'97 850 base wagon - IAC Valve won't shut off

tappolon · Post by **tappolon** » 16 Jul 2013, 18:26

OK so my ’97 Volvo 850 wagon has been intermittently (almost half the time) not starting for the past year+. I bought it last spring with ~200k miles on the odometer, which usually doesn’t work (along with the speedometer). I had it checked out by a good reputation volvo specialty shop to be confident I wouldn’t have any major issues with it and they said that the mechanical underbody needs a lot of work, otherwise it’s a very good vehicle. Well I didn’t have that $2000+ of work done and now I’m glad.

Last August, my Lady was out with her ten year old daughter and when they got back to the car it wouldn’t start. We made do with just the minivan while I was home on paternity leave and then I had to use my old beat up mitsubishi (that leaks exhaust into the car) when I didn’t get the Volvo running before going back to work. The starter didn’t even crank when I got to it to try it out. Basically when turning the key to the on position everything would shut down, all lights and door dinging, etc. The battery seemed to have a charge and lights were working. The radio wouldn’t work and after trying for a while and checking fuses the windows stopped working (and one of them was down and was stuck that way for about 2 months).

So, it spent some time at a shop and here’s how that went: First, the starter was replaced along with some fuses and some grounds were fixed. That didn’t help. Then he did some testing for spark and maybe timing, but got nothing. He thought it might be the camshaft and crankshaft timing sensors but called me back right away and said that it must be the computer because nothing was working – no power windows, interior dash lighting, spark, fuel pump, etc.; pretty much only the starter was doing anything but the engine wouldn’t start. Got a used computer for $40 including core charge and it was supposed to be for the B5254 non-turbo engine (Bosch brand P01270416), but it doesn’t match what was already in the car (Bosch brand P09125264), which I think is for a turbo or an older engine. The computer switch didn’t change anything, but on more tinkering the mechanic got the car to start and the windows to roll up (finally) when he bypassed the circuitry between the ignition switch, fuse box, and coil. So he replaced that circuitry and the car started and everything worked.

It worked for a few months without much trouble, then needed a jump a few times for about a month and then refused to start for over two weeks jumping it with my 4-cyl mitsubishi or a co-workers 6-cyl kia. About a month later it started with a jump from our 6-cyl minivan. I'm guessing the minivan was able to start it because it has more power running through it, but I also suspect moisture to be playing a part in the issue; it seems like the trouble has usually been during or following rainy weather. So we got it home on that jump start and it wouldn’t start again. I noticed the “W” (winter) mode light was blinking and the manual says that’s a fault in the automatic gearbox. Also the ABS light was on.

I let it sit for a few days and instead of jumping it I charged the battery. The 6 amp charger was getting a draw of about 4 amps DC and took about 20 hours of charging to work down to near 0 amps DC. It still wouldn’t start or crank. That’s when I noticed that the Idle Air Control Valve keeps humming away even after I lock the car and go away. Also it seems that there is occasional activation through a hose on the left side of the fuel rail. The instrument panel lights and clock stay on also when the car is turned off and locked. Another note is that in the past while driving on the freeway it has accelerated as though the cruise control was on, though I have not been able to get cruise to work (I assume because the speedometer isn't working).

I know it’s a long write-up. Key symptoms: IAC valve running when car off, instrument panel lights and clock stay on when car off, ABS light on, “W” mode light blinking (automatic gearbox fault), auto-acceleration.

So, where should I start?

Thanks

Post by **Ozark Lee** » 16 Jul 2013, 20:57

You have more than one issue here but I am highly suspect of the electrical portion of the ignition switch. Fortunately that is a real cheap and easy fix and even if it doesn't cure the instrument cluster lights staying on and the IAC valve running you were going to need one anyway.

The speedometer, perhaps the odometer, and perhaps the transmission problems are due to a bad ABS module. The modules have a 100% (OK maybe 99.9%) failure rate. If you are handy with a soldering iron you can repair it yourself or we have a member, Matty Moo, that will professionally rebuild the module for well under $100.00.

https://www.midwest-abs.com/ABS_Modules.php

Are there any aftermarket items installed in the car? If replacing the ignition switch doesn't work then aftermarket stuff is the next place to look for shorts in the wiring. You can also use an Ammeter in series with a battery cable to look at the parasitic current draw with everything in the car turned off. Typically the parasitic draw is around 25 to 30 mA but anything over 100 mA is trouble. If the current is high start pulling fuses, one at a time, while observing the current level. If you get a big drop then you have located the circuit that is causing the trouble.

