I spent the entire day Saturday going through this 1990 745 non turbo. Help me figure out why it finally started. Background: The vehicle always a slow starter in the mornings, runs fine all day. Hunts at idle in schoolkid pickup line, worse with A/C on. In last weeks cold snap (35F for us) it would not start that morning(friday). It tried to start but would never catch on more than 1 cyl. First I checked compression, got 180 on all 4 with increase with tsp oil added . I checked and found idle switch did not click until full throttle. I corrected this to click immediately at throttle app. I later conclude this is why the engine hunted at idle. I check with a spark tester and get good spark(3/8 gap tested) on all 4 cyl and regular. All plugs sooty, and misgaped to .040. Plugs hotter than spec (7's vs 6's). I cleaned with a rag (shoeshine style in gap) and set gaps to spec of .028in. Still would not start, sometimes dead as doornail sometimes life. Tried again Sunday aft. Started and ran for 30 sec on 1 cyl. I went for broke and took off air intake and injected approx 1 tbs gasoline into throttle body with throttle open. Reattached intake and started again on 1 cyl. Heated up and ran better on the 1 cyl to a steady state. Tried to drive but not quite enough power and could not accel. With the motor running listened and confirmed injector function listening through a screwdriver per Haynes. I then hooked up a timing light and got light from #4 plug wire only. Could not get light from any other plug wire even though all tested well on the sparktester previously. (note, I also previously swapped plug and coil wires from 940 w same engine.) After the timing light testing, other cyls started to kick in and finally some 10 minutes in, all cylinders were firing and engine was running great. This morning ,Monday, the engine started up immediately and is running great. Is this a case of fouled plugs, maybe goop in the tops of the pistons? Could all this have been caused by oil leaking into the cyls from valves? Rich running buildup from the mal adjusted throttle switch aggrevated by severe flooding? I would think the plug cleaning I did would have decarboned enough to start it. I wonder if a mouse crawled back out of the tailpipe(ref car wont start, cat converter blockage)?? The timing light seems to prove it was fouled plugs or old fouled plugs but it doesnt work great at putt putt speed. I guess this is a rhetorical post, but reply away. I think I just stepped into the oldest one in the books...fouled plugs. Id like to know others experiences with mis adjusted throttle switches.

Also,

1. Check for Vacuum leak.
2. Clean Throttle Body.
3. Resolder Fuel Pump Relay.

Ian

Sounds like you narrowed it down when you did the spark test with your timing light. I would check the dist. cap and rotor and then focus on known ignition system problem areas for your engine management system. Do you have Rex/Regina or Bosch?

bagle 87 745T Bosch LH 2.2

I did look at and clean distributer cap and rotor. Fould oil leaking past the dist Oring, but decided it was too simple to be the problem. I figure it is difficult to stop high voltage from jumping terminals. I think it is the regina system. I for sure have regina fuel as I replaced the single in tank fuel pump this summer. BTW, a clogged fuel filter will ruin your fuel pump and case no start/ hard start(130000 miles, I bought the car used). The coil is mounted on the lf shock tower and is rectangular, not typ cylinder. The same setup is on my '93 945. I didn't mention but did listen for the fuel pump to come on, and have new filter so I think it safe to put the relay/fuel delivery on the back burner. My wife just said it died once this morning on startup, so I am still concerned the problem is not licked. To check vacuum, just take off suspect ho hoses and finger test for suction while running? Will thee o2 sensor cause these rich running problems. Is there a way to hook up a pc to the ecu and check outputs and function of all the sensors? The Volvo engineers must be able to do that. Rodger on the throttle body cleanup- will get that this weekend. Thanks for responding.

Ok, I don't know anything about the regina system, but others here do. If I were you I would repost the problem with the title "regina ignition problem" or some such and you will probably get better advice. Also, you can search the archives here and see if you find anything.

Good Luck,

Bagle