5.0 dies and idle surge
James Seagroves
Any ideas about what device/sensor could cause the engine in my 89' GT
to die when I go from about 2000-3000rpm, and depress the clutch, as if
to shift or come to a stop? I can restart it with no problem, and the
engine doesn't die every time. Sometimes when I restart it, the engine
will surge from 500-900rpm, like it wants to cut off, but it will
eventually level off. This occurs with or without the air conditioner
on, but the problem is worse with the AC on. Any input is appreciated!!!
Buddy Seagroves
89' GT
Dave_...@vos.stratus.com
Maybe idle air bypass or TPS.. Did you get the codes out of the computer?
-Dave
Dave_...@vos.stratus.com
SAVE THIS ARTICLE! Go ahead, do it right now. You'll probably want to print
it out too but that can wait a few minutes.
In article <33D992CB...@NOSPAMMINGmindspring.com> MaxWedge <maxw...@NOSPAMMINGmindspring.com> wrote:
> Dave_...@vos.stratus.com wrote:
>
>> Maybe idle air bypass or TPS.. Did you get the codes out of the
>> computer?
>> -Dave
>
> Not yet. How do I get codes from a Ford??
You can (a) take it to a shop, (b) go to any parts store, give them about
$40 and tell them you want to get the diag codes out of your car or (c)
print/follow the article below.
I you go right out and buy one of the code readers, it's probably a real
good idea to read the article below, anyway. Rather than being the generic
"for Ford" info you'll get with a code reader, it's written with the 5.0
specifically in mind.
Also, if you *really* want to know what the computer's up to, there's a
great book called _How to Understand, Service and Modify Ford Fuel Injec-
tion and Electronic Engine Control_ by Charles O. Probst, SAE published
by Robert Bentley, Publishers.
Good luck,
-Dave
Subject: Getting the diagnostic codes out of your EEC-IV.
Below's a copy of an article written by Scott Griffith on how to get the
diagnostic codes out of the computer that controls your engine. This art-
icle has saved me tons of time and money - not to mention the huge quan-
tities of fuel we all know an unhappy 5.0 can suck down.
I run these tests about once a season or whenever something doesn't feel
right and they've never let me down. They're very comprehensive and easy
to run plus you don't have to understand rocket science or be an engineer
to run them. I highly recommend that anybody who wants to keep their engine
happy take the time to read through this.
Many thanks to Scott for entering all this info and allowing me to repost
it here.
Enjoy!
-Dave
Date: Wed, 23 Feb 94 16:03:16 PST
From: Scott.G...@eng.sun.com (Scott Griffith, Sun Lumpyware)
This article was originally written by me for the Northern California
Shelby Club newsletter, and run in a slightly edited form on the
Mustangs Mailing list.
-------------------------------------
Late Model Corner- the EEC-IV Self Tests
The smallblock Ford has come a long way in the last 30 years. In the
simple "good old" days, the hot setup was a sizable Holley and a hot
cam, and carburetion was set up with an eye on the plugs, an ear tuned
for detonation, and a nose near the tailpipe. Many of us have whiled
away a lot of pleasant hours this way over the years. And now we have
come to a time when there is a bleeding computer in there! A computer
that claims to understand how a motor is supposed to work, and that
hides all the fun stuff from us. For those of us with late models, it
seems like the fun is gone forever.
Well, not really. This computer is what makes it possible to hang a
Paxton on our cars with very little more than a couple of wrenches and
a drill, and to set it up for good power without investing a set or
two of melted-down pistons in the effort. It makes the thrash of
rejetting the night before an event, in an effort to get the thing to
run clean now that the new headers are installed, a thing of the past.
And surprisingly, it makes the process of maintaining and
troubleshooting all that federally-mandated pollution plumbing a
relatively easy project. It turns out that the damned thing is our
friend after all, especially once a few simple tricks are learned.
Since I am well known as a hopeless computer weenie, and there's no
way I'll ever be able to beat that rap, that's what this article is about.
