Lost in the forest...time for a C4 rebuild
06-29-2020, 08:55 AM
#166
Three Wheelin'
Thanks for the offer! I have work then a commitment later in the evening, but maybe I could cut out a little early.
I dropped the engine and checked my cam timing, 4-6 was off so I reset that side, triple checked everything was in the 1.6-1.8 range (993RS cams). Still not starting, but it’s close. Wondering if my rebuilt injectors are now the issue. They sat for a few months before I installed them (in a ziploc bag), not sure if that would cause issues with them sticking?
At this point, I’m not sure what the issue could be.
I dropped the engine and checked my cam timing, 4-6 was off so I reset that side, triple checked everything was in the 1.6-1.8 range (993RS cams). Still not starting, but it’s close. Wondering if my rebuilt injectors are now the issue. They sat for a few months before I installed them (in a ziploc bag), not sure if that would cause issues with them sticking?
At this point, I’m not sure what the issue could be.
Take one out and hook it up to 12v listen for a very distinct click like operating a nicely made pen. I was not smelling gas after hella cranking, that was also a sign. Did you check for injector signal with a noid light? You can also actuate the injectors using the hammer or clone, along with every other component it talks to.
06-29-2020, 09:30 AM
#167
I don't know if you followed my thread but rebuit injectors that had sat were precisely the cause of a no-start. I sent them back for a re-cleaning.
Take one out and hook it up to 12v listen for a very distinct click like operating a nicely made pen. I was not smelling gas after hella cranking, that was also a sign. Did you check for injector signal with a noid light? You can also actuate the injectors using the hammer or clone, along with every other component it talks to.
Take one out and hook it up to 12v listen for a very distinct click like operating a nicely made pen. I was not smelling gas after hella cranking, that was also a sign. Did you check for injector signal with a noid light? You can also actuate the injectors using the hammer or clone, along with every other component it talks to.
There is plenty of fuel in the rails, so I know fuel is getting at least to the back of the injectors, and I know there's spark.
Just need to make sure the fuel is getting into the engine and the fuel/spark is being delivered at the proper time. I don't have a hammer/clone, unfortunately, so am flying a bit blind there.
06-29-2020, 09:42 AM
#168
Three Wheelin'
I tried a test light, DVM... nothing would read the signal except the Noid Light (did not know such things existed til I needed one). Bob very kindly loaned me one and a set of known good injectors.
BTW if you need a reason to buy cool stuff check out Fluke's auto multimeters, some have injector pulse width reading mode. https://www.fluke.com/en-us/product/...ters/fluke-88v
Do you smell gas from the cranking?
BTW if you need a reason to buy cool stuff check out Fluke's auto multimeters, some have injector pulse width reading mode. https://www.fluke.com/en-us/product/...ters/fluke-88v
Do you smell gas from the cranking?
06-29-2020, 09:54 AM
#169
I tried a test light, DVM... nothing would read the signal except the Noid Light (did not know such things existed til I needed one). Bob very kindly loaned me one and a set of known good injectors.
BTW if you need a reason to buy cool stuff check out Fluke's auto multimeters, some have injector pulse width reading mode. https://www.fluke.com/en-us/product/...ters/fluke-88v
Do you smell gas from the cranking?
BTW if you need a reason to buy cool stuff check out Fluke's auto multimeters, some have injector pulse width reading mode. https://www.fluke.com/en-us/product/...ters/fluke-88v
Do you smell gas from the cranking?
I do smell gas from cranking. The car stumbles and nnneeeaaarrrlllyy starts, but not quite there. I know my injectors worked previously, but am thinking the sitting around gummed them up. We'll see after I get them cleaned/installed.
Fluke makes great stuff, unfortunately after the rebuild and deciding to do a G50 C2 swap there's no money left in the car fund for quite a while.
06-29-2020, 09:58 AM
#170
Three Wheelin'
Without a doubt it could be the injectors. Mine were GLUED shut, there was no vague notions of starting whatsoever. maybe yours are 80% shut etc. who cleaned them? i recall language from at least one of the big places saying install them at the end. but then a lot of the big places have absurd lead times. one of the many reasons I used Sssquid. Also cheaper.
I looked into this before and the summary is yes a test light is not capable. I also debated using this as an excuse to buy an iphone connected scope. But that was a distraction and expense I didn't need at the time.
I looked into this before and the summary is yes a test light is not capable. I also debated using this as an excuse to buy an iphone connected scope. But that was a distraction and expense I didn't need at the time.
06-29-2020, 10:00 AM
#171
Without a doubt it could be the injectors. Mine were GLUED shut, there was no vague notions of starting whatsoever. maybe yours are 80% shut etc. who cleaned them? i recall language from at least one of the big places saying install them at the end. but then a lot of the big places have absurd lead times. one of the many reasons I used Sssquid. Also cheaper.
I looked into this before and the summary is yes a test light is not capable. I also debated using this as an excuse to buy an iphone connected scope. But that was a distraction and expense I didn't need at the time.
