Intermittent cut-out

[xdig]

Just finished a 5-speed swap and 3-bar conversion on my SL. Finally got it running well except for an intermittent cut-out. Actually acts like I am running out of gas for a second and then runs fine (occasionally it will buck a couple of times and then run like nothing ever happened). So far this is occurring just off idle (light acceleration). Symptoms are similar to HEP that is going bad but doesn't completely die. I tried a brand new Mopar HEP but same issue. Also, I am not getting any codes. Any suggestions would be appreciated.

[CNH320]

Check ground wires are tight, if you had them off for the trans swap.

[xdig]

Check ground wires are tight, if you had them off for the trans swap.

Thanks. I replaced a bad injector ground and it seems to have helped but still occasionally cutting out. The last time it did this (an hour ago) I was taking off from a light, shifted to second, and was about to shift to third when it cut-out again. This time for longer (a couple of seconds) and then acted like nothing had happened. I will recheck grounds and have already replaced HEP. Anyone else have a similar problem?

[xdig]

On a long shot I swapped out the coil but no help. Still no codes. Any suggestions would be appreciated.

[cordes]

What cal are you running?

[chilort]

I've been playing hell to find a random miss problem. I've been through the electrical (plugs, wires, cap, rotor, coil, more plugs and more plugs, idle air control, tps, hep). I thought maybe it was a vacuum leak. I replaced all of the vacuum lines, check valves, brake booster valve, made my own vacuum block, used t-bolt clamps for my IC hose, and the PCV valve.

It was cam to crank timing. I'm not sure which way it as off, but after having reset this, I've had no problems.

[xdig]

What cal are you running?

Shelgame 2.5L, 3-bar, +40, cal. I drove the car about 20 miles this morning without it happening but it has been intermittent and so I don't think that it has just gone away. Any input or suggestion would be terrific. Thanks, David

[xdig]

I've been playing hell to find a random miss problem. I've been through the electrical (plugs, wires, cap, rotor, coil, more plugs and more plugs, idle air control, tps, hep). I thought maybe it was a vacuum leak. I replaced all of the vacuum lines, check valves, brake booster valve, made my own vacuum block, used t-bolt clamps for my IC hose, and the PCV valve.

It was cam to crank timing. I'm not sure which way it as off, but after having reset this, I've had no problems.

Wow, that is interesting (although this is not a miss problem, it just cut-outs completely for a second or so). I am running the S2 at 6 degrees advanced (which may be too much). I just haven't had a chance to dial it in properly. I'll check that next. Thanks!

[cordes]

Wow, that is interesting. I am running the S2 at 6 degrees advanced (which may be too much). I just haven't had a chance to dial it in properly. I'll check that next. Thanks!

I would dial that cam in straight up before I did any further testing with the cal.

[xdig]

I would dial that cam in straight up before I did any further testing with the cal.

I actually started with it "straight up" and I should have advanced it 2 degrees at a time but it ran much better advanced to 6 than it did at 0 so I just left it while I was working on other issues. I just haven't had a chance to go back and find the optimum setting. Thanks!

[chilort]

I've been calling it a miss, but cut-out. Whatever. I have a digital dash and the rpm drops for a second and it cuts out. Acts like everything is fine otherwise and no codes.

[xdig]

I've been calling it a miss, but cut-out. Whatever. I have a digital dash and the rpm drops for a second and it cuts out. Acts like everything is fine otherwise and no codes.

Thanks, I'll be checking that today.

[cordes]

I've been calling it a miss, but cut-out. Whatever. I have a digital dash and the rpm drops for a second and it cuts out. Acts like everything is fine otherwise and no codes.

I would highly suspect the HEP if the tach is cutting out.

[xdig]

I would highly suspect the HEP if the tach is cutting out.

That was my first thought but I replaced it with brand new Mopar HEP and no change.

[chilort]

X2. Not the HEP.

[cordes]

I'm stumped.

[chilort]

I have no idea what was causing it.

My car would cut out around 2000 rpm at light throttle. Not all the time but I could make it do it if I wanted to. Checked ignition timing as well and it seemed to jump around a bunch but I would essentially average it (and yes, I had the 2-wire temp sensor unplugged).

Now, with all of the crank, cam, inter timing set, the ignition timing stays dead on 12*.

What, why, how? I do not know. It idled well and ran like a scalded dog at full throttle. No bog, no nothing to indicate there was an issue other than the random miss. I wish I did know.

[JamesL]

That's part of the fun of owning these cars. No shortage of mysteries with all that wiring. I'd still be suspect of a ground problem to the ECU. Is the motor torqueing a little in the engine bay when it happens?

[87glhs]

Try wiggling the metal rotor wheel (located under the HEP) around either once the engine is warmed up, or try to check it immediately when the problem is occuring--if it's loose, you'll need to replace the distributor.

The nylon "rivets" that hold the wheel in place loosen up in time and the wheel will start floating around.

I had to deal with the same issue last summer with our TII 2.2L. It would miss randomly once the engine warmed up (about 10min).

[chilort]

Try wiggling the metal rotor wheel (located under the HEP) around either once the engine is warmed up, or try to check it immediately when the problem is occuring--if it's loose, you'll need to replace the distributor.

The nylon "rivets" that hold the wheel in place loosen up in time and the wheel will start floating around.

I had to deal with the same issue last summer with our TII 2.2L. It would miss randomly once the engine warmed up (about 10min).

I also checked this out. My metal rotor wheel was held securely to the base. No problem there. I am currently building an engine so I had another dizzy. The metal rotor wheel thing was held securely in that one too. One thing I noticed was that the dizzy itself, wheel and all, could rotate freely a couple of degrees. I posted on this very topic. I was told to mushroom out the base of the dizzy so it fully engages the oil pump. So I did that. The miss basically moved up the rpm band slightly.

I also thought about grounding issues. I checked all of my grounds for a voltage drop across them and for continuity one at a time (most volt/ohm meters are worthless in the very low resistance range. Turn of the car, disconnect all grounds, and reconnect only 1 ground. Now check the voltage between the "-" terminal of the battery and where the other end of your ground connects to. If you show 12v then you have a problem, that ground strap is junk. Wash, rinse, repeat). No problems. I added in an extra ground from the "-" side of the battery to the body. Still no fix.

Timing... timing, timing, timing, timing, timing.

I used to think the people that would throw timing out for the cure for everything were full of it..... doh!