86 TII Swapped GLH code54/HEP Issue

[HUFFZZ]

86 GLHT
TII swapped to 87 TII, re pinned LM and Map under the hood.

Car starts and idles fine, under very light throttle it will drive as normal but when there is a load put on it the car bucks and kicks like overboost but its not overboost. The car threw a code 54(fuel sync) early on but recently it has gone away and hasnt come back. When the code 54 was thrown I swapped out the HEP for 6 different ones and no change. I then went through the wiring diagnostics check for 8+V in each pin and found that when probing the grey connector while it is unplugged I get 8.77V from the Orange to the Black/Light Blue. But only 0.54V when probing the Orange to the Tan/Yellow wire. According to the diagnostics when this is found you check for continuity(resistance) between the terminal and pin 17 on the blue connector. I did this and there is perfect continuity, 1.5ohm of resistance. The manual says that if no voltage is found and there is under 5ohms of resistance replace the LM. We have tried 5 different LMs and no change. Now code 54 is back but I have now replaced all the following parts with new units, LM (new), Power Module (new), HEP (new), Fuel Pump (new), MAP (new) and also thought maybe it had fuel delivery issues so put a fuel pump in a bucket and jumped the pump straight from the battery and car still does it, plus before that even bypassed ASD Relay and same thing????

Any suggestions would be greatly appreciated.....

I figured I'd add that when the car was still stock (TI Suck through) it worked fine the car drove well and never had any issues.

[HUFFZZ]

is that crickets I hear!!!!! So basically nobody can help me or offer suggestions?

[PunKid]

I can't offer a solution, but my 85 GLH-T (slightly different distributor) would throw code 54 randomly. it seamed like heat saturation caused it, like traffic. I did have some luck cleaning all the connector and trying to make sure all the pins were tight and making good contact, and I went through the distributor and actually added an extra shim (it had some up and down end play). I also went through and cleaned all the grounds and even cleaned the distributor where the HEP goes (you can see a metal tab on the HEP that clearly say not a ground but it looks like it is). All of that made the problem show up way less but I never determined the exact problem.

I just converted to T2 myself and to 87 LM electronics. I have not fired up the car yet but I am hoping I do not have similar problems.

question when you added the two wires for the IAC did you know what pins on the IAC connector go to the PINs on the 87 LM?

I even went

[cordes]

http://minimopar.knizefamily.net/fault/code54.html

It sounds like you need to do some deeper digging into that HEP wiring.

[DevoBuzz]

I can't add much besides checking your grounds and making sure the alternator isn't hitting the rad support when under load.

[HUFFZZ]

Well I have 4 individual 4gauge grounds coming off the motor 2 from the intake and 2 from the motor itself but I'm thinking of adding one more ground right from the fuel rail to the firewall just becasue. The other thing I'm going to try now that you mentioned it PunKid is check all the connectors again as the car did run fine when it was stock and I have already gone over all the new wires added for the T2 Swap and they are all good. I'm just getting a tad discouraged that's all, wanted it running for the summer.

[turbovanman²]

Check the dizzy, it could be worn or the reluctor plate is loose-common.

Do you have it timed correctly? I would assume that if you have the distributor out of time by a lot, it would set that code.

[HUFFZZ]

Well bringing this back up as there has been some changes, the Code 54 went away for awhile I could drive the car up and down the street not getting into boost but as soon as I wanted to get into it the car would buck and kick like overboost let off the gas and start driving it normnally again and the car ran fine I then started thinking this was a total mechanical issue like maybe wastegate was bad or the arm fell off so I checked arm and it was still on then ran about 10psi into the wastegate and it actuated the arm so now I figured it's not wastegate so I figure try to drive the car again just to see and now getting code 54 again WTF!!!!!! I've checked the voltage at the grey connector with key on and I'm getting 9volts and 8.5volts so I know that's good and like I've said before the HEP is brand new Mopar piece????? I need help from anyone just pm me with any info that may help me I'm really thinking of getting rid of this car I hate to give up but this car has not ran right for at least 6months so ready to thorugh in the towel..........also sorry if I may have repeated myself just working on it now and this is what's going through my mind.

