Poss EPS donor car identified at the junk yard today (Page 1/2)
qwikgta MAR 07, 01:35 PM
Title should read "EHPS" vs. "EPS"

So walking the yard, found a 2013 Dodge Challenger. Motor/trans was pulled exposing the steering rack. Noticed it had a nice, compact steering rack and took note of it for a possible future project. Then I noticed that the hoses went off to the side and i traced them to a electric pump located under the front, passenger bumper. I pulled it all and brought it home for a great price. Good news is that it steers at the front of the spindle just like our cars do. Not sure of the electronics yet, maybe i'll get lucky and it will still work in a "limp" mode if all I can do is hook up power/ground. If anyone has any ideas please include them here. Pics attached.






Rob

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88 Coupe, CJB #95, LS376, F40 and a GT clip
88 GT "Daily Driver" w/ SIII 3800 NA

[This message has been edited by qwikgta (edited 03-07-2020).]

Spadesluck MAR 07, 04:37 PM
Not going to lie, power steering would be nice just for the convenience for sure. I do not mind old manual labor but it is 2020!
qwikgta MAR 07, 06:14 PM
yea, i agree, i'm fine with the stock steering, but i'm always looking out for new tech that may upgrade our cars. Thats why I'm fine if it only works in a limp mode. slow speed driving is the only place you really need it.
FieroJimmy MAR 07, 07:05 PM
If you don't have the vehicle speed message from the ABS module on startup, the EHPS module will not activate the pump. If the speed message is lost while the engine is on, it will continue with default values for assist until the next key cycle. To make it work without custom programming, you'd need at least 2 wheel speed sensors and the ABS module.

Getting the FCA EHPS module to see a vehicle speed signal from a GM computer might be possible as they both run on a CAN bus network, but it would need someone with a much more in depth knowledge of the protocols.

BTW, the EHPS module is part of the pump assembly. You've got 2 heavy wires for high current power (50A fuse) and ground, then the smaller connector is module power (10A fuse), Can C+ and Can C-.
qwikgta MAR 07, 10:39 PM

quote
Originally posted by FieroJimmy:

If you don't have the vehicle speed message from the ABS module on startup, the EHPS module will not activate the pump. If the speed message is lost while the engine is on, it will continue with default values for assist until the next key cycle. To make it work without custom programming, you'd need at least 2 wheel speed sensors and the ABS module.

Getting the FCA EHPS module to see a vehicle speed signal from a GM computer might be possible as they both run on a CAN bus network, but it would need someone with a much more in depth knowledge of the protocols.

BTW, the EHPS module is part of the pump assembly. You've got 2 heavy wires for high current power (50A fuse) and ground, then the smaller connector is module power (10A fuse), Can C+ and Can C-.



That sucks!
cvxjet MAR 08, 12:57 AM
I was looking into power steering approx' 2 years ago and read somewhere that the Charger/Challenger EPS might be a possibility in the future; Need someone to figure out the E-lectronics of the thing- and possibly make a "Kit" with adapters and electronic fixes.

Although when young it wasn't a big deal, now as I get older I am thinking it would be nice to have both easier low speed steering and a quicker ratio.....
OldGuyinaGT MAR 08, 01:06 AM
I'm interested in getting some sort of power steering into my 88 if possible, too. Not usually a problem but occasionally I have a gout flare up in my hand, so..

Anyway, if the EPS needs an ABS signal on startup - if we know what the signal looks like, can we fake it? If the signal isn't complex, it wouldn't be difficult to build a circuit to mimic it at startup, then let it go to default, or after a few seconds change the signal to something constant and just make the EPS think the car was moving at a constant speed all the time. I would think it would even be possible to build something to monitor the Fiero's VSS and convert or generate the EPS signal from it. But right now I don't know what the real EPS signal looks like.
qwikgta MAR 08, 05:08 AM
thats kind of my hope, we have a lot of really smart folks here who understand all this stuff. Hoping one of them could just put their brain to it and come up with something. I hadn't seen the discussion of the Dodge EHPS and EPS before and wanted to bring it to everyones attention.
darbysan MAR 08, 10:24 AM
Even if you can't figure out the signalling for the pump, if the rack can be made to fit it will be of value for those swapping in other engines that might already have Power Steering pump, like a 3800. In that case, it would be like a replacement of the F-body rack that some have converted to fit.

For me, I liked using the Vue EPS for a couple of reasons. 1) it had several styles of controller available cheaply on ebay; 2) No changes to the front steering and suspension of the Fiero, so no need for re-alignment expense; 3) It had been done successfully, and there was detailed info available online, especially on this site; 4) it was cheap- less than $200 total installed; and 5) no messy PS fluid, no need for running lines, etc.

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'87 GT , '00 3800 Series II SC, 4t65e, Vue Power Steering. (SOLD)

fieroguru MAR 08, 12:10 PM
If google is correct, this is a 2.75 lock to lock rack which would be an improvement to the 88 Fiero 3.4ish turns lock to lock. For me, it is all about getting a faster ratio as the stock 88 ratio is too high for some autocross cornering maneuvers (which currently require turning the wheel over 180 degrees). That is the first plus for this rack (but I would prefer a 2.5 if I could get it).

The location of the bushings should simplify mounting by using some flat steel tabs (the front ones might need bent slightly), so aside from welding, making the brackets to mount the rack could be fairly simple.

Since the rack is hydraulic, the pump could be from anything as well as being electric or mechanical, so I wouldn't get distracted on the dodge pump communication challenges - several other EPS pumps will work (have worked) in a fiero.

I think the real key here is measuring the rack length (inner tierod pivot to inner tie rod pivot). If it is the same as the 88 Fiero, then inner tie rod adapters would not be needed either... which also would simplify install.

If you get a faster ratio and installation uses simple brackets w/o needing custom machined adapters... then you might have a winner!