Satan causes intermittent power loss/bucking?

It could be as low as 30-32 psi while cranking or priming.

yea

i feel your waisting time throwing parts at this car... countless dollars your sinking into this problem that isnt fixing your concern,.... Im telling you right now im a ford technician and have sat here for nearly an hour reading every post on this car AND I SAY YOU HAVE AN ELECTRICAL DEMON... and nothing more... check your eec harness where it passes throught the firewall.. check the injector harness for rubbing on anything sharp... if any 12v source grounds out to the ecm it will cause exactly what your complaining about... sometimes it happens sometimes it doesnt...

Ive recently worked on a car where you would drive the car and it would occasionally feel like it had no power, buck, jerk, shutoff, idle bad,, everything your explaining and it ended up being the Hot 12 v signal wire going to the eec relay that powers up the computer... i thought it was something ignition related and started to do exactly what your doing, new coil, distributor, tfi module.. of course i didnt buy new i had other parts laying around to try out,,, but in the end i stopped throwing parts at it and started looking electrical.. as soon as i found the short the car idled perfectly, felt stronger then ever.. all concerns disappeared.. even the dreaded cold start stopped... and foxes are known for not staying running when cold...

give it a shot... stop throwing parts at it ..

I agree its a electrical problem, i got the same problem too amnit: I used to have a huge surging like it had a HUGE cam in it but i hooked up a fuel pump monitor signal since I never did when i did my mass air conversion, and now it runs soo smoooth, hasnt even hinted a surge or anything, its been about 4 days since i did it and so far so good. You have an 89 i think so you should already have this and not worry about it. Where is your timing at???? is it normal, or r u getting a ridiculously high timing like me? (60 degrees advanced ) Mine started doing this as soon as i dropped my new engine in she had this timing problem and my bucking, well the bucking really didnt show up right away it took about a 1,000 miles for the gremlin to show its face at cruising speeds. Im getting a code 18 Spout circuit grounded and i checked all those wires and theyre not grounded, have high resistance or open Also changed the tfi module and no change. I was thinking about the ignition pickup (PIP) besides that and the maf i dont no what else it could be. If you have a friend with a stang, start swapping suspecting parts to figure out what the problem might be. Im curious to see if u have whacky timing also.

A failing fuel pump relay normally sets codes 95 or 96.

Mass air conversion cars can set this code even though there is no problem. The mass air conversion requires the adding of a wire for the fuel pump sense.

For a systemmatic troubleshooting approach, this this:

Cranks OK, but No Start Checklist for Fuel Injected Mustangs

1.) Remove push on connector from starter solenoid and turn ignition switch on. Place car in neutral or Park. Remove coil wire from distributor & and hold 3/8” away from 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.) Coil
C.) TFI module
D.) PIP sensor in distributor
E.) ECC relay next to computer - look for 12 volts at the fuel injector red wires
F.) 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.
G.) Ignition switch - look for 12 volts at the ignition coil red/lt green wire.
H.) Computer

See the following links for wiring diagrams...

http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model cars

http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp for 89-93 model cars

http://www.autozone.com/servlet/UiB..._us/0900823d/80/1d/db/3c/0900823d801ddb3c.jsp for 94-98 model cars


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:
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 ECC test connector and jump the connector in the lower RH corner to ground. See http://www.mustangworks.com/article...c-iv_codes.html for a description of the test connector. 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 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.

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.) Blown fuse link in wiring harness. Look for 12 volts at the Orange/Lt Blue wire on the fuel pump relay. The fuse links live in the wiring harness near the starter solenoid.
F.) Fuel pressure regulator failed. Remove vacuum line from regulator and inspect for fuel escaping while pump is running.

Fuel pressure OK, the injectors are not firing.

A.) A Noid light available from Autozone, is one way to test the injector wiring.
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.

a.) Pull an injector wire connector off and look for 12 volts on the red wire when the ignition switch is on.
b.) No power, then look for problems with the 10 pin connecter (salt & pepper shakers at the rear of the upper manifold).
c.) No power and the 10 pin connections are good: look for broken wiring between the orange/black wire on the ECC relay and the red wire for the 10 pin connectors.


4.) Spark & fuel pressure OK.

A.) Failed IAB (no airflow to start engine). Press the throttle ¼ way down and try to start the car.
B.) Failed computer (not very likely)
C.) Engine ignition or cam timing off: only likely if the engine has been worked on recently).
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.

The ECC relay lives above the computer. It is hard to see & hard to get to unless
you have small hands. I ended up removing the passenger side dash speaker to be
able to see it & help get to it.

Are you getting the 12 volts at the red wire on the injectors? If so, the ECC relay
is working. If not, then either the relay or the fuse link that feeds it has failed.

Are you getting 12 volts at the ignition coil red/green wire with the ignition switch
on? If not either the fuse link or ignition switch has failed. See the second
diagram from Tmoss for more help.

Don't forget the TFI (even though it may be new) as a possible culprit.

See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host) for help on 88-90 wiring

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

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

Diagram courtesy of Tmoss and Stang&2birds.

I vote for the ignition switch. The +12V to the coil and power to energize the starter solenoid do not connect to the PCM.

When my ignition switch acted up and I changed it out it literally flew apart in my hands when I removed it. You'll need a special torx bit with a hole in the center to get the switch out.

Good Luck, Don

Are you getting 12 volts at the ignition coil red/green wire with the ignition switch
on? If not either the fuse link or ignition switch has failed.
Diagram courtesy of Tmoss and Stang&2birds.

Darkwriter77 said:

New ignition switch is in. Cranks and cranks, still no juice to the coil or plugs, still no start. So much for hoping for cheap fixes.

If the new computer doesn't do it, then it's off to Ford with it. Anyone got an industrial-sized bottle of KY Jelly I can borrow for when they surely try to tell me I need a whole new wiring harness, or some other insanely-priced item I haven't yet replaced?

Click to expand...

Look for a failed blue fuse link. It is the one that feeds power to the coil.

Diagram courtesy of Tmoss and Stang&2birds.

I have an extra A9L. If you are interested, PM me.

I know you've checked and cleaned a number of thing including grounds. Did you check the ground from the injector harness to the back of the driver's side cylinder head? I fought similar issues as you, i.e. bucking, missing when cold, dies on cold start. During my head swap, I was removing the injector harness and noticed the ground mentioned above was very dirty. Cleaned it and the ground strap that goes through the same bolt, problem solved. Starts very well in cold weather. Revs to 1500 and settles into a 1100 rpm idle for approx. 90 secs and then to normal idle. Give it a shot its free. Just thought you might have over-looked it.

Good luck and stick with it.