L28ET not getting injection or spark.
11-05-2009, 11:14 PM
#1
Encyclopedic Knowledge
Thread Starter
Join Date: Aug 2005
Location: Naperville, IL
Posts: 3,316
L28ET not getting injection or spark.
So a few weeks ago, before I had the fuel system finished (this is an S30 swap), we cranked the engine with a plug out and observed visible spark. I finished the fuel system last weekend, cranked it, and it wouldn't start. Pulled a plug to check spark, no spark. No hiss (nor smell) of fuel spraying into the cylinder either.
My background is almost exclusively in the Z32TT, so I don't even know where to start looking here. The only thing I recall changing/moving is the ECU (we mounted it), but I checked the connectors there and they seem tight. I live 250 miles away from the car and only get to work on it every other weekend or so, so I was kinda hoping someone with experience with the L28ET could give a few ideas of where to look when I go back next weekend. I need to get this thing running before snow starts so I can bring it home.
On a different note, when I first fired up the fuel pump and the system started getting pressure, there was a strange rhythmic howling noise coming from the fuel rails... is this normal when an engine's been sitting for a long time? It went away after a few minutes, but it was a sound I had never heard before. I'm gonna order a mechanical fuel gauge to make sure the system is pressurizing properly, but when I pulled the return off to ensure fuel was flowing through the system, it seemed to have adequate pressure.
My background is almost exclusively in the Z32TT, so I don't even know where to start looking here. The only thing I recall changing/moving is the ECU (we mounted it), but I checked the connectors there and they seem tight. I live 250 miles away from the car and only get to work on it every other weekend or so, so I was kinda hoping someone with experience with the L28ET could give a few ideas of where to look when I go back next weekend. I need to get this thing running before snow starts so I can bring it home.
On a different note, when I first fired up the fuel pump and the system started getting pressure, there was a strange rhythmic howling noise coming from the fuel rails... is this normal when an engine's been sitting for a long time? It went away after a few minutes, but it was a sound I had never heard before. I'm gonna order a mechanical fuel gauge to make sure the system is pressurizing properly, but when I pulled the return off to ensure fuel was flowing through the system, it seemed to have adequate pressure.
Last edited by ZLover4Life; 11-06-2009 at 12:13 PM.
11-06-2009, 06:53 AM
#2
On the first issue, it does sound like the ecu isn't getting power. What year is the L28ET? <81's were wired slightly diff than the 82-83>
There is an LED light inside the ecu which can be seen through a looking hole. With the key in the ON position, check to see if it's lit. Also double check any fuses or fuse links to the ecu. And lastly, make sure the coil and holding bracket is securely grounded. The square ignitor on the side of the bracket must be grounded to spark.
As for the hum / howl from the fuel lines... is it old fuel? Dirty? Any aftermarket fuel pressure regulator that could tell you the psi?
There is an LED light inside the ecu which can be seen through a looking hole. With the key in the ON position, check to see if it's lit. Also double check any fuses or fuse links to the ecu. And lastly, make sure the coil and holding bracket is securely grounded. The square ignitor on the side of the bracket must be grounded to spark.
As for the hum / howl from the fuel lines... is it old fuel? Dirty? Any aftermarket fuel pressure regulator that could tell you the psi?
11-06-2009, 12:21 PM
#4
Encyclopedic Knowledge
Thread Starter
Join Date: Aug 2005
Location: Naperville, IL
Posts: 3,316
On the first issue, it does sound like the ecu isn't getting power. What year is the L28ET? <81's were wired slightly diff than the 82-83>
There is an LED light inside the ecu which can be seen through a looking hole. With the key in the ON position, check to see if it's lit. Also double check any fuses or fuse links to the ecu. And lastly, make sure the coil and holding bracket is securely grounded. The square ignitor on the side of the bracket must be grounded to spark.
As for the hum / howl from the fuel lines... is it old fuel? Dirty? Any aftermarket fuel pressure regulator that could tell you the psi?
