Fleetwood Brougham V8-252 4.1L (1985)
PROM - Programmable Read Only Memory: All Technical Service Bulletins
Engine Controls - Surge or Chuggle at 52-60 MPH
Bulletin No.T
86-8
File in Group
6E
Number
21
Corp. Ref. No.
805 5816-31
Date
Oct. '85
SUBJECT:
REVISED SERVICE PROMS TO IMPROVE 52-60 MPH SURGE OR CHUGGLE
MODELS AFFECTED: 1985 FLEETWOOD BROUGHAM (RWD), ELDORADO, AND SEVILLE (FEDERAL AND ALTITUDE EMISSIONS),
ELDORADO BIARRITZ CONVERTIBLE (NATIONAL AND ALTITUDE EMISSIONS)
The following driveability condition may be noted in some 1985 Fleetwood Broughams, Eldorados, and Sevilles equipped with an HT4100 engine and
Federal (NA5), Altitude (NB2) or National (Eldorado Biarritz Convertible) emissions controls:
1.
Some vehicles may exhibit a 52-60 MPH surge or chuggle under moderate acceleration with the Torque Converter Clutch engaged (MAP
parameter .0.2 at about 85-90 kPa).
BEFORE installing the revised calibration PROM to improve a chuggle or detonation complaint, the following checks must be performed to verify
proper basic engine and/or fuel control operation.
1.
Perform the DFI System Check Chart in Section 6D4, subsection A of the 1985 Seville, Eldorado and Rear Wheel Drive Brougham Service
Information Manual. Diagnose and repair any trouble codes found as well as any fuel system rich or lean indications that may be discovered using
the "Field Service Mode Check" portion of the DFI System Check chart.
2.
Use the Symptoms diagnosis in section 6D4, subsection B of the 1985 Seville, Eldorado and Rear-Wheel-Drive Brougham Service Information
Manual. The symptom diagnosis chart that should be used is "SURGES AND/OR CHUGGLE".
The revised PROM will not repair a chuggle or detonation condition that is the result of a basic engine or fuel system condition. Installation of the
PROM into a car with an engine or fuel system condition will not repair a surge or chuggle -- a customer comeback will be the likely result.
Customers may notice that the TCC does not apply as frequently with the revised PROM calibration as with the original production PROM. In addition
to changing fuel, spark and EGR calibration, the new calibration changes the criteria used to apply TCC as follows:
Original Calibration
New Calibration
1.
Vehicle Speed greater than 48 MPH; 53 MPH;
2.
TPS reading from 6 to 23 degrees; 8 to 16 degrees;
3.
Delay before TCC is applied is 5 Secs. 15 Secs.
In summary, a vehicle equipped with the new calibration must be driven above the minimum speed and within the throttle angle limits specified for at
least 15 seconds before the TCC will apply.
PROM part numbers for 1985 Longitudinal HT4100 cars (excluding California emissions) are as follows:
Retrofit (Revised) PROM
Regular Service Replacement
Use For Surge
Use For Regular PROM
Replacement, Code 51, etc.
Broadcast
Service
Broadcast
Service Number
PROM I.D.
Code
Number
PROM I.D.
Code
"D" FED
1227381 *
103
HYA
16056001
102
HYA
"D" ALT
1227386 *
128
HYH
16056103
127
HYH
"E" "K" FED/MECH
1227382 **
137
DKD
1227382
137
DKD
"E" "K" FED/DIG
1227383 **
167
DKF
1227383
167
DKF
"E" NAT CONV/MECH 1227384 **
138
DKM
1227384
138
DKM
"E" NAT CONV/DIG
1227385 **
168
DKN
1227385
168
DKN
"E" "K" ALT MECH
1227387 **
159
DKK
1227387
159
DKK
"E" ALT CONV MECH 1227387 **
159
DKK
1227387
159
DKK
"E" "K" ALT DIG
1227388 **
189
DKL
1227388
189
DKL
"E" ALT CONV DIG
1227388 **
189
DKL
1227388
189
DKL