Injector Woes

dwleo

New Member
Jan 21, 2002
16
0
1
Vancouver, BC
OK Guys,
This is going to be long in order to explain my problem. (The engine in quesion is a 1992 5.0.)
I had a great summer with my car (hardly any rain) while it was insured for 6 months. No problems - I even got to stop looking at gauges every 30 seconds because it was running so well. (You can see whats coming.)
One day a few weeks prior to coming off the road for winter, I smelt hot coolant, and looking at my gauges saw the water temp was about 230, my voltage was in between 10 and 12 volts and since I was not too far from home I coasted/eased/drove it home. Pulled in the driveway and shut it down. Carefully opened the hood and found I had thrown my serpentine belt. I left the hood open and let it cool down. Next day I replaced the belt and my coolant and started it up. Smoooooth. Kept replacing cooland as it wrmed up until it was topped up. Great!. Then went out of town for 10 days and when I came back, I had only a few days left on the insurance and it was sunny, so away I go. Kept checking the gauges and all seemed fine. Toodeling along and enjoying the time. Then I smelt coolant again. Checked the gauges and the voltage was a little over 13.5 (approx) but my coolant was, again, over the moon. Crap!
Get home, lift the hood and found my filler cap pretending to be Old Faithful! Man, that was hot!
Let it cool down and discovered that when I put it on last time, I missed a lock tab so it could not hold pressure. refilled with coolant again and ....... it would not start. Cranks just fine but won't even hint about catching. Spray gas into intake and I can fire it up and it will stay running. Turn it off and try to restart - nothing, just cranks. Spray gas again and it's fine until I turn it off again.
Items checked so far:
1. Compression. No warped heads from overheating. Cylinders in the 134 range
2. Fuel. Almost 1/2 tank.
3. Fuel Pump. I can hear it cycling when I turn the key on.
4. Fuel pressure. Checked at schrader valve with engine off. Strong spray.
5. Spark. Good spark at plugs.
6. Dizzy. Pulled cap and it was dry. Sprayed water dispersment stuff anyway.
7. Salt & Pepper Shakers. Pulled them apart and cleaned them in case of moisture.
8. TFI. Pulled that off and checked and cleaned.
I hope someone can spot something obvious that I have missed.

Ideas are full welcome and very appreciated.
Thanks.

- Daryl
 
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I may as well say it, if not some else will. You need to pull codes and see what's up. There is a checklist that gets posted here once a month for cranks, but won't start. You might want to search that.

Maybe @jrichker can post it again..
 
Follow this checklist that was put together by @jrichker








Cranks OK, but No Start Checklist for Fuel Injected Mustangs

A word about this checklist before you start: it is arranged in a specific order to put the most likely failure items first. That will save you time, energy and money. Start at the top of the list and work your way down. Jumping around will possibly cause you to miss just what you need to see to find and fix the problem. Don’t skip any steps because the next step depends on the last step working correctly.


Revised 12-Dec-2011 to replace 10 pin salt & pepper connector graphic.

All text applies to all models unless stated otherwise.

Note: 94-95 specific changes are in red
starter-solenoid-wiring-with-test-jumper-gif.86254

1.) Remove push on connector (small red/blue wire) from starter solenoid and turn ignition switch to the Run position. Place car in neutral or Park and set the parking brake. Remove the high voltage coil wire from distributor & and hold it 3/8” away from the engine block. Jumper the screw to the big bolt on the starter solenoid that has the battery wire connected to it. You should get a nice fat blue spark.
Most of the items are electrical in nature, so a test light, or even better, a voltmeter, is helpful to be sure they have power to them.

