| Author | Message | ||
     Scott Scott (Scottoz) Member Username: Scottoz Post Number: 51 Registered: 02-2003 |
My 95 is idleing up and down - eratic idle. I discontected the stepper motor and it made a difference - it stopped the fluctation but idled high; I then reconnected the stepper motor and it idled eratically again. I then disconected the Hot wire air mass sensor and it made absolutely no difference. I assume therefore that the air mass sensor has gone out to lunch (I had a backfire that may have killed it). Does that sound right, and at what cost to replace it. I also have an intemittent hot and cold start problem. Engine spins well but no fire. No sparke on test. Coil not firing. I have put all new connections on coil - they are solid. When I move the harness leading to the coil around, it will then start straight away - has anyone had the same problem - could there be a crack in one of those small diamter wires leading to the coil. It is intermittent - about once every 2 days. When it starts it then runs very well except at idle (see above)••••••• thoughts? Cheers all. | ||
| Andy Thoma (Andythoma) Member Username: Andythoma Post Number: 205 Registered: 01-2003 |
Have you tried cleaning the stepper motor and the emission (breather) lines yet? | ||
| Scott Scott (Scottoz) Member Username: Scottoz Post Number: 52 Registered: 02-2003 |
Andy - I have cleaned the stepper motor, but not breather lines - what are they and where can I find them? Thanks mate | ||
| Scott Scott (Scottoz) Member Username: Scottoz Post Number: 53 Registered: 02-2003 |
There is plenty of material in the archives about the stepper motor, but not about the hot wire AMS. | ||
| Shaun Power (Shaunp) New Member Username: Shaunp Post Number: 2 Registered: 05-2003 |
I reckon your the amp module on the distributor is stuffed for a start. Try setting the base idle as well after cleaning the stepper. | ||
| Andy Thoma (Andythoma) Member Username: Andythoma Post Number: 206 Registered: 01-2003 |
On the left head cover is a reusable crank case breather or PVC valve. Attached to it is a series of hoses that goto a common T-piece and to the thottle body and such. Rovers North sells an emission kit, thats basically those pieces. Cleaning those could help, but is you already cleaned the stepper, I doubt they are your problem. I pulled mine and cleaned them out with carb cleaner. Check the resistance of the stepper motor and replace if needed. I can't remember the output but I think it should be like 60 ohms? I replaced mine with a GM part used in Gm truck on the 5.7l v-8. I believe the part number can be found in the tech section under part numbers. The cost was like $25 US, way better than the $150 the dealer wanted for that LR box it comes in. Personally I'd try the resistence test on the stepper motor first. Have you checked the ETCS or engine coolant temp sensor or the fuel temp sensors? That could be your hot/cold start issues. Also check your fuel pressure when the truck is hot and cold. Could be an intermittant fuel pump or clogged fuel filter. My truck had a hot idle problem I convinced that my issue was spark related, turned out my 95 had a bad fuel pump that was going in and out. A US spec 95 I don't think it has one of those amp modules, I think they came in 96 on. | ||
| Andy Thoma (Andythoma) Member Username: Andythoma Post Number: 207 Registered: 01-2003 |
Also the MAF, if it isn't throwing a code to the obd-1 display, it probably is okay. | ||
| Scott Scott (Scottoz) Member Username: Scottoz Post Number: 54 Registered: 02-2003 |
thanks for that - I will do the checks. Cheers. S PS - Will post the results | ||
| Daniel B. Brown (Bbrown) New Member Username: Bbrown Post Number: 3 Registered: 05-2003 |
Get a buddy with a lab scope to scope the IAC and the MAF . | ||
| Scott Scott (Scottoz) Member Username: Scottoz Post Number: 58 Registered: 02-2003 |
Dealer says AMS is stuffed - that seems right to me. Stepper is OK after a clean but is not getting right signals from AMS. Module in Distributor seems ok. Dealer says Rover Air Mass Sensor is $1300 OZ byt a reconditioned one is the one he reccomends at $650 OZ. | ||
| Roland Kutasi (Disco1) Member Username: Disco1 Post Number: 136 Registered: 10-2002 |
Let me get this right, but you did mention that you weren't always getting a spark, however, when you move the harness around that leads to the coil the engine would start? I would suspect a broken wire. Have you checked this possibility? It's a lot cheaper fix than a AMS. | ||
| Grant Lawson (Grant) Member Username: Grant Post Number: 67 Registered: 01-2003 |
What does the stepperr motor do, and any pics? | ||
| Shaun Power (Shaunp) New Member Username: Shaunp Post Number: 13 Registered: 05-2003 |
Grant the stepper is a throttle bypass valve that maintains idle speed when throttle is closed.It is common for this to gum up with crap and stick normally causes eratic idle speed and stalling. I clean them on ever service. | ||
| Jared Schnelle (Jared) Member Username: Jared Post Number: 107 Registered: 09-2002 |
Grant, as for what they look like, it has a 4 wire multi-plug that hooks into the back of it. It is threaded and is about 1 inch in diamater. There is a 1 1/4inch nut(plastic) that you use to tighten it, this makes it look like a really big spark plug. If you look at your Plenum Cover, the thing that says 3.9L on it, at the very back of it, there is a little plate that has a vacuum hose running to it, and that plate is screwed in with 3 allen head screws. Now, threaded into this is the stepper motor. Another way to find it easily is to find the very beginning of the fuel rail, and it's right above that. | ||
| anton venter (Antonventer) New Member Username: Antonventer Post Number: 4 Registered: 05-2003 |
Thanks Jared, good info. When starting my Disco revs go to 1250 and within 5-10second only slowly goes down to 900. Seems like dirty steeper motor (have cleaned stepper)Do tyhis always (cold or HOT) | ||
| Scott Scott (Scottoz) Member Username: Scottoz Post Number: 61 Registered: 02-2003 |
I fixed the sparke - the start up problem was co-incental it would seem - by the time of opened the bonnet and waggled the wires, that was enough time for the AMS and Stepper to do their thing on the second crank and get enough fuel in for start up. |
