VAM air temp sensor

[Paulofolympia]

I got a code that my vane air temp sensor is out of range. Anyone have experiences working around these. I think there is a VAM door that I need to insure opens and closes; a temp sensor somewhere; and on top I think is the potentiometer. Is this all one piece or one component? Can I access the temp. sensor with the whole VAM component still installed? Is the potentiometer removed and if so how? Does it slide off, unplug, or are there screws that mount it? Do I need to unbolt that big black bracket? Thanks.
61996200

[MikeFleming]

If you look inside the inlet side, you will see a thing hanging down from the top - that is the Vane Air Temp sensor. The black plastic cover can be removed by carefully prying it off around all four edges (then re-glue to put it back on to keep dirt and moisture out). I personally have not atempted to remove/replace the temp sensor, but I suspect others have. I have a spare somewhere in parts I bought years ago from Chris Roth.

So i suspect they can be repaired but you might look for a working spare as i suspect it to not be very pricey. Remember you want the large SVO VAM assy - any one from an SVO or 87/88 TC will work.

[Meotchh]

Paul, if you need a VAM, I might just have 3 or 4 to choose from.

[Paulofolympia]

Yes, thank you very much. I will try to PM you with my info. Tomorrow I plan to examine and clean my VAM; make sure the door is operating; check my codes to see if I continue to get a temp sensor error; check my fuel pressure; and if I still have a problem try to determine if it's spark or fuel.

[Meotchh]

OK. I have replied, just let me know what you want to do.

[Paulofolympia]

Hello, today I re-attached my boost controller with new hoses and clamps. That worked out alright. Any ideas why someone put goober on this fitting? I removed, cleaned, reinstalled my VAM. The temp.sensor had black carbon stuff on it which I gently cleaned off. All seems in order, my hot start issue is ok, my idle is better, and it drives better. My hard codes are clear when key on engine not running; but I have engine running code trouble. 24 problem with VAM temp sensor; 25 knock sensor problem; 34 EGR valve problem.
Fuel pressure is a giggly 30 psi. When I get into boost it giggles more dramatically around 37-38. It holds more steady at lower throttle opening. After I shut it down the pressure rises to stable 40 psi, but when I start it again it drops back down to a giggly 30 psi. I suppose I need to replace VAM, EGR, Knock sensor and fuel pump or pumps? Any ideas?
Thanks, Paul.620362046205
My book says I should be at 39 psi. Under boost it drops off still (less so in lower gears 1-2; more so in 3-4-5).

[MikeFleming]

Several points to make here.

1. Is the stated measured fuel pressure with or without the manifold vac hose connected to the FPR? The factory setting of 39 is without the vac hose connected - same as it would be with the key on, engine off. At 15 PSI of manifold boost pressure, there should be about 55 PSIG of fuel pressure (with vac hose connected to FPR). So yours sounds low - probably time for a new fuel pump.

Do you have a single or dual pump system?

3. There are hard and soft codes for KOER modes. After you change or fix something, clear all codes then re-test (run/drive the car for a bit) and re-scan to see if any new codes set.

2. A code 34 means specifically that knock was not sensed during the test. It DOES NOT mean the KS is bad.

To properly see sensed knock during the KOER, the engine needs to be at full operating temp - like driven for at least ten minutes and coolant >200 F), the throttle needs to hit WOT immediately during the snap test, and held until the RPM exceeds 3500RPM, and there must actually be some knock to be measured.

3. Does the EGR valve open at part throttle on a hot engine? Was there any RPM drop during the EGR portion of the KOER test? You cna also manually open the EGR valve to see that the idle quality worsens ot verify there is no complete blockage in the plumbing. Stick a small finger on the back side and push it open. Shouidl see <10% RPM drop with it flowing.

[Paulofolympia]

I didn't disconnect the vacuum line at the FPR (fuel pressure reg?) I don't know if I have a 2 fuel pump system- I hear the one in the back prime up when I turn the key on. My Chiltons seems to think I do? One pump will be in the tank; where would the 2nd (high press.) pump be located? I drove around before KOER and I held rpm's to 2000 for 2 min; but I failed to accomplish the WOT portion of the test. I will clear the codes and re-test in the next few days. Thanks again, I appreciate the help.

[MikeFleming]

Right rear chassis rail, inside, forward of the RR wheel well. Just under where the rear passenger buttocks would sit on the right side.

[Paulofolympia]

I removed, cleaned and reinstalled my VAM. The door seemed to be operating fine but the temp sensor was coated in black soot/carbon. I gently cleaned it all up and reinstalled. On my KOEO code test I got a code 11 which is the all clear. I again had a hot non start issue yesterday. After it cooled and I got it home I did a KOER code test and got a code 34 (EGR vlv. not opening) and a code 25 (no knock detected) but no temp sensor code. I did do the snap test (rev the engine). I removed the EGR valve and it was partly clogged; so I cleaned it all out and re-installed. It was again difficult to start and when it did it was only barely running at 400 rpm (as if on not all cylinders) and when I gave it throttle nothing happened- no increase in rpm- until several moments later it cleared up. Also my fuel pressure was hovering around a shaky 22 PSI until it cleared- then 30 psi.
Could the fuel pressure reg. have an affect on this; as it sits in the hot engine compartment and my non starts seem heat soak related. If it is fuel pump or pumps ('86) what brand/spec pumps should I look for? Is there an access to the tank pump from the cab or is it a tank drop/ remove scenario? I likely wont be able to do much more until this weekend except maybe swap in a new FPR. Also since the "no knock sensed during the dynamic test" came as an error code does that mean that the test was expecting one that didn't occur? Still not developing power under boost; hesitates, stumbles drops off. Thanks a bunch for your help; Paul.