I was corresponding with a friend the other day, and he asked a good
question. "I understand that the engine computer of the Mustang can be
accessed, and that error codes can be obtained and looked up in the
Ford manuals, but how are the codes accessed? Do you need some kind of
computer? Is it difficult? I'm not really interested in tuning my
engine right now, just in the error codes."
Nope, it's not high-tech at all. You just need a piece of wire, and
maybe a voltmeter if your car has no Check Engine light, and you can
run the EEC-IV Quick Tests in the privacy of your own garage. These
can give you an amazing wealth of information on the machine's health,
without getting your knuckles dirty, and without pulling one plug or
reaching for the leakdown tester. There are two tests you
can do: the Key-On, Engine Off test (KOEO), and the Key-On, Engine
Running (KOER). The two tests tell you different things, and each has
its place.
In order to run either test, the car has to be fully warmed up
to operating temperature, and the car must be in neutral (both these
steps are critical, or the only codes you will get will be the codes
for "coolant too cold" and "transmission not in neutral"! Also make
sure that the heater and A/C are off, or you'll get the code for "AC
is on", which is the same as the code for "tranny not in neutral"...
To run the tests, you must locate the EEC-IV test connectors. In the
late model Mustang, these are in the engine compartment, right in
front of the driver's side hood hinge. There are two connectors of
interest- one is a 6-pin connector, and the other is a single pin
connector. Both use 1/4" quick disconnect-style terminals, so you'll
probably want to make yourself a jumper about 8" long with a 1/4" male
QD terminal on each end, if you mean to do this often. Otherwise, any
random chunk of wire will do.
Here's the pinout for the EEC-IV connector, looking at it from the
working side (looking into the female terminals). Note that only these
three pins may actually have terminals in them- the other positions
may be empty:
Signal Return
|
V
_________________
/ ___ ___ \
/ \
| ___ ___ ___ ___ |
|___________________|
^ ^
| |
STO FP test
The left pin in the center group of 4 pins is the Self Test Output pin
(STO). The single terminal hanging loose is the Self Test Input pin
(STI). To run the test, you must either have a Check Engine light, or
hook up an analog voltmeter.
If you have the Check Engine light ('87 and later cars), just
watch it during the tests- it will flash the codes. Otherwise, hook up
your voltmeter between the positive terminal of the battery, and the
STO pin above- you'll count its needle sweeps to get the codes. The FP
test pin, when grounded, runs the fuel pump continuously- but that's
just FYI. You won't deal with that pin for these tests.
To enable the KOEO test, connect your wire jumper between the STI pin
(dangling off by itself) and the Signal Return pin above. Then, turn
the ignition on, but don't crank the starter- the EEC-IV will enter
the KOEO test. During this test, 5 things will happen.
First, you'll hear a bunch of clicking for a few seconds as the EEC-IV
exercises its valves and actuators, and takes readings from its
sensors.
Second, if you're using a voltmeter, you'll see a series of very fast
pulses go by- they may register a volt or two. These are the "fast
codes" that the real STAR scan testers use, but they go by too fast
(100x the normal scan rate) to be of any use to us. If you're
watching the CE (Check Engine) light, you won't see anything.
Third, you'll get the on-demand codes- these indicate what the EEC box
has found problems with _at the moment of the test_. They will be
presented to you as either flashes of the CE light, or sweeps of the
needle on the voltmeter. The code 21 would be presented as
flash-flash, pause, flash. The on-demand codes will be presented
twice- if the EEC-IV has found nothing wrong, it will give you code
11, twice:
flash, pause, flash, longer pause, flash, pause, flash.
The flashes and pauses for a given digit are each 1/2 second. The
longer pause between digits are 4 seconds. The longer still pauses
between codes are 6-9 seconds. If you'd like to see a code just to
see what they look like, leave the trans in gear (MT) or drive (AT),
or push in the clutch- and you'll get code 67 repeated twice. If there
is more than one code detected, they will be presented in sequence,
twice: 22, 47, 22, 47.
Fourth, you'll get the separator code. The Ford manuals call this code
10, but you can't see the _absence_ of a pulse for the 0- you'll just
see a 6-to-9 second pause after the last "on-demand" code, then a
single flash.
