no injector pulse== HELP

[blue coupe]

i hope this is in the right area, i need some advice. installed my new motor today and have no pulse. i have power to injectors with the key on, spark, and good fuel pressure. already changed pcm with my friends daily driver pcm, changed complete injector harness. the injector harness ground is grounded and engine to firewall is grounded and battery neg. is directly to block. any advise??

[blue coupe]

oh and i have only 1.5v at orange wire at tps!

[cb84capri]

yes you're in the right area. can you give us more details about the car?

cale

[blue coupe]

it is an 86 coupe. bought it rolling chassis and totally gutted interior even dash. it has the 87-93 dash in it and of course the matching wiring harness. the motor i just built which is a mild 302 fuel injected with a t-5. over time i gathered all the parts to complete mostly used which i had to replace with new. supprised, the fuel pump came on instantly and had spark instantly with no problems! put a noid light in injector connector and no light while cranking. with key on there is 12v at both pins which is normal but no groung while cranking. i am thinking now it could be the module on the side of the distributor, or the pick up coil inside the distributor. gonna pull the spout connector and see if it fires first then go from there.

[jeffcrummel]

Well you said it, module. I was going to ask if you used a noid. A couple of more thoughts, the lead going to the driver in the computer from the module and the driver inside the computer itself. I know you said it was out of your friends DD but...........you just never know till it's eliminated.

[blue coupe]

i just pulled out the spout connector and nothing!

[grabbergreen84]

and had spark instantly with no problems!

Then the pickup is OK. You can have the module tested at a parts store.

[blue coupe]

Then the pickup is OK. You can have the module tested at a parts store.

that is good to know gonna have the module tested tomorrow! thanks, i really want to get this thing running! i have built several mustangs at my shop but never had this problem!

[79turbocobra]

had same issue just bought a new rebulit dist at advanced since buying the parts for the dist were close to the same price.

[TWR2003]

it is an 86 coupe. bought it rolling chassis and totally gutted interior even dash. it has the 87-93 dash in it and of course the matching wiring harness.

Do you mean the car has ALL matching wiring harnesses? Or is the car a hodpodge of different year harnesses. What year is the underdash harness and what year is the underhood harnesses?

BTW there is no such thing as a '87-93' dash. They may look the same but the 87-89 is wired different from the 90-93.

[blue coupe]

engine wiring is a 91. how can ya tell the difference on what year wiring under the dash is?

[blue coupe]

just replaced ignition module and same thing!! i did find out that i have power on only one side of injector with key on. i ohm the ground from main pcm ground on kick panel and ground pin on injector and seems to be open!!

[blue coupe]

just changed out the complete pcm harness with another good harness and the EXACT same thing!! help!!

[JACook]

oh and i have only 1.5v at orange wire at tps!

^^^ I wouldn't replace a single part until you get to the bottom of this.

The ECU supplies +5V to the TPS, MAF, EGR position sensor, and Barometric pressure sensor.
If it's only supplying 1.5V, then either the ECU has issues, or it's not getting full supply
Voltage.

Start by checking the Voltage on the orange/white wire on the other sensors. If they're all
low, try disconnecting them to see if one of them is dragging down the +5V. If that all checks
out, check the ECU input Voltage and grounding.

Oh, and once you find the problem, if the TFI module you replaced was Motorcraft, and the
new one is not, put the original one back.

[TWR2003]

engine wiring is a 91. how can ya tell the difference on what year wiring under the dash is?

Look at this documentation and see if the wiring to the instument cluster matches the 87-89 or 90-93:

http://www.stangnet.com/tech/cluster87-93.pdf

When you turn the key to ON (without trying to start it) does you fuel pump PRIME? The pump should run for 1-2 seconds then shut down.

Is your fuel pump relay on the underhood harness or under the drivers seat?

[blue coupe]

fuel pump stays on, the relay is under the drivers seat

[JACook]

fuel pump stays on, the relay is under the drivers seat

Also a bad sign.

