| Author | Message | |||
     phil randall Experienced User Username: phil_randall Post Number: 11 Registered: 8-2006 |
can anyone help please. my 1990 turbo r no longer delivers full fuel enrichment when i put my foot down. I have checked with a multimeter the throttle position switch,air pressure transducer,coolant temp sensor,idle speed actuator,ac compressor signal and both crank sensors. the EHA valve appears to work in idle and part load mode but gets no milliamps for full load. All the components that i have checked are within the specifications in the manual with the exception of the air flow potentiometer. the voltage to the air pot is ok at 4.9v but it's output is 1.0v. the warm idle speed is high at about 700rpm and if i reduce the idle speed i get poor cold starts. The motronic fault code 2.1.2.3. "full load switch" can be induced by simply switching the ignition on and pushing the throttle pedal to the floor without the engine running. The motronic ecu has been checked by a specialist and has been returned as "no fault found" im now stumped as to what to do next!! any help would be greatfully recieved. thanks phil | |||
| Udo Hoffmüller Frequent User Username: udo Post Number: 86 Registered: 2-2008 |
Phil, the error message "full load switch" means that full load switch is closed but the engineECU recognizes part load, so the system is using part load map. This may happen because there is a second input for recognizing full load: the kickdown switch. Have a look at the wiring diagramm, in the circuit of the engineECU to the throttle position switch (pin 31 of the plug at the ECU) you will find the kickdown switch involved. Take off fuse F2 A4 and see what happens. Otherwise check the kickdown switch for propper operation. On my car (MCX35566) it worked! Good luck - Udo | |||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2504 Registered: 4-2003 |
Phil, I have had this issue on my KE2 Turbo R, an early fuel-injected car, and similarly on the KE3 Motronic of my Continental R, although the latter has a TPS potentiometer and the former a TPS switch. Yours has the Motronic but with a TPS switch, in between my relevant cars, but the theme applies. In both cases the frustration had been intermittent, but painlessly resolved in minutes by correcting a slightly-poor electrical connection in a wiring plug and socket. At first, wiggling the plug and socket fixed it for a few days, but finally by tinning the male connections of the plug with a soldering iron the problems have gone in each case. In the Continental R it upset all the gearchanges on its 4L80E, made it a gutless wonder, and on both it gave the impression of losing the turbocharger altogether along with having no kickdown behaviour on the 3L80 and the 4L80E alike. My Turbo R has no ECU diagnostics, whilst the diagnostics on the Conti read nothing as the error was a failure where TPS readings were within the acceptable range albeit static. The Conti had failed with the ECU recognising about ½ throttle at all times: no turbo and shocking gearchanges on light throttle. With any luck, you may find a similar minor issue easily solved. RT.   | |||
| Omar M. Shams Prolific User Username: omar Post Number: 245 Registered: 4-2009 |
Richard, Which connector are you talking about? I have the same problem with my 91 Turbo RL. Thanks Omar PS Our Continental Rs are the same colour!! | |||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2508 Registered: 4-2003 |
Omar, I’ll take some pictures when I am near the Turbo R (3-speed 3L80 transmission) again as I drive 300km to my workplace weekly. Below are pictures of a 1993 Turbo RL, the last without the full plastic treatment to destroy the appearance of the motor. The arrangement is similar to that of a 3L80 car's TPS switch although the locations vary. I have pulled the connector in question from underneath the metal duct. On cars with the 4L80E (4-speed with Electric actuation) transmission, this is the connector in question. The lower picture shows the connector at the TPS of the same car: this could give connection problems too I am sure. This TPS (potentiometer) is the area which gave trouble on my Continental R when the connector in the top picture had corroded pins. RT.   | |||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2509 Registered: 4-2003 |
pps: my Conti R is Racing Green code 9520119, a 2-pack paint. If yours is the same, fantastic. Everyone says how terrific it looks, so I hope that they are not just being nice !!  | |||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2510 Registered: 4-2003 |
Incidentally, General Motors renamed the Turbohydramatic 400 (TH400) and called it the 3L80 when the four speed overdrive version, the 4L80E, was introduced. The 4L80E shares most major components with the TH400, apart from the torque converted which locks on the 4L80E, although the sump and filter differ. Rebuild kits have most components in common. GM moved from naming their transmissions TH350, TH700 and the like, to a standardised system with a more meaningful set of codes. 3L80 or 4L80E means: 3 or 4 = 3 or 4 speed L = Longitudinal 80 = 8,000 lb nominal vehicle weight limit E (where denoted) = Electrically actuated gearchanges and pressure modulation Likewise, a 6L80E is a 6-speed variant of the THM400, and is fitted to Holden V8s and the like. Similarly, a 4L60E is nominally for a 6,000 lb vehicle. | |||
| Omar M. Shams Prolific User Username: omar Post Number: 246 Registered: 4-2009 |
Dear Richard, I will break both connections, clean them up and see if that makes any difference. Many thanks for taking the trouble to explain this to me. The colour of your car appeared to be a dark blue when I saw the images for the first time. Mine is indeed Blue. I have since remembered that you did tell me that yours was BRG. These cars are so beautiful that you will be hard pushed to identify any factory colour that makes them look ugly. I am still looking forward to hosting you and fellow enthusiasts here in Dubai. | |||
| Omar M. Shams Prolific User Username: omar Post Number: 247 Registered: 4-2009 |
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| phil randall Experienced User Username: phil_randall Post Number: 12 Registered: 8-2006 |
thanks udo and richard. i have checked and bridged the plug on the ecu side of the connector from the tps which brought the same fault code up. i then substituted the kickdown relay, that made no difference,also with the relay removed it remains the same. i then removed fuse f2 a4 as udo suggested but still the same code appears. All wires seem to have continuity from the components to the ecu plug but i will try to find some more connectors to check and clean. thanks phil | |||
| phil randall Experienced User Username: phil_randall Post Number: 13 Registered: 8-2006 |
hello all, im still at it.. doe's anyone know of a wiring diagram for the kickdown relay and associated components? i have found that with ignition on and relay removed the wire from the throttle position switch to pin 85 of the kickdown relay shows 12v until the full load switch closes, then it goe's to earth. pins 86 and 30 are linked at the relay socket and both are getting 12v when the ignition is on. it would be helpful if it could be confirmed that it's as it should be. thanks phil | |||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2514 Registered: 4-2003 |
Try This.
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| Richard Treacy Grand Master Username: richard_treacy Post Number: 2515 Registered: 4-2003 |
Item 27 in the diagramme is connected to pin 85 of the kickdown relay. Your diagnosis shows this to be correct. Pins 30 and 86 go to +12v ign as you state. Pin 87 connects to the transmission kickdown solenoid. So, possibly your solenoid in the transmission is faulty (a sump-off fix), the relay is faulty, the connections between the relay and transmission are poor, or there is a bad diode. Try connecting at the kickdown relay sockets points 85 and 86 together with a jumper and listen for a click in the transmission. If, with 85 and 86 jumpeered and there is still 12V with the ignition turned on but there is no click, measure for 12V at the transmission connector with the jumper in place and ignition turned on. If there is 12V there, suspect the solenoid. RT. | |||
| phil randall Experienced User Username: phil_randall Post Number: 14 Registered: 8-2006 |
thanks richard with the ignition on and my other half putting her foot down (no change there!) i can hear the gearbox solenoid click. with ign on i have tried closing the full load switch with the kickdown relay removed and still the code 2.1.2.3. appears, i have to check for the code because it doesn't illuminate the check engine light, p.s. i have also swapped relays any thoughts? thanks phil |
