I'm getting code 54. I've swapped in a brand new Mopar hep and the van still has drivability issues.
What should the harness to hep voltages be?
All measurements made with connector keyway facing up. I get the following:
Grey connector:
Left - bottom ~9V
Left - right ~9V
Black connector
Left - bottom ~9V
Left- right ~4.5V <--- is this a problem?
Should be roughly 8V on the orange power supply wire (don't know which pin off the top of my head). The two signal wires shouldn't see more than 5V on them with the sensor disconnected (tan with yellow stripe on grey connector, grey with black stripe on black connector). The code 54 is from the fuel injector sync sensor, which is the grey connector. Almost looks like a short between the power supply and the signal on the fuel injector sync.
OK, I checked it again. As before, I've got ~9V on the orange wire and ~9V on the tan with yellow tracer (signal wire). Would appear to be the problem. Correct? Sensor is/was disconnected.
The van runs, it just stumbles/quits momentarily while driving. Only Code 54 is stored after I cleared the computer.
I've also got 9V back on the same line back at the six way connector under the master cylinder. Looks like it could be a short between there and the SMEC. I hope it isn't a problem with the SMEC itself. I'm also reading the same voltage (9V) on pin 26 of the 60 way connector.
Looks like I'm about to get ankle deep in fricton tape...
Thanks for the feedback. Great site you have there btw.
OK. So the wiring appears to be good. With everything back together I'm seeing a little over 4 volts on the HEP sensor wire. Of course I only see this when everything is connected and running... doh!
I'm still having drivability issues though. The motor cough/cuts out intermittently. It can do it at idle, during accel, or when cruising at constant speed. It can be subtle to non-existent for periods of time, and other times it's downright embarrassing...
I've triple checked the cam timing, and the ignition timing is at 12°. Both are bang on.
I took the van out for a spin last night, and it ran OK, but stumbled a few times. Usually after I was back on the gas after rounding a corner or starting from a stop. I got back home and checked the codes: 15, 33 and 54. 33 would be a red herring I believe. I gutted the AC a long time ago.
Would speed sensor issues cause what I'm experiencing?
What about this recurring 54? Do HEP's go marginal? I thought they worked or they didn't. Can this code get set as a result of issues elsewhere?
Today the van had serious "morning sickness" It didn't want to run well at all. Coughing and sputtering. My voltage gauge was reading lower than normal. Code 47 was stored. I've not seen that one before. I went out at lunch and the thing better, and my voltage gauge was back up where is usually is. Gremlins. Aarrrgh.
Also wacky: This morning, I resorted to using a little brake boosting to keep the van's revs up when stopped. I found out that if I left the stop with the brakes dragging a little bit, the van accelerated and cruised *perfectly* (no hesitation, stuttering coughing or the like). As soon as accelerated or cruised without any brake drag the thing would cut out/cough intermittently again. If anyone has any idea what's up with that I'd love to know...
So the love hate - relationship continues.If this thing weren't so much fun to drive (when it works) I'd have given up a long time ago...
The recurring code 54 is telling you something. HEPs can die many ways. The most common is sudden death, either thermally (when hot) or completely. I've also had the little flat harnesses become intermittent from swaying around too much. Can you effect the idle by jiggling the HEP harnesses?
Voltage thing might be a grounding issue.
Nope. The van will sit there and idle just fine as I wiggle away. I've wiggled the thin flat wires, the connectors and the main harness across the front of the engine. Since I get code 54 using both the old and the new (both Mopar) HEPs, my thinking was also a wiring fault. Nothing clearly correlates though. I pulled the batt terminal off again to clear the codes, double checked all my connections, crawled under and checked/wiggled the speed sensor connection. Again van drove OK (a few hiccups) for a bit. Ran like crap (constant stuttering under accel) for a bit, then went back to running OK again.Can you effect the idle by jiggling the HEP harnesses?
Checked the codes and got 15, 33 and 54
I think I've found the problem.
