'82 Engine Cut-out upon Hard Acceleration
08-18-2013, 06:17 PM
#16
Burning Brakes
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Back with more input. Checked the AFM through it's whole range. looks perfect. I could get 0.01 V changes with the most delicate pressure on the flap. However, I did notice two things.
1. At Idle in the garage, I was able to get the motor to die just by turning the steering wheel!
2. On the road, I couldn't get more than about 35 MPH without constant hesitation (like hitting a rev limiter, but only at about 1100-12-000 RPM) I realized that it's been dong this all along but since I was never able to get very far without I dying, I hadn't realized it. If I keep the revs just under this point it will drive but turning the steeling wheel will make it bog down and nearly die.
Now I'm wondering if the T-belt really has sk8ipped a tooth or two. Being a 1982, it can actually break the belt w/o clashing valves & pistons.
Anyone have experience at that? Top contenders are T-Belt slip and L-Jet brain. - Ruf (Oh and Dave 928S, I LOVE your avatar. Only downunder!)
1. At Idle in the garage, I was able to get the motor to die just by turning the steering wheel!
2. On the road, I couldn't get more than about 35 MPH without constant hesitation (like hitting a rev limiter, but only at about 1100-12-000 RPM) I realized that it's been dong this all along but since I was never able to get very far without I dying, I hadn't realized it. If I keep the revs just under this point it will drive but turning the steeling wheel will make it bog down and nearly die.
Now I'm wondering if the T-belt really has sk8ipped a tooth or two. Being a 1982, it can actually break the belt w/o clashing valves & pistons.
Anyone have experience at that? Top contenders are T-Belt slip and L-Jet brain. - Ruf (Oh and Dave 928S, I LOVE your avatar. Only downunder!)
11-18-2013, 03:29 PM
#17
Burning Brakes
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SOLVED!
Thanks to everyone who commented on this issue and also the few who PMed me with suggestions, comment question.
Anyone with a pre LH-Jetronic car will know whet I mean when I say "Green Wire". Yup. that was it, but not the entire story. The GW was replaced about 4 yrs. ago and wasn't really a suspect, however, the far end where it plugs into the TIU (Transistor Ignition Unit) had a short along the line between the female plug for the GW and the large mulit-pin plug that goes into the TIU. This was caused by simple age, stiff insulation was putting a kink in the line where it bends going into the wiring harness.
Part Two, and this was the really "obvious once you think about it for two seconds" part. The 12V line from the starter to the coil and TIU was badly frayed, with bare wire intermittently shorting against the strap that holds the wires up off the ground.
This was only happening when I was driving down my steep driveway or going into a hard curve, allowing the wires to touch the strap and short out. That instantly killed the entire ignition system until the g-forces were over and contact was bracken. Once the car stopped, it would start up like a champ & run great until the next curve or until I got home ... Jeez!
Anyway, I did a T-Belt, Fuel Pump/Filter, Fuel Press Regs. and Damp, which all were very old or overdue so at least I didn't buy a new L-Jet unit, but I did find a cheap one online for $225.
Two Major Lesson
1. Old insulation is cracking a flaking off every wire on 30 yr. old cars, so shorts and open grounds are a real suspect.
2. When the fuel pressure is too high, the L-Jet unit will shut down the fuel injectors because the current required to open them is too high. Thus Fuel Press Regs that are stuck closed can look like a bad L-Jet.
Sharks. Gotta love em... - Ruf
Anyone with a pre LH-Jetronic car will know whet I mean when I say "Green Wire". Yup. that was it, but not the entire story. The GW was replaced about 4 yrs. ago and wasn't really a suspect, however, the far end where it plugs into the TIU (Transistor Ignition Unit) had a short along the line between the female plug for the GW and the large mulit-pin plug that goes into the TIU. This was caused by simple age, stiff insulation was putting a kink in the line where it bends going into the wiring harness.
Part Two, and this was the really "obvious once you think about it for two seconds" part. The 12V line from the starter to the coil and TIU was badly frayed, with bare wire intermittently shorting against the strap that holds the wires up off the ground.
This was only happening when I was driving down my steep driveway or going into a hard curve, allowing the wires to touch the strap and short out. That instantly killed the entire ignition system until the g-forces were over and contact was bracken. Once the car stopped, it would start up like a champ & run great until the next curve or until I got home ... Jeez!
Anyway, I did a T-Belt, Fuel Pump/Filter, Fuel Press Regs. and Damp, which all were very old or overdue so at least I didn't buy a new L-Jet unit, but I did find a cheap one online for $225.
Two Major Lesson
1. Old insulation is cracking a flaking off every wire on 30 yr. old cars, so shorts and open grounds are a real suspect.
2. When the fuel pressure is too high, the L-Jet unit will shut down the fuel injectors because the current required to open them is too high. Thus Fuel Press Regs that are stuck closed can look like a bad L-Jet.
Sharks. Gotta love em... - Ruf
