painted. should I sand a patch off to ground it to the strap?
** Where would I look for voltage before it gets to injectors?
** Would bad temp II, ref sensor, Ignition modules, TPS, no coil ground cause no power at injectors?
** Ways to test
- temp II
- ref sensor
- Ignition modules
- TPS
** Other ways to test ECU besides a loaner unit?
Thanx for all input.
* Engine installed
* New engine harness
* Rebuilt fuel injector harness
* New Speed reference sensor (CPS) Could be suspect
* Grounds cleaned under hood and double grounds to engine.
** Prior to engine pull my ECU (or whatever the fuel system brain is called) died. Currently I have another one known good. (Car ran with it) Could this have gone bad?
* Have good fuel pressure---Tested at end of rail via switched relay jumper.
* No spark on either bank --- via noid light.
* Tach needle jumps.
* Good relays for IV ignition, XX fuel, XXV LH.
* Not sure about electronic ignition XVI..I don't have a new one yet.
A little premature posting but cant get to car today and tomorrow.
Looking for a plan of attack..wanting to see who wants to play along..
Questions before I dig into WSM..Cant access until Sunday..Limited search availability too.
Things gonna do first
1. clean grounds at battery post and CE panel..they look good but I will clean em anyway.
2. Get a new battery..current shows good voltage, but I have had a low battery (Dead cell) give me headaches before with a show of good voltage.
3. Test for voltage at ignition modules. These are original AFAIK
4. test for signal coming from ECU.
5. I dont know how the ign coils get grounded from the bond that goes to the engine..The coils are painted. should I sand a patch off to ground it to the strap?
** Where would I look for voltage before it gets to injectors?
** Would bad temp II, ref sensor, Ignition modules, TPS, no coil ground cause no power at injectors?
** Ways to test
- temp II
- ref sensor
- Ignition modules
- TPS
** Other ways to test ECU besides a loaner unit?
Thanx for all input.
Last edited by firemn131; 05-19-2016 at 11:05 AM.
05-13-2016, 03:48 PM
#2
Team Owner
the fuel computer is called the LH the spark is EZK
best way to test is put your puter into a known running machine.
Why do you suspect a new CPS ?
have you replaced any of the running relays?
http://www.jdsporsche.com/fault%20find.html
best way to test is put your puter into a known running machine.
Why do you suspect a new CPS ?
have you replaced any of the running relays?
http://www.jdsporsche.com/fault%20find.html
05-13-2016, 03:54 PM
#3
Rennlist Member
If you have no sparks anywhere it tends to rule out dual items like the coils unless you have a double jeopardy situation. I suppose EZ units can fail but such seem to be very rare. surely there is someone not too far from you who can help you with a loaner EZ unit?
Rgds
Fred
Rgds
Fred
05-13-2016, 04:04 PM
#4
Rennlist Member
Coils need to be grounded via the hold down strap, the separate ground wires to the engine won't affect operation, a cheep timing light will tell you if you have spark.
Fuel Injectors all get +12v and its the Ground that is switched by the "LH" the "EZK" is for Spark (ecu's).
The Tach jumping is a good indication that something is coming from the CPS (timing pickup on top of upper bell). However it doesn't tell you if you have a good Square wave, it could be a "saw tooth" and that won't work.
So you had a no start issue before you removed the engine?
Temp II won't keep it for starting.
Check for Spark First, it's the easiest to test and this will show a good CPS too.
Then for Fuel, sounds like you have fuel at the rails but unsure if Injection is working.
Remember this is a "batch" fire system, all injectors open and close at the same time.
Edit: "* No spark on either bank --- via noid light."
Noid light is for Injection not spark
Fuel Injectors all get +12v and its the Ground that is switched by the "LH" the "EZK" is for Spark (ecu's).
The Tach jumping is a good indication that something is coming from the CPS (timing pickup on top of upper bell). However it doesn't tell you if you have a good Square wave, it could be a "saw tooth" and that won't work.
So you had a no start issue before you removed the engine?
Temp II won't keep it for starting.
Check for Spark First, it's the easiest to test and this will show a good CPS too.
Then for Fuel, sounds like you have fuel at the rails but unsure if Injection is working.
Remember this is a "batch" fire system, all injectors open and close at the same time.
Edit: "* No spark on either bank --- via noid light."
Noid light is for Injection not spark
05-13-2016, 04:10 PM
#5
Addict
Rennlist Member
Rennlist Member
It's easy to fail the LH ECU when working on the car if you are not careful to charge the battery while disconnected and not try to jump the car or start it with the charger hooked up. I agree that you should test the LH in a running car.