No spark, possible failed items in order of their probability:
A.) MSD or Crane ignition box if so equipped
B.) PIP sensor in distributor. The PIP sensor supplies the timing pulse to trigger the TFI and injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed. See paragraph 5A – Using a noid light will tell if the PIP is working by flashing when the engine is cranking.
C.) TFI module: use a test light to check the TFI module. Place one lead of the test light on the red/green wire on the ignition coil connector and the other lead on the dark green/yellow wire on the ignition coil connector. If the TFI is working properly, the test light will flash when the engine is cranked using the ignition switch.
D.) Coil
E.) No EEC or computer power - EEC or computer relay failure
86-93 models only: EEC relay next to computer - look for 12 volts at the fuel injector red wires.
94-95 models only: EEC or PCM power relay in the constant control relay module. Look for 12 volts at the fuel injector red wires.
Both 86-93 and 94-95 models: No 12 volts with the ignition switch in the run position on the fuel injector red wires. The relay has failed or there is no power coming from the ignition switch. Make sure that there is 12 volts on the red/green wire on the coil before replacing the relay.
F.) No EEC or computer power - fuse or fuse link failure
86-93 models only: Fuse links in wiring harness - look for 12 volts at the fuel injector red wires. All the fuse links live in a bundle up near the starter solenoid. Look for a 20 gauge blue fuse link connected to 2 black/orange 14 gauge wires.
94-95 models only: 20 amp EEC fuse in the engine compartment fuse box. Look for 12 volts at the fuel injector red wires.
G.) Ignition switch - look for 12 volts at the ignition coil red/lt green wire. No 12 volts, blown fuse link or faulty ignition switch. Remove the plastic from around the ignition switch and look for 12 volts on the red/green wire on the ignition switch with it in the Run position. No 12 volts and the ignition switch is faulty. If 12 volts is present in the Run position at the ignition switch but not at the coil, then the fuse or fuse link is blown.
Note: fuses or fuse links blow for a reason. Don’t replace either a fuse or fuse link with one with a larger rating than stock. Doing so invites an electrical fire.
Ignition fuse links may be replaced with an inline fuse holder and 5 amp fuse for troubleshooting purposes.
94-95 models only: Check inside fuse panel for fuse #18 blown – 20 amp fuse
H.) Missing or loose computer power ground. The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery.
In 86-90 model cars, it is a black cylinder about 2 1/2" long by 1" diameter with a black/lt green wire.
In 91-95 model cars it is a black cylinder about 2 1/2" long by 1" diameter with a black/white wire.
You'll find it up next to the starter solenoid where the wire goes into the wiring harness
I.) Computer.
J.) Bad or missing secondary power ground. It is located between the back of the intake manifold and the driver's side firewall. It supplies ground for the alternator, A/C compressor clutch and other electrical accessories such as the gauges.
K.) Engine fires briefly, but dies immediately when the key is released to the Run position. Crank the engine & when it fires off, pull the small push on connector (red wire) off the starter relay (Looks like it is stuck on a screw). Hold the switch in the crank position: if it continues to run there is a problem with either the ignition switch or TFI module. Check for 12 volts at the red/green wire on the coil with the switch in the Run position. Good 12 volts, then replace the TFI. No 12 volts, replace the ignition switch.

Wiring Diagrams:

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 94-95 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/94-95_5.0_EEC_Wiring_Diagram.gif


AutoZone wiring diagrams: You can navigate to the diagrams yourself via Repair Info | AutoZone.com and select the car year, make, model and engine. That will enable you to bring up the wiring diagram for your particular car.

2.) Spark at coil wire, pull #1 plug wire off at the spark plug and check to see spark. No spark, possible failed items in order of their probability: [/b]
A.) Moisture inside distributor – remove cap, dry off & spray with WD40
B.) Distributor cap
C.) Rotor
D.) Spark Plug wires
E.) Coil weak or intermittent - you should see 3/8" fat blue spark with a good coil

3.) Spark at spark plug, but no start.
Next, get a can of starting fluid (ether) from your local auto parts store: costs a $1.30 or so. Then pull the air duct off at the throttle body elbow, open the throttle, and spray the ether in it. Reconnect the air duct and try to start the car. Do not try to start the car without reconnecting the air duct.

Two reasons:
1.) If it backfires, the chance for a serious fire is increased.
2.) On Mass Air cars, the computer needs to measure the MAF flow once the engine starts.
If it starts then, you have a fuel management issue. Continue the checklist with emphasis of fuel related items that follow. If it doesn’t, then it is a computer or timing issue: see Step 4.

