geoff

All

I'm new to mustangs,need some advice.

Recently purchased 93 mustang, was running OK, did general service.
Car has some hesitation issues under accelaration. No codes.
Found small vacuum leak, replaced hoses and PCV, checked screen, now pulling 20 " at idle, temp OK.
I set the timingto 10o BTDC withlight, under these conditions:
[ul][*]at idle[*]at temp[*]with computer removed from circuit by removing the plug in cable (snout ?).[/ul]

Withcomputer in circuit, timingadvances toaround 20 at idle,increaseRPM timing goes to around 35. All seems normal.

Test drive, terrible hessitation, no power, no pinging that I can detect.
Here's what maddening, return to shop,at idle computer has timing sitting at 35 will not drop back down, turnengine off, restart back to 20 at idle. Remove snout, if thats the right term goes back to 10.

Something else bothers me, if I pulla vacuum on the line going to EGR valve it opens, engine pitch changes, butwith vacuum gauge "T" in line I never see vacuum coming from the control solinoid which feeds the EGR at any engine speed. Replaced this solinoid with part from ford, no difference. Checked supply vacuum on solinoid have the 20"

Other observation, exhaust headers seems to run very hot, perhaps due to lack of EGR function, can this explain the crazy timing situation ?

The car has had some work, after market aluminium drive shaft,H pipes, taller gears in back end.
Seems to me computer gone mad, but is not showinganengine check light.
Perhaps it has a non-stock chip ? how can one tell ?
Any ideas ?

r.barn

The EGR shouldnt mess with that.

You did run a code check and KOER test?

The computer will also run a cylinder drop test
to check each cylinder is firing off.

Hopefully Joel5.0 will chime in for you, he's the Ford EFI guru around here.

AdderMk2

replace your TFI module

geoff

Ok, changed the TFI module, timing is more stable, 10 at idle snout out, 15 with snout in, 32-34 under increaed RPM.
Sounds good when you rev it in the shop.
But problem still exists under driving conditions, servere hessitation between 2000-4000 RPM, and lack of power.
Still no check engine light, still no vacuum beling delivered to EGR valve from EV solonoid.

I'm thinking about buying a whole new distributor and ingnition coil ?
Could this be fuel delivery problem ?

r.barn

Would try replacing fuel filter and soaking injectors in injector cleaner overnite first.

stang8689

Cloged injecters will ruin your day

Joel5.0

DIY KOEO/KOER/Cylinder Balance Self-Test ...if you mean no codes as in code 11 KOEO self-test twice, + KOER code and code 90 from a cylinder balance test, need to continue troubleshooting non-EEC possibilities......however, if you mean "no codes" as in no codes are output from the system, that is a problem per se.

The fact that the CEL hasn't turned on, doesn't mean failure codes aren't logged, need to run the self-tests to check if you do have EGR related failures (which will cause the system to simply delete/bypass the EGR function, and will not cause driveability problems), but from the description of the problem, looks like you may have problems with the ignition system (PIP sensor, coil, plug wires, spark plugs).........

geoff

I'm heading to the parts store, i;ve checked my books what is the PIP sensor, is this located inside the distributor ?
I ran the codes, best I could with my digital volt meter,getting KOEO code 11.

aode08

Take your timing light, put it on each spark plug wire while reving 2,000-4,000 from idle.

If you noticed the light flashing slower or skipping(common) in that rpm range instead of flashing constant and faster on all wires as you increase idle, there is a problem.