P1238 code

azureblue · Post by **azureblue** » 29 Dec 2022, 07:45

yep, turbo doesn't spin up. I replaced the valve and 3 of the hoses, but that didn't solve it. Intercooler hoses look fine and tight. Car runs a little rough for a few seconds on cold day start up but runs fine after that. MPG is down. I wish I had a smoke tester, but I am going to get some starting fluid and try spraying the connections.
Ideas?

azureblue · Post by **azureblue** » 29 Dec 2022, 14:47

Spraying the joints didn't do anything. I had hopes of the idle coming up, which would indicate a leak, but nope. Everything looks buttoned up and solid. I found an almost new valve at the parts yard, and that did not solve the problem. Thinking back to the first round, after i fixed that problem, the turbo worked fine. That is, until I replaced the alternator, which meant removing the lower intercooler hose. But it is on solid and tight. Car idles smooth and runs fine - just no boost.

MDK · Post by **MDK** » 02 Jan 2023, 07:43

Turbo boost control valve.?. should be right by airbox.. unplug it and see what happens .. MDK

azureblue · Post by **azureblue** » 02 Jan 2023, 12:51

I'll try that -what should tehe effect be?
I replaced this one, with an almost new from the parts yard.. All turbo control hoses are solid and on tight. All intercooler hoses in place and tight..
Will a battery disconnect / reconnect help? I did not do that after replacing the control valve

MDK · Post by **MDK** » 02 Jan 2023, 15:47

.. disconnect &re connect battery?. that's something from the 80's.. you need a scan tool or vida. I've been told if you unplug the turbo boost control valve (not the hoses) the engine will run wide open... not all junkyard parts R good..maybe try another one ..is the waste gate stuck?

azureblue · Post by **azureblue** » 02 Jan 2023, 16:22

I don't think the WG is stuck. I could move it, and there was a good amount of resistance. The WG I got from the yard was practically new. Barely any dirt on it.
I'll try unplugging it tomorrow.. But it does act like a stuck Waste gate. Car idles great, starts from cold great, runs smooth...

azureblue · Post by **azureblue** » 03 Jan 2023, 07:22

the battery disconnect was to reset to CPU. I did that when replacing the alternator, but I don't know if it needs to be done when replacing the turbo pressure regulator sensor.

I swapped out the purge valve, and there was no change. It connects to a hard plastic pipe that runs underneath the fan housing, but I can't find the other end of it - it ends somewhere around the passenger side of the car. This doesn't have anything to do with the problem, does it?

Post by **scot850** » 03 Jan 2023, 09:41

Have you checked the MAF? Try disconnecting the MAF and see if it makes any difference. If it is bad, the car should then rev and run smoother.

Neil.

azureblue · Post by **azureblue** » 03 Jan 2023, 09:53

at 62 degrees cold start - started car - started easy and ran smooth. Disconnected MAF sensor and the car died.

Post by **vtl** » 03 Jan 2023, 14:03

Are you able to spin the turbine wheel by finger? Its bearing can be seized.

Also disconnect the hoses from TCV and apply vacuum by mouth (aka suck them

. Sometimes the WG/CBV membranes develop cracks/tears and does not hold vacuum.

Get any OBD reader and check the fuel trims (STFT, LTFT), they can point you to a vacuum leak.