I have a 2-litre petrol Rover 420, 12 years old, done 46500 miles. For last few months car only used once or twice a week for fairly short journeys.
Suddenly the engine has started running 'rough' intermittently when accelerating. Get the car out, set off thru' town, every time I accelerate it 'hiccups', shudders, jerks (sometimes with knocks/rattles) then goes OK. Out on the open road going above 30mph then usually OK - slow down/speed up no problem - but if I have to slow down for roadworks, speed-limit etc then the problem usually (but not always) returns. Only solution in town or slow-moving traffic seems to be to run at higher revs and in lower gear than normal, and accelerate very slowly. Car seems to idle OK when stationary - just the usual noises for its age. Any ideas as to possible area of problem please before I have to take it to garage for investigation???
(This may not be relevant,but.... Recently a heater hose came adrift and I lost coolant. Garage drained and refilled, but didn't get rid of all the air-locks, so I've had to top-up a couple of times since then. However coolant levels seem OK now.)
Rover 420 running 'rough'
- paul williams
- Posts: 237
- Joined: Wed Sep 24, 2008 12:47 pm
- Location: Telford,Shropshire
- Contact:
Re: Rover 420 running 'rough'
Hi,
sorry about the late reply, first I should say I haven't had a 400 so the following is only a supposition. I have had the symptoms you describe on a couple of cars and each time it was due to a faulty sensor in the ECU system. Most recently it was a Rover 800 and the fault was with the EGR ( Exhaust Gas Recycler) valve which was not working and effectively shut down the engine.
The symptoms were as you describe, on the 800 it was possible to query the ECU unit and it identified the EGR fault. Replacement cured the problem with the exception of the fact that because of the wrong mixture being sent to the engine it had also destroyed the CAT. In the end the CAT was replaced with a straight through tube and all was well, it still passed the MOT on emissions.
I would suggest therefore that if possible you use the ECU fault finding system to check all is well, if thats possible on the 400, and take it from there.
The following may be of some help, its for a Rover 416 with Honda ECU:
sorry about the late reply, first I should say I haven't had a 400 so the following is only a supposition. I have had the symptoms you describe on a couple of cars and each time it was due to a faulty sensor in the ECU system. Most recently it was a Rover 800 and the fault was with the EGR ( Exhaust Gas Recycler) valve which was not working and effectively shut down the engine.
The symptoms were as you describe, on the 800 it was possible to query the ECU unit and it identified the EGR fault. Replacement cured the problem with the exception of the fact that because of the wrong mixture being sent to the engine it had also destroyed the CAT. In the end the CAT was replaced with a straight through tube and all was well, it still passed the MOT on emissions.
I would suggest therefore that if possible you use the ECU fault finding system to check all is well, if thats possible on the 400, and take it from there.
The following may be of some help, its for a Rover 416 with Honda ECU:
RegardsIf the ECU (found under the passenger seat footwell carpet, behind a metal sheet) finds a fault within the engine management system, it will flash a code on the LED built within the ECU but visible through the peephole in the metal sheet - Long flashes = tens, shorts flashes = units EG 1 long flash = 10, 4 short flashes = 4, 10 + 4 = 14, so you have fault code 14 - if you have the above then a pause, then, for EG 3 short flashes, you have fault codes 14 and 3. It will pause then repeat the same code again if its only the one fault code - heres the codes:
Honda ECU error codes
1 Oxygen Sensor "A" (Primary)
defective circuit or unplugged / defective sensor
2 Oxygen Sensor "B"
defective circuit or unplugged / defective sensor
3 MAP Sensor (Manifold Absolute Pressure)
defective circuit or unplugged / defective sensor
4 CKP Sensor (Crankshaft Position Sensor)
defective circuit or unplugged / defective sensor
5 MAP Sensor (Manifold Absolute Pressure)
mechanical problem / disconnected piping
6 ECT Sensor (Engine Coolant Temperature)
defective circuit or unplugged / defective sensor
7 TP Sensor (Throttle Position)
defective circuit or unplugged / defective sensor
8 TDC Sensor (Top Dead Center)
defective circuit or unplugged / defective sensor
9 CYP Sensor (Cylinder)
defective circuit or unplugged / defective sensor
10 IAT Sensor (Intake Air Temperature)
defective circuit or unplugged / defective sensor
11 CO pot or CO pot Circuit
12 EGR Lift Sensor (Exhaust Gas Recirculation)
defective circuit or unplugged / defective sensor
13 BARO Sensor (Atmospheric Pressure)
defective circuit or unplugged / defective sensor
14 IAC Valve (Idle Air Control)
defective circuit or unplugged / defective sensor
15 Ignition Output Signal
missing or defective ignition output signal
16 Fuel Injector System
defective circuit or unplugged / defective fuel injector
17 VSS (Vehicle Speed Sensor)
defective circuit or unplugged / defective sensor
18 Ignition timing
19 Automatic Transmission Lock Up Control Solenoid Valve
defective circuit or unplugged / defective solenoid valve
20 Electrical Load Detector
defective circuit or unplugged / defective sensor
21 VTEC Solenoid Valve
defective circuit or unplugged / defective solenoid valve
22 VTEC Oil Pressure Switch
defective circuit or unplugged / defective oil pressure switch
23 KS (Knock Sensor)
defective circuit or unplugged / defective sensor
30 Automatic Transmission Signal: "A" / SEAF / SEFA / TMA or TMB
defective circuit or unplugged / defective sensor
31 Automatic Transmission Signal "B"
defective circuit or unplugged / defective sensor
41 Primary Oxygen Sensor - Heater
circuit malfunction
43 Fuel Supply System
defective or malfunctioning fuel supply system
45 System Too Lean or Too Rich
malfunction in the fuel monitoring systems
48 LAF Sensor (Lean Air Fuel)
defective circuit or unplugged / defective sensor
54 CKF Sensor (Crankshaft Speed Fluctuation)
defective circuit or unplugged / defective sensor
58 TDC Sensor 2 (Top Dead Center)
defective circuit or unplugged / defective sensor
61 Oxygen Sensor, Heated - Sensor 1 (Primary)
high voltage, low voltage, or slow response
63 Oxygen Sensor, Heated - Sensor 2 (Secondary)
high voltage, low voltage, or slow response
65 Oxygen Sensor Heater (Secondary)
malfunctioning or defective oxygen sensor heater
67 Catalyst system Efficiency Below Threshold
malfunctioning or defective catalyst system
70 Automatic Transmission
malfunction with the automatic transmission controls
71 Cylinder 1 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire
72 Cylinder 2 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire
73 Cylinder 3 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire
74 Cylinder 4 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire
75 Cylinder 5 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire
76 Cylinder 6 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire
80 Exhaust Gas Recirculation
insufficient flow detected
86 ECT Sensor (Engine Coolant Temperature)
circuit range / performance problem
90 Evaporative Emission Control System
leak detected in the fuel tank area
91 Fuel Tank Pressure Sensor
low input
92 Evaporative Emission Control System
insufficient purge flow
Paul Williams
1929 2litre Saloon
1934 P1 10HP
1951 Rover Cyclops
1974 P6 3500
1998 LR Discovery I
Re: Rover 420 running 'rough'
Welcome to the forum Karsten.
Yes please upload the article, it may help others who are having problems
Yes please upload the article, it may help others who are having problems