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New To Me 850r Running Very Badly!


Matts 850 GLT

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Hi

Just got a 96 855 R auto - it runs very badly. It tries to stall and doesn't boost. When I push on the throttle it stumbles and tries to backfire, then it runs fine for 5 or 6 miles, after that it is crap again for a few miles.

So far, Iv'e checked all the hoses, unplugged the MAF, checked the cat, all seems fine!

The only code that keeps returning is: 1-1-2 fault in ECU.

Could it really be a faulty ecu, i've never heard of that on here before?

What else can I check?

Getting desperate with this thing.

Matt

96 855 R auto (193,000 miles).

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Try cleaning the throttle body butterfly. Sometimes they get gummed up and dirty. Mine was running like yours and i sprayed carb cleaner all over inside the throttle body by the butterfly and it runs like a new car now. Hopes this helps............................TIM

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Do you know the service history of the car?

Have you done a Stage 0 Yet? I would start there before anything else.

Could be something as simple as a bad wire, or something as complex as the PVC (easy to do but alot is involved).

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Do you know the service history of the car?

Have you done a Stage 0 Yet? I would start there before anything else.

Could be something as simple as a bad wire, or something as complex as the PVC (easy to do but alot is involved).

No history, po said it was well maintained, it wasn't so I offered well below his asking price and he let me have it!

I have done stage 0. New plugs, leads, cap/rotor. New pcv, fuel filter and air filter. It is running with a 19t turbo.

When it stumbles it won't go over 20 mph, once it clears it accellerates fine then bogs down again.

Wierd

Matt

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or something as complex as the PVC (easy to do but alot is involved).

PVC= Polyvinyl Chloride...PCV= Positive Crankcase Ventilation.

OP..I would check ALL the grounds (engine and chassis)...clean them and then grease them with Dialectric grease

that may help with that code..running issues should be addressed by checking all vac. lines and intercooler/intake hoses. clean Throttle body like stated above.. Is MAF backwards?

Yes an ecu could be bad. not common, but not impossible. someone could have reversed polarity at the battery or shorted something (+ cables). was it doing this when you test drove it?

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Had a similar problem with a 960, may not be a bad ECU, but a faulty ECU cable harness or connector. The car would basically trigger into limp home mode whenever it was damp out. Turned out that the previous owner power washed the engine bay, causing corrosion in a bunch of connectors. In my case a Volvo dealer swapped out the ECU for a good one and the problem did not go away. Easy enough test if you can find someone who will swap ECU's with you for an hour.

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PVC= Polyvinyl Chloride...PCV= Positive Crankcase Ventilation.

OP..I would check ALL the grounds (engine and chassis)...clean them and then grease them with Dialectric grease

that may help with that code..running issues should be addressed by checking all vac. lines and intercooler/intake hoses. clean Throttle body like stated above.. Is MAF backwards?

Yes an ecu could be bad. not common, but not impossible. someone could have reversed polarity at the battery or shorted something (+ cables). was it doing this when you test drove it?

No, it drove ok just in limp mode, which po told me. Thats how I haggled.

It doesn't feel like limp mode. it runs fine then rough for a couple of mile then runs fine.

Where is the earth for the ECU?

Matt

Have you checked the compression? Sounds like a bad Valve.

No, but wouldn't a bad valve cause rough running all the time?

Matt

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Could be a simple ignition issue, pull the plugs, check the terminals are tight, and the wires are in good shape to start.

I once chased a similar problem years ago, opened my hood after dark with the engine running, the boot on the coil had a tear and was arching intermittently.

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Sounds like a MAF to me. Mine did it just like yours. replacing the maf with a good used one fixed it for me. But it wouldn't hurt to just go through everything. and yea a valve problem would be a constent running like s--t. do the ecu check like stated above, and do the same with the maf.

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