Fifth, you'll get the "continuous" codes- these are the codes that the
EEC-IV has stored in its non-volatile memory from events that have
occurred while you were driving in the past. Another 6-to-9 second
pause after the separator code, and you'll get another sequence of
2-digit codes that will look exactly like the on-demand codes. If all
is well, you'll once again see 11,11.
So for example- if at some point in the past your throttle position
sensor has wigged out while driving, you'll get a 23 in the continuous
codes. If it's still wigged out at the time you start the test,
you'll see it as a 23 in both the on-demand and continuous codes.
One last item is how to clear the continuous codes, so that you can
see if new ones crop up. This is simply done by disconnecting and then
reconnecting your jumper after all the tests have been run and the
codes have been received.
Pretty simple, _very_ powerful. Unquestionably your friend. Perhaps
there's something to this computer stuff, after all.
To do the KOER test, set the car up as above. Then with the
STI/signal return jumper disconnected, start up and run it at 2000 RPM or
so for two minutes, to thoroughly warm up the EGO sensors and get
everything stable. Shut down, reconnect the jumper, and immediately
restart, and the EEC-IV will go into the KOER test.
Several things will happen. The first is that you'll get the engine ID
code- 2 pulses for a 4-cylinder, 3 pulses for a 6, and 4 for a V8.
Then the EEC-IV will begin playing with its actuators and sensors,
trying to fool them into going to the extremes of their ranges. During
this interval the car will run very poorly at times- it may go rich,
lean, stumble, buck, and do all manner of unpleasant things. This will
last from 6 to 20 seconds.
After this interval, the motor will smooth out and begin an even idle.
You will then see a single flash or sweep of the needle. This is the
Dynamic Response code, which is your cue. After this code, you have 10
seconds to snap the throttle wide open, just long enough to get above
2000 RPM. Once the engine gets above 2000 RPM (it won't take long at
WOT with no load!), release the throttle, and let the engine go back
to idle. This part is lovingly called the "goose test". The EEC-IV
needs to see what happens at high throttle settings to make sure all
of its sensors and actuators work properly, so you get to help out by
goosing it. This test will last from 4-15 seconds.
The goose test is followed by fast codes (which only those of us stuck
with a meter will be able to see, and we can't do anything with them),
followed by the KOER on-demand codes exactly as above. If all was well,
you'll get 11-11. If you didn't goose it enough, you'll get a 77 and
get to do it over again.
At this point you can optionally run the SEFI or Cylinder Balance
test. If you have an '87 or later, lightly tap the throttle (it only
takes a small movement) WOT), and release it. Owners of '86s will have
to go WOT briefly. After a little while, the EEC-IV will begin
cutting the injector to each cylinder in turn, and looking for a drop
in RPM. If there is no drop associated with any individual cylinder,
then there is some problem there (that may or may not be related to
the injection system- you could have a valve problem, or a fouled
plug, or a shop towel stuck in the intake runner, and get the same
effect). This test takes about 90 seconds. If a cylinder is found by
this test to be weak, a single-digit code will be flashed telling you
which one (1-8). If all is well, the code will be 9. If it gives you a
77, it got confused (perhaps you bumped the throttle) and you need to
start over and rerun the test.
'87 and later cars can then rerun the SEFI test after it finished,
again by just tickling the throttle (saves having to go back through
the whole KOER test). It also relaxes the criteria for "fail" with
each retest, so if one cylinder fails the first time but passes the
second, it's only a little weak- whereas if it fails 3 times in a row,
it's profoundly dead. Those of us with '86s have to go back to Square 1 to
rerun, and we don't get this progression of thresholds to help us
troubleshoot.
There's much more to it than this- but that gets way beyond the scope
of one month's article. This is the procedure, to get you started. Next
month's article will document the codes and their meanings. But if
you're really interested in this stuff, this is where the Ford factory
"Engine and Emissions Diagnosis Manual" (the H manual), and/or the
Watson book entitled "How to Tune and Modify Ford Fuel Injection" that
I wrote about last month are needed.