[ngl9766]

Id verify the injector voltages at the 10 pin connectors. They are known for creating gremlins. Also there is a factory splice in the harness about a foot or so from the ecu where pin 37 and 57 come together and form a common wire that goes to the sensors. Verify voltage at either pin to be sure you have the 5 volts required. JA Cook mentioned all the sensors earlier. Disconnect all the affected sensors prior to trouble shooting. If your voltages are then good, then plug in each sensor one at a time until you find the culprit. All your smog stuff powers off the hot lead as well. FWIW when I built my harness I ohm'd each wire and had less than .02 ohms on every wire.

[ngl9766]

Most importantly is your ground especially the one near the ecu. Your computer essentially switches the grounds for every circuit so its super critical that it is installed on a bare metal surface that is clean.

[ngl9766]

Also I just learned that the 86 is an odd animal when it comes to EFI. I am not sure if you went SD or MAF or if your using and 86 harness but I know that their is a set of wires roughly 6ft in length that run under the dash to the 3 prong connector in the drivers side kick panel. This controls your fuel pump and is tied into your tail light harness. A quick search will bring up a few of these threads where the guys did a a freakin awsome job of documenting this info.

[TWR2003]

My theory is I think you may have some mis-matched harnesses. It is possible to have harnesses from different years that will physically mate at all the connectors but actually not have the correct pinouts at those connectors and hence the EEC system will not operate.

A 91 underhood harness should have 2 connectors that connect it to the underdash harness - 8pin round brown (mates in the engine comp), and 8 pin rectangular green (mates in passenger comp near the EEC). I would check that they are connected and that the wires on each side of the connectors maintain the same color code. There should be no connectors that 'go to nothing'.

However, assuming all is correctly harnessed and grounded and you still cannot get 5V on ORG/WHT at TPS, EVP, or MAP/BP and you cannot get a normal fuel pump prime sequence then I would highly suspect a failed EEC. Irregardless of harnesses if you connect the EEC to 12V and ground and cannot get 5+/-.1V (VREF) at pin 26 (ORG/WHT or BRN/WHT depending on harness year) the EEC has failed. Do you have access to a spare EEC that you can borrow to verify?

[TWR2003]

Also there is a factory splice in the harness about a foot or so from the ecu where pin 37 and 57 come together and form a common wire that goes to the sensors. Verify voltage at either pin to be sure you have the 5 volts required.

Pin 37 and pin 57 = VPWR = 12V (not 5V which is VREF = pin 26)

[blue coupe]

ok so far i have replaced pcm and injector harness, verified pcm works because it fired up in another stang, complete distributor, and checked grounds and ohm out ground wires from computer to injector ground side of connector. so far that noid light has not lit up, which we checked the light on another car and it works. gonna borrow a break out box for simplicity and really check each pin. still concerned about the wiring under dash. another concern is 5v reference. this thing is driving me crazy!! i will not give up!!! thanks for all the great info so far!

[TWR2003]

ok so far i have replaced pcm and injector harness, verified pcm works because it fired up in another stang, complete distributor, and checked grounds and ohm out ground wires from computer to injector ground side of connector. so far that noid light has not lit up, which we checked the light on another car and it works. gonna borrow a break out box for simplicity and really check each pin. still concerned about the wiring under dash. another concern is 5v reference. this thing is driving me crazy!! i will not give up!!! thanks for all the great info so far!

Good work.

Do me a favor. Pull the connector from the TFI module on the distributor. Also disconnect the small RED/BLU wire from the starter relay (so the engine will not crank). On the TFI connector check the RED/GRN wire for 12V in RUN and START. Check the RED/BLU wire for 12V in START only.

[blue coupe]

oh yeah is there a purpose for the extensions on the salt and pepper shaker connectors?? is it just an extension or do the pins change locations inside the extension??