Volvo RWD 700 Forum

OBD says 2-2-3 "signal missing to/from idle valve"

This is really an intermittent stall followed by an intermittent hard start.

It might be several days later it starts right up or it might re-start immediately. (I've replaced the FPR and the Speed Sensor). This has been going on for months now. (I decided to start a new thread because it is so old).

The OBD code is fairly recent. Months ago it had no code. The first thing I did was clean the throttle body and IAC (IAC bench-tested okay). Last week OBD was 2-2-3 and whatever the code is for the knock sensor...(this time it is only an OBD code for IAC).

I replaced the Speed Sensor and it ran like a champ for a week. You can feel the FPR "click" on. It has a full tank of gas and I can hear the transfer pump with a rubber hose "stethoscope" in my ear.

QUESTION: could a faulty IAC cause this 745 to intermittently stall at 30 MPH or less?

"This is really an intermittent stall followed by an intermittent hard start."

I agree with Chris about ignoring the IAC code for now. The next time you get the "intermittent hard start" (assuming that means NO start), feel for TWO Fuel relay clicks — one when the Key is turned on, and another when you crank the starter.

If you don't get that second click, we can explore the possibilities, such as checking for ECU control (i.e., ground pulses at the injectors as in THIS POST).


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Check for ground pulses: I'll need a "noid light" ---

It is intermittent, and it usually restarts... it just stalls and sometimes it won't start right away.

So, to reiterate, if I unplug one of the injectors, plug in the test light, and, it doesn't start AND doesn't light then the ground pulses aren't arriving.

If the noid light flashes and it doesn't start it is something else.

Replaced FPR. When I cranked-it myself and it didn't start I took off the ashtray and put my fingers on the FPR. It clicked and I believe that I heard the fuel pump going.

I'm not sure about a 2nd click at the FPR but I felt a definite second click from the front row of relays. No start. Is the second FPR click more subtle?

Cranked it again. FPR clicks (not sure about a second click at the FPR but definite second click on front relays). No start.

Cranked it again & it starts. No differance felt on clicks from first two trys.
Shut it off. Tried it again. Starts. No differance felt on clicks when it starts and when it doesn't start.

Replaced RSR. Didn't fix it.

Stalled again after driving down the street. Started right up again.

Could it be the ignition switch? Fuse tray? FPR blue plastic socket?

From Mon Jul 20 00:57 EST 2009...
Could it be the ignition switch?
• Anything is possible, but that would be way down on my list of "known suspects".
Fuse tray?
• Also not too likely, as with the relay rack socket terminals mentioned below.
FPR blue plastic socket?
• Don't understand "blue plastic socket". The Fuel relay should be White, and plugged into a relay rack "socket", as shown in the FAC figure below:


From Mon Jun 29 07:09 EST 2009...
So, to reiterate, if I unplug one of the injectors, plug in the test light, and, it doesn't start AND doesn't light then the ground pulses aren't arriving?
• Correct. Most likely (known) cause would be a failing Crank Position Sensor, which would mean no timing pulses to Rex Ignition CU and thus no spark or "awakening" of the Regina FI ECU.

If the noid light flashes and it doesn't start it is something else.
• Correct, but "something else" would be rare, compared to what I outlined above. The flashing noid light would confirm the CP Sensor, Ignition timing pulses, and FI ECU injector control pulses. That would leave the basic fuel supply to suspect, i.e., Fuel relay, Pump, or something rare like pump wiring or relay rack terminals. I don't see any of those as likely causes of an intermittent problem, when compared to something like the CPS.

Well... one more (infrequent) suspect does come to mind: the ignition coil contacts.
If they weren't making good contact, everything else would work, but the spark plugs would become fuel-soaked after several starting attempts in close succession. The coil can be removed to clean the contact terminals, as shown below:


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Sorry about my unclear and misleading description "intermittent hard start" ---
the symptom pattern is confusing.

It has always started after some interval; it is an easy start if it restarts in 2-seconds and seems more like a "no start" when it fires-up after 3 or 4 repeated attempts but has been a definite no-start for two weeks.

When it runs okay for a week or months after I've seemingly "fixed-it"---
then stalls and won't start again for a couple of hours I have other more colorful vocabulary that is perhaps even more useless. I digress.

Sorry about my unclear and misleading description "intermittent hard start" ---
the symptom pattern is confusing.

It has always started after some interval; it is an easy start if it restarts in 2-seconds and seems more like a "no start" when it fires-up after 3 or 4 repeated attempts but has been a definite no-start for two weeks.

When it runs okay for a week or months after I've seemingly "fixed-it"---
then stalls and won't start again for a couple of hours I have other more colorful vocabulary that is perhaps even more useless. I digress.

The way I see it, if your foot is on the throttle at all, then the IAC plays no part in keeping it running. If you're cruising along at 30mph and it suddenly dies while your foot is still on the throttle, look elsewhere for the culprit.

Check the big 3 - Fuel pump relay, radio suppression relay, and the fuel pump itself.

Also, you can disassemble the ignition coil/power stage and clean the internal contacts and all mating surfaces and possibly cure an ignition problem - common problem on Reginas and costs nothing to do.

Good luck.