Spark, fuel, compression.. no start
#1
Instructor
Thread Starter
Spark, fuel, compression.. no start
(1980 porsche 928, US. Ljet. automatic)
I have been attempting to trouble shoot my issues by myelf but i am completely stumped!
I am positive of the following: i have spark, and i have compression. I am not 100% sure about the fuel end of things, however my fuel pump is running when the car is turning over, also even if i am not getting fuel from my injectors the cold start valve should be giving enough gas to fire at least, and it has previously been working before my no start issue. I have spark, although as some people may know i replaced my distributor and may have not properly set my timing. If my timing is off shouldnt my car at least backfire? All it does is crank and crank and crank. No firing sounds at all. It should not be a compression issue because i have had the car running in the past and i have had no issues with it. My thoughts have been that the electrical was not getting enough power from a weak battery so i replaced it with a stronger battery and nothing. I have also thought i was flooding my engine so i removed the pump relay and pushed the pedal to the metal while cranking... still nothing.
Some theories of mine are that the air flow meter is not working properly, and also that before cleaning my fuse panel the car ran on the cold start valve but after cleaning and replacing it the car will not start. Anybody know what might be my issue?
I have been attempting to trouble shoot my issues by myelf but i am completely stumped!
I am positive of the following: i have spark, and i have compression. I am not 100% sure about the fuel end of things, however my fuel pump is running when the car is turning over, also even if i am not getting fuel from my injectors the cold start valve should be giving enough gas to fire at least, and it has previously been working before my no start issue. I have spark, although as some people may know i replaced my distributor and may have not properly set my timing. If my timing is off shouldnt my car at least backfire? All it does is crank and crank and crank. No firing sounds at all. It should not be a compression issue because i have had the car running in the past and i have had no issues with it. My thoughts have been that the electrical was not getting enough power from a weak battery so i replaced it with a stronger battery and nothing. I have also thought i was flooding my engine so i removed the pump relay and pushed the pedal to the metal while cranking... still nothing.
Some theories of mine are that the air flow meter is not working properly, and also that before cleaning my fuse panel the car ran on the cold start valve but after cleaning and replacing it the car will not start. Anybody know what might be my issue?
#2
Team Owner
OK lets start with timing put the engine at TDC then remove the cap look and see where the rotor tip is pointing.
It should be centered at the hash mark on the housing.
next check that the finger rotor on the distributor shaft is not turning, its held in place with a roll pin
If thats good then put it back together.
spray some starting fluid into the intake and crank it, if its properly timed then it should start to run.
check the ground strap at the battery replace it if its original, clean the positive terminal connections
Report what you found.
It should be centered at the hash mark on the housing.
next check that the finger rotor on the distributor shaft is not turning, its held in place with a roll pin
If thats good then put it back together.
spray some starting fluid into the intake and crank it, if its properly timed then it should start to run.
check the ground strap at the battery replace it if its original, clean the positive terminal connections
Report what you found.
#3
Instructor
Thread Starter
OK lets start with timing put the engine at TDC then remove the cap look and see where the rotor tip is pointing.
It should be centered at the hash mark on the housing.
next check that the finger rotor on the distributor shaft is not turning, its held in place with a roll pin
If thats good then put it back together.
spray some starting fluid into the intake and crank it, if its properly timed then it should start to run.
check the ground strap at the battery replace it if its original, clean the positive terminal connections
Report what you found.
It should be centered at the hash mark on the housing.
next check that the finger rotor on the distributor shaft is not turning, its held in place with a roll pin
If thats good then put it back together.
spray some starting fluid into the intake and crank it, if its properly timed then it should start to run.
check the ground strap at the battery replace it if its original, clean the positive terminal connections
Report what you found.
#4
Burning Brakes
Follow Stan’s advice. Then, if it starts on the starter fluid and then stalls, you’re not getting fuel. Many possibilities there but extremely common with ljet to have a bad ground (esp the ground on the passenger cam cover) or bad fuel injection relay either of which will prevent injectors from opening. So clean grounds (clean them all wyait as documented in many threads) and try a new relay if the car runs on starter fluid.
#5
Team Owner
Please pay attention and follow these instructions dont discount them because you found a spark.
OK lets start with timing put the engine at TDC,
then remove the cap look and see where the rotor tip is pointing.
It should be centered at the hash mark on the housing.
Next check that the finger rotor on the distributor shaft is not turning, its held in place with a roll pin
If thats good then put it back together.
OK lets start with timing put the engine at TDC,
then remove the cap look and see where the rotor tip is pointing.
It should be centered at the hash mark on the housing.
Next check that the finger rotor on the distributor shaft is not turning, its held in place with a roll pin
If thats good then put it back together.
#6
RL Community Team
Rennlist Member
Rennlist Member
As Stan walks you through this, it's a good idea to make yourself a fuel pump relay jumper to keep in the car at all times, as well as a spare fuel pump relay.
I made my jumper with a switch so I could plug it in and then flip the switch to turn it on or off. I also labeled the wires so I remember which contacts to plug them into. In my 4 years of ownership of my 79 K-Jet car, I've had 2 fuel pump relay failures - a crank but no start at a gas station after filling up where the car had been running just fine on a 120 mile trip with 3 or 4 starts after arriving, and then after a high speed pass of my wife in her 997 where the car died pulling into the neighborhood.
Good luck.
I made my jumper with a switch so I could plug it in and then flip the switch to turn it on or off. I also labeled the wires so I remember which contacts to plug them into. In my 4 years of ownership of my 79 K-Jet car, I've had 2 fuel pump relay failures - a crank but no start at a gas station after filling up where the car had been running just fine on a 120 mile trip with 3 or 4 starts after arriving, and then after a high speed pass of my wife in her 997 where the car died pulling into the neighborhood.