This morning I'm getting 16V across the battery. Field voltages are all over the map.
Would a duff alternator be causing my problems?
Possibly. Could still be a grounding issue causing both...
Well the alternator failed the DC output test at the auto parts store so i bought a reman and it didn't fix the problem. Battery and field voltages are much more cosistent now though.
I've been checking grounds and I can't find anything wrong. Power grounds and signal grounds all post well under 1 ohm w.r.t neg batt terminal or the ground strap on the block.
New problem though. I was looking over things at the fuel rail and noticed a slight kink in the bend at the supply line. Thinking this might be part of the problem I (very carefully) tried to straighten it up but no go. It was so brittle it just cracked open...
So I'm off to search on fixing /replacing that. I'm guessing a whole new rail is the only option...
You can silver solder it. What I did was cut out the bend, make a new bend out of brass tubing that fits perfectly over the old tube, and solder the two parts back together. Held up for years. You have to support the supply hardline on those 2pc fuel rails.
Guess the alt was a separate issue. I hate it when that happens. When it rains it pours sometimes. Something is still screwy with the code 54, though. Hopefully it is the real cause of your problems. If you have access to a scope, I would hook it up to the fuel injector sync signal line and watch it with the engine running and start shaking the harnesses around. If it's really intermittent, the engine will still run since the ECU only looks at it briefly when it wants to know which cylinder it is firing. Short of that, maybe hok a meter to the 8V supply and see if you can make it flake out by moving things around.
Have you tried a different ECU?
I was thinking such a repair could be done, but I'll probably just pick up a used one.
...as in oscilloscope? I got plenty of those kicking around work. Will give 'er a go. I assume I don't need anything really fast, since the pulse width can't be that short. Correct?If you have access to a scope...
I wish I had a spare ECU or even another HEP to try. I thought about going back to the dealer with my "new" HEP and see if they were willing to switch it or at least test it in another turbo car. I'd really like to conclusively eliminate the HEP itself as the source of my problems.
Anyway, gotta get the fuel situation fixed up first. Thanks.
Well I get a nice square wave off the fuel synch line. With a little "tooth" in every 4th pulse, which i assume is the fin with the window.
The signal is good when I wiggle the wires around. I loose trigger when the van cuts out but I'm pretty sure that's b/c the supply voltage is dropping also.
Man, this is frustrating. I'd really like to understand why the cutout/stumbling problem disappears almost entirely if I drag the brakes as I'm accelerating.
I checked my cam and ignition timing for the 4th time. It'a all dead nuts. I pull 18" of vacuum at idle. I replaced the chassis to manifold ground strap and confirmed the front one (to the battery) is solid. don't know where to go next. Can the MAP be bad w/o throwing a code? Would a bad one give this kind of driveablilty issues?
If you drag the brakes while accelerating, the motor will lean back and stay there. What if you put the scope on the 8V with tiggering off and the sweep real slow? Do you see it cut out?
Aaaarrrgh.Fuel Filter...
I put a new one in after work today (the "old" one was new only two years ago), and presto, the van runs like a champ again. I guess at 17 years of age it might be necessary to change it a little more frequently.
Just got back from a test spin. I had a couple of brief studders but no codes. Gonna grease all my connections again and then wrap up and secure the wiring.
Thanks for your input.
Well that was short lived. Van was running like a POS again this am.
Hehe...it tricked you. Don't you love that?
In a word: No.Don't you love that?
I'm now giving serious consideration to replacing the fuel filter...
...with a MATCH!
Your not alone with this problem. My sundance with 89 smec wiring doing the same thing. I change heps 3 times it gets better at first and then goes back to being pain in the butt. I got another smec to try on mine but my turbo seals went this week and it smoke like crazy now.
Mine randomly cuts out at any time. It seem to be worst when my radio playing. But I did check my volts at the hep and I was getting 5 volts on the signal wire.
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