On the other hand, if you just get 11's, then fill the tank and go out
for a flog with my blessings. That's the most likely outcome- luckily
for us enthusiasts, one thing that Ford hasn't changed in the last 30
years is that the smallblock motor is one of the most reliable machines in the
history of Man. And nobody need ever know that you've given in and
become a part time computer weenie, too. Happy testing!
-skod
Copyright 1993 Scott Griffith- All rights reserved.
--
Scott Griffith, Sun Microsystems Lumpyware
expatriate SCCA New England Region Flagging/Communications worker
(and driver, of anything that turns both right and left,
and can pass tech...) Return Path : sk...@sun.COM
Date: Wed, 23 Feb 94 16:03:21 PST
From: Scott.G...@eng.sun.com (Scott Griffith, Sun Lumpyware)
To: chu...@rahul.net
This article was originally written by me for the Nothern California
Shelby Club newsletter, and run in a slightly edited form on the
Mustangs Mailing list.
-------------------------------------
Late Model Corner- the EEC-IV Self Test Error Codes
Well, it's time to grab the bull by the tail and look at the situation
headon. I'm going to try and paraphrase the EEC-IV selftest code
dictionary, and get it online here. Now, note that the codes mean
different things depending upon what model car you have- I'm going to
do a very Mustang-specific thing and list only the meanings for 5.0L
SEFI and SVO 2.3L Turbo applications. So you guys lurking here with
the Escorts, pickup trucks, and SHOs may not find these definitions to
your liking.
Also, these codes are assembled from 4 different sources- the Ford
service self-test code summary guide, the '86 H manual, the Watson
book, and the little book that came with my blinky toy. And they don't
always agree on what means what. So this rev 1.1 list may be
subject to some change!
My thanks to Dan Malek for his kind research into the codes for the
2.3L Turbo motors for the SVO.
In these definitions, the EEC-IV is referred to as the ECA. It's not
only good form, it's less to type.
In parenthesis after the code itself will be flags for the tests
during which it may occur: "o" for KOEO, "r" for KOER, and "c" for
continuous or memory codes. Codes flagged with an asterisk will cause
the MIL (Malfunction Indicator Light, better known as the Check Engine
light) to come on.
EEC-IV Diagnostic Codes, Rev. 1.1 2/25/93
11 (orc): No problems found in this portion of the test
12 (r): ECA could not increase idle speed above normal idle.
Suspect throttle body coking.
13 (r): ECA could not lower idle speed. Suspect Idle Bypass
valve problems.
14 (c): Intermittent PIP signal operation. Suspect
PIP sensor or TFI module, or grounding or interference problems at the
TFI module.
15 (o): ECA ROM test failure- failure is internal to ECA. (c) ECA KAM
(Keep Alive RAM Memory) failure.
16 (r): 2.3 Turbo. ISC can't keep engine from stalling. Check for short
to ground in ISC circuit.
17 (r): 2.3 Turbo. Can't maintain curb idle speed. Check for incorrect idle
adjustment, faulty throttle body, intake air leaks.
18 (r*): Loss of TACH signal from TFI (Thick Film Integration- the
module on the side of the distributor) module to the ECA. There is an
open in the SPOUT circuit. Suspect SPOUT connector.
19 (o): Failure of ECA voltage regulator. Replace ECA.
21 (or): ECT (Engine Coolant Temp) out of range. Coolant is less than
50degF for KOEO, or less than 180degF for KOER, or greater than
250degF for either. If coolant temp is in proper range, suspect ECT
sensor (It won't be, for KOER tests on cars tha have a 160degF
thermostat!)
22 (orc*): MAP (Manifold Absolute Pressure, for speed-density cars) or
BP (Barometric Pressure, for mass-air cars) sensor signal out of
range. Suspect MAP or BP sensor and harness.
23 (or): Closed throttle TP (Throttle Position) sensor voltage out of range.
Suspect TP sensor.
24 (or): ACT (Air Charge Temperature) sensor voltage out of range. Suspect
ACT sensor and harness. 1984-85 2.3 Turbo - Vane Air Flow voltage out of
range.
25 (r): 2.3 Turbo. Knock Sensor failure.