Clue – listen for the fuel pump to prime when you first turn the ignition switch on. It should run for 5-20 seconds and shut off. To trick the fuel pump into running, find the EEC test connector and jump the connector in the Upper RH corner to ground. The EEC connector is near the wiper motor and LH hood hinge.

attachment.php


If the relay & inertia switch are OK, you will have power to the pump. Check fuel pressure – remove the cap from the Schrader valve behind the alternator and depress the core. Fuel should squirt out, catch it in a rag. Beware of fire hazard when you do this. In a pinch, you can use a tire pressure gauge to measure the fuel pressure. It may not be completely accurate, but you will have some clue as to how much pressure you have. If you have any doubts about having sufficient fuel flow/pressure, rent a fuel pressure test gauge from the auto parts store. That will tell you for sure if you have adequate fuel pressure.


4.) No fuel pressure, possible failed items in order of their probability:
A.) Tripped inertia switch – Coupe & hatch cars hide it under the plastic trim covering the driver's side taillight. Use the voltmeter or test light to make sure you have power to both sides of the switch
B.) Fuel pump power relay – located under the driver’s seat in most stangs built before 92. On 92 and later model cars it is located below the Mass Air Flow meter. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
C.) Clogged fuel filter
D.) Failed fuel pump
E.) 86-90 models only: Blown fuse link in wiring harness. Look for 12 volts at the Orange/Lt Blue wire on the fuel pump relay.
91-93 models only Blown fuse link in wiring harness. Look for 12 volts at the Pink/Black wire on the fuel pump relay.
The fuse links for all model years 86-93 live in the wiring harness near the starter solenoid.
94-95 models only: 20 amp fuel pump fuse in the engine compartment fuse box. Look for 12 volts at the Dark green/yellow wire on the constant control relay module.
F.) Engine seem to load up on fuel and may have black smoke at the tailpipe. Fuel pressure regulator failed. Remove the vacuum line from the regulator and inspect for fuel escaping while the pump is running. If fuel is coming out the vacuum port, the regulator has failed. Check the regulator vacuum line for fuel too. Disconnect it from the engine and blow air though it. If you find gas, the regulator has failed.

5.) Fuel pressure OK, the injectors are not firing.
A.) The PIP sensor in the distributor tells the computer when to fire the injectors. A failing PIP sensor will sometimes let the engine start if the SPOUT is removed.
A noid light available from any auto parts store, is one way to test the injector circuit to see if the injectors are firing. The noid light plugs into the fuel injector harness in place of any easily accessible injector. Plug it in and try to start the engine: it will flash if the injector is firing.
B.) I like to use an old injector with compressed air applied to the injector where the fuel rail would normally connect. I hook the whole thing up, apply compressed air to the injector and stick it in a paper cup of soapy water. When the engine cranks with the ignition switch on, if the injector fires, it makes bubbles. Cheap if you have the stuff laying around, and works good too.
D.) Pull an injector wire connector off and look for 12 volts on the red wire when the ignition switch is on.
E.) No power, then look for problems with the 10 pin connecter (salt & pepper shakers at the rear of the upper manifold).

See the graphic for the 10 pin connector circuit layout.
salt-pepper-10-pin-connectors-65-jpg.68512

The injector power pin is the VPWR pin in the black 10 pin connector.


F.) No power and the 10 pin connections are good: look for broken wiring between the orange/black wire on the EEC relay and the red wire for the 10 pin connectors.
G.) TPS voltage exceeds 3.7 volts with the throttle closed. This will shut off the injectors, since the computer uses this strategy to clear a flooded engine. Use a DVM, a pair of safety pins, and probe the black/white and green wires to measure the TPS voltage.
On a 94-95 Mustang, probe the black/white and grey/white wires to measure the TPS voltage.
It should be .5-.1.0 volts with the key on, engine not running. Note that if the black/white wire (signal ground) has a bad connection, you will get some strange readings. Make a second measurement using the battery post as the ground to eliminate any ground problems. If the readings are different by more than 5%, you may have a high resistance condition in the black/white signal ground circuit.

