I think I'm going to cry...96 850T wont start...again

[ANIGAV Inc.]

I'm not afraid to put this out there but I'm at the end of my rope. I loved my volvo and I now hate it and its killing me.

Here is a link to my old thread about my old problem..https://www.matthewsvolvosite.com/chat/p ... highlight=

Sigh....
To recap
My car started to accelerate on its own one day. It would maintain 55mph with the cruise off and my foot no where near the gas pedal. Crazy I know. Imagine trying to stop at a light.

It would do this off and on until I decided to unplug the IAC. The car idled a lil low but ran fine. I could drive it for a few days with the IAC disconnected and it would eventually give me an attitude until i plugged it back up.

*Upon reconnecting the auto acceleration problem would return. I went to a local boneyard and picked up 4 (yes FOUR) IAC's and the auto drive problem came back. Although it is possible I find it very unlikely that 5 IAC's are faulty.

During this whole replacement process she sometimes wouldn't start w/o assistance. It would take so long to turn over I would need to jump cuz my battery would run down.

After a while the car would start and run fine but only with the IAC wire disconnected. Weird.

So here I sit. Stranded at my parents house because my car wont turn start. I have plenty of gas, wires are good, I'm throwing a code but more than likely thats from my disconnecting the IAC.

I can only think that its the TPS now but I dont have tons of money to toss at everything i "think it is" please guys.
I'm at teh end of my rope here and I dont know what to do.

Why wont my car start and run correctly?[/url]

[Ozark Lee]

Is there any chance that your throttle body is sticking open?

That isn't a common problem but it shouldn't have been a common problem on my daughter's Porsche either.

Check the throttle cable spool and the linkage to the throttle body. Pull the linkage off - it is a "snap fit" ball type fitting, it will pop off with a moderate amount of force - and verify that the throttle body snaps back to the closed position when released and that its operation is smooth.

...Lee

[ANIGAV Inc.]

As a former Porsche owner I know oh too well about things that "shouldn't" be the problem.
Its possible but I dot think its likely at this point. I sea foamed the engine via the vacuum port 3 times and took throttle body cleaner and a tooth bush to the throttle body plate and surround.

When i move the tb by hand it snaps back quite quickly.

[Ozark Lee]

It seems it is coming back to things electrical to the IAC. I have not disconnected the IAC on any of my Volvos but on my Suburbans, after the huge ice storm and the squirrels decided to nest under my hood, once the electrical to the IAC valves was disconnected (chewed through) the car wanted to idle at around 2800 RPM.

I will try to dig through VADIS to find voltage readings before I leave to the cabin - If I can't find it quickly it may be late Monday before I get back to you since I don't have VADIS on the computer at the lake.

...Lee

[Ozark Lee]

Sorry for the delay - I couldn't find this before I left and I still can't find voltage readings.

Here is what VADIS has to say about the IAC valve.









I'll keep looking for voltage readings and procedures but at least this will tell you what the inputs are.

...Lee

[bobsnow100]

I would also check the throttle cable operation and smoothness. Have someone press the gas pedal and make sure it is opening and closing fully while you're looking at it under the hood,making sure it is not getting bound up on something in the engine compartment.
Make sure you interior rug isn't bunched up under the gas pedal causing the engine to race. I have seen that before.
It seems like if it maintains 55mph without touching the pedal that something is binding.

[ANIGAV Inc.]

Sorry for the delay.

You guys won't believe this. I got a code for the coolant temp sensor but thought nothing of it in regards to this problem.

I mean lets get serious how often does one hear that a coolant sensor causes a car to accelerate or not start at all?

Well i replaced the sensor with one from a boneyard. Car starts up on teh first time and cruises like it was brand new. Weird.

[MadeInJapan]

Coolant sensors make these cars do weird things when they go bad.

[bockreiter]

Sorry for the delay.

You guys won't believe this. I got a code for the coolant temp sensor but thought nothing of it in regards to this problem.

I mean lets get serious how often does one hear that a coolant sensor causes a car to accelerate or not start at all?

Well i replaced the sensor with one from a boneyard. Car starts up on teh first time and cruises like it was brand new. Weird.

I just replaced my coolant temp sensor. It had the same symptom. Idled realy high, gauge didn't indicate any temperature and "raced" when approaching a stop light. What clued me to the temp sensor was the gauge not displaying any temperature. But I never did get a code for the coolant temp sensor. Go figure.

[Volgrrr]

Sorry for the delay.

You guys won't believe this. I got a code for the coolant temp sensor but thought nothing of it in regards to this problem.

I mean lets get serious how often does one hear that a coolant sensor causes a car to accelerate or not start at all?

Well i replaced the sensor with one from a boneyard. Car starts up on teh first time and cruises like it was brand new. Weird.

I just replaced my coolant temp sensor. It had the same symptom. Idled realy high, gauge didn't indicate any temperature and "raced" when approaching a stop light. What clued me to the temp sensor was the gauge not displaying any temperature. But I never did get a code for the coolant temp sensor. Go figure.

Coolant temperature goes faulty - which makes the ECU think the engine coolant is not up to the correct operating temperature so the ECU makes the fuel mixture richer to compensate.

Result - erratic engine revs or the engine over-revs to burn off the richer fuel mixture.