Please excuse me if someone has already solved this issue; I've looked through every forum though, and haven't found a solution yet.

I have a 1987 244DL with 147K miles. I bought it quite cheap, and the body and interior are really very nice. My problem is this: When the engine is cold (and only when it's cold... Not freezing; I live in Oregon, so "cold" is 40-50 degrees outside), there is a distinct hesitation right about 2,000 rpm. If I hold the throttle steady at that speed, it's accompanied by a surge. It's been fitted with a remanufactured Bosch AMM (which was woefully out of adjustment... Giving it a thorough cleaning and correcting the idle mixture made a huge improvement). I have cleaned the throttle body and re-fitted it with a new gasket, cleaned the flame trap, replaced the plugs, wires, cap, rotor, vacuum hoses that were suspect, replaced the air intake hose, removed and cleaned the IAC and verified proper operation, replaced the coolant temperature sensor (the old one was out-of-spec), verified proper voltage and cycling of the oxygen sensor, verified correct TPS operation, checked the AMM for correct voltage and resistance, checked the timing, listened for even injector pulses... Each step I've taken has made an improvement (at first, it would die immediately after start up. Then restart, but die when a gear was selected. Then restart, not die, then stumble, hesitate and surge down the road until the temperature gauge indicated half way to normal operating temperature). After the needle swings past that point, the old brick runs like it's got a rocket strapped to the trunk lid.

Nobody at the european car garages, or Volvo specialists here have come up with the "magic bullet", and they say that I'm on the right track by cleaning, pulling and replacing components, and that if I'd brought my Volvo to them, they would be doing the same thing, but I'd be charged for it. I'm about to rip out what's left of my hair if I can't get this solved. Being an '87, it isn't equipped with OBDI, and from what I've gathered, the injection system on the 1987, 1988 and 1989 are unique to those years. I do not have a cold start valve (I've seen this as a suggested solution more than once) Can anyone help me? Nobody around here seems to be able to.

 

86, 87, 88 had LH 2.2, 89 got LH 2.4 which included the onboard diagnostics. 87,88 cars are virtually identical for whatever thats worth.

I believe the 87 has a cold start injector, which is only used when the engine is cold, perhaps this is not working well? they got rid of it in later years.

how about the wiring to the hall sensor inside the distributor? is that intact and in good condition?

p.s.. our 87 240GL sedan has about 400K miles on it, we're the original owners. it was starting to show some age related funky problems this last year or so, but I think we've sorted them all out. at least for now.

 

The distributor wiring is in good shape. My car isn't fitted with a cold start injector; even if it was, a faulty cold start injector would only be problematic when starting. Mine starts with no trouble, but for the first few minutes acts like its running lean. The fuel pressure regulator has been suggested as a culprit... Thoughts?

 

I've not done this, but on 2.2 cars, I believe there's a procedure where you disconnect the idle air controller and manually adjust the idle air screw, then reconnect the IAC.

87 /was/ the last year of the "biodegradable" engine wiring harnesses. our 87 finally needed the main injection harness replaced (I found one on CL which was the updated version specific to 87/88 cars, and in nearly new condition, had been installed, then the car wrecked, so was being parted out). sadly, you can't get the ignition harness anymore, so if that is flaking out (probably where it goes between the alternator and the engine as thats a spot likely to get drenched in any oil leaks or spills).

the connector for the chrysler ignition controller was a problem spot for us, I had to unplug it, clean the contacts, and carefully pinch them a bit so they fit on the pins tighter. don't rock this one when you pull it out, just pull straight out. in my case, it was causing a total no-start.

 

You're correct about grounding the IAC to close it, then adjust the idle with the thumb screw on the throttle body. I have done this, and I'll check the harness. I did check and clean the contacts for the ICM; I'll try making them a bit more snug. Would any of these be temperature dependent?

 

Problem SOLVED! Rich Sr. of Rich's Volvos Only in Portland, Oregon correctly diagnosed my problem as a faulty ECM. The ECM was misinterpreting the coolant temperature signal. It failed other resistance and voltage tests, too. Surprising that it even ran at all! He had a good used ECM on the shelf that I happily purchased for a very fair price and motored happily on my way. Thanks to all!