Good luck.
#7
Instructor
Thread Starter
Follow Stan’s advice. Then, if it starts on the starter fluid and then stalls, you’re not getting fuel. Many possibilities there but extremely common with ljet to have a bad ground (esp the ground on the passenger cam cover) or bad fuel injection relay either of which will prevent injectors from opening. So clean grounds (clean them all wyait as documented in many threads) and try a new relay if the car runs on starter fluid.
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#8
Rennlist Member
It appears you don't know if the timing is off and if so how far so, No, it might not backfire.
That fuel pump bypass from Petza looks dandy. Mine looks like this and by comparison is bailing wire, but it works:
#9
Rennlist Member
Just because you hear a fuel pump running doesn't mean you're getting fuel to the injectors. Simplest test is a visual one. After cranking you can pull a spark plug and see if it's wet or not with gasoline. Then go from there in your troubleshooting efforts.
#10
Nordschleife Master
If the timing is way off, it may not back fire.
I know you had an issue being 180 out (firing on the top of the exhaust/intake stroke instead of top of compression).
Is that fixed?
Are you certain what you think is TDC actually is?
Check the distributor position. For that, 'close' is good enough to get it running.
The issue with the ground strap is NOT the connections. Its the ground strap itself. It's not uncommon for the strap (which is a braid of fine wire) to corrode to the point it will not carry enough current. It shows continuity with a meter, but won't carry the load it needs to. One test for this is to run a single jumper cable from the battery to a good ground in the back.
If the car is cranking strongly with the new battery, your strap may be fine
Have you tried starting fluid?
If it fires, that would let you know that the spark, spark timing and cam timing are all ok.
I know you had an issue being 180 out (firing on the top of the exhaust/intake stroke instead of top of compression).
Is that fixed?
Are you certain what you think is TDC actually is?
Check the distributor position. For that, 'close' is good enough to get it running.
The issue with the ground strap is NOT the connections. Its the ground strap itself. It's not uncommon for the strap (which is a braid of fine wire) to corrode to the point it will not carry enough current. It shows continuity with a meter, but won't carry the load it needs to. One test for this is to run a single jumper cable from the battery to a good ground in the back.
If the car is cranking strongly with the new battery, your strap may be fine
Have you tried starting fluid?
If it fires, that would let you know that the spark, spark timing and cam timing are all ok.
#11
Rennlist Member
Try to let go of the frustration. It often takes a lot of patience to resolve all the little issues, and there is always more things that can go wrong than you can think of right away. When you think you have checked all the things that could be wrong and it still does not work, there are two things to do:
0) remember that patience is the difference between you driving a 928 and a Tercel.
1) recheck the things you think you have checked. You could always have overlooked or mis-understood something. Ask a master (Greg B, for example) how many times he double checks everything before he closes up an engine or a transmission. It will be many, because even a master can make a mistake.
2) expand your list of things that could be wrong.
Checking the timing is your next step, and it is free. Be aware that there are two points in the overall rotation of the engine that are TDC, so you may need to pull back a cam sprocket cover to make sure you have the right one. Backfiring is a condition you get when your timing is off a little bit. if it is way off then you can get nothing. Also, when checking timing be aware that sometimes people put the harmonic balancer on backwards which will raise hell with where you think TDC is, so just take a moment to confirm it is correct.
Another thing that might help narrow it down is a 'noid' light that will help you see if your injectors are firing or not. O Reilly rents them for free. They also rent compression gauges for free, if you want to double check this just so you can be confident in something. I like to use a timing light to confirm spark as well check timing, but I don't see them in the free rental.
0) remember that patience is the difference between you driving a 928 and a Tercel.
1) recheck the things you think you have checked. You could always have overlooked or mis-understood something. Ask a master (Greg B, for example) how many times he double checks everything before he closes up an engine or a transmission. It will be many, because even a master can make a mistake.
2) expand your list of things that could be wrong.
Checking the timing is your next step, and it is free. Be aware that there are two points in the overall rotation of the engine that are TDC, so you may need to pull back a cam sprocket cover to make sure you have the right one. Backfiring is a condition you get when your timing is off a little bit. if it is way off then you can get nothing. Also, when checking timing be aware that sometimes people put the harmonic balancer on backwards which will raise hell with where you think TDC is, so just take a moment to confirm it is correct.
Another thing that might help narrow it down is a 'noid' light that will help you see if your injectors are firing or not. O Reilly rents them for free. They also rent compression gauges for free, if you want to double check this just so you can be confident in something. I like to use a timing light to confirm spark as well check timing, but I don't see them in the free rental.
#12
Instructor
Thread Starter
Thanks all for your advice and words of wisdom. I will be sure to double and tripple check that i have everything right. I will rent a compression tester and noid set. I will also be making a pump jumper. I will also be checking my rotor as well as the cam shaft timing marks and time the car correctly! Im hoping to get outside soon to fix my issue summer is coming fast according to the groundhog and i want to be ripping down the streets asap
#13
Instructor
Thread Starter
UPDATE!!! Went outside today in the very hot minnesotan weather (upper 30s) and low and behold she fired up! Took a few turns but she starts!! I will soon be figuring out all if the vaccuum leaks because she idles at around 2k and when i shift into gear it drops around 900 or more. I will also be doing basic maintenance (plug wires,plugs, filters, oil, etc.) i am VERY excited for this summer now! NO MORE HEADACHE!!!