CamSensor replaced, no tach still. D.I.S.??

[FrancisPennysac]

So here's the deal

I have a 1993 MTX SHO that I just picked up, I replaced the CAM sensor and managed to get it running but it runs very rough.. all the KOER test I did don't "sho" (ha ha) any codes.. I may try again later on.

basically i bought it for 400$ and its in GREAT shape besides it not running right.
I checked the plugs/wires, and put brand new cam sensor on. STILL NOTHING on the tach.. and I mean nothing, not even the slightest sign of life.. as with other post regarding the CAM sensor going bad. the car runs horrible, won't barely idle and requires WOT to maintain itself running.

I saw a schematic that showed the D.I.S. sensor being AFTER the CAM sensor, meaning the CAM sensor can be good but if the message from the D.I.S. is bad it won't matter if its good. The D.I.S. defaults to being TBDC +10 IIRC...???? as it controls the coils and there relationship to the cam sensor/tach/ccrm.. again correct me if I am wrong. I don't want to throw money at stuff. i want to FIX stuff

Wed I will found out for certain, the car DOES start so this rules out the crank sensor. If after I change the D.I.S. sensor and still nothing I won't know what to check next.

I have already checked the obvious, Vaccum leaks, Grounds, pulled the MAF, it made no difference. when i do pull the CAM sensor the car will NOT start no matter what.

So to be a little more indepth the D.I.S. sends a signal to the tach that IT receives from the CAM sensor, So if the D.I.S. system is bad the tach won't even do anything regardless of the CAM sensor being good. I got that info straight from the wiring diagram SHOwing what each pin on the D.I.S. runs and such.

I have seen numerous posting of people saying mixed things. so thats my understanding of it as of now.
Please correct me If I am wrong.

 

[zoomlater]

Did you already verify the plug wires are in the correct order? Do you know what brand of wires and plugs that are installed?

http://www.shopowered.com/images/diagrams/89-95_plug_wire_routing.jpg

Do the rest of the lights turn on when you turn the key to the accessory position? I had a dead tach (and thought I needed a new cam sensor) and didn't realize the fuse blew until I saw I had no dash lights when turning the key to the on position

 

[Off Road SHO]

I bet the DIS's ground is missing.

Tom

 

[rubydist]

don't forget the pcm as a possible culprit - they are starting to have some reliability issues now that they are ~20 years old.

you have dis, pcm, wiring, grounding and coils as primary candidates. beyond that you have vac leaks, iat, tps, mafs, etc. as possibilities.

I'm betting you find more than one issue.

 

[FrancisPennysac]

OK so I checked the ground strap, they are there the mount to the uim, on the big bolt that goes into a bracket on the topside of rear of engine near bank 1.using a flat strap all the grounds look good. Fuses are fine all my other gauges and such work completely normal, as well as I have dash lights and such.

Pics of the CORRECT grounds would be forever helpful for us "new sho" guys atleast I could reference what is and what should never be.

I know MAF, TPS, and IAT, were replaced (atleast that what I was told) Like all the grounds under the engine bay were taken off, cleaned and re placed (the previous owner tried his luck to no avail)

The reason I lean D.I.S. is there is a visible crack on the outer casing pointing towards the back of engine, as well as it looks like its been "crunched" from the motor rocking around..( i believe that would be from a bad from engine mount) the lower corner near the bottom rear moutnting bold the whole case is smushed like 1/2 inch. YES before you ask I did remove it, an verify the two bottom bolts are tight, there was not any thermal paste behind it, but I know that won't "hurt" it for now

The CCRM has been replaced with another one (the car had fuel issues that were fixed) the CCRM say's "Sho Source" and has a big old "M" stamped on it. My issue would be I have no clue what letter "J"?? "M"?? the car SHOULD have??????

The car now gets fuel fine, yes plugs are in correct order I checked that yesterday. The are Autolight IIRC.. the fit as they should (they didn't look like they were NOT for the car) there is another coil in the trunk that I will be trying if the D.I.S. doesn't solve my problem.

I know the car gets fuel pressure correctly now, I get 37ish PSI at the engine with it running, and I can visibly see fuel spitting out the exhaust, so its clearly a spark/timing issue.

Thanks for all your great help I try to be as descriptive as I can.

 

[SHOdded]

Is the DIS itself cracked or the harness to/from the DIS? Wont hurt to try a new DIS, make sure to put a thin coat of dielectric or thermal grease on the back prior to mounting it. The TPS is also a frequent suspect.

I would pull the plugs first tho to see what they have to say. Then the wiring, for cracks, breaks or pinching.

Just to confirm you referred to the PCM not the CCRM, right?

