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TCS valve on firewall of 92 9000 T?

I have found the TCS valve on the firewall. It is connected to the intake via a check valve. Check valve does not allow air to blow out from the intake but it does allow air to go in, albeit slowly. I checked by blowing and sucking. On sucking air out of the intake (towards the valve), it held the vacuum. I could blow air into the intake but not very well. Is this normal or could the check valve be bad?

What does this valve do?

The one on the firewall looks similar, mounting is slightly different, but I can swap them temporarily to test. Does anyone know what that valve does?

It has been in the low to mid teens here lately for high temp (F) and will warm up this week. I will fool with it when it is a bit warmer.

Thanks for any help,

Charles

Reply to
Charles
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You are on the right track - try replacing the check valve first, it sounds a bit gummy. Do the one on the manifold while you are at it.

Basically - the TCS valve is reading manifold vacuum and pressure to get feedback on it's decisions regarding firing. If there is any kind of blockage or problem in the air-reading - it triggers and error until shutdown and restart - when it check again and, finding all to be within range, resets.

Find another mechanic who doesn't view the part as swapable. The Tech II read out is actually not always correct in that it doesn't have a way to check if the readings the sensors are providing are faulty. It simply fails the system - and provides procedure for replacing all the parts until it gets a correct reading.

In short - it assumes that all the mechanical and electrical connecting systems have already been confirmed as being operating withing the correct ranges.

Reply to
Dexter J

I replaced the check valve with one from an 86 900T. This valve goes from the valve cover to the intake manifold. It was working but is bigger diameter (inside diam) and has much freer flow.

It made the problem with the engine cutting out significantly worse, and I mean SIGNIFICANTLY WORSE. The car was barely driveable. This makes me think we are on to something.

So I put the old check valve back. I took out the solenoid valve and checked it; it seems to work. The hose from the solenoid back to the TCS unit seemed to be a bit cracked on each end, so I replaced that.

Next is to get new plugs, replace the check valve with a new one and make a switch to read out the codes via the check engine light. I might wait to put in the new plugs to see if the check valve fixes it.

I already replaced the manifold check valve 'cause it was blowing oil out the dipstick and I didn't like that. The 900T check valve worked just fine there but I went and bought the proper part and put it in a few months ago.

Thanks for your help!

Merry Christmas!

Charles

Reply to
Charles

A plesure brother Charles - Merry Christmas.

Reply to
Dexter J

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