Trending Topics
05-13-2016, 05:36 PM
#8
Addict
Rennlist Member
Rennlist Member
He says no spark but used a noid light which means no injector pulse, and later affirms no injector signal. So maybe no injector pulse.
OP can you clarify what you tested? Any spark test?
OP can you clarify what you tested? Any spark test?
05-13-2016, 06:11 PM
#9
You are not going to get an injector pulse until you get spark. As was said, focus on the no spark issue first.
05-13-2016, 07:19 PM
#10
Addict
Rennlist Member
Rennlist Member
I reiterate:
"No spark on either bank --- via noid light."
"** Where would I look for voltage before it gets to injectors?
** Would bad temp II, ref sensor, Ignition modules, TPS, no coil ground cause no power at injectors?"
One piece of ambiguous info and two references to voltage at injectors. If he used a noid light he was testing injectors and not spark. We should find out if the spark was checked and how.
-Joel.
"No spark on either bank --- via noid light."
"** Where would I look for voltage before it gets to injectors?
** Would bad temp II, ref sensor, Ignition modules, TPS, no coil ground cause no power at injectors?"
One piece of ambiguous info and two references to voltage at injectors. If he used a noid light he was testing injectors and not spark. We should find out if the spark was checked and how.
-Joel.
05-14-2016, 10:06 AM
#11
Rennlist Member
Thread Starter
Ok, Good Morning,
Thanx for the input.
Some clarification and a path forward.
I was mistaken when I said no spark.----Meant no impulse at injector.
i will move forward with the assumption that the ignition modules are good.
I will sand down some of the coatings on coils to get a good path for ground then verify spark.
I have had a new CPS be bad on more than one occasion.
I will go through the process of checking LH.
John S.,
I intend on getting a rebuilt ECU from you. I am waiting until running because of the time clock for warranty..hopefully I will only need to get one from you unless my current loaner is toast also..I probably wont be able to lay on hands until tomorrow..I may have a fellow 928 in the area to try my current ecu in..
The battery was out of car as soon as I started pulling the motor..so, hopefully I didn't fry the loaner ECU also.
Thanks for inputs...
Thanx for the input.
Some clarification and a path forward.
I was mistaken when I said no spark.----Meant no impulse at injector.
i will move forward with the assumption that the ignition modules are good.
I will sand down some of the coatings on coils to get a good path for ground then verify spark.
I have had a new CPS be bad on more than one occasion.
I will go through the process of checking LH.
John S.,
I intend on getting a rebuilt ECU from you. I am waiting until running because of the time clock for warranty..hopefully I will only need to get one from you unless my current loaner is toast also..I probably wont be able to lay on hands until tomorrow..I may have a fellow 928 in the area to try my current ecu in..
The battery was out of car as soon as I started pulling the motor..so, hopefully I didn't fry the loaner ECU also.
Thanks for inputs...
05-14-2016, 11:50 AM
#12
Rennlist Member
Thread Starter
Progress..
So I had a few minutes this morning..
Sanded down circumference on coils..
I now have pulse at injectors..
I will check for spark and ignition when I am able to move it outside..
So I had a few minutes this morning..
Sanded down circumference on coils..
I now have pulse at injectors..
I will check for spark and ignition when I am able to move it outside..
05-18-2016, 08:08 PM
#14
Rennlist Member
Thread Starter
Update.
I removed and reworked the CE panel..It looked good though.
All new fuses and relays. DEOXED
Cant get power to starter through normal sequence.
I have fuel flow
Impulse at injectors and spark..
How do I know...
I got it started for the first time tonight..like first making love..
1. I currently have the FP relay on a switched jumper.
2. I have bypassed starting circuit and switched jumper between start post and pin in the 14 pin to starter.
Starts and sounds amazing..soo loud..I will get a HOA violation..lol
I swapped all relays out and still cant get the starter power when I turn the key..
Maybe ignition switch, but The key does have to be on for it to start and relays activate..
Cant get power to the starter.
good continuity throughout the whole circuit.
Starter was operating with key last week!!
Dive back into theory tonight..
a little closer..
I removed and reworked the CE panel..It looked good though.
All new fuses and relays. DEOXED
Cant get power to starter through normal sequence.
I have fuel flow
Impulse at injectors and spark..
How do I know...
I got it started for the first time tonight..like first making love..
1. I currently have the FP relay on a switched jumper.
2. I have bypassed starting circuit and switched jumper between start post and pin in the 14 pin to starter.
Starts and sounds amazing..soo loud..I will get a HOA violation..lol
I swapped all relays out and still cant get the starter power when I turn the key..
Maybe ignition switch, but The key does have to be on for it to start and relays activate..
Cant get power to the starter.
good continuity throughout the whole circuit.
Starter was operating with key last week!!