...Lee

tappolon · Post by **tappolon** » 24 Jul 2013, 21:30

OK I got a replacement for the electronic part of the ignition switch and I used the post copied below to replace it. I am getting no different response when I try to start it. Are you sure I needed to spend that $35 to replace it anyways, because I can send it back?

The ABS module wouldn't be causing a no start like this, right? It's good that it seems like a simple fix, but I'll focus first on getting it to work before dealing with how well it works.

There are no aftermarket parts installed at all that I know of or can see in it, though it is my first volvo.
I will look into getting an ammeter. So do you mean that a 25-30 mA draw is normal anywhere, but over 100 mA is the problem component? Or is it supposed to be closer to 0 mA but 25-30 mA may not be a big problem? How do I check? I think I've had this process described to me before. So I need to start with one lead of the ammeter on a battery cable somewhere then the other lead on an electrical component or after it in the circuit? Then if there is a high draw that means something in between the two leads is the problem, right? It sounds simple in concept, but those wires run everywhere so the prospect is a little daunting. Any suggestions on approaching it?

Thanks.

Volvo 850 Ignition Switch Replacement:
https://www.matthewsvolvosite.com/forums ... =1&t=37398

Post by **abscate** » 25 Jul 2013, 05:22

You put the ammeter between the battery cable (either one, removed) and the appropriate battery terminal. Ammeters go into series in a circuit so that all of the current in the wire passes through the ammeter.

Make sure all of your doors, rear hatch, glovebox, are closed. Any light on will register as current draw and mask a potential problem.

I don't like to dump on unseen mechanics but someone who got into "computer replacement" based on your symptomss isn't too familiar with Electrical troubleshooting, IMHO.

tappolon · Post by **tappolon** » 11 Oct 2014, 17:54

Thanks for the honest opinion about the mechanic. Yeah I tried to get him to make up for his horrible oversights and expensive "troubleshooting" by doing some simple stuff on my minivan, but he refused to be reasonable. Well I won't go with the "cheap" alternative again. We have a volvo specialist just 3 blocks from home.

Volvo specialists did a whole system eval and charged for it, then dried out the distributor cap and it worked... for a week. Then it was dead again. I brought it back in and they replaced the horribly corroded grounding cables, engine to firewall. I had seen the corrosion, but wasn't sure what the cables even were. I am surprised the multitude of people and research I have done never pointed to grounding cables, but I am told it is very rare for them to be a problem.

Unluckily for me, now I have a crank but no start condition (which, I explained to my unoptimistic 12 yr old, is more hopeful than the previous no crank, no nothin condition). The fuel pump relay jumpwire doesn't work, but it sounds more eager to start when I change it. I am contemplating getting a replacement relay as a first next step, but I should probably go back to my research about this condition if the fuel pump relay jump doesn't work. I will keep the ABS suggestion above in mind during research and also review the codes I was given after the volvo specialist eval (though I am worried those are meaningless because the groundwire shorting could have caused all sorts of codes).

Cheers!

tappolon · Post by **tappolon** » 17 Oct 2014, 08:20

In the meantime before doing anything else, I fully charged the battery up and tried to start. Two key findings here are 1) the fuel pump engages when I turn the key, 2) the engine did start, but then cut out after 30 seconds. Started again and cut out sooner and got harder to start again. I have more research to do, but I think I will next need to check on various sensors, probably get codes read.

Post by **erikv11** » 17 Oct 2014, 23:23

Are you sure the fuel pump is engaging every time now? This still sounds like it could (maybe) be a failing fuel pump, or even a failing fuel pump relay. A failing fuel pump is often intermittent like that before it dies completely. A good way to check on the fuel supply is to check if there is fuel pressure at the rail.

When the shop dried out the distributor cap, did they say anything about a potential problem with the rear cam seal? There is no reason for the cap to need to be dried out unless you power washed the engine or a cam seal is blown out, for example due to a clogged PCV. I would remove the cap myself and inspect inside of it for any oil or moisture. It should be bone dry.

Post by **abscate** » 19 Oct 2014, 05:40

Volvo specialists did a whole system eval and charged for it, then dried out the distributor cap and it worked... for a week. Then it was dead again. I brought it back in and they replaced the horribly corroded grounding cables, engine to firewall. I had seen the corrosion, but wasn't sure what the cables even were. I am surprised the multitude of people and research I have done never pointed to grounding cables, but I am told it is very rare for them to be a problem.

Yeah, we missed that here...ground cables are a common problem on these old cars and will definitely cause all kinds of seemingly unrelated problems. I think you need to get an electrical wiring diagram off the web and find/evaluate /replace ALL your grounds...and there are a lot of them.

I'm sending you a 100 dollar gift certificate, good on an annual membership fee to MVS

Next step on your Nostart, check fuel pump pressure on rail