6.) Spark & fuel pressure OK.
A.) Failed IAB or improperly set base idle (no airflow to start engine). Press the throttle ¼ way down and try to start the car. See the "Surging Idle Checklist for help with all your idle/stall problems.
B.) Failed computer (not very likely)
C.) Engine ignition or cam timing off: only likely if the engine has been worked on recently. If you removed the distributor, there is a good probability that you installed it 180 degrees out of time.
D.) Firing order off: HO & 351 use a different firing order from the non HO engines.
HO & 351W 1-3-7-2-6-5-4-8
Non HO 1-5-4-2-6-3-7-8
E.) No start when hot - Press the throttle to the floor & try starting it if you get this far. If it starts, replace the ECT.
F. ) Engine that has had the heads off or valves adjusted. Do a compression test to make sure the valves are not adjusted too tight. You should have a minimum of 90 PSI on a cold engine.
 
OK, here is the latest developement and the new setback (or is it? Hmmmm.)

Worked my way through the checklist and had some readings from the TFI module which were not consistant. So I replaced the TFI module (those aren't cheap!) and tried it. No difference. Drat!
Worked through the checklist again and in checking for power at the injector, I found none where I had some before. Whaaaaaat?
Backed up rechecked the spark at plugs - none. Checked spark at coil and setting the test plug and turning key to 'run' I get a very good single spark. Just turning the key on. But in 'start', no spark. Turn it off and try again. Turn key to 'run' = single spark - turn key to 'start' = no spark. So I pulled my coil to check it. Coil should have a resistance between the incoming leads of .4 ohms to 5 ohms. I had 10 ohms - not in range. Resistance from positive lead to main terminal is suppossed to be 6K ohms to 15K ohms. I have 8K ohms - so within range. Now being 8 ohms out on the primary, is that enough to screw up the spark? Otherwise I am leaning towards the PIP sensor in the dizzy.
But I haven't checked it yet.
 
Check for 12 volts on the red/blue wire on the TFI when you crank the engine using the ignition switch. If it isn't present you have problems with the ignition switch or wiring. Good 12 volts and the TFI is defective The red/blue wire causes the TFI to change its internal settings to give more spark while cranking the engine.

Diagrams courtesy of Tmoss & Stang&2birds

Ignition switch wiring
IgnitionSwitchWiring.gif


Fuel, alternator, A/C and ignition wiring
fuel-alt-links-ign-ac.gif


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

O2 sensor wiring harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangO2Harness.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pin out
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

87-92 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang87-92 PowerWindowWiring.gif

93 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang93PowerWindows.gif

T5 Cutaway showing T5 internal parts
http://www.veryuseful.com/mustang/tech/engine/images/5_Speed_Cutaway_Illustrated.jpg

Visual comparison of the Ford Fuel Injectors, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/Ford_Injector_Guide.jpg
 
OK to date:
Battery is good and have spark at plugs. Fuel is in tank
I have 12v at pump and can make the pump run on by shorting the fuel pump test pin to ground.
The TFI is new as I thought originally that that was the problem. It has 12v and ground showing.
Using noid light shows no pulse at injectors - possible PIP problem
Checked TPS and results are with key on/engine off:
1. VOM lead to ground and piercing black lead - .2v (should be .9 - 1.5v)
also increasing the throttle opening has NO effect on the VOM.
2. VOM lead to ground and piercing red lead - 5.9v (should be 4.5 - 5v)
3. VOM lead to battery positive and piercing green lead - 12v (should be 11 - 12v)

So there is an anomily in the first two tests and possibly in the PIP.
PIP was a candidate for moisture (as is the TPS) when it overheated.

Could it be both? Or is one affecting the other? I wouldn't change out the PIP but rather change the whole dizzy.
Another test????? Change both????
(almost there, I think)
__________________
 
It is quickly narrowing down to the PIP sensor in the distributor. The no pass on the Noid test is the tip off.


PIP Sensor functionality, testing and replacement:
The PIP is a Hall Effect magnetic sensor that triggers the TFI and injectors. There is a shutter wheel alternately covers and uncovers a fixed magnet as it rotates. The change in the magnetic field triggers the sensor. A failing PIP sensor will often set code 14 in the computer. They are often heat sensitive, increasing the failure rate as the temperature increases.