26 (or): VAF (Vane Air Flow, 2.3L Turbo) or MAF (Mass Air Flow) signal out
of range. Suspect sensor and harness.
27 (r): VSS (Vehicle Speed Sensor) voltage too low, IVSC (Integrated
Vehicle Speed Control) test.
28 (r): Servo leaking up, IVSC (Integrated Vehicle Speed Control) test.
28 (or): 1986+ 2.3 Turbo. Vane Air Temperature out of range.
29 (c): VSS (Vehicle Speed Sensor) voltage too low.
31 (orc*): EVP (EGR Valve Position) or PFE (Pressure Feedback EGR)
sensor voltage too low, or EVR (EGR Vacuum Regulator) circuit
problems.
32 (orc): EVP or PFE voltage below closed limit.
33 (rc*): Insufficient EGR flow detected.
34 (orc): EVP or PFE voltage above closed limit during operation.
34 (r): 2.3 Turbo. EGR On/Off not working.
35 (orc*): EVP or PFE voltage too high during operation.
36 (r): Insufficient RPM increase, IVSC test.
37 (r): Insufficient RPM decrease, IVSC test.
38: Not defined for this application.
39: Not defined for this application.
41 (r): EGO sensor voltage always below "lean" on bank #1. (c*): No EGO
sensor transitions detected, bank #1.
41 (c): 2.3 Turbo. EGO read lean for more than 15 seconds while in closed
loop.
42 (r): EGO sensor voltage always above "rich"
42 (c): 2.3 Turbo. EGO read rich for more than 15 seconds while in closed
loop.
43 (c): 2.3 Turbo. EGO read lean for more than 3 seconds at WOT.
44 (r): Problems in the thremactor air system, bank #1. Suspect AIR
pump, diverter valve, solenoids, harness.
45 (r): Thermactor air is always upstream. Suspect diverter
valve, solenoids, harness.
46 (r): Thermactor air unable to dump to atmosphere. Suspect
diverter valve, solenoids, harness.
47 (o): Speed control command switches not working, IVSC test.
48 (o): Speed control command switches shorted to ground, IVSC test.
49 (o): Speed control ground circuit open, IVSC test.
51 (orc*): ECT voltage too high (coolant too cold, circa -40degF!).
Suspect ECT, harness.
52 (o): PSPS (Power Steering Pressure Switch) circuit open. Suspect PSPS,
harness. (r): PSPS did not change states.
53 (orc*): TP sensor voltage too high (indicates WOT condition).
54 (orc*): ACT (air Charge Temperature) sensor voltage too high.
55: Not defined for this appication.
56 (orc*): MAF (VAF for 2.3 Turbo) sensor voltage too high.
57: Not defined for these applications.
58 (o): 1986+ 2.3 Turbo. ACT out of range.
58 (c): 1986+ 2.3 Turbo. VAT out of range.
59: Not defined for these applications.
61 (orc*): ECT voltage too low- indicates coolant temp greater than 250degF.
62: Not defined for this appication.
63 (orc*): TP sensor voltage too low.
64 (orc*): ACT (1984-84 2.3 Turbo, VAT) sensor voltage too low, indicates
intake air temp greater than 250degF.
65: Not defined for this appication.
66 (rc*): MAF (2.3 Turbo, VAF) below minimum test voltage.
67 (o): Clutch switch open, AC left on, transmission in gear.
68 (oc): 1986+ 2.3 Turbo. VAT out of range.
69: Not defined for this appication.
71 (rc): 2.3L turbo only. ECA software reset detected- key power lost.
Check ECA power harness.
72 (r): MAP sensor, insufficient vacuum detected during Dynamic
Response test.
72 (c): 2.3 Turbo. VPWR (Vehicle power to EEC) intermittent.
73 (r): Insufficient goose during Dynamic Response test. Rerun test,
goose it harder. 2.3 Turbo - Faulty Throttle Position sensor.
74 (r): BOO (Brake on/off) action not observed during Dynamic Response
test. We shouldn't see this with the Mustangs.
75 (r): BOO switch always closed.