Dive back into theory tonight..
a little closer..
Last edited by firemn131; 05-18-2016 at 09:42 PM.
05-19-2016, 02:42 PM
#15
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
There was another no-crank thread in the last week. Need to find it and link it here. It details the diagnostic steps to getting the starter relay to work. Let me search a little...
From LT Texan's thread:
The starter circuit includes a few key (sorry...) things that fall into the relay-relay-relay and ground-ground-ground categories. Add in the ignition switch and the neutral-safety switch, plus the connection pass-through at the 14-pin connector under the hood.
The starter relay gets coil power from the ignition switch via terminal/circuit 50. The 50 designation is generally used for the starter trigger. The other side of the relay coil sees ground through the neutral-safety switch on the side if the gearbox on automatic cars. The ground for that switch is in the spare wheel well. The connector for that switch is in there too. So the order of diagnosis would have you swap a known-good (common recommendation: horn) 53b relay into the starter relay socket. Then clean the ground point in the spare wheel well area, and the connector to the neutral-safety switch. The connector for the speedo sensor on -'89 cars is in there too. DeOxit would be a good method, or at minimum disconnect and reconnect the connectors a few times.
On the power side of the relay: Do the cleaning and DeOxit on the 14-pin under the hood. The last connection to clean is the smaller wire that triggers the solenoid, the connection at the solenoid.
If you continue to have the problem, lift the carpet and cover over the CE panel, and cycle the key to the start position while listening for the starter relay to click. If no click then the problem is in the coil circuit described above, plus it can be the ignition switch. Diagnosis for the coil side includes using your DMM to confirm coil voltage from the ignition switch at the starter relay socket, and a good ground through the neutral-safety switch and the ground connection you cleaned in the spare-wheel well.
If the relay clicks and the starter doesn't crank, your DMM will help you find voltage at the white 50 wire in the 14-pin connector under the hood, and again at the small terminal at the starter solenoid. You can use the DMM from the relay socket to test the loop through the starter solenoid too, including the solenoid coil. With relay clicking but no response from the starter/solenoid, sometimes a firm whack on the solenoid will free it up if it's stuck.
Other things... The neutral-safety switch is configured to close when the gear selector lever is in Neutral or Park position. Immediately on having the no-start condition, try cycling the gear lever completely through all gears a new times, then stop in Neutral and try the key again. The switches fail very rarely, but sometimes a shift cable is worn-stretched to the point where the switch isn't pushed all the way to the end of its travel when Park is selected.
These steps will get you to the problem.
From LT Texan's thread:
The starter circuit includes a few key (sorry...) things that fall into the relay-relay-relay and ground-ground-ground categories. Add in the ignition switch and the neutral-safety switch, plus the connection pass-through at the 14-pin connector under the hood.
The starter relay gets coil power from the ignition switch via terminal/circuit 50. The 50 designation is generally used for the starter trigger. The other side of the relay coil sees ground through the neutral-safety switch on the side if the gearbox on automatic cars. The ground for that switch is in the spare wheel well. The connector for that switch is in there too. So the order of diagnosis would have you swap a known-good (common recommendation: horn) 53b relay into the starter relay socket. Then clean the ground point in the spare wheel well area, and the connector to the neutral-safety switch. The connector for the speedo sensor on -'89 cars is in there too. DeOxit would be a good method, or at minimum disconnect and reconnect the connectors a few times.
On the power side of the relay: Do the cleaning and DeOxit on the 14-pin under the hood. The last connection to clean is the smaller wire that triggers the solenoid, the connection at the solenoid.
If you continue to have the problem, lift the carpet and cover over the CE panel, and cycle the key to the start position while listening for the starter relay to click. If no click then the problem is in the coil circuit described above, plus it can be the ignition switch. Diagnosis for the coil side includes using your DMM to confirm coil voltage from the ignition switch at the starter relay socket, and a good ground through the neutral-safety switch and the ground connection you cleaned in the spare-wheel well.
If the relay clicks and the starter doesn't crank, your DMM will help you find voltage at the white 50 wire in the 14-pin connector under the hood, and again at the small terminal at the starter solenoid. You can use the DMM from the relay socket to test the loop through the starter solenoid too, including the solenoid coil. With relay clicking but no response from the starter/solenoid, sometimes a firm whack on the solenoid will free it up if it's stuck.
Other things... The neutral-safety switch is configured to close when the gear selector lever is in Neutral or Park position. Immediately on having the no-start condition, try cycling the gear lever completely through all gears a new times, then stop in Neutral and try the key again. The switches fail very rarely, but sometimes a shift cable is worn-stretched to the point where the switch isn't pushed all the way to the end of its travel when Park is selected.