I'm at a loss here. I spent the whole day tracking down why I had no spark. Figured that out just to find out now I have no fuel. Fuel pump has power. Getting fuel to fuel rail, just not spraying so I can start the car. car will sputter off of starting fluid. I don't know what to do next to figure this out.

 

Year of the car?

 

Its an 87 N/A GXL with 169,xxx miles on the body. The s4 motor took a crap so I got a great deal on a s5 block. I then took all of my s4 parts on the s5 block. Dropped the motor in then nothing. Replaced both coil packs and the cas. Now i have great spark. Will fire up and starting fluid.

 

How are you specifically measuring for injector pulse?

 

I had a tool called a diaod light or something like that. But I figured out the problem. I had a ground wire no connected. It fires right up now. Wont idle at all might be due to bad gas I think. Plus I have a few connectors that I have no idea where they go.

 

what was your issue, where was your ground wire, off.
having the same problem with a car that came from some guy who sold it because he could not figure out the the spark but no fuel issue.

so far I have checked all the common grounds under the hood then the grounds for the ecu at the ecu plugs, also checked the power supply's for the ecu, there all there. still no injector pulse. I also have my 12v to the ecu on each injector wire which tells me the main relay is doing its job when the key is in the run position.

does any one know where pin 2c is suppose to get its ground from, where in the car I mean not on the diagrams.

also I am wondering if there is an ecu schematic, so I can look at where the injector transistors are getting there grounds from, plus I would also like to know where each injector gets its crank signal from exactly. I know there are 4 wire imputs for crank signal but I want to know where they go in the ecu and trace them to there transistor to see which one switch's which ground.

 

updates?

 

 

have you found the solution yet? I’m having this same problem new fuel pump new injectors the fuel rails get gas and there is spark but it does not start

 

i have swapped the ecu the injector resistor the pump regrounded all the grounds and added ground to the ecu i finally gave up and parked it in the field next to my office someone told me it could be in the ignition my only guess would be that its that or the ecu i swapped was bad as well but the weird thing is it was running off of one side before and now nothing also if i take the leads from the computer to the injectors and tap them to ground it will fire right up the cass is good bcause the rpm gauge jumps i have no idea everyone that gets it theres running just says oh i found a ground and it fixed it well i have grounded everything i know to ground let me know

 

Confirm what injectors you're running either by color and connector shape, and/or part number. Low impedance injectors should be ran with resistor packs, high impedance injectors should be ran without resistor packs.

Check and see if you have spark. If you dont have injector pulse or spark, you may have a bad CAS or connection to the CAS. Just read you have RPM pulse

ECU gound is near the transmission on the passenger side IIRC

 

ok so i gave up on this car a while but im about to tackle it again as a recap i have regrounded every factory ground again swapped resistors 2 different sets of injectors swapped ecu grounded the ecu with another ground new fuel pump has fuel pressure and i skinned the 2 green wires from the ecu that send pulse and put a wire on each if u tap it to the frame it fires right up so the ecu is not sending the pulse if and if the wire were grounded from ecu to injector would spray all the time i have noid light it no pulse i have been told there is some kind of ground from the ignition or signal of some sort to the ecu i even took the ecu apart and i know a little bit about circuit boards no melted anything so is there another way to get ground pulse maybe upgrade something in the fuel system and mine is the non turbo model
any ideas cause the only thing i can think is that i have 2 bad computers or whatever goes into the ecu to tell it to pulse is bad would appreciate any thoughts thanks

 

do they not teach punctuation where you're come from?

 

Yeah that was giving me a headache.

Are you getting spark? It's not likely you have 2 bad ECUS. Have you tested your CAS? Checked for power at the ECU?

 

yes i have checked the cas
it runs fine if you spray it with brake kleen or when u tap the green wires for a pulse

 

Try jumping 12v to the fuel pump while youre trying to start it and see if it runs.

 

So like i said earlier i had given up on the car for a while and left it sitting in the field with my other get to later projects . Now I am back on the case got the car home charged the battery up and tried it just to see if it magically would start running as the others in this thread have done it did not . So i sprayed a little brake clean in the intake and just as before she fired right up. My next move was to try the 12 volt to the fuel pump trick that did nothing . The problem is no ground pulse from the ecu . my question is what wire from the ignition to the ecu powers on to tell it to pulse or where and what wire does the signal come from ? Because i have checked and regrounded every wire and added extra wires . I have skinned the 2 green wires that go to the injectors and tapped them to ground while starting the car and it will fire right up and noid lit it . I am pretty sure if i get the ecu to do its job im gold but have no idea where to go next . Any help would be greatly appreciated.
Thanks

I forgot one thing when i first got the car it ran but only off half the motor and it sat in my old junkyard for 2 years before anyone touched it again .

 

I am getting the exact same problem. 1989 S5 n/a I have spark, SAFC is reading RPM, TPS and the maf. I have a solid ground to the ECU. The ECU is getting a solid 12v. The Injector plug has 12v. The ground pin from the injector to the ecu is making perfect contact. Noid light displays no pulse, engine doesn't start. Waiting for someone to read entirely to understand that everything is working but the ECU is NOT sending a ground pulse to fire the injectors. I am waiting on an ECU to show up later today and I will respond with my findings.

 

Did it fix it i think i ordered a bad used one myself and either im gonna order another one or just get an after market injection set up let me know how u ended up

 

It ended up being no power to the injectors. Somehow through the computer, it sends 12v so you may see 12v at the injector, but it's not enough to actually operate the injectors. I have a swap, so after I found it in the fsm, I put power to the two b/y wire i believe on one of the plugs by the ecu and it solved my problem. Engine started right up.