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Discussion Starter #1
Hi All,

i have a motronic TS motor that wont rev past about 5000 rpm where it instead starts to ping fantastically. Below this the motor is a champ with loads of torque. Plugs and leads are relatively new and fuel filter is new. Any suggestions welcome as I need to solve this ASAP!

Cheers
 

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Discussion Starter #3
Thanks Sape, thats very optimistic. At this stage im suspecting something with the engine management
 

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What fuel are you running?
 

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Discussion Starter #5
It doesnt seem to matter, it will do it on 98. I've stuck a blue fuel quality plug in to see if that helps. Have also tested each distributor, all plugs firing correctly.

At first it didnt seem to ping, just felt like a rev limiter. Now it pings. Its got loads of torque compared to my 75TS (the problem motor is in a 105) but has a very disappointing top end :(
 

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You *sure* the tach is accurate? Mine read very low when I had it tested. The pots they used are very poor and degrade over time, causing low readings.

You probably should verify that with an external tach before proceeding. You may have actually been hitting the rev limiter.
 

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It doesnt seem to matter, it will do it on 98. I've stuck a blue fuel quality plug in to see if that helps. Have also tested each distributor, all plugs firing correctly.

At first it didnt seem to ping, just felt like a rev limiter. Now it pings. Its got loads of torque compared to my 75TS (the problem motor is in a 105) but has a very disappointing top end :(
Well, I think you'll need to start looking at a the air flow meter.
Use a multi-meter and make comparisons to the 75TS to make sure it sends out the same AFM signal.
Check when the vane is fully closed (ignition on, but engine not running).
When the engine is idling.
And, again with the ignition on but the engine not running, physically push the vane to full open.
The voltages should be [email protected] close to 1 another. If they aren't, then there is a problem.
Harder to test will be the spring tension if someone has been messing with it. A sensitive touch to compare how much effort it takes to just push them both off of fully closed, is about all I can suggest. You'll have to do comparisons between the 2.

It would be worthwhile to make sure the Inlet Air Temperature sensor is working correctly, too. The IAT can have a significant effect on ignition timing.
With the ignition off, measure the resistance between the IAT's wires (there is only 2 of them) and assuming the 2 cars at at the same about the same temperature, the resistance between the 2 AFMs should be about the same.
Check the ECU's (not the gauges) coolant temperature sensor too, in the same way, while your at it. It will change a lot more based on the 2 engines temperature, so maybe best to let the 2 cars sit overnight and check first thing.

And after writing all of that. Just pinch the AFM from the TS and put it in the 105 and do a test drive.............. :oops:
 

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Hi guys, I'm chasing another 75TS problem (see 75TS missing thread), and have pulled the cover off the ECU and found the fuel quality plug. I wasn't expecting to find a relay plugged into the red holder (Type 23)? rather than a wire jumper? What does this mean? Car is a very unmolested '91 model.
 

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Hi guys, I'm chasing another 75TS problem (see 75TS missing thread), and have pulled the cover off the ECU and found the fuel quality plug. I wasn't expecting to find a relay plugged into the red holder (Type 23)? rather than a wire jumper? What does this mean? Car is a very unmolested '91 model.
i think it is just a jumper really. Its not a relay, just looks like one
 

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Yes Kevr, it tested like that and other input from BB members confirmed it. Thanks all.
 
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