Some simple checks to do before replacing the PIP sensor or distributor:
You will need a Multimeter or DVM with good batteries: test or replace them before you get started.. You may also need some extra 16-18 gauge wire to extend the length of the meter’s test leads.
Visual check first: look for chaffed or damaged wiring and loose connector pins in the TFI harness connector.
Check the IDM wiring – dark green/yellow wire from the TFI module to pin 4 on the computer. There is a 22K Ohm resistor in the wiring between the TFI and the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 22,000 ohms +/- 10%.
Check the PIP wiring - dark blue from the TFI module to pin 56 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the SPOUT wiring – yellow/lt green from the TFI module to pin 36 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the black/orange wire from the TFI module to pin 16 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the red/green wire; it should have a steady 12-13 volts with the ignition switch on and the engine not running.
Check the red/blue wire; it should have a steady 12-13 volts with the ignition switch in Start and the engine not running. Watch out for the fan blades when you do this test, since the engine will be cranking.
If you do not find any chaffed or broken wires, high resistance connections or loose pins in the wiring harness, replace the PIP sensor or the distributor.

The PIP sensor is mounted in the bottom of the distributor under the shutter wheel. In stock Ford distributors, you have to press the gear off the distributor shaft to get access to it to replace it. Most guys just end up replacing the distributor with a reman unit for about $75 exchange

PIP problems & diagnostic info
Spark with the SPOUT out, but not with the SPOUT in suggests a PIP problem. The PIP signal level needs to be above 6.5 volts to trigger the computer, but only needs to be 5.75 volts to trigger the TFI module. Hence with a weak PIP signal, you could get spark but no injector pulse. You will need an oscilloscope or graphing DVM to measure the output voltage since it is not a straight DC voltage.

See http://www.wellsmfgcorp.com/pdf/counterp_v8_i2_2004.pdf and http://www.wellsmfgcorp.com/pdf/counterp_v8_i3_2004.pdf for verification of this little detail from Wells, a manufacturer of TFI modules and ignition system products.
 
OK.. Holidays over and I went and bought a replacement dizzy
No change. Crap.
Here is what is known:
1. gas in tank
2. spark at plugs
3. 12v at pump and cycles when key turned on and relay clicks accordingly
4. TFI Module ground on pin 6 and 12v at start on pin 3
5. 0.9v at TSP
6. eec pin 40 & 60 - no drop when cranking
7. 12v at injectors

The noid light on the injectors only flashes faintly when cranking so I am assuming that:
a) It should be flashing brightly and, if so, then there is a problem in the circuit. or;
b) faint is normal and I will be going crazy(er) or this whole mess.

I am getting soooo tired of this.
 
2/3's there (I think)
Could not figure out how I reverted back to where I couldn't start even when squirting gas into the intake. It turns out that the fuel pump relay was interrmitant and finally decided to not work at all. That and a poor ground got me back to my original problem - no start from 'start' but can run when squirted.
The noid light will flash regularly when running this way and when in the KOEO situation. However, when cranking it flashes very, very lightly. Almost indistinguisable. This situation was present in all the injectors I tested.
Could this be in that same harness (original) that I bypassed the TFI pin6 and EEC pin 16?
 
Just checked the run from the TFI to computer with interesting results.
TFI pin 1 to comp #56 should be 0.2 to 1.5 ohms. Mine reads 6.9 ohms.
TFI pin 2 to comp #36 should be 0.2 to 1.5 ohms. Mine reads a variable 4 - 25 ohms.
TFI pin 3 should be 12 - 13 volts in 'run'. Mine reads 12 - 13 volts.
TFI pin 4 should be 12 - 13 volts in 'start'. Mine reads 12 - 13 volts.
TFI pin 5 to Comp #4 should read 22k ohms (+/- 10%). I got 28.7K which is 4K over but I don't think critical.
TFI pin 6 to comp #16 should be 0.2 to 1.5 ohms. Mine reads 8 ohms.
So TFI pins 1, 2 & 6 are suspect. I'll start replacing those wires and see what transpires unless someone can enlighten me further on this.
I think TFI pin 1 to comp 56 is the most likely as this is the PIP out.