[cordes]

I had the WORST problem with this at SDAC this year. I did everything you could think of and the problem is still there just a little bit.

I would do things in this order.

1. close down the terminals in the hep wiring a little for more snug of a fit.

2. Clean all connections with an electric cleaner and reapply dielectric grease.

3. Inspect all wiring related to the HEP.

4. Inspect the splices which are in the harness pretty much half way between the HEP connectors and the connector at the battery.

5. Close down the connections at the LM and PM to ensure a better connection.

Doing those things got my car to a drivable state.

[HUFFZZ]

Ok I'll give that a go, does car your car still go into boost though after doing all these things? Did you do all connectors on the PM and LM? I know Ihave continuity going to HEP from the LM and I have 9.5v and 9v at the grey connector did you have the same as this as well before you did all those things?

[cordes]

Ok I'll give that a go, does car your car still go into boost though after doing all these things? Did you do all connectors on the PM and LM? I know Ihave continuity going to HEP from the LM and I have 9.5v and 9v at the grey connector did you have the same as this as well before you did all those things?

I forget my voltages now, but I think that's right. I thought that one of them was about 5v and the other was 8.95, but it has been a while now and I haven't written it down. I actually switched HEP connectors and installed some Packard style connections. That didn't really make much of a difference, but I know it's not the HEP connectors now for sure.

My car would go into boost, but it is a SMEC car. I did have my Omni set up with an LM and it would cut out at exactly 6PSI no matter what I did. I eventually pulled the entire harness to discover that it was much worse than what it originally looked like. I suspect that it was just a wiring issue which would only show itself when the system was taxed from WOT and higher RPMs.

[4 l-bodies]

What wires did you change going from 86 to 87? It should have been exactly as listed below. Just want to make sure you aren't running 3 bar map on two bar calibration, or vice versa. Check all your terminals at red and blue connector at LM. These can go bad from getting unplugged a million times, plus moisture causing terminals to corrode. Did your LM still have plastic bag around it? Any white fuzz on blue and red connectors? Sorry if this seems redundant, but your asking for help.
Just to review wiring changes you made:

Power loss light moved from Blue 4 to Red 4
VSS move Blue 14 to Red 9
Add new AIS wire to Red 16
Add new AIS wire to Red 22
Add Map power to Red 1
Add Map Signal to Blue 19
Map ground. Tap into underhood maybe charge temp sensor. (black with light blue tracer) This will eventually tie into Red 25.

Next I would consider taking out the underhood harness so you can inspect everything carefully. Have another GLHS harness you could borrow?
Todd

[HUFFZZ]

What wires did you change going from 86 to 87? It should have been exactly as listed below. Just want to make sure you aren't running 3 bar map on two bar calibration, or vice versa. Check all your terminals at red and blue connector at LM. These can go bad from getting unplugged a million times, plus moisture causing terminals to corrode. Did your LM still have plastic bag around it? Any white fuzz on blue and red connectors? Sorry if this seems redundant, but your asking for help.
Just to review wiring changes you made:

Power loss light moved from Blue 4 to Red 4
VSS move Blue 14 to Red 9
Add new AIS wire to Red 16
Add new AIS wire to Red 22
Add Map power to Red 1
Add Map Signal to Blue 19
Map ground. Tap into underhood maybe charge temp sensor. (black with light blue tracer) This will eventually tie into Red 25.

Next I would consider taking out the underhood harness so you can inspect everything carefully. Have another GLHS harness you could borrow?
Todd

Nope that's ok I need the help and asking those questions makes me re-think what has been done who knows maybe I screwed up somewhere LOL.......

[HUFFZZ]

Well the car runs and drives my buddy was nice enough to work on the car and what he found out was kind of a kick in the teeth, So the engine harness was swapped out for one out of an 87 shelby charger and after the old harness was pulled he saw what the cause was my powersteering pulley ate through the engine harness pretty much fussing all the wires together and when ever I would accelerate the motor would shift back pulley would rub on said wires and cuz the car to act like it was over-boosting.......So anyhow the runs and drives just have to set timing I think it's off a little.