76 (r): 2.3L Turbo only. Insufficient VAF variation seen during
Dynamic Response test.
77 (r): No goose detected durning Dynamic Respose test. Rerun
test, goose it harder.
78: Not defined for these applications.
79 (o): A/C or defroster on, tranny not in neutral.
81 (o): TAD or AM-2 (Thermactor Air Diverter) solenoid circuit
failure, or SCVNT (Speed Control Vent) circuit failure (IVSC test).
81 (o): 2.3 Turbo. Boost control circuit failure.
82: TAB or AM-1 (Thermactor Air Bypass) solenoid circuit failure.
82 (o): 2.3 Turbo. Check EDF signal to Integrated Controller for short to
ground.
83 (o): 2.3L Turbo only. Check for EDF signal to Integrated Controller for
open circuit.
84 (o): EVR solenoid circuit failure. 2.3 Turbo - Check for EGR solenoid
open circuit.
85 (o): CANP (Canister Purge) solenoid circuit failure.
85 (o): 2.3 Turbo with Automatic (T-Bird). Check for 3-4 shift solenoid
open circuit.
86: Not defined for these applications.
87 (oc): FP relay circuit failure- suspect intertia switch, fusible link,
FP relay.
88 (o): 2.3 Turbo with Automatic (T-Bird). Check converter clutch override
for open circuit.
89: Not defined for these applications.
91 (r): EGO sensor voltage always lean, bank #2. Suspect vacuum leaks,
EGR system, plugs, plug wires, EGO sensor. (c*): No oxygen sensor
transitions detected, bank #2.
92 (r): EGO voltage sensor always rich. Suspect high fuel pressure, CANP
problems, PCV problems, saturated EVAP canister, EGO sensor.
93: Not defined for these applications.
94 (r): Thermactor Air System problem on bank #2.
95 (oc): Fuel Pump Monitor circuit problems, processor to motor
ground. Suspect inertia switch, FP realy, harness.
96 (oc): FP circuit failure, battery to processor.
97: Not defined for these applications.
98 (r): Hard fault present. The ECA is running in FMEM (Failure
Effects Management Mode), so something is royally screwed up that the
KOEO test should have told you about. Rerun KOEO and fix whatever you
find there.
99: Not defined for these applications.
And there you have it. My fingers are _smoking_- that's enough for now.
-skod
Copyright 1993 Scott Griffith- all rights reserved
--
Scott Griffith, Sun Microsystems Lumpyware
expatriate SCCA New England Region Flagging/Communications worker
(and driver, of anything that turns both right and left,
and can pass tech...) Return Path : sk...@sun.COM
Thanks to tn...@mansci.watstar.uwaterloo.ca for sending these along.
----------------- FREQUENTLY USED EEC-IV ABBREVIATIONS -----------------------
A/C Air Conditioning
ACCS A/C Cycling Switch
ACC A/C Clutch Compressor
ACT Air Charge Temperature sensor
ACV Thermactor Air Control Valve
AXOD Automatic Transaxle Overdrive
BOO Brake On/Off switch
BP Barometric Pressure sensor
CANP Canister Purge solenoid
CCO Converter Clutch Override
CFI Central Fuel Injection
CID Cylinder Identification sensor
CKT Circuit
DIS Direct Ignition System
DVOM Digital Volt/Ohm Meter
ECA Electronic Control Assembly (processor, computer)
ECT Engine Coolant Temperature sensor
EDF Electric Drive Fan relay assembly
EED Electronic Engine Control
EGO Exhaust Gas Oxygen sensor (see HEGO)
EGR Exhaust Gas Recirculation system
EGRC EGR Control solenoid or system
EGRV EGR Vent solenoid or system
EVP EGR Position sensor
EVR EGR Valve Regulator
FI Fuel Injector or Fuel Injection
FP Fuel Pump
FPM Fuel Pump Monitor
GND or GRND Ground
HEDF High Speed Electro Drive Fan relay or circuit
HEGO Heated EGO sensor
HEGOG HEGO Ground circuit
HO High Output
HSC High Swirl Combustion, engine type
IDM Ignition Diagnostic Module
IGN Ignition system or circuit
INJ Injector or Injection
ISC Idle Speed Control
ITS Idle Tracking Switch
KAM Keep Alive Memory
