Hello Volvo forums!

Hope this thread finds you well, and that you may be able to point me in the right direction. I have recently "inherited" for the lack of a better word, a 1986 240 DL Wagon that is actually in exceptional condition. While the paint may be slightly faded, the interior is pristine and the engine bay is about as clean as it gets. However, I have been having an issue with the vehicle and it has completely stumped my novice mechanical skill. When I put the car in drive and accelerate, the vehicle begins to stutter at low RPMs and occasionally dies. If the car is in reverse or in neutral and I give the car gas,the engine revs up as if nothing was wrong. Fuel filter was recently replaced and has less than 100 miles on it. I have the Bentley manual, which I found isn't much help when you dont even know where to start. Any ideas on where to start, or of who in the Tampa area would be of any assistance. Look forward to hearing from you all, and thank you so much for your help.

Joe A.

 

stumbles off idle can be caused by a lot of things, ignition, fuel delivery, air or exhaust leaks, etc.

82-87 volvos suffered from biodegradable wiring harnesses. the insulation wires inside the black harness tubes in the engine compartment can crumble and fail, if this happens, all bets are off.

stuttering in forward only but not in reverse could, I suppose, have to do with a bad engine mount, allowing the engine to move excessively in one direction and causing some part of the wiring or intake ducting to fail. you should change both engine mounts AND the differential mount (as it is the third point of the triangle) if this is the case.

the LH 2.2 volvo 240's used a chrysler ignition control unit thats mounted on the inside of the fender just behind the right headlight, this controller has a plug thats quite fragile and can cause issues.

 

Start by a good basic "tune up": plugs, wires, cap, rotor, etc. Who knows when they were checked? Check the fuel pressure, fuel pump may be at fault as well as many other things.

 

I will take a peek at the mounts today and update later. Also noticed the vacuum hose missing that goes to the ignition unit, just can't figure out where on the ignition unit it runs to. Thanks for the leads!

 

at the bottom corner of the ICU, I think on the edge facing the headlight, is a vacuum bellows. there's a nipple on there for the vacuum hose, and thats used to control ignition advance.

if you unplug the chrylser ICU, be /very/ gentle with the plug, do not rock it, only pull it /straight/ out. the pin sleeves loosen up very easily then don't make good contact. I'd clean it up with some electrical contact cleaner spray, use a fine point to sligthly tighten the individual sleeves, then apply a thick layer of silicone dielectric grease all around the outside of the plug, and plug it straight in. that ignition harness, at least for the 87/88's, is unobtanium, no longer made.

 

Thanks Pierce for the heads up! In between the storms here I was able to run out and check a few things. Looks like I was wrong in regards to the ICU, as I followed your direction and their was already a vac hose running from it. So instead I took a picture of where the hose was missing from and will throw it up here so you guys can help me identify where it needs to go.

 

that vacuum hose on top with the inline one way valve normally goes to the firewall and is used by the HVAC for air flap control.

 

So since the AC is not in working order at the moment, just disregard?

 

well, the vacuum activated flaps are also used for the heater and defroster vents, even without A/C. the 3-4 buttons on the dash for defrost, recirculate, floor heat, all use vacuum to open/close the various control flaps. start the car, turn the fan to about 3, push the defroster button in, do you get air out the top vents aimed at the windshield? and pop that button back out, does that air mostly stop? push the floor heat button, does air come blasting out the footwell vents, and stop when the floor button is closed? if that all works, then that vacuum circuit must be hooked up /somewhere/.

Off the top of my head, other places vacuum lines have to go to...

A) big one to the power brake booster, the one-way is built into the right angle fitting on the booster 'drum'.

B) the ignition control unit, as you've already checked.

C) the fuel pressure regulator, this lowers fuel pressure under high vacuum, and raises it when the throttle is wide open.

D) the charcoal canister fuel vapor recovery system, the vacuum is used to actuate the purge valve.

E) only if you have it, the EGR controller (I think EGR came later, like 1990-ish, and initially only on California bound cars).

.... I'm probably forgetting something.

 

You should always start by checking the connections of wires and hoses. It is amazing how many issues can be caused by a simple loose connection.


I had an issue with the car stumbling, that turned out to be the spade terminal on the wire to the coil being loose. It was slipping off under acceleration causing the car to die, but it would then start right back up because the "memory" of the wire caused it to move back into contact with the coil. A gentle squeeze with a set of pliers tightened up the connector and no more problems.