There is an LED light inside the ecu which can be seen through a looking hole. With the key in the ON position, check to see if it's lit. Also double check any fuses or fuse links to the ecu. And lastly, make sure the coil and holding bracket is securely grounded. The square ignitor on the side of the bracket must be grounded to spark.
As for the hum / howl from the fuel lines... is it old fuel? Dirty? Any aftermarket fuel pressure regulator that could tell you the psi?
Fuel was brand new, filter was brand new, I had just refinished the tank myself, installed brand new 3/8" fuel lines and hoses, and the fuel came out of the return line crystal clear. No aftermarket FPR (could, as a matter of fact, be the 1983 original), but a mechanical fuel gauge is about to be ordered so I can monitor the fuel system (I was hoping I wouldn't need to check that before it was running so I thought I'd hold off on spending the money in case I needed to spend it elsewhere).
11-06-2009, 12:27 PM
#5
One other question... when there was no spark & no fuel, did the fuel pump prime every time you tried to start it? It should prime for 5 sec every time. The pump may not be getting power, which would ether be the relay, or the fuel pump control module (trapezoidal looking box right by the ecu) isn't getting power / isn't grounded.
11-06-2009, 01:36 PM
#6
Encyclopedic Knowledge
Thread Starter
Join Date: Aug 2005
Location: Naperville, IL
Posts: 3,316
... fuel pump control module? Keep in mind, this is an S30 chassis... I wired my simple electric pump (not a 280ZX pump) directly to the original mechanical pump's power/ground wires. And as I said, the system was pressurized (and the pump is audible), so I know there is fuel in the system. It simply wasn't being sprayed into the cylinders.
11-06-2009, 06:45 PM
#8
Intrawebz Wizard
Join Date: Feb 2009
Location: Vernal, UT
Posts: 3,176
... fuel pump control module? Keep in mind, this is an S30 chassis... I wired my simple electric pump (not a 280ZX pump) directly to the original mechanical pump's power/ground wires. And as I said, the system was pressurized (and the pump is audible), so I know there is fuel in the system. It simply wasn't being sprayed into the cylinders.
11-06-2009, 07:54 PM
#12
Intrawebz Wizard
Join Date: Feb 2009
Location: Vernal, UT
Posts: 3,176
11-06-2009, 07:59 PM
#13
Yeppers. No need to check the resistors if there aren't any. 
Page 1 has 81 swap info, page 2 has 82-82 info: http://forums.hybridz.org/showthread.php?t=99620
Page 1 has 81 swap info, page 2 has 82-82 info: http://forums.hybridz.org/showthread.php?t=99620
11-14-2009, 04:09 PM
#18
Über User
Join Date: Sep 2005
Location: lemont, Illinois
Posts: 9,532
yeah it was a very strange noise the fuel made, it had a hard time priming, and this is a 73 so no prime sequence just on or off. the ECU did light up first night, cranked it and good spark. the last night when we tried to start it i didnt get a chance to check for spark but he said there wasn't. its possible we just knocked a wire loose. we gotta check that ECU light again. the fuel pump i suspect might have been so old its BUMED out, or maybe something is up with the FPR/fuel rail...
11-15-2009, 09:57 PM
#23
Taste My Rainbow
Join Date: Feb 2006
Location: LOST VEGAS
Posts: 2,418
Well if you are getting a signal from the CAS to the coil it sounds like it can be the little "ignitor" that is attached to the bracket. Those go bad from time to time. They are expensive to replace, but there is an alternative. Go to the tech section and read about the GM HEI ignition control module. Its a sticky that I made that can help alot. If you are not getting a signal from the CAS to at least the ECU then your CAS can be bad as well. You can swap out the CAS from a Z31 dizzy.
11-16-2009, 09:54 AM
#25
Taste My Rainbow
Join Date: Feb 2006
Location: LOST VEGAS
Posts: 2,418
^^^ Where do you get your info Not completely true? All Carb'd Z's thats true but when it went to Fuel Injection they use the same pump as the s130's.
so that means talking stock now
70-74 4-6 psi
75-83 30+ Psi
My car now is doing around 40 psi
so that means talking stock now
70-74 4-6 psi
75-83 30+ Psi
My car now is doing around 40 psi