This is the CCRM
http://www.shosource.com/catalog/product_info.php?products_id=42

 

[luigisho]

The PCM is the engine computer behind the glove box with the big wiring connector on the other side of the firewall in the engine compartment. I don't recall which CCRM (located above the radiator) is correct for that car. The rule is to replace with the same letter designation that it came with. Not tach points to the DIS but a wrong or faulty CCRM will most likely not run correctly. I would replace the DIS module and fix the engine movement. Too much movement can cause wiring issues over time by breakage or rubbing through shielding or whatever. The last thing you want to do is spend an eternity chasing hard to find wiring issues on a $1500 car

 

[zoomlater]

I think it is the DIS as well, I have had a few fail on me. Did you try clearing the codes and then pulling them after the engine has been running

 

[rubydist]

the fact that the dis has no thermal paste behind it is a big issue. it doesn't have to run long to overheat the dis without paste. so, I would change dis at this point.

the ccrm for a 93 mtx should be correct at "M"

 

[Off Road SHO]

What ^ he said. Those suckers get real hot during normal use. Without the thermal paste a transistor or two may have been toated.

Tom

 

[FrancisPennysac]

I leave for a few hours and look what happens?? The awesomeness and pure muscle of you "Ess-Aight-Ohh" guys shines through..

Seriously thanks so much all your input that is already here, through my own finding and not just being a lazy *****..I know forum life and it sucks but I expected there to be PLENTY of info on a car from the early 90's by now.. I was correct and thankful/relieved at the same time.

and for the answers you all provide now..

I can tell owning and learning about this car will be fun and interesting..

I did find out the Code I need is "M" in-case the D.I.S. doesn't work/fix my issue. But I will clear and try to get the codes again..if it still doesn't run right.

Before I buy a used CCRM..(thanks for clearing that up PCM vs CCRM, it is what I was referring to) I will get a set of plugs and wires to ENSURE they are correct.

If not then lots of fun locating wires that run this, that and the other.. But honestly im thinking faulty sensors n such before wiring harness itself... let's hope I am right.

I'll update soon as I plug the DIS in.. lol

I do see a couple extra plugs up near the CAM sensor that are not plugged into anything.. I believe I read this is because they used the same harness for ATX cars??? just wanna be sure..

Next will be actually fixing the leaking CAM sensor.. and find out how to quite down the ticking on the top end.. (im thinking it needs its 60K, Valve adjustment) But the rest of engine looks great doesn't leak or anything.

 

[SHOdded]

Fuel injectors tick. That's just the nature of the beast. If it's light ticking and rhythmic, it's normal most likely. You can always post a video (with attention to audio) for us to listen to/look at. You would have to host the video on a filesharing site like photobucket, flickr, etc.

 

[FrancisPennysac]

Lol funny you say that, I am well aware of fords fuel injector tick..My normal 4 cylinder Mystique literally ticks like a bomb under idle..

I've had people tell me my timing belt must be off...blah blah blah..or I have a bent valve (on a NON-interference motor) lol

So yeah I am aware of it.. this sounds different then the tick I am used to..Louder?? Then again I can't say I've heard many 3.0 Yamaha Engines in my life..so i don't know what sounds normal for a 3.0 SHO motor with almost 136k on it.

Ill pay more attention next time i start it.. yes I will get some video.

 

[Emerald93shoatx]

Have you verified the timing is correct?. Timing belt hasnt streched or skipped etc..?. Also maybe run a compression test on the cylinders.?

Sent from my LG-D852 using Tapatalk

 

[FrancisPennysac]

I have not checked timing belt and such as there is much more involved to do that then swap out a sensor... I haven't even gotten the car to my place yet it's still sitting where I bought it.. But I will verify if this doesn't fix it.. same with compression test.

 

[sperold]

If you have not tried this yet, unplug the cam sensor and start the car and see if it runs better. It will take you 3 or 4 attempts to start, as the system has to guess the starting point of the timing.
The tachometer not working and running rough are 2 signs that you can't ignore, and they point to the cam sensor, new or not.

Other than that, I would look at the timing belt jumping a tooth or two, or it got installed wrong, which is easy to do. The no codes situation makes that a possibility. But it would take a 2 tooth jump, or more, to show the symptoms you describe.

I have run the car without the spout connector installed, and it affects performance a bit, but it does not keep it from running well generally. A SHO will run well enough to go through an E-Test facility with no comments.

I have 2 SHOs with mangled DIS units, cracks everywhere, and Zap Straps holding on the connectors, with no effect on it working correctly.

 

[FrancisPennysac]

Installed D.I.S. still nothing.. I pludded and replaced the plugs, still nothing. I did get the tach working it must have been stuck to the needle it rest on.. I know sounds stupid right.. well it is

The gauges are missing there cover and because of this I decided just to touch the tac needle.. sure enough it jumps right up to 750rpmish.... and stays there.. so the TACH is working.

The car does have some wiring messed with for the fuel pump and I have no clue wtf was done

When i paperclip jump the EEC to pull codes the car runs MUCH better...but not perfect.

At this point I am out of money/time and it is getting junked. My daily driver just decided to snap it's front springs after 165K.. so that is now my concern..

Anyone want a SHO 1993 Green with Full Leather? and options..?? you have until end of day thurs to come get it .. YES I am serious. Offer me more than 200 and it's yours .. 484-661-9137 CALL ME, DON'T TEXT PLEASE!!

the car is located just north of BATH, PA out near Allentown.

I would need to be towed. period. the shop it is at NEEDS it moved. IT IS not INSPECTED.