I looked into this before and the summary is yes a test light is not capable. I also debated using this as an excuse to buy an iphone connected scope. But that was a distraction and expense I didn't need at the time.
06-29-2020, 02:00 PM
#172
Rennlist Member
Boy my injectors were cleaned years ago by Witchhunter and and just installed then into my engine. I may do that 12v check before trying to start my car. Good tip.
06-29-2020, 05:30 PM
#173
Rennlist Member
I've had injectors sitting for quite a while that worked fine..that was a few years. Were they optimal?-Probably not but certainly not bad enough to cause a no-start condition. I'm just saying that you should continue looking 
06-29-2020, 05:45 PM
#174
I just want an easy solution one of these times. I'll figure it out eventually, just hoping one of the more simple things will be the solution.
06-29-2020, 06:06 PM
#175
Rennlist Member
I had a 90s Mustang that I killed the ECU on that behaved very similarly. In my case, I had mis-wired an o2 sensor extension harness which killed the ECU instantly. We found it by killing a second ECU 
. What I'm getting at is - I have an extra motronic ECU that you can try if you like but you should check your wiring very closely first because the only request I would have is that if you toast it, you buy it
Along those lines of thinking....try disconnecting some of the engine sensors...most of them will not prevent the car from firing - perhaps there's something dead there.
I didn't go all the way back in the thread....but...any chance some of the rockers are too tight? A compression test at this point would tell you a lot.
. What I'm getting at is - I have an extra motronic ECU that you can try if you like but you should check your wiring very closely first because the only request I would have is that if you toast it, you buy it Along those lines of thinking....try disconnecting some of the engine sensors...most of them will not prevent the car from firing - perhaps there's something dead there.
I didn't go all the way back in the thread....but...any chance some of the rockers are too tight? A compression test at this point would tell you a lot.
06-29-2020, 06:11 PM
#176
I had a 90s Mustang that I killed the ECU on that behaved very similarly. In my case, I had mis-wired an o2 sensor extension harness which killed the ECU instantly. We found it by killing a second ECU . What I'm getting at is - I have an extra motronic ECU that you can try if you like but you should check your wiring very closely first because the only request I would have is that if you toast it, you buy it
Along those lines of thinking....try disconnecting some of the engine sensors...most of them will not prevent the car from firing - perhaps there's something dead there.
I didn't go all the way back in the thread....but...any chance some of the rockers are too tight? A compression test at this point would tell you a lot.
. What I'm getting at is - I have an extra motronic ECU that you can try if you like but you should check your wiring very closely first because the only request I would have is that if you toast it, you buy it Along those lines of thinking....try disconnecting some of the engine sensors...most of them will not prevent the car from firing - perhaps there's something dead there.
I didn't go all the way back in the thread....but...any chance some of the rockers are too tight? A compression test at this point would tell you a lot.
I'll try disconnecting sensors one at a time once I get the injectors back tomorrow/installed.
I have hydraulic rockers (993 cams/towers/rockers) in the car, so no risk of them being overtight.
06-30-2020, 01:21 AM
#177
I had another random thought today. Is there a way I could have swapped the L and R bank injector plugs? I’m not sure off the top of my head if the harness is symmetrical or not, it it could be that I brain farted and swapped 1-3 and 4-6 plugs...
06-30-2020, 08:32 AM
#178
Three Wheelin'
Unlikely based on wire lengths and until the 964 (thru 3.2) they were batch fired. Injector timing can be 180 out and the car will run.
do any of your local friends have a hammer clone or scan tool? Some thing that is reassuring about it besides being able to test the injectors is being able to test and actuate many other sensors and things which gives you a degree of confidence in the health of the ICU.
did you rig a fuel pressure test setup?
confirm spark to all six visually and with inductive light?
do any of your local friends have a hammer clone or scan tool? Some thing that is reassuring about it besides being able to test the injectors is being able to test and actuate many other sensors and things which gives you a degree of confidence in the health of the ICU.
did you rig a fuel pressure test setup?
confirm spark to all six visually and with inductive light?
06-30-2020, 08:57 AM
#179
Unlikely based on wire lengths and until the 964 (thru 3.2) they were batch fired. Injector timing can be 180 out and the car will run.
do any of your local friends have a hammer clone or scan tool? Some thing that is reassuring about it besides being able to test the injectors is being able to test and actuate many other sensors and things which gives you a degree of confidence in the health of the ICU.
did you rig a fuel pressure test setup?
confirm spark to all six visually and with inductive light?
do any of your local friends have a hammer clone or scan tool? Some thing that is reassuring about it besides being able to test the injectors is being able to test and actuate many other sensors and things which gives you a degree of confidence in the health of the ICU.
did you rig a fuel pressure test setup?
confirm spark to all six visually and with inductive light?
I don't have a hammer locally, unfortunately. I rented a fuel pressure tester, but it didn't have the correct fitting, going to see if I can borrow one from my friend's shop today.
I have spark at all 6 plugs, confirmed by pulling the wire and plugging in a spark plug.
