Hello,
I need some help. I am having a problem with my 84GL b23f lh2.0 AW70. I have been working on this car for almost a year. I have replaced a great deal of parts as well as having spent literaly hundreds of hours trying to make this a nice car.
Heres the problem-The car runs great until the rpm gets over 2800rpm. I drive pretty sane, so this is only in overdrive at 65+ MPH. Above 65 the engine starts to miss, just enough to make the car jerk a little. Under 65, she runs great, smooth, strong, except for a slight miss at idle. Not enough to make it idle 'rough' but just a percievable miss every few seconds, although idle is a little high. In the last year, here are the parts I've replaced;
1. Alternator 2.Starter 3.Battery 4.distributor(replaced with a rebuilt) 5.plugs,cap(s),rotors(s),wires(s) 6.Traded ICU's 7.repiared and replaced any suspect wiring(inc. lh 25A blade fuse),rerouted all wires under the crank except alt.-starter wire and cleaned every connection(inc. all fuses) on the car. 8.knock sensor 9.O2 sensor 10.coolant temp. sensor 11. Throttle switch(s) 12.fuel pump relays 13. both fuel pumps (twice)+filters+press. regulator 14.All gaskets from head up 15.new intake valves and seals 16.flame trap oil return hose 17.intake bellows 18. AMM(remanufactured)19.front crank, cam and intermediate shaft seals. 20. Fuel injector seals(twice)21.trans.filter 22.Tailshaft bushing/seal 23.center support bearing and related parts 24. loose universal joint
Here are the parts I haven't replaced yet;
1.Jetronic control unit 2.IAC(did rebuild per faq) 3.KNown good ICU
Here's what I've done so far;
First I thought it was ignition related. Ended up repacing almost the whole system with all Bosch parts but didn't help. Then I thought it might be electrical, so I p[ulled the engine harness, and the seats/carpet and looked at/cleaned/fixed everything wiring related. Then I thought fuel delivery so I replaced the pumps, first with autozone cheapo's then with Bosch inc. filters. also Fuel pressure regulator with a bosch. Removed throttle body and cleand(twice) as well as adj. throttle switch on the bench w/ feeler gauge. Intake mamifold gasket, intake bellows. Tried the sensors, replaced, rewired, tested, but not it. I pulled the oil pan and cleaned/measured the oil pump also replaced oil return pipe. Replaced front engine seals plus oil filler pipe and oil cap seals. Then driveline, trans. filter, tailshft parts, center support parts, a loose u-joint, cleaned/lubed spline fitting. Made it ride better, but... I also own the IPD shim kit, so I have adj. the valves numerous times. Took off the camshaft and tried to measure as best I could with my cheapo dig. caliper, seemed fine, bearing surfaces looked acceptable. Valve spring height was ok. replaced intake valves and lapped all valves befor reinstalation. Then I bought a used but working AMM, no change. Used ignition ICU, engine sounded stronger/better spark, but nothing. I even replaced the exhaust system from the manifold back.
After each of these repairs I would test and try things using my brand of logic as well as anything I could find in Bentley, Haynes, and Green Manuals.
I thought I might have had a wire that was broken inside and it didn't move enough until 65+MPH winds, then I discovered the in neutral, I could press the gas 3/4 to the floor and the engine would rev. to 4500 then cut back to 4000 and fluctuate there as though I had a rev. limiter or something. If I floored it, almost 5000rpm, but the engine sounded strange/rattly/unorganized/noisy/backfired a couple of times??? I'm not sure how to put that sound into words, but about 5000rpm was all she had. In gear though the misfire/jerkyness starts as I approach 3000Rpm.If I shift into a lower gear, still misfire after 3000. If I floor it durring these misfire times, the engine will keep on pulling but also have these jerks. Compression test showed 160-165psi with hot engine in all 4.
I can't think of what else at the moment, but I'm getting close to having replaced the whole car piece by piece. If I could fix this one thing, the car would run awesome, as it does below 65mph.
Can anyone give me any insight? What have I missed? What should I focus on now? What else can I do? Has anyone ever been so obsessed with a 21 year old car with a bad paint job?
Thanks for reading this, Kenneth