The Vulva is givin' me trouble!!

[SMITTY]

That's the 1994 Vulva (or Volvo, whichever you prefer) 940 sedan winter beater I have.

We've had a '93 on winter duty for the past 10 years without any major issues. Worst one that car had was a stalling event that was traced to a bad ground - where I have no clue. I added a bunch of extra grounds and the problems went away.

So with 940's, there are 2 different fueling and ignition systems that were sold at random when these cars were new. Our '93 has the Rex/Regina system, while my beater has the Bosch system. Easiest way to tell them apart is by the ignition coil. If it's on the driver's side and looks like some space-aged, complex square box on the strut tower, that's a Regina. If it has a traditional old-school round coil up above the HVAC fan on the passenger side firewall, that's the Bosch system. This problem child has the Bosch system. The Bosch uses 2 fuel pumps (STUPID!!!) - a low pressure one in the tank, then a higher pressure one under the car next to the fuel filter. Regina uses a single fuel pump in the tank like every other car on the road since 1986.

To save some typing, I'll cut and paste my post in the most recent Coffee chat:

I have this hard start / severe misfire issue when engine is first started cold. Was present last year, but only lasted 1 second and cleared out. Now I have to hold the pedal to the rug to get it to start, then hold it at 3,500 RPM for at least 30 seconds before it clears out! Once warm, fires right up instantly and idles a little high (always did that). Brand new plugs, wires, cap, rotor - all top shelf part brands (as close to OE as you can get). Also has a new temp sensor (the correct one - for the ECU), and I cleaned both the TB and the idle air control last season trying to correct the high idle. Zero vacuum leaks. 35 PSI fuel pressure. The timing does jump around, which is odd - that's controlled by the ECU. Our '93 is rock solid at 15° at idle. This tells me it's time to throw some carburetors on this thing next summer. I don't have time or patience for this B/S!!! I need this thing to work 4 months a year!

So, holding the pedal to the rug has me thinking a rich condition ... like a leaking injector. BUT ... the car starts EASIER in WARMER weather - that's the opposite of a rich symptom! A rich mixture will become even richer with an increase in temperature, and leaner with a decrease.

So far, on the coldest days I can barely get it started. I have to hold it to the rug, and crank ... and crank ....and crank until that 11 year old battery starts sounding like she's about to give up the ghost (not yet!)

I was thinking maybe my recent timing belt swap ended up with the cam timing 1 tooth retarded ... but after driving it home in the warmer temps tonight, it had plenty of low-end power. Can't be off.

My next experiment will be trying to start it after it hits 60° tomorrow - hasn't been above 40° in close to a month. If it does start, when the temps hit the teens in a few days and it's extremely hard to start again, I'm going to hold a heat gun to the computer. If a warm to hot computer fixes the problem, I know I have to source a magic box, or send it out to be refurbished.

Any theories you fellers might have, I'm all ears! Unless it ends up being something simple and/or stupid that I should've picked up on, this thing is getting a pair of carburetors and a different ignition system before next season ... or maybe THIS season soon!

[warminmn]

Leaky intake gasket? I had a Beretta that started exactly like that with a leaky intake. Colder it was, harder it started. Started ok on warm days. Ran good once warmed up.

Edit: Ive never owned or worked on a Volvo, just a thought

[Rob R.]

Leaky intake gasket? I had a Beretta that started exactly like that with a leaky intake. Colder it was, harder it started. Started ok on warm days. Ran good once warmed up.

I had the same thought, sounds like an intake gasket. Once it warms up and things expand a bit the leak seals up. I also had a car one time that would start hard and idle rough when cold, it turned out to be an EGR valve that would not close all the way.

If you can’t find anything wrong mechanically, find someone with a Snap On scanner. Other than firing the parts cannon at it the scanner is the only way to see if there is a sensor acting up.

[anthony7812]

Sounds like a quick squirt of Cosby Sauce in a can (startin fluid) might be your winter time friend.

[waytomany?s]

I'd bet gas is draining out of the fuel line back to tank. When cold some seal somewhere isn't quite sealed. When warm it's happy. Start easy and work up the harder stuff. If you do it the other way, everything will be new when you're done. Not that that's bad, but it causes way more aggravation through the process.

[Hambden Bob]

No codes showing,Smitts..?? If so,I'm lovin' all theories presented so far by these guys..!! Just for funnsies,the next time you go to cold start "The Little Furschluginer" turn the key on without cranking it and wait 30 seconds. It'll let those fuel pumps pressurize to their limits. Listen for how long those little bleeps run for during that 30 second key on time. Then try it.. Glad Your "Mechanicly Demented Keyster" started this Topic Thread..!! We'll disembowel this thing together and come up with an answer..!!

[Toddburn]

Smitts, possibly a bad fuel pressure regulator.

[Toddburn]

Smitts, possibly a bad fuel pressure regulator.

[SMITTY]

Great stuff fellas! Much appreciated!

So just went out there now - car has been sitting 16 hours, it's damp, wet, raining, and 57°. First I checked fuel pressure with my tire gauge, since it's the only thing I can fit under that section of the fuel rail where the nipple is. 20 PSI, and it squirted when I removed the gauge. So that rules out the check valve. I've seen these cars start and run on less than 15 psi. Normal is 35-45.