KAPWR Keep Alive Power
KOEO Key On Engine Off
KOER Key On Engine Running
KS Knock Sensor
L Liter(s)
LOS Limited Operation Strategy (computer function)
LUS Lock-Up Solenoid
MAF Mass Air Flow sensor, meter or circuit
MA PFI Mass Air Sequential Port Fuel Injection system
MCU Microprocessor Control Unit
MIL Malfunction Indicator Light
MPFI Multi Port Fuel Injection
NDS Neutral Drive Switch
NGS Neutral Gear Switch
NPS Neutral Pressure Switch
OCC Output Circuit Check
OHC Over Head Camshaft (engine type)
OSC Output State Check
PFE Pressure Feedback EGR sensor or circuit
PFI Port Fuel Injection
PIP Profile Ignition Pickup
PSPS Power Steering Pressure Switch
PWR GND Power Ground circuit
RWD Rear Wheel Drive
SC Super Charged (engine type)
SIG RTN Signal Return circuit
SIL Shift Indicator Light
SPOUT Spark Output Signal from ECA
SS 3/4 - 4/3 Shift Solenoid circuit
STAR Self Test Automatic Readout (test equipment)
STI Self Test Input circuit
STO Self Test Output circuit
TAB/TAD Thermactor Air Bypass/Diverter Tandem soleniod valves
TFI Thick Film Ignition system
TGS Top Gear Switch (cancels SIL operation in top gear)
THS Transmission Hydraulic Switch
TP/TPS Throttle Position Sensor
TTS Transmission Temperature Switch
VAF Vane Air Flow sensor or circuit
VAT Vane Air Temperature
VBATT Vehicle Battery Voltage
VM Vane Meter
VOM Analog Volt/Ohm Meter
VPWR Vehicle Power supply voltage (regulated 10-14 volts)
VREF Voltage Reference (ECA supplied reference voltage 4-6 volts)
VSC Vehicle Speed Control sensor or signal
VSS Vehicle Speed Sensor or signal
WAC WOT A/C Cut-off switch or circuit
WOT Wide Open Throttle
Stephen Palmieri
James Seagroves <ing...@bnr.ca> wrote:
>Any ideas about what device/sensor could cause the engine in my 89' GT
>to die when I go from about 2000-3000rpm, and depress the clutch, as if
>to shift or come to a stop? I can restart it with no problem, and the
>engine doesn't die every time. Sometimes when I restart it, the engine
>will surge from 500-900rpm, like it wants to cut off, but it will
>eventually level off. This occurs with or without the air conditioner
>on, but the problem is worse with the AC on. Any input is appreciated!!!
>
>Buddy Seagroves
>89' GT
Had the same problem. When I'd come to a stop and put the clutch in,
the engine would die but would start right up again. I read that it
was most likely the EGR valve. I took it out and tested it and sure
enough it was sticking open. I cleaned it up with some carb cleaner
and haven't had the problem since. I'd reccomend testing it before you
clean it up so you know if it was causing the problem or not. Before
you unbolt it (it's the device located on the back on the throtle
body) make sure you get a gasket to replace the old one. Hope this
helps.
George Shepherd
Also check the idle bypass valve. These get dirty and act up much in the
manner you describe.
Stephen Palmieri <ste...@baja.viis.shr.dec.com> wrote in article
<33eea731...@mrnews.mro.dec.com>...
SEEverist
>Also check the idle bypass valve. These get dirty and act up much in the
>manner you describe.
This is a good one. I had a similar problem and the idle bypass needed to
be cleaned. It is mounted to the front of the throttle body. Just
disconnect the electrical connection, unbolt from throttle body and clean.
It can be taken apart too, it is two pieces. Don't lose the o-ring. I
clean this a few times a year. Also while your there, clean out the
throttle body too.
You can also have another person depress the throttle all the way down to
see if the butterfly is opening all the way under full throttle. This
however has nothing to do with your stalling, but it may help your w.o.t.
performance.