Pumps always run as they should with key on, and builds 35 PSI instantly.

Hopped in and turned the key - fired right up! Didn't run well - idle was low and rough - probably 400 RPM or less, but it ran with no foot on the pedal. So that confirms it's certainly a cold weather issue. I've already put a can of ether in the car right at the start of the season in preparation for colder temps - I know it's coming ... and I ain't getting stranded!

Regulator is plausible, but when they fail they usually leak fuel into the vacuum line. Not that it can't fail without a leak - I'll have to investigate that further, but now that I've confirmed it's a cold weather issue, that rules out a leaking injector or an excessively rich condition. That would get worse with warmer temps.

Intake gasket is a great suggestion, but I don't think that's the case here. In the length of time it takes to get the engine to smooth out, that area of the head is still ice cold. That's easy enough to test, so I'll get my spray bottle of water and test that out later. Another point however - normally intake leaks result in a very high idle when cold. I have the opposite problem - low idle cold, high idle hot. It's an odd one!

Oh, and this is a '94 - OBD-I so no P codes, but there is a blinking light code thing I'll need to read at some point. It's a PITA because I always forget where to plug in the little dongle there, and what the codes mean. I'll have to print something out and keep it in the car. It's a constant problem since the Regina codes are totally different from the Bosch codes, so I can't compare the '93 to the '94.

Can't expect anything to be simple when I own it - that's just the way of the universe!!!

[snuffy]

Maybe some 88 blend gas got mixed in somehow in the past - unheard of.

Maybe try a tankful of ethanol free blend and see what happens - path of least resistance- not to mention time savings as well.

I had a '94 960. Wish I had kept it.

[Rob R.]

That is why I suggested putting a good scanner on it. I had an ‘88 Grand Marquis with a stumble I could not figure out - local shop put a SnapOn scanner on it and in 5 minutes I had the diagnosis (ECT sensor was not working correctly). Similar story with a Lincoln that needed a TPS sensor.

[SMITTY]

Snuffy, great idea & suggestion ... but I live in a communist gulag where we're not allowed the convenience of pumping ethanol free fuel into ANYTHING - cars or fuel cans. We can't even buy off-road diesel (#2) at the pump! That only comes from an oil company via truck, and by large volume only. I could get E0 at the airport, but lead deposits aren't going to help things, and $5.75 a gallon on the low end is a bit spendy. I have a barrel of E0 here that I filled in NH, but that's a precious commodity for my small engines - don't want to waste it in a car. It's not really going to tell me anything I don't already know. I've got a rich condition that acts like a lean condition - very confusing!! There are no pumps locally that are over an E10, except along the MA Pike where you can buy E85. I never get gas on the Pike since it's a ripoff, so it's impossible that any ethanol above what is blended in for E10 is in there. In addition to that, this problem has been there since I bought the car - it has just progressed to an even worse state after sitting unused this past summer.

Rob, there's nowhere to plug a scanner in on these cars. They come from the factory with a male pin tethered to a plastic block with female ports in it under a plastic cover on the driver's side fender - whichever port you plug into (numbered 1-6) will decide what system you're testing - airbags, FI, ignition, ABS and that's about it. The other 2 are blank if I remember right.That's what I was referencing in my last post - I've got to figure out the codes and what they mean, and figure out what port I'm supposed to be plugged into. I can never remember, and finding the info is a bit of a PITA - always takes some time. There's a red LED that flashes with a pause, giving you a 3 digit code which repeats twice (if I remember right) then it moves on to the next code. I definitely need to do that.


Exhaust smells rich, the fact that you have to hold the pedal down to start indicates rich, but the fact that the problem goes away in warmer weather indicates the opposite. These cars are usually as reliable as a stone ax, so I'm leaning more and more towards a computer issue. I'll probably at least unplug it and check pins for corrosion at some point this week. Maybe leave the cover off it so I can give it a whack when starting. BUT ... the problem appears to fix itself in closed loop ... so that would tell me the computer is fine. Although, the computer still has to control the open loop phase excluding all the sensors, aside from temperature. Not sure if the MAF is in play here or not.

That's another difference between Bosch and Regina systems. Regina systems have what you would think is a MAF, but it's just an intake air temp sensor. The Bosch system has an actual MAF. They both look similar but are VERY different internally. Unplugging the MAF seems to make it start easier, but it barely idles.

[Freddy]

Mouse nest in this side of the air filter path? It'll make 'em rich..... revving up will move enough fuzz to get 'er going. When you park, they refurbish their living room & the problem is back.

[SMITTY]

I wish it were that easy, Freddy! Great point though.

That was the 1st thing I checked after it sat most of the summer. I think I took it on 2 trips to the store after I washed the Ram and didn't want to get it dirty in the rain. Might have put 200 miles total on it last summer - the wifey used it while I did some maintenance and minor repairs (rack boots - they last 1/3rd the time of the originals these days) for a few days one week.

[Hambden Bob]

Smitts,when You (or one of these guys in a post) ran some auxiliary grounds to various spots to clear up a previous trouble,did one get installed on the chassis of the computer itself..??